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Using renewable photocatalysts for pollutant degradation represents a promising approach to addressing environmental water challenges by harnessing solar energy without additional energy consumption. However, for the practical use of photocatalysts, it is necessary to improve catalyst efficiency, considering cost and biocompatibility. In this study, we developed a new superabsorbent photocatalyst for the degradation of organic dyes in water. Our photocatalyst comprises halloysite nanotubes (HNTs) with a large outer diameter and Si-O and Al-O groups on the outer and inner surfaces, respectively; graphene oxide (GO) possessing numerous sp2 bonds and light-conductive properties; and ZnO, which can degrade organic molecules via a photon source. By exploiting the superabsorbent properties of GOs for organic dyes and stabilizing ZnO nanoparticles on HNTs to inhibit aggregation, our photocatalysts demonstrated significantly improved degradability compared to ZnO nanoparticles alone and combinations of ZnO with HNTs or GO. The structural characteristics of the nanocomposites were characterized using SEM, EDX, Raman spectroscopy, and XRD. Their enhanced photocatalytic activity was demonstrated by the degradation of rhodamine b in water, showing 95% photodegradation under UV illumination for 60 min, while the ZnO nanoparticles showed only 56% dye degradation under the same condition. Additionally, the degradation rate was enhanced by four times. Furthermore, the catalysts maintained their initial activity with no significant loss after four uses, showing their potential for practical implementation in the mass purification of wastewater.

We report a joint experimental and theoretical work on the steady-state spectroscopy and time-resolved emission of the coumarin C153 dye in methanol. The lowest energy excited state of this molecule is characterized by an intramolecular charge transfer thus leading to remarkable shifts of the time-resolved emission spectra, dictated by the methanol reorganization dynamics. We selected this system as a prototypical test case for the first application of a novel computational protocol aimed at the prediction of transient emission spectral shapes, including both vibronic and solvent effects, without applying any phenomenological broadening. It combines a recently developed quantum–classical approach, the adiabatic molecular dynamics generalized vertical Hessian method (Ad-MD|𝑔|�VH), with nonequilibrium molecular dynamics simulations. For the steady-state spectra we show that the Ad-MD|gVH approach is able to reproduce quite accurately the spectral shapes and the Stokes shift, while a ∼0.15 eV error is found on the prediction of the solvent shift going from gas phase to methanol. The spectral shape of the time-resolved emission signals is, overall, well reproduced, although the simulated spectra are slightly too broad and asymmetric at low energies with respect to experiments. As far as the spectral shift is concerned, the calculated spectra from 4 ps to 100 ps are in excellent agreement with experiments, correctly predicting the end of the solvent reorganization after about 20 ps. On the other hand, before 4 ps solvent dynamics is predicted to be too fast in the simulations and, in the sub-ps timescale, the uncertainty due to the experimental time resolution (300 fs) makes the comparison less straightforward. Finally, analysis of the reorganization of the first solvation shell surrounding the excited solute, based on atomic radial distribution functions and orientational correlations, indicates a fast solvent response (≈100 fs) characterized by the strengthening of the carbonyl–methanol hydrogen bond interactions, followed by the solvent reorientation, occurring on the ps timescale, to maximize local dipolar interactions.

Bismuth vanadate (BiVO4) is a narrow-bandgap semiconductor (~2.41 Ev) that responds to visible light. The efficiency of degradation of organic dyes is indexed by methylene blue (MB). After 150 min, the efficiency of MB degradation by pure BiVO4 was about 20%. Its adsorption performance and electron–hole pair migration ability are weak, and the photocatalytic activity of pure BiVO4 needs to be improved. BiVO4 doped with rare earth ions can facilitate the separation of photogenerated electron–hole pairs, thereby enhancing photocatalytic activity in the visible light range. This study investigates changes in the structure and morphology of BiVO4 doped with different atomic percentages of terbium (Tb). BiVO4 powders were prepared by the hydrothermal method with different atomic percentages of Tb (at% = 0, 1, 3, and 5). Doping Tb benefits the coexistence of monoclinic/tetragonal heterostructures, which changes the band gap and improves degradation efficiency. After 150 min of visible light irradiation, the photocatalyst doped with 3 atomic percent of Tb exhibited 98.2% degradation of methylene blue. The degradation percentage of MB remained stable in the presence of 3at%Tb-doped BiVO4 composite. The optimal parameters for the amount of photocatalyst added were studied. Real-field simulations of metal ions and inorganic salts both retain high levels of degradation efficiency.

The development of effective sorbents based on cheap natural raw materials for water purification from synthetic organic dyes is an important environmental problem. It is known that layered silicates are distinguished by mechanical strength, thermal and chemical resistance, high dispersion, ion exchange, availability and low cost. However, the main disadvantage of natural clays is their insufficiently high sorption capacity with respect to organic toxicants. Therefore, to increase it, the surface of clay minerals is modified by various physical and chemical methods. The object of study is kaolin from the Glukhovets deposit (Ukraine), the main rock-forming mineral of which is kaolinite. After its thermal modification followed by acid activation with chloride acid, sorbents with sufficiently high structural-sorption properties and increased sorption capacity with respect to the synthetic organic dye, methylene blue, are obtained. The influence of the conditions for the synthesis of ceramic materials on the physicochemical features of the dye removal from the aqueous medium is studied. The dependence of the values of methylene blue sorption by silicate sorbents on the temperature of kaolin treatment and the concentration of chloride acid, which was used for its acid activation, is studied. It has been established that the specific surface of the obtained samples is significantly affected by both the kaolin treatment temperature and the concentration of perchloric acid. Thus, under certain experimental conditions, sorption materials were obtained with a specific surface area of 140m2/g, which significantly exceeds that for the original kaolin, which is 9m2/g. A significant increase in the sorption capacity of acid-activated samples compared to the original clay and heat-treated forms was established. The value of the maximum sorption of methylene blue for acid-activated samples exceeds that for natural kaolin by almost 2 times and reaches 16mg/g.

We have studied the impact of achiral substituents on the chiral supramolecular architectures of diketopyrrolo[3,4-c]pyrrole-1,2,3-1H-triazole (DPP) dyes. We decorated the same chiral DPP motif with substituent groups on the nitrogen atoms of the lactam moiety: the hydrophobic n-octyl alkyl chain, the hydrophilic tri(ethyleneglycol) (TEG) chain and the thermo-cleavable tert-butoxycarbonyl (t-Boc) carbamate group. In spite of having identical conjugated chromophore and chiral appendages, in aggregated form the three dyes displayed profoundly different optical,chiroptical,electrochemical and thermal features. ECD measurements revealed differences in the aggregation modes, which would be in accessible by most other techniques. We found strong chiroptical features, which would have major implications in the context of chiral organic opto-electronics and in the development of other highly innovative technological applications.

In this study, a carboxylated carbon nanotube-grafted Ag3PO4@AgIO4 (CNT-COO−/Ag3PO4@AgIO4) composite was synthesized through an in situ electrostatic deposition method. The synthesized composite was characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and energy-dispersive X-ray spectroscopy (EDS). The electron transfer ability of the synthesized composite was studied using electrochemical impedance spectroscopy (EIS). The CNT-COO−/Ag3PO4@AgIO4 composite exhibited higher activity than CNT/Ag3PO4@AgIO4, Ag3PO4@AgIO4, and bare Ag3PO4. The material characterization and the detailed study of the various parameters thataffect the photocatalytic reaction revealed that the enhanced catalytic activity is related to the good interfacial interaction between CNT-COO and Ag3PO4. The energy band structure analysis is further considered as a reason for multi-electron reaction enhancement. The results and discussion in this study provide important information for the use of the functionalized CNT-COOH in the field of photocatalysis. Moreover, providinga new way to functionalize CNT viadifferent functional groups may lead to further development in the field of photocatalysis. This work could provide a new way to use natural sunlight to facilitate the practical application of photocatalysts toenvironmental issues.

In the search for functional organic biomaterials, leather constituted by collagen fibers was coated with a conducting polymer, polypyrrole. The coating was carried out during the oxidation of pyrrole in an aqueous solution of poly(N-vinylpyrrolidone) in the presence of five organic dyes: crystal violet, neutral red, methyl orange, acriflavine, and methylene blue. This technique ensures the uniform coating of collagen fibers with polypyrrole and incorporation of organic dyes. The surface morphology was observed with scanning electron microscopy and the transverse profile, reflecting the penetration of the conducting phase into the leather body with optical microscopy. While the polypyrrole coating endows leather with electrical conductivity, organic dyes are expected to affect the polymer morphology and to provide an antibacterial effect. The lowest sheet resistance and antibacterial activity were obtained with crystal violet. This type of coating was characterized in more detail. Infrared spectroscopy confirmed the coating of collagen fibers with polypyrrole and dye incorporation. Mechanical properties were extended to the cyclic bending of the leather at various angles over 5000 cycles. The relative resistance changes were a few percent, indicating good electrical stability during repeated mechanical stress., Ministry of Education, Youth and Sports of the Czech Republic [FRC RO70200003025/2102], Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: FRC RO70200003025/2102

