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As one of the most potential platforms for heterogeneous catalysis, two‐dimensional porphyrin‐based covalent organic frameworks (COFs) have attracted great research interests. In this work, following the correlation of COF structure and their performance, a type of donor–acceptor 2D COF (Por‐COF‐Zn) based on porphyrin and thiophene units was designed and easily constructed by one‐pot method using 5,10,15,20‐tetra‐(4‐aminophenyl)porphyrin (TAPP), thieno[3,2‐b]thiophene‐2,5‐dicarbaldehyde, and zinc acetate. The as‐synthesized COF material is tested to show high crystallinity and good thermal and chemical stability. The Brunauer–Emmett–Teller (BET) measure results show that the specific surface area of Por‐COF‐Zn is 413.6 m2g−1, and the pore volume is 0.279 cm3g−1. Transient photocurrent response and EIS measurement also demonstrate that Por‐COF‐Zn exhibits an efficient separation of photogenerated electron/hole pairs. The photocatalytic performance of the resulted COF was further evaluated by using intramolecular cyclization of N‐phenyl‐o‐phenylenediamine and benzaldehyde to form benzimidazole derivative. The catalyst system exhibited good to high conversion efficiency, moderate substrate applicability, and excellent stability and recyclability for the catalytic cyclization approach of benzimidazoles. The catalytic mechanism should be contributed to the synergistic effect of organic framework and metallic zinc. Our current work also provides valuable information for understanding COF‐based photocatalytic systems and further highlight new insights to meet new challenges of heterogeneous photocatalysis. [ABSTRACT FROM AUTHOR]

Heterogeneous visible light photocatalysis is a compelling approach to address sustainability in synthetic photochemistry. However, the use of solid‐state photocatalysts remains very unpopular in organic synthesis because of their limited accessibility and the black‐box effect associated to the lack of rational between their molecular structure and their photochemical properties. Herein, we disclose the synthesis, characterization, photocatalytic properties and synthetic applications of a simple and readily available solid‐state conjugated organic polymer, poly‐(para‐phenylene ethynylene) 1, which exhibits a strong oxidative power upon irradiation with visible light (E(1*/1⋅−)=+1.67 V vs SCE). Comparisons with structural analogues highlighted the superior photocatalytic activity of this linear semiconductor, on account of its fully conjugated architecture. The associated excited‐state reactivity enabled the transformation of various amines into imines in batch and continuous flow reactors together with straightforward photocatalyst recycling. Mechanistic investigations revealed concomitant photoredox and energy transfer pathways, that led to the formation of the desired products. Ultimately, the inline generation of imines was exploited in telescoped three‐component Ugi reactions (3CR) in batch and flow toward biologically relevant α‐acylaminoamides. [ABSTRACT FROM AUTHOR]

The work aims to biosynthesize and characterize titanium dioxide nanoparticles (TiO2-NPs) to evaluate antimicrobial activity, cytotoxicity, and photocatalytic activity (under visible irradiation). X-ray diffraction (XRD), N2 adsorption/desorption, zeta potential (ZP), field emission gun scanning electron microscopy (FEG-SEM), and scanning electron microscopy with energy-dispersive X-ray analysis (SEM–EDX) were used to characterize. The antibacterial potential was evaluated by minimal inhibitory activity (MIC) against S. aureus and P. aeruginosa. Central composite rotational design (CCRD 23) was used for experimental design. XRD diffractogram and FEG-SEM micrograph showed characteristic peaks of TiO2-NPs (about 32 nm) and spherical shapes, respectively. TiO2-NPs had a negative charge surface (− 4.9 mV) with type V and H1 hysteresis and SBET = 118 m2 g−1, Dp = 9.2 nm and Vp = 0.2 cm3 g−1. EDX results indicated the presence of TiO2-NPs and the effectiveness of the green synthesis. The antimicrobial activity showed that there was no inhibition of any pathogen. About the safety profile, there was no reduction in cell viability in the 293 T, MDBK, and HaCat cell lines, and reactive oxygen species (ROS) generation did not cause significant differences about the untreated control, indicating biocompatibility. The photocatalytic activity showed degradation of 90% of RhB dye using the ideal condition ([RhB] = 10 mg L−1, [TiO2-NPs] = 3.5 g L−1, and pH = 7.0) by CCRD under visible irradiation with a pseudo-first-order kinetic model (k = 0.0146 min−1). Therefore, TiO2-NPs present applications as alternative metallic nanoparticles for wastewater treatment and show potential for antimicrobial activity. [ABSTRACT FROM AUTHOR]

Polymeric carbon nitride has attracted significant interest in heterogeneous photocatalysis due to its activity under visible‐light irradiation. Herein, we report on using carbon nitride‐coated NMR tubes for in situ studies of photocatalytic reaction mechanisms. In a first step, we exploited carbon nitride‐coated crimp vials as batch photoreactors for visible photocatalytic fluorinations of unactivated C(sp3)−H bonds, with moderate to excellent yields and reusability over multiple cycles. Eventually, carbon nitride‐coated NMR tubes were used as a photoreactor by coupling them with optical fiber irradiation directly inside the spectrometer. This enabled us to follow the reaction with in situ NMR spectroscopy identifying reactive intermediates otherwise elusive in conventional analyses. The method provides advantages for the study of photocatalytic mechanisms of complex reactions and substantially reduces the need of comparative tests for depicting reaction intermediates and conversion pathways. [ABSTRACT FROM AUTHOR]

Recently, the removal of tetracycline, a toxic material, from aquatic medium has been a trending subject of research. Several different technologies including adsorption, biological removal method, solvent extraction, coagulation, chemical reduction, photocatalysis and ion exchange method for removal of tetracyclines from wastewater have been reported. However, photocatalysis of tetracyclines (TC) has gained huge interest because of more efficient mineralization of TC into CO2 and water. Several different nanomaterial based photocatalytic assemblies for the removal of tetracyclines have been widely reported for the removal of tetracyclines which have not been critically reviewed in the literature. This study provides an overview of recent progress of classification, synthesis, characterizations, mechanism of inorganic and metal organic framework nanocatalytic assemblies on photocatalysis of tetracyclines in aquatic medium. Additionally, kinetics and factors affecting the photocatalysis of tetracyclines have been discussed briefly. Future perspectives have also been presented for further advancement in this area. [ABSTRACT FROM AUTHOR]

Mn x Co 1-x Fe 2 O 4 nanoparticles with compositions x = 0, 0.25, 0.50, and 0.75 were synthesized using a straightforward surfactant-free solvothermal route. The nanoparticles' microstructure, morphology, and size distribution were studied by X-ray diffraction and transmission electron microscopy. Raman spectroscopy was used to obtain information about their vibrational properties and the cation distribution in the spinel lattice. UV–visible and diffuse reflectance spectroscopy were used to study their photocatalytic activity and optical properties. The behavior of Mn x Co 1-x Fe 2 O 4 nanoparticles in an aqueous medium and its effects on the photocatalytic activity were highlighted by ζ-potential measurements. Their magnetic properties were investigated using M − H curves and ZFC-FC measurements. The results allowed us to study the solvothermal route's effectiveness for synthesizing well-crystallized ultra-small size Mn x Co 1-x Fe 2 O 4 nanoparticles with promising photocatalytic and superparamagnetic properties. They also provided insights into the effects of manganese's cobalt substitution on the spinel lattice's cation distribution and the mechanisms behind their observed physical properties. [ABSTRACT FROM AUTHOR]