Rhodamine B (RhB) is one of the prominent dyes discovered to be carcinogenic and mutagenic substance present in the ecosystem. Alteration of the characteristics of TiO2 through modification with clay influences the behavior of some organic molecules at its surface, and thus its photocatalytic properties. This study investigates the photocatalytic degradation of RhB using TiO2-activated kaolinite composite (TiO2-AKC). TiO2-AKC was prepared in absolute ethanol and characterized using SEM, EDX, TEM, BET and FTIR. The photodegradation of RhB using TiO2-AKC at room temperature under visible-light was studied at various time intervals and the concentration of RhB was monitored using Ultraviolet-Visible spectrophotometer. Characterisation of TiO2-AKC revealed an adequate distribution of TiO2 over the AKC surface, with an enhanced surface area (TiO2-AKC 808 m2g-1, TiO2 50.0 m2g-1, AKC 20.6 m2g-1) necessary for effective degradation. The degradation was efficient in TiO2-AKC than in sole TiO2 resulting in 99.51% and 88.35%, respectively. The experimental data was analysed using zeroth and first order kinetics, parabolic diffusion, and modified Freundlich model. The degradation kinetics conforms to first order kinetics in TiO2-AKC and sole TiO2. The mechanism of the degradation using TiO2-AKC fit into modified Freundlich model and parabolic diffusion model while sole TiO2 was best described by parabolic diffusion model. KEY WORDS: Kaolin, Kinetics, Organic dyes, Photodegradation, Pollutants, Titanium(IV) oxide Bull. Chem. Soc. Ethiop. 2022, 36(1), 13-24. DOI: https://dx.doi.org/10.4314/bcse.v36i1.2&nbsp

Background Increasing the yield of nanomaterials using the same reactor size and fixing most of the reactants and conditions will greatly improve the production process by saving time, energy and efforts. Titanate nanotubes are mainly prepared by hydrothermal process, in which TiO2 powder reacts with NaOH at certain conditions to form the desired nanotubes. It was reported that it is a must to use high concentrations of NaOH (10 N) to enable the tubular form formation, and the amount of NaOH from the stoichiometry point of view is much higher than that of TiO2; this means excess amounts of NaOH are not used and washed off. This work was designed to improve the production yield by making use of this excess amount of NaOH. Results More than 60 g of sodium titanate nanotubes was prepared using simple hydrothermal method. The prepared nanotubes were characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy and BET surface area analysis. The adsorption capacity of these nanotubes was tested against three commonly used dyes: methyl orange, crystal violet and thymol blue. The samples showed great affinity toward crystal violet and lower activity toward methyl orange and thymol blue, where they achieved more than 90% removal efficiency under different experimental conditions. Conclusions Sodium titanate nanotubes were prepared in large amounts using modified hydrothermal method. The obtained nanotubes efficiently removed crystal violet from water. This improved synthesis of titanate nanotubes will reduce the total cost of nanomaterials production, and subsequently the treatment process, since titanate nanotubes are used in adsorption and photocatalysis processes.

The morphology, structure, and magnetic properties of Fe3O4 and Fe3O4@C nanoparticles, as well their effectiveness for organic dye adsorption and targeted destruction of carcinoma cells, were studied. The nanoparticles exhibited a high magnetic saturation value (79.4 and 63.8 emu/g, correspondingly) to facilitate magnetic separation. It has been shown that surface properties play a key role in the adsorption process. Both types of organic dyes—cationic (Rhodomine C) and anionic (Congo Red and Eosine)—were well adsorbed by the Fe3O4 nanoparticles’ surface, and the adsorption process was described by the polymolecular adsorption model with a maximum adsorption capacity of 58, 22, and 14 mg/g for Congo Red, Eosine, and Rhodomine C, correspondingly. In this case, the kinetic data were described well by the pseudo-first-order model. Carbon-coated particles selectively adsorbed only cationic dyes, and the adsorption process for Methylene Blue was described by the Freundlich model, with a maximum adsorption capacity of 14 mg/g. For the case of Rhodomine C, the adsorption isotherm has a polymolecular character with a maximum adsorption capacity of 34 mg/g. To realize the targeted destruction of the carcinoma cells, the Fe3O4@C nanoparticles were functionalized with aptamers, and an experiment on the Ehrlich ascetic carcinoma cells’ destruction was carried out successively using a low-frequency alternating magnetic field. The number of cells destroyed as a result of their interaction with Fe3O4@C nanoparticles in an alternating magnetic field was 27%, compared with the number of naturally dead control cells of 6%.

In this study, we report one-pot, single step synthesis of silver nanoparticles stabilized by using arbutin. The concentration of reducing agent (NaBH4) used in the preparation was kept at double, and arbutin was used as a stabilizing agent. The confirmation of prepared silver nanoparticles was done by color change and UV-Vis surface plasmon resonance peak at 435 nm in UV-Vis spectrum. Size dispersion of nanoparticles was carried out by Dynamic Light Scattering (DLS) and surface charge on nanoparticles. Stability was analyzed by Zeta potential. A strong negative charge indicated that nanoparticles are well stabilized throughout the solution. Morphology and 3D topographic images were obtained by Atomic Force Microscopy (AFM). The crystalline nature of nanoparticles was elucidated by X-ray diffraction analysis. The size and morphology of solid, well-grinded nanoparticles was proceeded by Scanning Electron Microscopy (SEM). The catalytic activities of nanoparticles were carried out against methylene blue, methyl orange, safranin, and eosin. The results demonstrated that synthesized silver nanoparticles commenced the degradation reaction of dyes mentioned. Prepared silver nanoparticles are found to have adequate catalytic activity, as it can be comprehended in time-dependent UV-Vis spectrums of dyes after treating them with AgNPs.

ZnO-based dye-sensitized solar cells exhibit lower efficiencies than TiO2-based systems despite advantageous charge transport dynamics and versatility in terms of synthesis methods, which can be primarily ascribed to compatibility issues of ZnO with the dyes and the redox couples originally optimized for TiO2. We evaluate the performance of solar cells based on ZnO nanomaterial prepared by microwave-assisted solvothermal syn- thesis, using three fully organic benzothiadiazole-based dyes YKP- 88, YKP-137, and MG-207, and alternative electrolyte solutions with the I−/I3−, Co(bpy)32+/3+, and Cu(dmp)21+/2+ redox couples. The best cell performance is achieved for the dye−redox couple combination YKP-88 and Co(bpy)32+/3+, reaching an average −− efficiency of 4.7% and 5.0% for the best cell, compared to 3.7% and 3.9% for the I /I3 couple with the same dye. Electrical impedance spectroscopy highlights the influence of dye and redox couple chemistry on the balance of recombination and regeneration kinetics. Combined with the effects of the interaction of the redox couple with the ZnO surface, these aspects are shown to determine the solar cell performance. Minimodules based on the best systems in both parallel and series configurations reach 1.5% efficiency for an area of 23.8 cm2., Área de Química Física

Commonly exhibited in museum galleries, animal mummies have been the focus of interest of both visitors and researchers alike. The study of these animal remains not only provides new insights into embalming techniques, but also brings a unique perspective on religious, social and economic practices. Twenty animal mummies are discussed in this study, including cats, ibises, crocodiles, calves and birds of prey from the collections of the British Museum (London, UK) and the Museo Egizio (Turin, Italy). The external textile wrappings encasing the mummified body of the animals were investigated with the main aim of identifying the colourants used. In fact, these are mostly patterned using undyed and coloured (mostly red, brown and black) linen strips. Broadband multispectral imaging (MSI) was initially carried out to obtain preliminary information at the macro-scale on the distribution and chemical nature of the colouring agents. Fibre optic reflectance spectroscopy (FORS) was then used to survey several coloured areas of the textile wrappings. Safflower (Carthamus tinctorius) and red ochre were identified non-invasively. Representative samples were then taken and observed using optical microscopy (OM) and scanning electron microscopy (SEM), in order to obtain information at the micro-scale on the distribution of the colouring agents on the fibres, as well as the presence of other materials, including those from environmental contamination. Energy dispersive X-ray spectrometry (EDX) revealed the elemental composition of particles and clear areas of the fibres, whereas high performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS) provided the identification of the organic dyes at a molecular level. The use of hydrolysable and condensed tannins, in combination with iron as a mordant, was found to be used in the very dark shades, which generally corresponded to the textiles with the worst state of preservation. Nevertheless, other aspects, such as fibre processing and bleaching, fungal attack and presence of coating materials appeared to play a role in the evaluation of the conservation state of these textiles. The characterisation of the dyes and the additional inorganic materials contributed to elucidating the production technology of the colours used for animal mummification, and provided insights into ancient dyeing methods.

Hydrothermally assisted magnetic ZnO/Carbon nanocomposites were prepared using the selective biowaste of pomelo orange. Initially, the carbon aerogel (CA) was prepared hydrothermally followed by a freeze-drying method. Furthermore, the iron oxide nanoparticles were deposited onto the surface of carbon using the co-precipitation method and we obtained magnetic carbon nanocomposite, i.e., Fe3O4/C (MNC). Moreover, the ZnO photocatalysts were incorporated onto the surface of MNC composites using a hydrothermal process, and we obtained ZnO/MNC composites. The ZnO/MNC (55%), ZnO/MNC (65%) and ZnO/MNC (75%) composites were prepared by a similar experimental method in order to change the weight ratio of ZnO NPs. Using a similar synthetic procedure, the standard ZnO and Fe3O4 nanoparticles were prepared without the addition of CA. The experimental results were derived from several analytical techniques, such as: X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman and diffuse reflectance spectroscopy (DRS-UV). The synthesized carbon, ZnO, Fe3O4, ZnO/MNC (55%), ZnO/MNC (65%) and ZnO/MNC (75%) composites were examined through the photocatalytic degradation of methylene blue (MB) under visible-light irradiation (VLI). The obtained results revealed that the composites were more active than carbon, ZnO and Fe3O4. In particular, the ZnO/MNC (75%) composites showed more activity than the rest of the composites. Furthermore, the recycling abilities of the prepared ZnO/MNC (75%) composites were examined through the degradation of MB under identical conditions and the activity remained constant up to the fifth cycle. The synthetic procedure and practical applications proposed here can be used in chemical industries, biomedical fields and energy applications.