Herein, a 3D sponge-like polypyrrole/TiO2 (Ppy-TiO2) composite aerogel was developed for the first time to remove hydroxybenzotriazole (HOBt) from water. Mesoporous TiO2 was prepared via a sol–gel method, and then the Ppy-TiO2 composite hydrogel was prepared by oxidative polymerization and converted to aerogel by freeze-drying. The morphological, compositional, and surface characteristics of the prepared materials were detailly characterized. The characterization studies revealed that pure anatase mesoporous TiO2 nanoparticles were successfully prepared and incorporated into amorphous 3D Ppy with a porous chain-like network structure. Coupling Ppy and TiO2 extended the light absorption to the visible region and decreased the electron/hole recombination rate. The performance studies revealed that the Ppy-TiO2 composite has higher adsorption and photocatalytic activities than the sum of the individual components. Optimum performance was obtained at pH 5.3 using 0.25 g/L of the Ppy-TiO2 composite with a Ppy: TiO2 mass ratio of 1:1. The intermolecular hydrogen bonding was pivotal in the adsorption process which was multilayer. The degradation of HOBt occurs primarily by holes, then superoxide anion radicals. The total organic carbon (TOC) analysis showed a 90% reduction in carbon content after 30 min of treatment. The toxicity study indicated that the photocatalytic process decreased the toxicity of the HOBt solution. The synergism between adsorption and photocatalysis, easy separation, and reusability promote the application of Ppy-TiO2 composite aerogel for water treatment. [ABSTRACT FROM AUTHOR]

Porous organic polymers (POPs) are emergent tailor‐made materials, which can be accessed by covalent polymerization of diligently designed molecular building blocks in a bottom‐up fashion. Acridone, a well‐known chromophore that undergoes intersystem crossing (ISC) with near‐unity quantum yield akin to benzophenone, was structurally elaborated into a building block and subjected to Friedel‐Crafts polyalkylation to afford a series of POPs, namely, Ac‐MePOP, Ac‐OMePOP, and Ac‐CBPOP. These POPs exhibit remarkable porosity and significant absorption in the visible region. Of the three polymers, Ac‐CBPOP with the highest BET surface area of ca. 1027 m2/g is shown to serve as an excellent heterogeneous photocatalyst for visible light‐mediated oxidative transformations, that is, oxidative coupling of benzylamines to imines and cyclocondensation of o‐phenylenediamines with aldehydes to benzimidazoles under oxygen atmosphere. It is further shown that Ac‐CBPOP can be reused for several reaction cycles without any loss of catalytic activity with its stability intact. Mechanistic studies show that 1O2 serves as the key reactive oxygen species, formed by the energy transfer from Ac‐CBPOP to 3O2, in the photocatalytic oxidation reactions. The results demonstrate the development of stable photocatalytic POP materials with tailor‐made properties by a bottom‐up covalent polymerization of programmed molecular building blocks. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have garnered significant interest within the scientific community due to their distinctive ability to act as organic semiconductors responsive to visible light. This unique attribute makes them up-and-coming candidates for facilitating photocatalytic organic reactions. Herein, two donor–acceptor COFs, TPE-BSD-COF and TPE-BD-COF, have been designed and synthesized by incorporating electron-rich tetraphenylethylene and electron-deficient benzoselenadiazole and benzothiadiazole units into the framework through a Schiff-base polycondensation reaction. Both COFs exhibit exceptional crystallinity and enduring porosity. TPE-BSD-COF and TPE-BD-COF exhibit broad light absorption capabilities, a narrow optical band gap, and low electrochemical impedance spectrum (EIS) levels, indicating that the two COFs are effective heterogeneous photocatalysts for the reductive dehalogenation of phenacyl bromide derivatives under blue LED irradiation. A high photocatalytic yield of 98% and 95% was achieved by TPE-BSD-COF and TPE-BD-COF catalysts, respectively, within only one hour. [ABSTRACT FROM AUTHOR]

Abstract Herein, a 3D sponge-like polypyrrole/TiO2 (Ppy-TiO2) composite aerogel was developed for the first time to remove hydroxybenzotriazole (HOBt) from water. Mesoporous TiO2 was prepared via a sol–gel method, and then the Ppy-TiO2 composite hydrogel was prepared by oxidative polymerization and converted to aerogel by freeze-drying. The morphological, compositional, and surface characteristics of the prepared materials were detailly characterized. The characterization studies revealed that pure anatase mesoporous TiO2 nanoparticles were successfully prepared and incorporated into amorphous 3D Ppy with a porous chain-like network structure. Coupling Ppy and TiO2 extended the light absorption to the visible region and decreased the electron/hole recombination rate. The performance studies revealed that the Ppy-TiO2 composite has higher adsorption and photocatalytic activities than the sum of the individual components. Optimum performance was obtained at pH 5.3 using 0.25 g/L of the Ppy-TiO2 composite with a Ppy: TiO2 mass ratio of 1:1. The intermolecular hydrogen bonding was pivotal in the adsorption process which was multilayer. The degradation of HOBt occurs primarily by holes, then superoxide anion radicals. The total organic carbon (TOC) analysis showed a 90% reduction in carbon content after 30 min of treatment. The toxicity study indicated that the photocatalytic process decreased the toxicity of the HOBt solution. The synergism between adsorption and photocatalysis, easy separation, and reusability promote the application of Ppy-TiO2 composite aerogel for water treatment.

To operationalise the heterogeneous photocatalysis process, the present study investigated the efficiency of TiO2-P25 nanoparticles immobilised on glass beads using the heat attachment method to remove cefazolin (CEF) as an antibiotic contaminant. The characteristics of the glass beads coated with TiO2-P25 nanoparticles were probed by the Scanning Electron Microscopy (SEM) technique. The immobilised TiO2-P25 nanoparticles manifested considerable efficiency in CEF removal in different operational conditions. The impact of various parameters, such as the ultraviolet light radiation time, initial concentration of CEF, light source power, inlet liquid volumetric flow rate, and pH of the solution, on the efficiency of CEF removal were examined. The results reveal that the removal percentage goes up as the irradiation time, volumetric flow rate, pH of the solution, and light source power increase while declining with a rise in the initial concentration of CEF. According to the findings, an initial CEF concentration of 20 mg L−1 is entirely removed by 40 min UV irradiation with a 16 W light source, the volumetric flow rate of 300 mL min−1, and the pH of 9.5. The reaction rate constant and adsorption coefficient of CEF on immobilised TiO2 were estimated at 0.622 mg L−1 min−1 and 0.095 mg−1 L via Langmuir- Hinshelwood kinetics. The outcomes of the mineralisation studies also display a considerable reduction of TOC and evolution of significant mineralisation products, like $$NO_3^ - $$ N O 3 − , $$NO_2^ - $$ N O 2 − , $$NH_4^ + $$ N H 4 + , and $$SO_4^{2 - }$$ S O 4 2 − . The experimental results were modelled by artificial neural networks (ANN). Comparing the experimental results with the ANN-predicted data shows the acceptable efficiency of modelling with ANN. The minimum MSE, R2 value for all data (validation, training, and test), and R2 value for simulated data were obtained at 0.00027811, 0.9971, and 0.9809, respectively. The relative importance of the parameters affecting the process evaluated by the ANN weights indicates that the irradiation time is the most important factor in the photocatalytic removal of CEF. [ABSTRACT FROM AUTHOR]

Two types of poly-porphyrin-based heterogeneous photocatalysts including insoluble polymer and water-soluble nanoparticles exhibited excellent photocatalytic activity in visible-light-induced dehydrogenation in water. The extremely low catalyst loading (0.01 ​mol%) of water-soluble nanoparticles provided so far the highest turnover frequency (TOF) value (333 h-1) for such transformation among reported records.

Despite the advancements in alternative fuels and energy sources, there continues to be a significant global dependence on oil production and extraction. A substantial volume of oilfield-produced water (OPW) is generated during the production and extraction processes of oil fields. Recurrent OPW treatments encountered significant challenges in addressing this particular type of wastewater. Advanced oxidation processes (AOPs) are regarded as a promising alternative approach for the degradation of recalcitrant organic compounds in the OPW. This review focuses on the characterization of OPW. The treatment of organic pollutants in wastewater using AOPs, such as ozonation, Fenton oxidation-based processes, heterogeneous photocatalysis, and persulfate oxidation, is comprehensively reviewed in terms of their efficiency for pollutant degradation. The primary challenges in this field and the future directions for development are proposed, with the aim of providing a valuable reference for achieving highly effective treatment of OPW. HIGHLIGHTS Characteristics of oilfield-produced water were analyzed.; Treatment of oilfield-produced water using advanced oxidation processes was discussed.; Recommendation and future research are proposed.;

In recent years, heterogeneous photocatalysis has emerged as a promising alternative for the treatment of organic pollutants. This technique offers several advantages, such as low cost and ease of operation. However, finding a semiconductor material that is both operationally viable and highly active under solar irradiation remains a challenge, often requiring materials of nanometric size. Furthermore, in many processes, photocatalysts are suspended in the solution, requiring additional steps to remove them. This can render the technique economically unviable, especially for nanosized catalysts. This work demonstrated the feasibility of using a structured photocatalyst (ZnO, g-C3N4, and carbon xerogel) optimized for this photodegradation process. The synthesized materials were characterized by nitrogen adsorption and desorption, X-ray diffraction (XRD), and diffuse reflectance spectroscopy (DRS). Adhesion testing demonstrated the efficiency of the deposition technique, with film adhesion exceeding 90%. The photocatalytic evaluation was performed using a mixture of three textile dyes in a recycle photoreactor, varying pH (4.7 and 10), recycle flow rate (2, 4, and 6 L h−1), immobilized mass (1, 2, and 3 mg cm−2), monolith height (1.5, 3.0, and 4.5 cm), and type of radiation (solar and visible artificials; and natural solar). The structured photocatalyst degraded over 99% of the dye mixture under artificial radiation. The solar energy results are highly promising, achieving a degradation efficiency of approximately 74%. Furthermore, it was possible to regenerate the structured photocatalyst up to seven consecutive times using exclusively natural solar light and maintain a degradation rate of around 70%. These results reinforce the feasibility and potential application of this system in photocatalytic reactions, highlighting its effectiveness and sustainability. [ABSTRACT FROM AUTHOR]

Imines are essential intermediates in organic transformations, and is generally produced by dehydrogenative condensation of alcohols and amines with the assist of specialized catalysts and additives. Heterogeneous photocatalysis provides a sustainable platform for such process without the using of toxic oxidants, yet a functionalized photocatalyst with optimized co‐adsorption of reactants needs to be developed to promote the stoichiometric oxidative condensation under ambient conditions. Here, we show that benzyl alcohol and aniline adsorb non‐interferingly on the Fe node and the linker sites of the MIL‐53(Fe) metal organic frameworks (MOFs), respectively. The co‐adsorption of both reactants barely influences the reduction of molecular oxygen to generate oxygen radicals, resulting in efficient formation of benzaldehyde under visible light. Additionally, the weak adsorption of water together with surface acidity of the MIL‐53(Fe) promote a rapid condensation of benzaldehyde with aniline and the depletion of generated water, achieving an efficient C−N bond creation for a wide range of substrates. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials have emerged as a frontier in materials science, offering unique properties due to their atomically thin nature. Among these materials, bismuthene stands out due to its exceptional optical, electronic, and catalytic characteristics. Bismuthene exhibits high charge carrier mobility, stability, and a tunable bandgap (0.3–1.0 eV), making it highly suitable for applications in transistors, spintronics, biomedicine, and photocatalysis. This work explores the so far reported synthesis methods for obtaining 2D bismuthene, including bottom-up approaches like chemical vapor deposition and molecular beam epitaxy, and top-down methods such as liquid-phase exfoliation and mechanical exfoliation. Recent advancements in understanding 2D bismuthene structural phases, electronic properties modulated by spin-orbit coupling, and its potential applications in next-generation photocatalysts are also reviewed. As is retrieved by our literature review, 2D bismuthene shows great promise for addressing significant environmental challenges. For instance, in CO2 reduction, integrating bismuthene into 2D/2D heterostructures enhances electron transfer efficiency, thereby improving selectivity toward valuable products, such as CH4 and formic acid. In organic pollutant degradation, bismuth subcarbonate (Bi2O2CO3) nanosheets, obtained from 2D bismuthene, have demonstrated high photocatalytic degradation of antibiotics under visible light irradiation, due to their increased surface area and efficient generation of reactive species. Moreover, bismuthene-based materials exhibit potential in the photocatalytic water-splitting process for hydrogen production, overcoming issues associated with UV-light dependence and sacrificial agent usage. This review underscores the versatile applications of 2D bismuthene in advancing photocatalytic technologies, offering insights into future research directions and potential industrial applications. [ABSTRACT FROM AUTHOR]

In this study, we pioneered the synthesis of nanoflower-shaped TiO2-supported Au photocatalysts and investigated their properties. Au nanoflowers (Au NFs) were prepared by a Na-citrate and hydroquinone-based preparation method, followed by wet impregnation of the derived Au NFs on the surface of TiO2 nanorods (TNR). A uniform and homogeneous distribution of Au NFs was observed in the TNR + NF(0.7) sample (lower Na-citrate concentration), while their distribution was heterogeneous in the TNR + NF(1.4) sample (higher Na-citrate concentration). The UV-Vis DR spectra revealed the size- and shape-dependent optical properties of the Au NFs, with the LSPR effect observed in the visible region. The solid-state EPR spectra showed the presence of Ti3+, oxygen vacancies and electron interactions with organic compounds on the catalyst surface. In the case of the TNR + NF(0.7) sample, high photocatalytic activity was observed in the H2-assisted reduction of NO2 to N2 at room temperature under visible-light illumination. In contrast, the TNR + NF(1.4) catalyst as well as the heat-treated samples showed no ability to reduce NO2 under visible light, indicating the presence of deformed Au NFs limiting the LSPR effect. These results emphasized the importance of the choice of synthesis method, as this could strongly influence the photocatalytic activity of the Au NFs. [ABSTRACT FROM AUTHOR]