Porphyrins have a large π–π conjugation force between molecules, and they are easy to aggregate in solution, which affects the photoelectric properties of porphyrins. Connecting porphyrins to polymer links through covalent bonds not only retains the mechanical properties and thermal stability of polymer materials, but also has the photoelectric properties and catalytic properties of porphyrins, which improves the availability of materials. In this study, first, a porphyrin ligand with double bonds in the side chain was designed and the corresponding copper and zinc complexes were synthesized by adjusting the metal ions in the center of the pyrrole ring. Then, the metalloporphyrin complexes were copolymerized with methyl methacrylate (MMA), and two metalloporphyrin/PMMA copolymers were obtained: CPTPPCu/PMMA and CPTPPZn/PMMA. The structure of the compounds was characterized by IR, 1H NMR, MS, and UV-Vis spectra. Metalloporphyrin/PMMA copolymers were prepared into electrospun fiber materials by electrospinning. The morphology of the composites was studied by SEM, and the thermal stability and optical properties of electrospun fibers were studied by TGA and FL. The catalytic activity of electrospun fiber materials for the degradation of organic dyes was studied. The results showed that the efficiency of the metalloporphyrin/PMMA copolymer in photocatalytic degradation of methylene blue (MB) was better than that of the PMMA electrospun fiber blended with metalloporphyrin.

Currently, carbon quantum dots (CQDs) have been widely investigated as an enhancing photocatalytic component of various nanocomposites. In this study, hetero-structures containing carbon quantum dots (CQDs) associated to zinc oxide were prepared following two one-pot procedures: (i) a hydrothermal approach in which commercial ZnO was used as carrier for CQDs; and (ii) an approach in which the ZnO/CQDs samples were produced in situ by adding zinc acetate to an aqueous suspension of CQDs. CQDs were prepared in advance by a low-temperature hydrothermal (LHT) treatment of useless humins wastes produced by the glucose dehydration in an acidic medium. These samples were characterized by several techniques such asadsorption-desorption isotherms of liquid nitrogen at 77K, X-ray diffraction (XRD), infrared diffuse reflectance with Fourier transform (DRIFT) and UV-vis spectroscopy. The photocatalytic behavior of these materials was investigated in the degradation of methylene blue (MB). The obtained results revealed electronic interactions between CQDs and ZnO which have as an effect an enhancement of the charge separation and diminution of the charge recombination. In accordance, a correlation between the photocatalytic activity and the intrinsic properties of ZnO/CQDs has been evidenced. The highest photocatalytic activity corresponded to the heterostructure containing highly dispersed narrow sized CQDs onto ZnO. Under visible light irradiation and after 180 min of irradiation, MB was degraded by as much as 97.6%.

Herein, a simple, cost-effective, and in-situ environmentally friendly approach was adopted to synthesize carbon dot-adorned silver nanoparticles (CDs@AgNPs) from yellow myrobalan (Terminalia chebula) fruit using a hydrothermal treatment without any additional reducing and or stabilizing agents. The as-synthesized CDs@AgNP composite was systematically characterized using multiple analytical techniques: FESEM, TEM, XRD, Raman, ATR-FTIR, XPS, and UV-vis spectroscopy. All the results of the characterization techniques strongly support the idea that the CDs were successfully made to adorn the AgNPs. This effectively synthesized CDs@AgNP composite was applied as a catalyst for the degradation of organic dyes, including methylene blue (MB) and methyl orange (MO). The degradation results revealed that CDs@AgNPs exhibit a superior catalytic activity in the degradation of MB and MO in the presence of NaBH4 (SB) under ambient temperatures. In total, 99.5 and 99.0% rates of degradation of MB and MO were observed using CDs@AgNP composite with SB, respectively. A plausible mechanism for the reductive degradation of MB and MO is discussed in detail. Moreover, the CDs@AgNP composite has great potential for wastewater treatment applications.

Expansion microscopy (ExM) has been widely used to detect biomolecules in cultured cells and tissue samples due to its enablement of super resolution imaging with conventional microscopes, via physical expansion of samples. However, reaction conditions inherent to the process bring about strong fluorescent signal loss during polymerization and digestion and thus limit the brightness of the signal obtained post expansion. Here, we explore the impact of stabilizer-containing organic fluorophores in ExM, as a mitigation strategy for this radical-induced dye degradation. Through direct conjugation of 4-nitrophenylalanine (NPA) to our previously developed trifunctional reagents, we validate and demonstrate that these multifunctional linkers enable visualization of different organelles with improved fluorescent intensity, owning to protection of the dyes to radical induced degradation as well as to photoprotection upon imaging. At this point, we cannot disentangle the relative contribution of both mechanisms. Furthermore, we report anchoring linkers that allow straightforward application of NPA or Trolox to commercially available fluorophore-conjugated antibodies. We show that these anchoring linkers enable complete retention of biological targets while increasing fluorophore photostability. Our results provide guidance in exploring these stabilizer-modified agents in ExM and methods for increased signal survival through the polymerization steps of the ExM protocols. ispartof: CHEMISTRY-A EUROPEAN JOURNAL vol:28 issue:66 ispartof: location:Germany status: published

Aim. Study of the efficiency (E) of purification of solutions from organic dyes depending on the type of dye, the composition of the Cu-Zn-ferrite composite (FC) and its repeatability, creation of a mathematical model of the cleaning process. Methods. The photocatalytic and sorption properties of FCs were studied spectrophotometrically during the purification of solutions from methyl violet MV, methylene blue MB, and Congo red CR. The mathematical model of the cleaning process was created using the MATLAB application package (Toolbox subsystem). Results. It is shown that the first order of reaction is observed in the entire time interval of the purification process when the mechanism is changed from the predominant photocatalysis to adsorption within 3–5 h. The specific activity of FC is high when purified from all dyes at a mass ratio of “FC: dye” (n) ≥ 500. Anionic character CR reduces E purification in comparison with MV and MB. Re-use of FCs with a reduced E is advisable in case of prolonged contact of FC with colored solutions in sedimentation tanks. Optimization of the total cleaning processes was carried out by deriving third-order regression equations "E – n – time" with an expanded range of optimal values of the process parameters. Conclusions. The purification efficiency and activity of individual FCs vary depending on the type of dye and the ferrite composition. FCs are more efficient in the purification of solutions from MV and MB than from CR. Optimal n varies within 700–1370. The regression equations are derived by the least squares method, which allow to optimize the process in terms of FC activity, efficiency and time of the process., Цель. Изучение эффективности (Е) очистки растворов от органических красителей (КР) в зависимости от типа КР, состава Cu-Zn-ферритного композита (ФК) и повторности его использования, создание математической модели процесса очистки. Методы. Фотокаталитические и сорбционные свойства ФК изучали спектрофотометрически при очистке растворов от метилвиолета МВ, метиленового синего МС и Конго красного КК. Математическая модель процесса очистки создана с помощью пакета прикладных программ MATLAB (подсистема Toolbox). Результаты. Показано соблюдение первого порядка реакции во всем временном интервале процесса очистки при смене механизма с преобладающего фотокатализа на адсорбцию в течение 3‒5 ч. Удельная активность ФК высокая при очистке от всех КР при массовом соотношении «ФК : КР» (n) 500. Анионный характер КК снижает Е очистки по сравнению с МВ и МС. Повторное использование ФК с пониженной Е целесообразно при длительном контакте ФК с окрашенными растворами в отстойниках. Проведена оптимизация суммарных процессов очистки путем выведения уравнений регрессии третьего порядка «Е ‒ n ‒ время» с расширенной областью оптимальных значений параметров процесса. Выводы. Эффективность очистки и активность отдельных ФК изменяются в зависимости от типа КР и состава феррита. ФК более эффективны при очистке растворов от МВ и МС, чем от КК. Оптимальное n варьирует в пределах 700‒1370. Методом наименьших квадратов выведены уравнения регрессии, позволяющие оптимизировать проведение процесса по активности ФК, эффективности и времени процесса., Мета. Вивчення ефективності (Е) очищення розчинів від органічних барвників (БР) залежно від типу БР, складу Cu-Zn-феритного композиту (ФК) та повторності його використання, створення математичної моделі процесу очищення. Методи. Фотокаталітичні та сорбційні властивості ФК вивчали спектрофотометрично при очищенні розчинів від метилвіолету МВ, метиленового синього МС та Конго червоного КЧ. Математична модель процесу очищення створена за допомогою пакету прикладних програм MATLAB (підсистема Toolbox). Результати. Показано дотримання першого порядку реакції у всьому часовому інтервалі процесу очищення за зміни механізму з переважаючого фотокаталізу на адсорбцію протягом 3‒5 год. Питома активність ФК висока при очищенні від усіх БР за масового співвідношення «ФК : БР» (n) ≥ 500. Аніонний характер КЧ знижує Е очистки у порівнянні з МВ і МС. Повторне використання ФК із зниженою Е доцільно за тривалого контакту ФК із забарвленими розчинами у відстійниках. Проведено оптимізацію сумарних процесів очищення шляхом виведення рівнянь регресії третього порядку «Е ‒ n ‒ час» з розширеною областю оптимальних значень параметрів процесу. Висновки. Ефективність очищення та активність окремих ФК змінюються залежно від типу БР та складу фериту. ФК ефективніші для очищення розчинів від МВ та МС, ніж від КЧ. Оптимальне n варіює в межах 700‒1370. Методом найменших квадратів виведено рівняння регресії, що дозволяють оптимізувати проведення процесу з активності ФК, ефективності та часу процесу.