Solar photocatalysis is considered as one of the best methods for "green" purification of environment. Accordingly, efficient, stable, and low-price materials must be developed for possible commercial application. Herein, flower-like bismuth molybdate (Bi 2 MoO 6) photocatalysts were successfully synthesized by CTAB-assisted hydrothermal process, and then surface modified with platinum by photodeposition. The obtained materials were characterized by various methods, including XRD, DRS, XPS, SEM, TEM, ESR, photoluminescence spectroscopy and photoelectrochemical tests. Photocatalytic activity was tested mainly for tetracycline (TC) antibiotic degradation under visible-light irradiation (λ > 420 nm), including scavenger tests and experiments for different operation conditions (TC concentration, photocatalyst dose, pH value, in the presence of inorganic salts, water taken from different reservoirs). It has been found that the best photocatalyst containing 0.5 wt% of platinum exhibits 94.2 % TC removal during 60-min visible-light irradiation, reaching the reaction rate constant of 0.0392 min−1 (exceeding the data reported up to now). It is proposed that exceptional photocatalytic performance is caused by the synergy between the uniform flower structure (efficient light harvesting and large specific surface area) and double function of platinum deposits, i.e., as a sink for electrons (hindering charge carriers' recombination) and a plasmonic sensitizer (allowing energy transfer from excited platinum to oxygen). Superoxide radicals (•O 2 −) are the main oxidation species, as proven by the quenching experiments and EPR analysis. However, in the case of platinum-modified samples, singlet oxygen plays also an important role, and thus an energy transfer from plasmonic platinum to oxygen could be expected. Additionally, TC degradation pathways, elucidated by the detection of intermediates, and the toxicity data (TC and its degradation products), assessed by a quantitative structure–activity relationship (QSAR) method, have confirmed that photocatalytic degradation of TC is indeed an environmental-friendly method, highly recommended for the decomposition of persistent organic compounds. [ABSTRACT FROM AUTHOR]

Featured Application: Elimination of Emerging Pollutants (pesticides) present in effluents from industrial wastewater treatment plants. Emerging pollutants in wastewater pose significant risks to human health and wildlife, particularly due to their persistence in treated effluents from WWTPs. Very recent research has focused on developing new techniques based on advanced oxidation processes using inorganic and organic photocatalysts for treating polluted effluents under visible light. This study investigates a pesticide-removal system utilizing heterogeneous photoactive polymeric materials P2, P3, and P4. These materials, engineered as hydrophilic polymeric microparticles and functionalized with Rose Bengal, have demonstrated efficient singlet oxygen generation and first-order kinetics in the degradation of AHMPD, a pyrimidine fungicide. Given that most studies in the literature have concentrated on urban WWTPs, with less emphasis on industrial wastewater treatment, this research focused on real water samples from the effluent of an industrial WWTP in the agri-food sector, which processes large volumes of citrus and where high concentrations of AHMPD and other pesticides were detected at certain times of the year. The degradation potential of photoactive materials P3 and P4 was evaluated, achieving removal rates of AHMPD up to 85% under conditions of pH = 11 with 48 h of exposure to visible light. [ABSTRACT FROM AUTHOR]

In recent decades, numerous studies have indicated the substantial role semiconductors could play in photocatalytic processes for environmental applications. Materials that contain a semiconductor as a photocatalyst have a semi-permanent capacity for removing harmful gases from the ambient air. In this paper, the focus is on TiO2. Heterogeneous photocatalysis using TiO2 leads to the degradation of NO/NO2, benzene, toluene, and other priority air pollutants once in contact with the semiconductor surface. Preliminary evidence indicates that TiO2-containing construction materials and paints efficiently destroy the ozone precursors NO and NO2 by up to 80% and 30%, respectively. Therefore, the development of innovative coatings containing TiO2 as a photocatalyst was in the foreground of research activities. The aim of this was for coatings to be used as building and construction materials, mainly outdoors, e.g., on building façades on high-traffic roads for the degradation of priority air pollutants (NOx and volatile organic compounds) in the polluted urban atmosphere. Though there are advantages connected with the application of TiO2, due to its band gap of 3.2 eV, these are limited. TiO2 is effective only in the UV region (ca. 5%) of the solar spectrum with wavelengths λ < 380 nm. Hence, efforts are made here, as in many research studies, to dope TiO2 with transition metals to increase its activity using visible light, which will extend its application to indoor environments. In our studies, experiments were conducted with 0.1% (w/w) and 1% (w/w) Mn-TiO2 admixtures, and the ability of the modified photocatalysts to degrade NO by both solar and indoor illumination was evaluated. The surface chemistry at the air/catalyst interface, governed by the photoelectric characteristics of TiO2 and the formation of reactive oxygen species with co-occurring redox reactions, is reviewed in this paper. The factors affecting the application of TiO2 for the degradation of priority air pollutants as single compounds or mixtures are discussed. We investigated, particularly, the degradation of mixtures of priority compounds at typical concentrations in ambient air and confined spaces. This is a realistic approach, because pollutants are present as mixtures, rather than as individual compounds in ambient and indoor air. Moreover, organic polymers as paint constituents were found to be the primary source for carbonyl formation, e.g., formaldehyde, acetaldehyde, etc., during the heterogeneous photocatalytic processes conducted on TiO2-enriched coatings. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes, including photocatalysis, have been proven effective at organic dye degradation. Tailored porous materials with regulated pore size, shape, and morphology offer a sustainable solution to the water pollution problem by acting as support materials to grafted photocatalytic nanoparticles (NPs). This research investigated the influence of pore and particle sizes of photocatalytic MICROSCAFS® on the degradation of methyl orange (MO) in aqueous solution (10 mg/L). Photocatalytic MICROSCAFS® are made of binder-less supported P25 TiO2 NPs within MICROSCAFS®, which are silica–titania microspheres with a controlled size and interconnected macroporosity, synthesized by an adapted sol–gel method that involves a polymerization-induced phase separation process. Photocatalytic experiments were performed both in batch and flow reactors, with this latter one targeting a proof of concept for continuous transformation processes and real-life conditions. Photocatalytic degradation of 87% in 2 h (batch) was achieved, using a calibrated solar light simulator (1 sun) and a photocatalyst/pollutant mass ratio of 23. This study introduces a novel flow kinetic model which provides the modeling and simulation of the photocatalytic MICROSCAFS® performance. A scavenger study was performed, enabling an in-depth mechanistic understanding. Finally, the transformation products resulting from the MO photocatalytic degradation were elucidated by high-resolution mass spectrometry experiments and subjected to an in silico toxicity assessment. [ABSTRACT FROM AUTHOR]

The bismuth-layered ferroelectric (BLF) oxides are promising photocatalysts due to their wide band gap, photo-coupled ferro properties, Pb-Free composition, and excellent chemical stability. In this study, polycrystalline SrBi 4 Ti 4 O 15 (SBT) is used as the target photocatalyst, and its photocatalytic performance was evaluated in terms of Rhodamine-B dye degradation under UV light. Moreover, the influence of metal deposition (Ag, Zn, Fe, and Bi) was also explored. The powders of SBT and its metal-decorated derivatives were synthesized and structural, compositional, and optical properties were studied in detail using XRD, XPS, EDS, FTIR, UV–Vis, Raman, and PL spectroscopy. The pristine SBT powders showed 19% photodegradation after 60 min of exposure to UV radiation. Metal nanoparticles deposited on the surface of the SBT were found to improve photocatalytic capacity and a nearly threefold increase (53%) in degradation rate was achieved for Bi-decorated SBT. The rate constant and the turnover frequency are 0.01336 min - 1 and 13.2 × 10 - 3 mol Rh - B mol metal h - 1 , respectively. The degradation was observed to follow a Langmuir–Hinshelwood (LH) model, indicating that the process is first order. [ABSTRACT FROM AUTHOR]

The overall objective of this study was to develop cost-effective treatment processes for 1,4-dioxane removal that were safe and easy to scale up. Degradation of 1,4-dioxane was conducted and compared for the first time by heterogeneous photocatalysis and a photo-Fenton-like process under cool white fluorescent light in mild conditions, using two types of commercial nanoparticles–titanium dioxide (TiO2) and nanoscale zero-valent iron (nZVI), respectively. Both types of nanoparticles removed >99.9% of 1,4-dioxane in a short period of time. Hydroxyl radicals (·OH), superoxide radicals (·O2-), and hydrogen peroxide (H2O2) were detected in both degradation processes; photogenerated holes (h+) were critical in the degradation of 1,4-dioxane by the photocatalytic process using TiO2. 1,4-Dioxane can be degraded at pH 7 in TiO2/light system and at pH 3 in nZVI/light system, and faster degradation of 1,4-dioxane at even higher concentration was achieved in the former system. Increase in light intensity accelerated 1,4-dioxane degradation, which followed first order kinetics in both systems. In wastewater effluent, the removal of 1,4-dioxane was slower than that in deionised water, which likely reflected the complex compositions of the wastewater effluent. Under combined UVA and visible light illumination, a two-stage degradation process was proposed for 1,4-dioxane for the first time by TiO2 nanoparticles; this study also demonstrated for the first time 1,4-dioxane degradation by the photo-Fenton-like process using nZVI. The cost-effective solutions using commercial nanoparticles under fluorescent light developed in this study can be potentially applied to treat water contaminated by high concentrations of 1,4-dioxane in large-scale. [ABSTRACT FROM AUTHOR]

Heterogeneous photocatalysis is an alternative to mineralizing emerging pollutants. The present study focuses on the kinetic model of salicylic acid photocatalytic degradation in an aqueous solution as a function of pollutant concentration and light intensity. The intrinsic kinetic model parameters were determined using a differential photocatalytic reactor with immobilized TiO2 based on experiments and numerical simulations. Five degradation experiments with different light intensities were performed for a turbulent flow rate of 4.7 L/min and salicylic acid concentration of 20 mg/L. Light intensities used for the kinetic experiments were obtained by computational fluid dynamics (CFD) simulation using the radiation transfer equation that was pre‐validated. The TiO2 immobilized method presents low leaching of the catalyst and good degradation efficiency. The intrinsic kinetic model showed to be first‐order both for the pollutant concentration and for the light intensity and can be applied in simulation to optimize and design photocatalytic reactors. [ABSTRACT FROM AUTHOR]

This study investigated the influence of thermal treatment on the photocatalytic performance of ZnCr layered double hydroxide-based mixed metal oxides in the degradation of methylene blue and brilliant cresyl blue organic dyes under simulated solar light irradiation. The photocatalysts were synthesized using a simple coprecipitation method and subjected to thermal treatment at temperatures ranging from 100°C to 900°C. Additionally, the study explored the antibacterial activity against Escherichia coli and Staphylococcus aureus using a novel antibacterial experimental setup. It not only involved the introduction of ZnCr samples into BioPeptone/prepared cell suspension to enhance photocatalyst–bacteria cell contact but also included research on antibacterial activity induced by solar irradiation and also in the absence of light, providing crucial insights into photocatalytic antibacterial activity of ZnCr photocatalysts. Despite satisfactory efficiencies observed for all thermally treated ZnCr samples (removal efficiency ranging from 40% to 90%), ZnCr 900 (thermally treated at 900°C) exhibited exceptional performance, achieving nearly 100% removal efficiency and complete growth inhibition for both bacteria. Integrating these findings with structural and textural characterization data, as well as kinetic studies, our comprehensive analysis enhances the understanding of structure-dependent photocatalytic activities. These insights open possibilities for the application of ZnCr photocatalysts in water purification and environmental remediation.

Water molecules, which act as both solvent and reactant, play critical roles in photocatalytic reactions for methanol conversion. However, the influence of water on the adsorption of methanol and desorption of liquid products, which are two essential steps that control the performance in photocatalysis, has been well under‐explored. Herein, we reveal the role of water in heterogeneous photocatalytic processes of methanol conversion on the platinized carbon nitride (Pt/C3N4) model photocatalyst. In situ spectroscopy techniques, isotope effects, and computational calculations demonstrate that water shows adverse effects on the adsorption of methanol molecules and desorption processes of methanol oxidation products on the surface of Pt/C3N4, significantly altering the reaction pathways in photocatalytic methanol conversion process. Guided by these discoveries, a photothermal‐assisted photocatalytic system is designed to achieve a high solar‐to‐hydrogen (STH) conversion efficiency of 2.3 %, which is among the highest values reported. This work highlights the important roles of solvents in controlling the adsorption/desorption behaviours of liquid‐phase heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are attracting increasing interests as photocatalysts for solar-driven hydrogen production from water. This paper reports on a comparative study of using either acetic acid (AA) or trifluoroacetic acid (TFA) as the representative UiO-66 organic modulators for synthesizing visible light responsive UiO-66(Zr)-X (X: NH2 or NO2) photocatalysts for water splitting. The results show that photocatalytic hydrogen generation from a water/methanol mixture can be improved by varying the nature and amount of the modulator employed to prepare the different UiO-66(Zr)-X (X: NH2 or NO2) solid derivatives. UiO-66(Zr)-NH2 was the most active photocatalyst, followed by UiO-66(Zr)-NO2, both prepared with 12 equivalents of AA with respect to the organic ligand. This UiO-66(Zr)-NH2 solid was more active than the parent MOF in photocatalytic overall water splitting (OWS) (H2 and O2 production of 450 and 160 µmol·g−1, respectively, in 5 h; apparent quantum yield (AQY) at 400 nm of 0.06%) in the absence of methanol and compares favourably with analogous reports. Information on the photocatalytic activity of the most active solids of both series was obtained by means of a series of techniques, including ultraviolet–visible (UV–vis) diffuse reflectance, X-ray photoelectron spectroscopy (XPS), laser flash photolysis (LFP), electron spin resonance (ESR), photoluminescence and photoelectrochemical measurements together with density functional theory (DFT) calculations. The results showed that organic acid modulators can be used to enhance the photocatalytic activity of missing linker UiO-66 defective materials in solar-powered water splitting. [ABSTRACT FROM AUTHOR]