Aim. Study of the efficiency (E) of purification of solutions from organic dyes depending on the type of dye, the composition of the Cu-Zn-ferrite composite (FC) and its repeatability, creation of a mathematical model of the cleaning process. Methods. The photocatalytic and sorption properties of FCs were studied spectrophotometrically during the purification of solutions from methyl violet MV, methylene blue MB, and Congo red CR. The mathematical model of the cleaning process was created using the MATLAB application package (Toolbox subsystem). Results. It is shown that the first order of reaction is observed in the entire time interval of the purification process when the mechanism is changed from the predominant photocatalysis to adsorption within 3–5 h. The specific activity of FC is high when purified from all dyes at a mass ratio of “FC: dye” (n) ≥ 500. Anionic character CR reduces E purification in comparison with MV and MB. Re-use of FCs with a reduced E is advisable in case of prolonged contact of FC with colored solutions in sedimentation tanks. Optimization of the total cleaning processes was carried out by deriving third-order regression equations "E – n – time" with an expanded range of optimal values of the process parameters. Conclusions. The purification efficiency and activity of individual FCs vary depending on the type of dye and the ferrite composition. FCs are more efficient in the purification of solutions from MV and MB than from CR. Optimal n varies within 700–1370. The regression equations are derived by the least squares method, which allow to optimize the process in terms of FC activity, efficiency and time of the process., Цель. Изучение эффективности (Е) очистки растворов от органических красителей (КР) в зависимости от типа КР, состава Cu-Zn-ферритного композита (ФК) и повторности его использования, создание математической модели процесса очистки. Методы. Фотокаталитические и сорбционные свойства ФК изучали спектрофотометрически при очистке растворов от метилвиолета МВ, метиленового синего МС и Конго красного КК. Математическая модель процесса очистки создана с помощью пакета прикладных программ MATLAB (подсистема Toolbox). Результаты. Показано соблюдение первого порядка реакции во всем временном интервале процесса очистки при смене механизма с преобладающего фотокатализа на адсорбцию в течение 3‒5 ч. Удельная активность ФК высокая при очистке от всех КР при массовом соотношении «ФК : КР» (n) 500. Анионный характер КК снижает Е очистки по сравнению с МВ и МС. Повторное использование ФК с пониженной Е целесообразно при длительном контакте ФК с окрашенными растворами в отстойниках. Проведена оптимизация суммарных процессов очистки путем выведения уравнений регрессии третьего порядка «Е ‒ n ‒ время» с расширенной областью оптимальных значений параметров процесса. Выводы. Эффективность очистки и активность отдельных ФК изменяются в зависимости от типа КР и состава феррита. ФК более эффективны при очистке растворов от МВ и МС, чем от КК. Оптимальное n варьирует в пределах 700‒1370. Методом наименьших квадратов выведены уравнения регрессии, позволяющие оптимизировать проведение процесса по активности ФК, эффективности и времени процесса., Мета. Вивчення ефективності (Е) очищення розчинів від органічних барвників (БР) залежно від типу БР, складу Cu-Zn-феритного композиту (ФК) та повторності його використання, створення математичної моделі процесу очищення. Методи. Фотокаталітичні та сорбційні властивості ФК вивчали спектрофотометрично при очищенні розчинів від метилвіолету МВ, метиленового синього МС та Конго червоного КЧ. Математична модель процесу очищення створена за допомогою пакету прикладних програм MATLAB (підсистема Toolbox). Результати. Показано дотримання першого порядку реакції у всьому часовому інтервалі процесу очищення за зміни механізму з переважаючого фотокаталізу на адсорбцію протягом 3‒5 год. Питома активність ФК висока при очищенні від усіх БР за масового співвідношення «ФК : БР» (n) ≥ 500. Аніонний характер КЧ знижує Е очистки у порівнянні з МВ і МС. Повторне використання ФК із зниженою Е доцільно за тривалого контакту ФК із забарвленими розчинами у відстійниках. Проведено оптимізацію сумарних процесів очищення шляхом виведення рівнянь регресії третього порядку «Е ‒ n ‒ час» з розширеною областю оптимальних значень параметрів процесу. Висновки. Ефективність очищення та активність окремих ФК змінюються залежно від типу БР та складу фериту. ФК ефективніші для очищення розчинів від МВ та МС, ніж від КЧ. Оптимальне n варіює в межах 700‒1370. Методом найменших квадратів виведено рівняння регресії, що дозволяють оптимізувати проведення процесу з активності ФК, ефективності та часу процесу.

In order to properly reuse food waste and remove various contaminants from wastewater, the development of green, sustainable and clean technologies has demonstrated potential in the efficient inhibition of secondary pollution to the environment. In this study, an economical and green method was used to prepare biochar from crisp persimmon peel (CPP) using flash-vacuum pyrolysis at different temperatures (200–700 °C; referred to as CPP200–CPP700). CPP200 has high polarity, low aromaticity and high oxygen-containing functional groups that exhibit superior MB adsorption capabilities. CPP200 that was prepared at a relatively low temperature of 200 °C exhibited a high adsorption capacity of 59.72 mg/g toward methylene blue (MB), which was relatively higher than that for alizarin yellow R (4.05 mg/g) and neutral red (39.08 mg/g), indicating that CPP200 possesses a higher adsorption selectivity for cationic dyes. Kinetics investigation revealed that the kinetic data of CPP200 for the adsorption of MB was better fitted by a linear pseudo-second-order model. Isothermal studies indicated that the linear Langmuir model was more suitable for describing the adsorption process. The adsorption thermodynamics illustrated that the adsorption of MB onto CPP200 was spontaneous and endothermic. EDS and IR analyses of CPP200 for both pre- and post-adsorption of MB showed that electrostatic interactions between oxygen-containing groups on biochar and target MB dominated the adsorption procedure, in addition to hydrogen bonding interactions. Reusability tests confirmed the excellent regeneration characteristics of CPP200, indicating that CPP200 may be used as a green, sustainable, highly efficient and recyclable adsorbent for the selective removal of cationic organic dyes.

The adsorptive performance of mesoporous silica-based materials towards inorganic (metal ions) and organic (dyes) water pollutants was investigated. Mesoporous silica materials with different particle size, surface area and pore volume were prepared and tailored with different functional groups. These materials were then characterised by solid-state techniques, namely vibrational spectroscopy, elemental analysis, scanning electron microscopy and nitrogen adsorption–desorption isotherms, allowing the successful preparation and structural modifications of the materials to be confirmed. The influence of the physicochemical properties of the adsorbents towards the removal of metal ions (Ni2+, Cu2+ and Fe3+) and organic dyes (methylene blue and methyl green) from aqueous solutions was also investigated. The results reveal that the exceptionally high surface area and suitable ζ-potential of the nanosized mesoporous silica nanoparticles (MSNPs) seem to favour the adsorptive capacity of the material for both types of water pollutants. Kinetic studies were performed for the adsorption of organic dyes by MSNPs and large-pore mesoporous silica (LPMS), suggesting that the process follows a pseudo-second-order model. The recyclability along consecutive adsorption cycles and the stability of the adsorbents after use were also investigated, showing that the material can be reused. Current results show the potentialities of novel silica-based material as a suitable adsorbent to remove pollutants from aquatic matrices with an applicability to reduce water pollution.

We report a joint experimental and theoretical work on the steady-state spectroscopy and time-resolved emission of the coumarin C153 dye in methanol. The lowest energy excited state of this molecule is characterized by an intramolecular charge transfer thus leading to remarkable shifts of the time-resolved emission spectra, dictated by the methanol reorganization dynamics. We selected this system as a prototypical test case for the first application of a novel computational protocol aimed at the prediction of transient emission spectral shapes, including both vibronic and solvent effects, without applying any phenomenological broadening. It combines a recently developed quantum–classical approach, the adiabatic molecular dynamics generalized vertical Hessian method (Ad-MD (Formula presented.) VH), with nonequilibrium molecular dynamics simulations. For the steady-state spectra we show that the Ad-MD|gVH approach is able to reproduce quite accurately the spectral shapes and the Stokes shift, while a ∼0.15 eV error is found on the prediction of the solvent shift going from gas phase to methanol. The spectral shape of the time-resolved emission signals is, overall, well reproduced, although the simulated spectra are slightly too broad and asymmetric at low energies with respect to experiments. As far as the spectral shift is concerned, the calculated spectra from 4 ps to 100 ps are in excellent agreement with experiments, correctly predicting the end of the solvent reorganization after about 20 ps. On the other hand, before 4 ps solvent dynamics is predicted to be too fast in the simulations and, in the sub-ps timescale, the uncertainty due to the experimental time resolution (300 fs) makes the comparison less straightforward. Finally, analysis of the reorganization of the first solvation shell surrounding the excited solute, based on atomic radial distribution functions and orientational correlations, indicates a fast solvent response (≈100 fs) characterized by the strengthening of the carbonyl–methanol hydrogen bond interactions, followed by the solvent reorientation, occurring on the ps timescale, to maximize local dipolar interactions, This research was funded by ICSC—Centro Nazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing, funded by European Union—NextGenerationEU— PNRR, Missione 4 Componente 2 Investimento 1.4 (F.S and G.P); MICINN Project PID2019-110091GBI00 (JC); H2020-LC-SC3-2020-RES-RIA-101006839 project “CONDOR” and MUR-PNRR (NEST— Network 4 Energy Sustainable Transition, Estended Partnership—PE000002 (SG, BV and NA)