Crystal violet (CV), a cationic dye, has been demonstrated to be a powerful carcinogen, a mitotic toxin and poisonous to mammalian cells such that the predominant presence of the dye invariably causes several effects of destruction to mankind and it necessitates a clarion call to do away with this nuisance before it can produce a snowball effect. The recent widespread reporting of the photocatalysis‐mediated degradation of CV as an emerging technique for removing this dangerous dye from aqueous mediums highlights its effectiveness. Numerous researchers have contributed substantially to describing how photocatalysis‐based nanomaterials could be used to degrade CV. The fundamentals and the factors that predominantly influence CV degradation are highlighted in this work. These factors include the nature of nanomaterials, catalyst concentration, dye dosage, pH of the solution in use, temperature and light intensity. Additionally, thorough kinetics and mechanistic descriptions are also included to give crucial insights into the light‐mediated reaction of CV. The present study's findings have the potential to alleviate practitioners and researchers of the burden of having to navigate through numerous studies under each category of parameters to get an exhaustive overview of all of the different variables that may affect the photocatalytic degradation of CV dye. In order to further enhance the photocatalytic degradation efficiency of CV, researchers can expand on this study by investigating novel strategies to lessen the impact of certain elements that adversely affect the photocatalytic reaction process. The potential prospects for extending the advancement of scientific study in this area are also explored. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Prions are proteinaceous pathogens responsible for a variety of devastating diseases in mammals, including scrapie in sheep and goats, chronic wasting disease in cervids, and Creutzfeldt–Jakob disease (CJD) in humans. They are characterized by their exceptional persistence to common inactivation procedures. This applies to all possible sources of prion contamination as prions may be present in the tissues and biological fluids of infected individuals. Hence, efficient prion inactivation procedures are still being sought to minimize the risk of intra- or inter-species transmission. In the past, photocatalytic treatment has been proven to be capable of efficiently oxidizing and inactivating prions. In the present study, the efficacy of homogeneous photo-Fenton-based photocatalysis as well as heterogeneous photocatalysis with TiO2 in reducing RML mouse scrapie infectivity was evaluated. Prion inactivation was assessed by means of a bioassay, and the results were confirmed by in vitro experiments. While the prion infectivity of the RML mouse scrapie was reduced after treatment with the photo-Fenton reagent, the heterogeneous photocatalytic treatment of the same prion strain completely eliminated prion infectivity. [ABSTRACT FROM AUTHOR]

In this contribution, the performance of powdered titanium dioxide (TiO2)–based photocatalysts was evaluated in a pilot photocatalytic plant for the degradation of different dyes, with an investigated volume of 1 L and solar simulated light as irradiation source. Five different samples, synthesized in our laboratories, were tested in the pilot plant, each consisting of TiO2 nanoparticles (NPs) coupled with a different material (persistent luminescent material and semiconductor material) and treated in different thermal conditions. All synthesized samples have been subjected to X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller analysis (BET), and transmission electron microscopy (TEM) characterization, to shed light on the influence of introducing other materials on titania characteristics. To study and evaluate the significance of the parameters affecting the process in the pilot plant, a chemometric approach was applied, by selecting a mathematical model (D-Optimal) to simultaneously monitor a large number of variables (i.e., 7), both qualitative and quantitative, over a wide range of levels. At the same time, the recovery of the synthesized photocatalysts was studied following a novel promising recuperation method, i.e., annulling the surface charge of the suspended samples by reaching the isoelectric point (pHPZC) of each sample, for the quantitative precipitation of TiO2 nanoparticles. [ABSTRACT FROM AUTHOR]

The use of heterogeneous photocatalysis in biologically contaminated water purification processes still requires the development of materials active in visible light, preferably in the form of thin films. Herein, we report nanotube structures made of TiO2/Ag2O/Au0, TiO2/Ag2O/PtOx, TiO2/Cu2O/Au0, and TiO2/Cu2O/PtOx obtained via one-step anodic oxidation of the titanium-based alloys (Ti94Ag5Au1, Ti94Cu5Pt1, Ti94Cu5Au1, and Ti94Ag5Pt1) possessing high visible light activity in the inactivation process of methicillin-susceptible S. aureus and other pathogenic bacteria—E. coli, Clostridium sp., and K. oxytoca. In the samples made from Ti-based alloys, metal/metal oxide nanoparticles were formed, which were located on the surface and inside the walls of the NTs. The obtained results showed that oxygen species produced at the surface of irradiated photocatalysts and the presence of copper and silver species in the photoactive layers both contributed to the inactivation of bacteria. Photocatalytic inactivation of E. coli, S. aureus, and Clostridium sp. was confirmed via TEM imaging of bacterium cell destruction and the detection of CO2 as a result of bacteria cell mineralization for the most active sample. These results suggest that the membrane ruptures as a result of the attack of active oxygen species, and then, both the membrane and the contents are mineralized to CO2. [ABSTRACT FROM AUTHOR]

Biomass-based composites (BCPs) containing TiO2 were successfully synthesized by one-step sol–gel method and applied to methylene blue (MB) removal from water. The calcination temperature and the appropriate TiO2/biomass ratio played an important role on adsorption and photocatalytic capacity of the composites. The effects of variables, such as composites concentration (50–200 mg L−1), initial pH (5–9), and irradiation intensity (10–40 W m−2), were investigated applying response surface methodology for process optimization. The BCP400-50:50 (meaning composite formed by 50%:50% Ti: coconut biomass) exhibited the best removal performance (94%), surpassing the commercial TiO2-P25 (53%). Differently from other studies that focused specifically on photocatalysis performance, the present study investigated the adsorption mechanisms for MB removal by BCP. The adsorption data were well described by the Langmuir isotherm (maximum capacity of 294.12 mg g−1) and pseudo-second-order kinetic models indicating chemisorption as the rate-limiting mechanism of the process. Coconut shell biomass showed great potential for the application in BCP composites. Since BCPs had high MB adsorption capacity, it provides an attractive complementary water treatment option due to the low cost and abundant availability of such agro-industrial waste. [ABSTRACT FROM AUTHOR]

Nanoparticles of TiO2 doped with low amount of Fe were synthesized from natural ilmenite obtained from alluvial gold mine wastes. The obtained TiO2 were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), UV-Vis diffuse reflectance, thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results confirm the formation of mesoporous TiO2 nanoparticles in anatase phase with 0.05 wt.% of iron possibly replacing some titanium places. All the characterizations were performed to the synthesized solid and the reference materials (TiO2 anatase and Degussa P25). The photocatalytic activity of both the synthesized solid and references were evaluated in the photo-oxidation of cyanide in aqueous medium under UV illumination. An experimental design type Box-Behnken was performed choosing three different parameters: the initial concentration of cyanide (50, 150 and 250 ppm) the catalyst load (0.1, 0.5 and 1.0 g L-1) and the oxygen source. The percentage of cyanide conversion was chosen as response in the design obtaining as optimal conditions [CN-]0 = 50 ppm, catalyst load = 0.6 g L-1 and air bubbling. Under these conditions it was reached 32, 32 and 89% of cyanide conversion for Fe-TiO2 synthesized, TiO2 anatase and Degussa P25, respectively.