The development of effective sorbents based on cheap natural raw materials for water purification from synthetic organic dyes is an important environmental problem. It is known that layered silicates are distinguished by mechanical strength, thermal and chemical resistance, high dispersion, ion exchange, availability and low cost. However, the main disadvantage of natural clays is their insufficiently high sorption capacity with respect to organic toxicants. Therefore, to increase it, the surface of clay minerals is modified by various physical and chemical methods. The object of study is kaolin from the Glukhovets deposit (Ukraine), the main rock-forming mineral of which is kaolinite. After its thermal modification followed by acid activation with chloride acid, sorbents with sufficiently high structural-sorption properties and increased sorption capacity with respect to the synthetic organic dye, methylene blue, are obtained. The influence of the conditions for the synthesis of ceramic materials on the physicochemical features of the dye removal from the aqueous medium is studied. The dependence of the values of methylene blue sorption by silicate sorbents on the temperature of kaolin treatment and the concentration of chloride acid, which was used for its acid activation, is studied. It has been established that the specific surface of the obtained samples is significantly affected by both the kaolin treatment temperature and the concentration of perchloric acid. Thus, under certain experimental conditions, sorption materials were obtained with a specific surface area of 140 m2/g, which significantly exceeds that for the original kaolin, which is 9 m2/g. A significant increase in the sorption capacity of acid-activated samples compared to the original clay and heat-treated forms was established. The value of the maximum sorption of methylene blue for acid-activated samples exceeds that for natural kaolin by almost 2 times and reaches 16 mg/g., Розробка ефективних сорбентів на основі дешевої природної сировини для очищення вод від синтетичних органічних барвників є важливим екологічним завданням. Відомо, що шаруваті силікати відрізняються механічною міцністю, термічною та хімічною стійкістю, високою дисперсністю, здатністю до іонного обміну, доступністю та дешевизною. Проте основним недоліком природних глин є їх недостатньо висока сорбційна здатність по відношенню до органічних токсикантів. Тому для її підвищення проводять модифікування поверхні глинистих мінералів різними фізичними та хімічними методами. Об’єктом дослідження є каолін Глуховецького родовища (Україна), основним породоутворюючим мінералом якого є каолініт. Після його термічного модифікування з подальшою кислотною активацією хлоридною кислотою отримано сорбенти із достатньо високими структурно-сорбційними властивостями та підвищеною сорбційною здатністю по відношенню до синтетичного органічного барвника – метиленового блакитного. Було вивчено вплив умов синтезу керамічних матеріалів на фізико-хімічні особливості видалення даного барвника із водного середовища. Досліджено залежності величин сорбції метиленового блакитного силікатними сорбентами від температури обробки каоліну та концентрації хлоридної кислоти, яка використовувалась для його кислотної активації. Встановлено, що на питому поверхню одержаних зразків суттєво впливає як температура обробки каоліну, так і концентрація хлоридної кислоти. Так, при певних умовах проведення експериментів було отримано сорбційні матеріали із величиною питомої поверхні 140 м2/г, що значно перевищує таку для вихідного каоліну, яка становить 9 м2/г. Встановлено значне підвищення сорбційної здатності кислотно активованих зразків у порівнянні з вихідною глиною та її термічно обробленими формами. Величина максимальної сорбції метиленового блакитного для кислотно активованих зразків перевищує таку для природного каоліну майже у 2 рази та досягає 16 мг/г.

Organic dyes and heavy metals often coexist in industrial effluents, and their simultaneous removal is a grand challenge. Herein, a hydrochar and MgAl layered double hydroxide (HC–MgAlLDH) nanocomposite was prepared via a facile one-step hydrothermal route, and applied to remove anionic Congo red (CR), cationic Methylene blue (MB) and Pb(II) from aqueous solutions. The nanocomposite was formed by interweaving amorphous HC and crystalline MgAlLDH nanoplates and possessed more functional groups, lower zeta potential and larger specific surface area than uncomposited MgAlLDH. Batch removal experiments showed that the components HC and LDH dominated the CR and MB removals, respectively, whereas Pb(II) removal was conjointly controlled by the two components. The maximum Langmuir removal capacities of the nanocomposite to sole CR, MB, or Pb(II) were 348.78, 256.54 or 33.55 mg/g. In binary and ternary systems, the removal capacities of CR and MB only slightly decreased, while the capacity of Pb(II) increased by 41.13–88.61%. The increase was related to the coordination of Pb(II) with the sulfur-containing groups in dyes and the precipitation of PbSO4. Therefore, the simultaneous removal of CR, MB and Pb(II) was involved in a synergistic effect, including electrostatic adsorption, π–π interaction, coordination and precipitation. The present work shows that the HC–MgAlLDH nanocomposite has great potential for wastewater integrative treatment.

Thiosulfate is an inorganic ligand that forms a soluble light-sensitive cadmium thiosulfate complex, and cadmium sulfide (CdS) with a “size effect” can be produced via ultraviolet (UV) irradiation. This study investigated the activity of CdS nanoparticles (NPs) precipitated from a cadmium thiosulfate complex via UV irradiation on photocatalytic dye degeneration. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that the decomposition products were spherical CdS NPs. The photocatalytic activity of the CdS NPs was evaluated based on the degradation rates of methylene blue, rhodamine B, and methyl orange. With 25 mg of CdS NPs and a dye concentration of 10 mg L−1, the degradation rates of the three dyes under visible light were 36%, 90%, and 80%, respectively. A kinetic study revealed that the photocatalytic degradation rate of the CdS NPs followed first-order kinetics, and the rate constants for the three dyes were determined to be 0.0051, 0.0762, and 0.0144 min−1, respectively. The CdS NPs exhibited a stable photocatalytic performance after three cycles of methylene blue degradation. This indicates that CdS NPs formed from a cadmium thiosulfate complex after UV irradiation can be used for photocatalysis, which will save resources and help in environmental conservation.

This study reports a versatile process for the fabrication of a microporous heterogeneous palladium nanocatalyst on a novel spherical, biodegradable, and chemically/physically resistant catalyst support consisting of chitosan (CS) and cigarette waste-derived activated carbon (CAC). The physicochemical properties of the microporous Pd-CS-CAC nanocatalyst developed were successfully determined by FTIR, XRD, FE-SEM, TEM, BET, and EDS techniques. TEM studies showed that the average particle size of the synthesized Pd NPs was about 30 nm. The catalytic prowess of microporous Pd-CS-CAC was evaluated in the reduction/decolorization of various nitroarenes (2-nitroaniline (2-NA), 4-nitroaniline (4-NA), 4-nitrophenol (4-NP), and 4-nitro-o-phenylenediamine (4-NPD)) and organic dyes (methyl red (MR), methyl orange (MO), methylene blue (MB), congo red (CR), and rhodamine B (RhB)) in an aqueous medium in the presence of NaBH4 as the reducing agent at room temperature. The catalytic activities were studied by UV-Vis absorption spectroscopy of the supernatant at regular time intervals. The short reaction times, mild reaction conditions, high efficiency (100% conversion), easy separation, and excellent chemical stability of the catalyst due to its heterogeneity and reusability are the advantages of this method. The results of the tests showed that reduction/decolorization reactions were successfully carried out within 10-140 s due to the good catalytic ability of Pd-CS-CAC. Moreover, Pd-CS-CAC was reused for 5 consecutive times with no loss of the initial shape, size, and morphology, confirming that it was a sustainable and robust nanocatalyst.

In this study, a series of Al-doped metal-organic frameworks (AlxZr(1−x)-UiO-66) were synthesized through a one-step solvothermal method. Various characterization techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and N2 sorption measurement, suggested that the Al doping was uniform and barely influenced the crystallinity, chemical stability, and thermal stability of the materials. Two cationic dyes, safranine T (ST) and methylene blue (MB), were selected for investigating the adsorption performances of Al-doped UiO-66 materials. Al0.3Zr0.7-UiO-66 exhibited 9.63 and 5.54 times higher adsorption capacities than UiO-66, 498 mg/g and 251 mg/g for ST and MB, respectively. The improved adsorption performance can be attributed to π-π interaction, hydrogen bond, and the coordination between the dye and Al-doped MOF. The pseudo-second-order and Langmuir models explained the adsorption process well, which indicated that the dye adsorption on Al0.3Zr0.7-UiO-66 mostly occurred through chemisorption on homogeneous surfaces. A thermodynamic study indicated the adsorption process was spontaneous and endothermic. The adsorption capacity did not decrease significantly after four cycles.

The main objective of this study was to assess the usefulness of exhausted activated carbon-based filter cartridges for the removal of organic pollutants from aqueous solutions using the example of two model pollutants: synthetic dyes with different particle sizes, i.e., methylene blue (MB) and malachite green (MG). In order to determine the organic dyes’ adsorption mechanism, the effects of phase contact time, initial dye concentration, pH, and temperature of the system were investigated. Langmuir and Freundlich isotherm models were employed to analyze the experimental data. Additionally, all adsorbents were characterized in terms of the ash content, type of porous structure, presence of surface functional groups, pH value, and iodine adsorption number—which is one of the quality control parameters of activated carbons. Adsorption tests have shown that carbonaceous materials from bottle filters and filter jugs can be successfully used for the removal of organic dyes from the liquid phase. The maximum sorption capacity of this type of adsorbent towards methylene blue was 333.06 mg/g, while in the case of malachite green it was 308.75 mg/g. For all carbonaceous materials, a better fit to the experimental data was achieved with a Langmuir isotherm than a Freundlich one. It has also been shown that the efficiency of MB and MG adsorption from aqueous solutions decreases with increasing temperature of the system—the best results were obtained at 25 °C. A better fit of the kinetics data was achieved using the pseudo-second order model.

Aurivillius oxides ferroelectric layered materials are formed by bismuth oxide and pseu-do-perovskite layers. They have a good ionic conductivity, which is beneficial for various photo-catalyzed reactions. Here, we synthesized ultra-thin nanosheets of two different Aurivillius oxides, Bi2WO6 (BWO) and Bi2MoO6 (BMO), by using a hard-template process. All materials were characterized through XRD, TEM, FTIR, TGA/DSC, DLS/ELS, DRS, UV-Vis. Band gap material (Eg) and potential of the valence band (EVB) were calculated for BWO and BMO. In contrast to previous reports on the use of multi composite materials, a new procedure for photocatalytic efficient BMO nanosheets was developed. The procedure, with an additional step only, avoids the use of composite materials, improves crystal structure, and strongly reduces impurities. BWO and BMO were used as photocatalysts for the degradation of the water pollutant dye malachite green (MG). MG removal kinetics was fitted with Langmuir—Hinshelwood model obtaining a kinetic constant k = 7.81 × 10−2 min−1 for BWO and k = 9.27 × 10−2 min−1 for BMO. Photocatalytic dye degradation was highly effective, reaching 89% and 91% MG removal for BWO and BMO, respectively. A control experiment, carried out in the absence of light, allowed to quantify the contribution of adsorption to MG removal process. Adsorption contributed to MG removal by a 51% for BWO and only by a 19% for BMO, suggesting a different degradation mechanism for the two photocatalysts. The advanced MG degradation process due to BMO is likely caused by the high crystallinity of the material synthetized with the new procedure. Reuse tests demonstrated that both photocatalysts are highly active and stable reaching a MG removal up to 95% at the 10th reaction cycle. These results demonstrate that BMO nanosheets, synthesized with an easy additional step, achieved the best degradation performance, and can be successfully used for environmental remediation applications.

The same carbon-based nanomaterials have shown their potential photocatalytic applications toward environmental and energy-related problems based on their excellent light absorption abilities. Herein, we summarized the findings associated with visible light and sunlight-induced photocatalysis, specifically using carbon dots (CD), doped-CD, and their nanocomposite as an advanced photocatalytic material. Doped-CD and CD-based composite have improved light absorption abilities compared to bare CD, which is the essential parameter for photocatalysis applications. Various parameters, such as fabrication methodologies, efficiency, and stability, have also been discussed. The possible mechanistic insights involving the photocatalysis method applied in multiple chemical reactions have been discussed in detail, including degradation of organic dye, reduction of higher toxic oxidation states of metal ions, CO 2conversion, water splitting, organic transformation reaction, and NOx removal, etc.

The present work describes the effect of Ce3+ ion doping on the structural, morphological, and magnetic properties of spinel manganese ferrite (MnFe2O4) nanocrystallites (NCs) using various instrument techniques. Rare earth element (REE) Cerium (Ce3+) doped MnFe2O4 NCs were prepared by a simple microwave combustion technique. In the present scenario, ferrites are widely used for photocatalytic dye degradation and antibacterial applications. Aiming to achieve this, we prepared Ce3+ doped MnFe2O4 NCs by microwave combustion method and urea as burning agent and the obtained powder samples were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), high resolution scanning electron microscope (HR-SEM), high resolution transmission electron microscope (HR-TEM) and vibration sample magnetometer (VSM) techniques. The pure spinel phase formation was confirmed by XRD analysis. FTIR spectra show two prominent absorption bands under 1000 cm−1, which confirms the formation of the spinel structure. HR-SEM and HR-TEM pictures demonstrated a sphere-shaped morphology and also expose the combination and agglomeration of grains, which are mostly due to the magnetic characteristics of the samples. The magnetic properties of the synthesized MnCexFe2−xO4 (x = 0.0, 0.1, 0.3, and 0.5) NCs were studied by VSM analysis at room temperature (RT) shows ferromagnetic behavior. The photodegradation results showed that MnFe2O4 and Ce doped MnFe2O4 NCs have a higher potential to degrade methylene blue (MB) and the sample MnCe0.3Fe1.7O4 NCs showed superb photocatalytic performance (91.53%) compared to other samples. The antibacterial activities of Gram-positive S. aureus, B. subtilis and Gram-negative K. pneumonia and E. coli were investigated using pure and Ce3+ substituted MnFe2O4 NCs and a higher activity for MnCe0.3Fe1.7O4 NCs than other samples was observed, which indicated that they can be used in biomedical applications.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES The consumption of electric energy in the world has grown about 2.2% above the average in recent years, with fossil fuels being one of the main sources, with this simultaneously growing concern about global warming. Among the new ways to produce energy in a cleaner way, the use of solar panels has great prominence, but traditional panels have a high cost, making their mass production impossible. Dye-sensitized solar cells (DSSC) have become a viable alternative and environmental concerns motivate the search for metal-free sensitizers. However, metal-free DSSCs have a moderate efficiency in converting solar energy into electrical energy. Several works sought more efficient sensitizers, modifying the donor, electron acceptor or π bridge. There are enough data in the literature to help understand the relationship between the molecular properties of sensitizers and the energy conversion efficiency of DSSC. In this context, the present work applied statistical methods to relate molecular descriptors with cell quantum yield. Molecular descriptors were calculated using electronic structure methods both in the ground state and in the excited state. Classical methods were also used to obtain classical descriptors. The set of sensitizers was randomly divided into two sets: the training set with 50 dyes and the test set with 25 dyes, where the choice was made randomly for each after performing the hierarchical grouping and using the Stepwise and PLS technique we developed 4 models. The training set was initially used to determine the model and the test set was used to evaluate the models. After choosing the 4 models, they were validated, using another set of 24 different dyes. Since the models were found and validated, the last step is to use the model developed to propose new sensitizers with higher quantum yields in photovoltaic efficiency. O consumo de energia elétrica tem crescido no mundo cerca de 2,2% acima da média nos últimos anos, sendo os combustíveis fósseis uma das principais fontes, com isto cresce simultaneamente a preocupação com o aquecimento global. Dentre as novas formas de produzir energia de maneira mais limpa, o uso de painéis solares tem grande destaque, porém os painéis tradicionais têm um custo elevado, impossibilitando sua produção em massa. Células solares sensibilizadas por corantes (DSSC), têm se constituído como uma alternativa viável e inquietações ambientais motivam a busca por sensibilizadores livres de metais. Porém, os DSSC livres de metais apresentam um rendimento moderado na conversão de energia solar em energia elétrica. Vários trabalhos buscaram sensibilizadores mais eficientes, modificando o doador, o receptor de elétrons ou a ponte π. Há dados suficientes na literatura para auxiliar no entendimento da relação entre as propriedades moleculares dos sensibilizadores com a eficiência da conversão de energia da DSSC. Neste contexto, o presente trabalho aplicou métodos estatísticos para relacionar descritores moleculares com o rendimento quântico da célula. Os descritores moleculares foram calculados usando métodos de estrutura eletrônica tanto no estado fundamental como no estado excitado. Métodos clássicos também foram utilizados para a obtenção de descritores clássicos. O conjunto de sensibilizadores foi dividido aleatoriamente em dois conjuntos: o de treinamento com 50 corantes e o de teste com 25 corantes, onde a escolha foi feita de forma aleatória de cada após realizar o agrupamento hierárquico e usando a técnica de Stepwise e PLS desenvolvemos 4 modelos. O conjunto de treinamento foi inicialmente usado para determinar o modelo e o conjunto de teste foi usado para avaliar os modelos. Após a escolha dos 4 modelos, eles foram validados, usando um outro conjunto de 24 corantes diferentes. Sendo os modelos encontrados e validados a última etapa é usar o modelo desenvolvido para propor novos sensibilizadores com maiores rendimentos quânticos na eficiência fotovoltaica. São Cristóvão

In this paper, a typical austenitic stainless steel was used as a catalyst in the visible photo-Fenton degradation process of two model dyes, methylene blue and methylorange, in the presence of hydrogen peroxide and potassium persulfate as free radical-generating species. The concentration intervals for both peroxide and persulfate were in the range of 333–1667 μg/L. Very high photodecoloration efficiencies have been achieved using peroxide (>93%), while moderate ones have been achieved using persulfate (>75%) at a pH value of 6.5. For methylene blue, the maximum mineralization yield of 74.5% was achieved using 1665 μg/L of hydrogen peroxide, while methylorange was better mineralized using 999 μg/L of persulfate. The photodegradation of the dye occurred in two distinct steps, which were successfully modeled by the Langmuir–Hinshelwood pseudo-first-order kinetic model. Reaction rate constants k between 0.1 and 4.05 h−1 were observed, comparable to those presented in the reference literature at lower pH values and higher concentrations of total iron from the aqueous media.