Covalent organic frameworks (COFs) have garnered significant interest within the scientific community due to their distinctive ability to act as organic semiconductors responsive to visible light. This unique attribute makes them up-and-coming candidates for facilitating photocatalytic organic reactions. Herein, two donor–acceptor COFs, TPE-BSD-COF and TPE-BD-COF, have been designed and synthesized by incorporating electron-rich tetraphenylethylene and electron-deficient benzoselenadiazole and benzothiadiazole units into the framework through a Schiff-base polycondensation reaction. Both COFs exhibit exceptional crystallinity and enduring porosity. TPE-BSD-COF and TPE-BD-COF exhibit broad light absorption capabilities, a narrow optical band gap, and low electrochemical impedance spectrum (EIS) levels, indicating that the two COFs are effective heterogeneous photocatalysts for the reductive dehalogenation of phenacyl bromide derivatives under blue LED irradiation. A high photocatalytic yield of 98% and 95% was achieved by TPE-BSD-COF and TPE-BD-COF catalysts, respectively, within only one hour.

In this work, a comparison was made between the synthesis of niobium-based materials (Nb2O5), both in terms of material characterization and catalytic performance. The methods used were chemical mixtures: modified sol-gel and Pechini. The materials were calcined at different temperatures (753, 873 and 993K) and characterized by the following techniques: photoacousticspectroscopy (PAS), zero charge point (pHPZC), scanning electron microscopy (SEM/EDS), thermogravimetric analysis (TGA/DTG) and X-ray diffraction (XRD). The photocatalytic process was carried out to evaluate the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under UV radiation (250 W mercury vapor lamp) and different experimental conditions. In addition, to better understand the influence of parameters such as pH, catalyst concentration (0.2, 0.5 and 0.8 g L−1) and calcination temperature, a Design of Experiments (DoE) was used. The results indicated that despite having similar structures and phases in the XRD analysis, the morphology presents two distinct surfaces, due to the preparation method. Differences in the synthesis method affected the catalytic activity in the parameters studied. Although the zero charge point values are close (6.18-6.36), we observed differences in the band gap depending on the calcination temperature. In the optimal condition studied, the catalyst prepared by the sol-gel method obtained the best results. [ABSTRACT FROM AUTHOR]

As a spontaneous renewable energy-based technology, with an astonishing ability to destroy recalcitrant organic pollutants under ambient conditions, solar-driven heterogeneous photocatalysis has sparked immense interest over the past decade. However, creating photocatalysts with astounding visible-light harnessing capacity and undemanding recuperation persists as a significant hurdle to the widespread exploitation of photocatalysis in water treatment. Herein, we propose a potentially nontoxic, robust, durable, and self-supporting photocatalyst, based on the in situ growth of few-layer (FL) WS2 nanosheets on the interpenetrating channels of nitrogen (N)-doped graphene aerogel (henceforth denoted as "WNGA"). Constructed through a mild hydrothermal processing scheme, WNGA shows self-floating capability, exceptional mechanical resilience, and remarkable solar absorption in the visible range. In addition, the coexistence of pyridinic N species and FL-WS2 clusters synergistically provides surplus active sites for catalytic reactions. Besides, the interconnected conductive networks of WNGA coherently upregulate charge separation and transfer in 3D. As a result of these beneficial attributes, WNGA presents prominent photocatalytic activity and excellent recycling stability. For instance, through a combination of adsorption and partial oxidation, WNGA can dissociate up to 93% caffeine, the most widely consumed psychoactive substance, into innocuous products over multiple cycles. As a figure-of-merit for the commercial potential of WNGA, we also demonstrate the photocatalytic degradation of caffeine in four different real matrixes, viz., tap water, pond water, municipal wastewater, and hospital wastewater. The exceptional photocatalytic properties, improved durability, and facile retrieval opportunities validate the application potential of WNGA to eliminate psychoactive substances in aqueous environments. [ABSTRACT FROM AUTHOR]

Visible‐light‐induced halide‐exchange between halide perovskite and organohalide solvents has been studied in which photoinduced electron transfer from CsPbBr3 nanocrystals (NCs) to dihalomethane solvent molecules produces halide anions via reductive dissociation, followed by a spontaneous anion‐exchange. Photogenerated holes in this process are less focused. Here, for CsPbBr3 in dibromomethane (DBM), we discover that Br radical (Br⋅) is a key intermediate resulting from the hole oxidation. We successfully trapped Br⋅ with reported methods and found that Br⋅ is continuously generated in DBM under visible light irradiation, hence imperative for catalytic reaction design. Continuous Br⋅ formation within this halide‐exchange process is active for photocatalytic [3+2] cycloaddition for vinylcyclopentane synthesis, a privileged scaffold in medicinal chemistry, with good yield and rationalized diastereoselectivity. The NC photocatalyst is highly recyclable due to Br‐based self‐healing, leading to a particularly economic and neat heterogeneous reaction where the solvent DBM also acts as a co‐catalyst in perovskite photocatalysis. Halide perovskites, notable for efficient solar energy conversion, are demonstrated as exceptional photocatalysts for Br radical‐mediated [3+2] cycloaddition. We envisage such perovskite‐induced Br radical strategy may serve as a powerful chemical tool for developing valuable halogen radical‐involved reactions. [ABSTRACT FROM AUTHOR]

These days, textile industries pose a more significant threat to surface water and groundwater sources directly or indirectly by discharging wastewater containing various dyes and organic pollutants to these water sources. The phase-junction-engineered heterogeneous photocatalysis carried out by visible light-driven semiconductor photocatalysts is opening a new window for the degradation of environmental organic pollutants. In this work, we have reported a one-step bottom-up hydrothermal synthesis of biphasic tungsten oxide (o/h-WO3) and performed a photodegradation experiment under visible light irradiation for the efficient degradation of organic pollutants such as Methylene blue (MB) and Methyl violet (MV), respectively. The X-ray diffraction, RAMAN, transmission electron microscopy and ultraviolet–Vis characterization techniques were used to investigate the structural, morphological and optical properties of the as-synthesized o/h-WO3. Moreover, the low calculated band gap (∼2.8 eV) and the anionic nature of o/h-WO3 suggest it as an efficient visible light-driven photocatalyst suitable for heterogeneous photocatalysis. The photodegradation experiment performed under visible light using o/h-WO3 photocatalyst showed better degradation efficiency of 71% and 89% for MB and MV, respectively, in 100 min. The dyes followed first-order kinetics, and their kinetic rate constants were calculated using the Langmuir–Hinshelwood model. Furthermore, the recyclability study of the photocatalyst was also performed and discussed the underlying mechanism for the photodegradation of the organic dyes. [ABSTRACT FROM AUTHOR]

In agriculture, there is a constant search for increased productivity, which leads to increased use of fungicides, insecticides, and inoculants, among other products to perform seed treatment before planting. After treatment, the machines and equipment are sanitized, generating a liquid residue with potentially negative environmental impacts. This study aimed to characterize and evaluate the toxicity of the effluent generated from washing soybean seed treatment machines and suggest treatment methods for this residue. The applied treatment was a combined process of coagulation followed by heterogeneous photocatalysis and ozonization. The treatments caused a significant decrease in the concentration of sedimentable solids (95.22%), total solids (25.26%), and total dissolved solids (9.14%). The chemical oxygen demand and the active ingredient thiamethoxam were also reduced by 31.55% and 40.98%, respectively. Despite the reduction of the physical and chemical parameters of the effluent, it still presented acute toxicity to the bioindicators Artemia salina L. and Eisenia fetida since these showed mortality in the tests. The results confirm the risk that this effluent presents to the environment and highlights the importance of continuing the search for new treatment technologies to promote the reduction of the physicochemical parameters and the final toxicity. [ABSTRACT FROM AUTHOR]