Ο καρκίνος είναι σήμερα μία από τις κυριότερες αιτίες θανάτου και αποτελεί ένα σημαντικό εμπόδιο στην αύξηση του προσδόκιμου ζωής σε παγκόσμιο επίπεδο. Με βάση τις εκτιμήσεις του Παγκόσμιου Οργανισμού Υγείας το 2019, ο καρκίνος αποτέλεσε τη δεύτερη κύρια αιτία θανάτου. Παραδοσιακά, η θεραπεία αυτής ασθένειας περιλαμβάνει μέθοδούς όπως η χειρουργική εκτομή, η ακτινοθεραπεία και η χημειοθεραπεία, ωστόσο η διαφοροποίηση του μικροπεριβάλλοντος των διαφορετικών τύπου καρκίνου εξακολουθεί να αποτελεί ακόμα και σήμερα μια τεράστια πρόκληση. Η καθυστερημένη διάγνωση των όγκων καθώς η σημαντική έλλειψη που παρατηρείται στον τομέα των στοχευμένων θεραπευτικών παραγόντων έχει ωθήσει το ενδιαφέρον της επιστημονικής κοινότητας στην ανάπτυξη νέων εργαλείων ώστε να επιτευχθεί ταυτόχρονα έγκαιρη διάγνωση και θεραπεία του καρκίνου. Σε αντίθεση με τους φυσιολογικούς ιστούς, το μικροπεριβάλλον των καρκινικών κυττάρων διαθέτει μοναδικά μεταβολικά χαρακτηριστικά όπως η υπερέκφραση ορισμένων ενζύμων (π.χ. νιτροαναγωγάση, β-γαλακτοσιδάση) και υποδοχέων (π.χ. υποδοχείς αβιδίνης) καθώς επίσης και διαφορετικές φυσικοχημικές ιδιότητές (π.χ. pH, ιξώδες και πολικότητα). Προκειμένου να επιτευχθεί έγκαιρη και αποτελεσματική διάγνωση των καρκινικών κυττάρων, αρχικά αναπτύξαμε διαγνωστικές ενώσεις οι οποίες εκπέμπουν φθορισμό την περιοχή του εγγύς υπερθύρου και οι οποίες στη συνέχεια συνδυάστηκαν μέσω σταθερών δεσμών με διάφορα μικρά μόρια (π.χ. τροποποιημένα ανάλογα D-βιοτίνης, τριφαίνυλοφωσφίνης, μορφολίνης και τοσύλομαδος) ώστε να τις κατευθύνουν στα καρκινικά κύτταρα. Για να χαρτογραφήσουμε το μικροπεριβάλλον των καρκινικών κυττάρων (αυξημένα επίπεδα βιοθειολων, ROS, νιτροαναγώγασης, β-γαλακτοσιδάσης) οι ενώσεις αυτές συνδυάστηκαν μέσω διασπώμενων συνδετών με διάφορους μοριακούς ιχνηθέτες με αποτέλεσμα τη δραματική απόσβεση του φθορισμού τους. Παράλληλα, εφαρμόζοντας μια άκρως διαφορετική προσέγγιση ώστε να επιτύχουμε ταυτόχρονα έγκαιρη διάγνωση και θεραπεία του καρκίνου, χρησιμοποιώντας ένα μόνο μόριο, συνθέσαμε έναν καινοτόμο αυτό-διασπώμενο συνδέτη. Στο πρώτο βήμα προσαρτήσαμε σε αυτόν τον συνδέτη τη χρωστική μας η οποία διάθετε ενσωματωμένο κάποιον ογκοστοχευτικό παράγοντα και σε ένα δεύτερο βήμα το αντικαρκινικό φάρμακο γεμσιταβίνη.Συνδυάζοντας τον παράγοντα απεικόνισης με τους μοριακούς ιχνηθέτες και τους διάφορους ογκοστοχευτικούς παράγοντες συντέθηκαν και χαρακτηρίστηκαν πλήρως 16 διαγνωστικές και 2 θεραπογνωστικές ενώσεις. Οι ενδιάμεσες και τελικές ενώσεις καθαρίστηκαν με κατάλληλες τεχνικές όπως η χρωματογραφία στήλης και RP-HPLC και ταυτοποιήθηκαν με 1D/2D φασματοσκοπία NMR και φασματομετρία μάζης. Ακολούθησαν πειράματα μέσω φασματοσκοπίας UV-Vis και φθορισμού οπού ελέγχθηκε η απόκριση, η ταχύτητα απόκρισης και η εκλεκτικότητα των ενώσεων παρουσία κατάλληλου ανάλυτη. Στη συνέχεια, σε ορισμένες ενώσεις πραγματοποιήθηκε in vitro και in vivo αξιολόγηση σε κύτταρα, zebrafish και ποντίκια που έφεραν ξενομοσχεύματα καρκινικών κυττάρων. Τέλος η σταθερότητα των θεραπογνωστικών ενώσεων ελέγχθηκε μέσω μιας εξατομικευμένης μεθοδολογίας RP-HPLC που αναπτύξαμε σε ένα εύρος τιμών pH και σε πλάσμα ανθρωπίνου αίματος. Cancer is one of the leading causes of death today and consists a major barrier to increase life expectancy worldwide. According to the World Health Organization in 2019, cancer was the second leading cause of mortality. Traditionally, the treatment of this disease includes methods such as surgical resection, radiotherapy and chemotherapy, however the differentiation of the tumor microenvironment remains a huge challenge. The delayed tumor diagnosis combined with the significant lack observed in the field of targeted therapeutic agents has attached the interest of the scientific community to develop innovative tools in order to achieve simultaneous early diagnosis and treatment of cancer.In contrast to normal tissues, the microenvironment of cancer cells has unique metabolic characteristics such as the overexpression of certain enzymes (e.g. nitroreductase, β-galactosidase) and receptors (e.g. avidin receptors) as well as different physicochemical properties (e.g. pH, viscosity and polarity). To achieve an early and effective diagnosis of cancer cells, we initially developed fluorescent probes emitting in the near infrared region, which were afterwards combined via stable bonds with various small molecules (e.g. modified analogues of D-biotin, triphenylphosphine, tosyl group, morpholine) to achieve selective targeting of cancer cells. To map the tumor microenvironment (e.g. elevated levels of biothiols, ROS, nitroreductase, β-galactosidase) these compounds were combined via cleavable linkers with a variety of molecular tracers leading to the quenching of the fluorescent signal. At the same time, a different approach was applying to achieve in the same time early diagnosis and treatment of cancer, utilizing a single molecule, so an innovative self-immolative linker was synthesized. In the first step, we attached our fluorescent dye, which had a built-in oncogenic agent, following the installation of the anti-cancer drug gemcitabine.By combining the imaging agents with the molecular tracers and the various oncotargeting elements, 16 diagnostic and 2 theragnostic compounds were fully synthesized and characterized. The intermediate and final compounds were purified by appropriate techniques such as column chromatography and RP-HPLC and identified by 1D / 2D NMR spectroscopy and mass spectrometry. The response, the velocity and the selectivity of the fluorescent probes in presence of the proper analyte were evaluated by UV-Vis and fluorescence spectroscopy. In vitro and in vivo evaluation were performed in live cancer cells and xenografted zebrafish and mice. Finally, the stability of the theragnostic prodrugs was evaluated through a specified RP-HPLC methodology in a range of pH values and in human blood plasma. 296 σ.

Water pollution by organic dyes, and its remediation, is an important environmental issue associated with ever-increasing scientific interest. Conducting polymers have recently come to the forefront as advanced agents for removing dye. The present review reports on the progress represented by the literature published in 2020-2022 on the application of conducting polymers and their composites in the removal of dyes from aqueous media. Two composites, incorporating the most important polymers, polyaniline, and polypyrrole, have been used as efficient dye adsorbents or photocatalysts of dye decomposition. The recent application trends are outlined, and future uses also exploiting the electrical and electrochemical properties of conducting polymers are offered., Foundation for Sarcoidosis Research, FSR: AD 70202001026/1100; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT

Due to their good magnetic properties, excellent biocompatibility, and low price, magnetic iron oxide nanoparticles (IONPs) are the most commonly used magnetic nanomaterials and have been extensively explored in biomedical applications. Although magnetic IONPs can be used for a variety of applications in biomedicine, most practical applications require IONP-based platforms that can perform several tasks in parallel. Thus, appropriate engineering and integration of magnetic IONPs with different classes of organic and inorganic materials can produce multifunctional nanoplatforms that can perform several functions simultaneously, allowing their application in a broad spectrum of biomedical fields. This review article summarizes the fabrication of current composite nanoplatforms based on integration of magnetic IONPs with organic dyes, biomolecules (e.g., lipids, DNAs, aptamers, and antibodies), quantum dots, noble metal NPs, and stimuli-responsive polymers. We also highlight the recent technological advances achieved from such integrated multifunctional platforms and their potential use in biomedical applications, including dual-mode imaging for biomolecule detection, targeted drug delivery, photodynamic therapy, chemotherapy, and magnetic hyperthermia therapy.

Conducting polymers (CPs) combine the electrical properties of semiconductors and material properties of organic polymers. Polypyrrole (PPy) and polyaniline (PANI) are the most studied CPs due to their relatively high electrical conductivity (typically several units S cm-1 ), environmental stability, ease of preparation, good processability and low cost. Organic dyes have similar properties as surfactants, with an interesting ability to form various organized templates in water that could during synthesis tailor PPy morphologies to various nanostructures with high yield and improved electrical conductivity. Herein, PPy was prepared in the presence of cations dyes, safranin and phenosafranin, and anionic dye, methyl red, to obtain various nanostructures. The effect of dye concentration, oxidant-to-pyrrole mole ratio and other polymerization conditions on the physicochemical properties of the produced PPy was carefully investigated. Pyrrole was polymerized in the frozen reaction media at −24 řC in the presence of safranin, Acid Blue 25 (AB) or methyl orange (MO). Prepared one-dimensional nanostructures exhibited high yield and improved conductivity; the highest conductivity of 175 S cm−1 was obtained when safranin was used. Polypyrrole nanotubes prepared in the presence of MO were carbonized at 650...

The present study focuses on clinoptilolite (CLI)-rich natural zeolitic tuffs and their photocatalytic activity in the degradation of cationic organic dyes. CLI from different regions was tested in the photocatalytic degradation of methylene blue (MB) as a model cationic dye. The photocatalytic tests were performed at room temperature and atmospheric pressure under visible light irradiation. For all the CLI samples, the highest activity was observed at pH = 6. Total MB degradation varied between 70 and 91% (C0 = 10 mg dm–3, 0.2 g dm–3 of photocatalyst, during 300 min). It is suggested that the presence of Fe species in the studied tuffs is responsible for the photocatalytic activity. The activity increases linearly with the Fe content in the tuffs. The MB photodegradation follows the Langmuir–Hinshelwood kinetic model. The recyclability tests showed good stability and efficiency of the photocatalyst. The degradation rate decreased from 91 to 69% during three reaction cycles, indicating a promising potential of natural zeolites in the treatment of textile industry wastewater.

In this work, we have prepared single-perovskite- type materials. This research deals with the photocatalytic degradation of synthetic organic dyes: Methylene blue (MB), Naphthol Green B (NG), and Rhodamine B (RDB). Materials used for these experiments are simple nanocrystalline oxide-based perovskites comprising transition metals and lanthanides which were synthesized via the modified citrate sol-gel method. Single perovskite CeNiO3 was used as a parent compound, and we further increased the configurational entropy by adding different lanthanide cations on Ce position and transition metal cations on Ni position. All the materials used for photocatalytic degradation were characterized by powder X-ray diffraction, thermogravimetric analysis, and Brunauer-Emmet- Teller surface area analysis. The photocatalytic activity was monitored during irradiation at the wavelength of maximum absorbance for each dye (663 nm for MB, 734 nm for NG, and 554 nm for RDB) using UV/Vis spectroscopy. The results indicate a reduction of maximum absorbance of tested dyes in the given time frame which confirms the efficiency of synthesized photocatalysts.

This paper presents a comparison of the simultaneous preparation of di-O-alkylated and ether–ester derivatives of fluorescein using different methods (conventional or microwave heating). Shortening of the reaction time and increased efficiency were observed when using a microwave reactor. Moreover, described here for the first time is the application of a fast, simple, and eco-friendly ball-assisted method to exclusively obtain ether–ester derivatives. We also demonstrate that fluorescein can be effectively functionalized by O-alkylation carried out under microwave or ball-milling conditions, saving time and energy and affording the desired products with good yields and minimal byproduct formation. All the synthesized products as well as pH-dependent (prototropic) forms trapped in the SiO2 matrix were examined using UV–Vis and fluorescence spectroscopy.

We recently demonstrated that diaryl-naphthopyran photochromic dyes are efficient for sensitization of TiO(2) mesoporous electrodes, thus allowing the fabrication of photo-chromo-voltaic cells that can self-adapt their absorption of light and their generation of electricity with the light intensity. Herein we report the synthesis, the characterisation of two novel photochromic dyes based on diaryl-naphthopyran core i.e NPI-ThPh and NPI-FuPh for use in Dye Sensitized Solar Cells (DSSCs). Compared to our reference dye NPI, the molecules only vary by the nature of the spacer, a thiophene or a furan, connecting the photochromic unit and the phenyl-cyano-acrylic acid moiety used as the anchoring function. We found that swapping a phenyl for a thiophene or a furan leads to an improvement of the absorption properties of the molecules both in solution and after grafting on TiO(2) electrodes, however their photochromic process becomes not fully reversible. Despite better absorption in the visible range, the new dyes show poorer photochromic and photovoltaic properties in devices compared to NPI. Thanks to UV-Vis spectroscopy, DFT calculation, electrical characterization of the cells, and impedance spectroscopy, we unravel the factors limiting their performances. Our study contributes to better understand the connection between photochromic and photovoltaic properties, which is key to develop better performing molecules of this class.

It is still a challenge for wastewater treatment to develop efficient yet low-cost photocatalysts on a large scale. Herein, a facile yet efficient method was devised to successfully synthesize ZnO/Fe2O3 nanoflowers (NFs) by using metal organic framework ZIF-8 as the precursor. The photocatalytic activities of the as-prepared hetero-ZnO/Fe2O3 NFs are purposefully evaluated by photocatalytic degradation of methylene blue (MB) and methyl orange (MO) under UV light irradiation. The resulting ZnO/Fe2O3 NFs display even higher photocatalytic activities than those of single-phase ZnO and Fe2O3 as a photocatalyst for the degradation of both MB ad MO. Particularly, nearly 100% MB can be photocatalytically degraded in 90 min under UV light irradiation using the hetero-NFs photocatalyst. The enhanced photocatalytic properties are probably ascribed to the synergistic contributions from the suitable band alignment of ZnO and Fe2O3, large surface area, and strong light absorption property. Radical scavenger experiments prove that the photogenerated holes, ·OH and ·O2-, play key roles in photocatalytic degradation process of organic dyes. Accordingly, the photocatalytic degradation mechanism of hetero-ZnO/Fe2O3 NFs towards dyes is tentatively proposed. The work contributes an effective way to rationally design and fabricate advanced photocatalysts with heterojunction structures for photocatalytic applications.

Contaminated water due to industrial organic dyes presents a significant challenge to sustainability. As a material of green energy, photocatalysts offer an effective and environmentally friendly way to deal with organic dyes for water treatment. A series of simple and highly efficient iron photocatalysts with carbene ligands were developed, which, under the illumination of sunlight, can rapidly degrade multiple organic dyes in water at room temperature, including rhodamine B (RhB), indigo carmine (IC), methyl blue (MB), and congo red (CR). The field-only surface integral method was carried out to determine the absorption spectrum of photocatalyst particles. Under the optimized experimental conditions which were selected by the orthogonal experiments for four dyes, 0.5a@Fe2O3 and 2c@Fe2O3 demonstrated good stability and photocatalytic activity. These two composite materials not only have the ability to remove 98.0% of the degradation in 10 s, but also maintain high reactivity after a few cycles of repeated use.

Increasing concentration of pollutants has significantly affected the quality of water, especially for organic dyes-contained water/wastewater. This is probably reduced effectively through adsorbing the pollutants onto potential materials-based adsorbents. Chitosan/graphene oxide (CTS/GO) hybrid networks utilizing as adsorbents are attracting considerable interest owing to the available functional groups, which can remove plenty of the organic dyes from water/wastewater. In this review, the progress and expansions of CTS/GO hybrid networks-based adsorbents are summarized and discussed in detail. Following the general introduction and properties of each material system (i.e., CTS, GO and CTS/GO hybrid networks), the CTS/GO hybrid networks-based emerging adsorbents with coupling numerous other support materials (i.e., reduced GO, magnetic iron oxide, polymeric materials, metal-organic frameworks, etc.) are compared and discussed in short, at same time that some common organic dyes used in adsorption studies are also introduced. Besides, adsorption technique and mechanisms (i.e., adsorption kinetics and isotherms) focus on the CTS/GO hybrid networks' role are discussed as well. Although there are still some challenges from the reviewed researches, the CTS/GO hybrid networks-based emerging materials can be considered promising and potential adsorbents. Moreover, this review can provide a clear overview of CTS/GO hybrid networks-based adsorbents in organic dye removal applications to readers.

A facile two-step synthesis of ternary hetero-composites of ZnO, CuO, and single-walled carbon nanotubes (SWCNTs) was developed through a recrystallization process followed by annealing. A series of nanocomposites were prepared by varying the weight ratio of copper(II) acetate hydrate and zinc(II) acetate dihydrate and keeping the weight ratio of SWCNTs constant. The results revealed the formation of heterojunctions (ZnO–SWCNT–CuO, ZSC) of three crystal structures adjacent to each other, forming a ternary wurtzite-structured nanoparticles along with defects. Enhanced charge separation (electron-hole pairs), reduced band gap, defect-enhanced specific surface area, and promoted oxidation potential were key factors for the enhanced photocatalytic activity of the ternary nanocomposites. OH• radicals were the main active species during dye degradation, and O2−• and h+ were also involved to a lesser extent. A type II heterojunction mechanism approach is proposed based on the charge carrier migration pattern. Among the synthesized nanocomposites, the sample prepared using copper(II) acetate hydrate and zinc(II) acetate dihydrate in a 1: 9 ratio (designated a ZSC3) showed the highest photocatalytic activity. ZSC3 achieved 99.2% photodecomposition of methylene blue in 20 min, 94.1% photodecomposition of Congo red in 60 min, and 99.6% photodecomposition of Rhodamine B in 40 min under simulated sunlight. Additionally, ZSC3 showed excellent reusability and stability, maintaining 96.7% of its activity even after five successive uses. Based on overall results, the ZSC sample was proposed as an excellent candidate for water purification applications.

This work studies the interaction of organic nanoparticles (ON) with various dyes in aqueous solution, to elucidate the role of ON on transport and fate of dyes in the environment, and on dyes removal from wastewater. Studied dyes are Acid Red 66 (AR66), Methylene Blue (MB), Reactive Black 5 (RB5), and Reactive Violet 5 (RV5). ON are extracted from organic matter of anthropogenic origin through resuspension of its colloidal fraction, and successive filtration and dialysis of the obtained suspension. Mechanisms of interaction are investigated initially through three-dimensional excitation emission matrix (3DEEM) analysis. Obtained data indicate that dynamic interactions occur strongly between dye molecules and ON aggregates. 3DEEM spectra of mixed samples containing ON together with one of the tested dyes, present a shape similar to the one of ON alone, but each of them is characterized by specific differences in terms of peaks quenching and shift. The analysis of these singularities suggests that dye molecules are bound to the functional groups of ON through H-bonds, according to the following steps: i) dyes reach the surface of ON aggregates; ii) the molecules pass through the hydrophilic surface of ON aggregates, and reach their hydrophobic core; iii) the dyes are sequestrated into the hydrophobic core of ON aggregates. Nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopies analysis confirm the formation of supramolecular aggregates with stable micellar hydrophobic structure, mainly consisting of aliphatic fractions of ON, which explain the disappearance of aromatic groups signals from dyes.