A broadly used dye, methylene blue (MB), adversely impacts human health and water resources, which triggers efficient methods for its elimination. Semiconductor-based heterogeneous photocatalysis is an environmentally friendly approach that effectively degrades organic pollutants. The purpose of the current work is to elucidate and validate the application of a promising g-C3N4/GO/SnFe2O4 (CGS) composite for the environmental remediation of methylene blue dye. The ternary CGS composite has been synthesized using a solvothermal approach. The fabricated composites were analyzed through FTIR, XRD, SEM/EDX, UV–VIS spectroscopy, TEM, and XPS. The photoactivity of composites and affecting parameters (pH, H2O2 dosage, composite amount, initial dye concentration, and irradiation time) were observed in sunlight illumination. The optimal conditions for photocatalytic degradation were pH = 5, photocatalyst dosage = 30 mg/100 mL, H2O2 dosage = 6 mM, and initial dye concentration (IDC) of 10 ppm employing ternary CGS composite, and MB dye was degraded effectively within 1 h. Ninety-eight percent degradation efficacy was attained by employing ternary CGS composite under the optimized conditions. Scavenging analysis suggested that •OH radicals were the key reactive oxygen species (ROS) responsible for the photodegradation of MB dye. Furthermore, the CGS nanocomposite exhibited outstanding recyclability of 84% after five consecutive runs, demonstrating its potential for use in practical applications, particularly pollutant removal. [ABSTRACT FROM AUTHOR]

Improvement in the photocatalytic selectivity is imperative for the effective and efficient utilization of catalysts. In this study, a molecularly imprinted polymer-coated iron-doped titanium dioxide (Fe-TiO2@MIP) nanocomposite was successfully synthesized by precipitation polymerization while using RB-19 as a template. The synthesized nanocomposites (Fe-TiO2@MIP and Fe-TiO2@NIP) were characterized by Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer–EMMETT–Teller (BET), and UV–visible spectrophotometry. The optimized binding experiments revealed a high imprinting factor of 5.0 for RB-19. The catalytic degradation efficiency and selectivity of Fe-TiO2@MIP enhanced to almost complete degradation of RB-19 from 70% for the parent Fe-TiO2 and 76% for Fe-TiO2@NIP. An outstanding degradation selectivity of RB-19 was achieved compared to other competitive dyes. Finally, the analysis of the non-degraded and degraded RB-19 by ESI–MS revealed the presence of different intermediates that fits well with the proposed degradation mechanism. The study opens new possibilities of selective photo-degradation of targeted contaminants that may ultimately lead to efficient use of photocatalysts. [ABSTRACT FROM AUTHOR]

The possibility of stabilization of zinc(II) 2,3,9,10,16,17,23,24-octa[(3,5-sodium biscarboxylate)phenoxy] phthalocyaninate (ZnPc16) by its hybridization with the surface of graphene oxide (GO) sheets via van der Waals or coordination bonds with functional groups of the carbon matrix in the GO hydrosols has been investigated. A combination of physicochemical analysis methods (scanning electron microscopy, fluorescence microscopy, powder X-ray diffraction, and Raman spectroscopy) has been employed to confirm the integration of ZnPc16 with GO nanosheets and to study the morphology and structure of the obtained hybrid materials. Using electronic absorption spectroscopy, it has been found that, regardless of the hybridization method, the binding of the macrocycles to the inorganic particles increases the stability of ZnPc16 in an aqueous medium being irradiated with visible light. The analysis of spectral kinetic data has shown that, in contrast to the system obtained by direct integration of ZnPc16 and GO, the hybrid material formed by coordination bonding of the components via zinc acetate (Zn(OAc)2) as a binding metal cluster is able to exhibit photocatalytic properties in oxidative photodegradation of some model organic pollutant substrates (rhodamine 6G, 1,5-dihydroxynaphthalene, and 1,4-nitrophenol). The proposed colloid-chemical approach to the stabilization of photoactive water-soluble phthalocyaninates makes it possible to increase their resistance to photoinduced self-oxidation and can be adapted for various derivatives of tetrapyrrole compounds possessing photosensitizing properties. [ABSTRACT FROM AUTHOR]

This study reports the synthesis and characterization of tungsten trioxide‐based catalysts for the photocatalytic degradation of N‐nitrosodiethylamine (NDEA) in wastewater. Tungsten trioxide (WO3) was synthesized using the thermal treatment method (TTM) and hard template replication method (HTRM) and impregnated with lanthanum (La), iron (Fe), chromium (Cr), and silver (Ag) to enhance its light absorption ability. The synthesized catalysts were characterized using various techniques, including UV‐Vis spectroscopy, Brunauer–Emmett–Teller (BET), Barrett–Joyner surface area and porosity, X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). The experimental design approach used a response surface methodology (RSM) with a face‐centered central composite design (FCCCD) technique. Catalyst loading (%), pH of solution, and catalyst concentration (g/L) were chosen as design factors, with the response variable being NDEA degradation efficiency (%). The obtained data were analyzed, and a quadratic model was chosen as the best fit with statistically significant model terms as observed from the analysis of variance (ANOVA). 3D interaction plots were generated to explain the effect of the various interaction terms of the quadratic model. The results showed that the pH of the solution was the major factor affecting NDEA degradation efficiency. The mean degradation efficiency of NDEA was 93.03% for Fe/WO3, 88.90% for Ag/WO3, 86.48% for La/WO3, and 84.03% for Cr/WO3. These findings demonstrate the potential of tungsten trioxide‐based catalysts impregnated with various metals for the effective treatment of NDEA in wastewater through heterogeneous photocatalysis. [ABSTRACT FROM AUTHOR]

The disposal of effluents from food industries into surface waters represents a serious environmental problem, mainly due to the presence of dyes in their composition, which alters the photosynthetic capacity of aquatic plants. In addition, many of the by-products generated by their degradation can be toxic and non-biodegradable. In this research, a photocatalytic reactor constructed from quartz tubes was designed and built to be applied in an advanced oxidation processes (UV/TiO2), for the degradation of indigo carmine blue food dye, in an aqueous solution. A factorial design 2³ was performed, where three variables were studied: the dye concentration (20 and 30 mg/L); the pH of the solution (4 and 10), and the TiO2 dosage (20 and 30 mg/L). The aqueous solution was subjected to constant circulation, inside the quartz tubes in order to carry out the experiments. The results showed that pH is the parameter with the greatest impact on degradation efficiency, which showed that at basic pH (10) a degradation rate of 99.91% was achieved, against 34.95% at acidic pH (4). It was concluded that the photo reactor using solar energy, presented itself as a strategic alternative for the removal of contaminants, including recalcitrant, such as synthetic dyes, which contribute to agro-industrial sustainability. [ABSTRACT FROM AUTHOR]