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• A modified reflux method was conducted to synthesize TiO 2 /MIL-100(Fe) composites. • TiO 2 /MIL-100(Fe) composites provide multifunction, including adsorption, photocatalytic and heterogeneous photo-Fenton reaction for removing organic dyes. • MIL-100(Fe) could be used as a supporter to fix TiO 2 and adsorb dyes due to its high specific surface area. • TiO 2 /MIL-100(Fe) composites could absorb visible light to conduct photocatalytic and heterogeneous photo-Fenton reactions simultaneously. • The kinetics analysis of dark adsorption and light reaction belonged to the pseudo-second-order model. Since TiO 2 photocatalysts were only ultraviolet-light-responsive and homogeneous photo-Fenton had some drawbacks in generating iron sludge, multifunctional TiO 2 /MIL-100(Fe) composites were synthesized to remove organic dyes under simulated solar light irradiation. Commercial TiO 2 and MIL-100(Fe) precursors were mixed in one pot using a modified reflux method in 12 h, 18 h, and 24 h to fabricate TiO 2 /MIL-100(Fe) with different weight ratios of the TiO 2 and Fe(NO 3) 2 precursors, including 0.07, 0.15, and 0.30. MIL-100(Fe) was used to efficiently distribute TiO2 and adsorb dyes due to its high specific surface area. Besides, TiO 2 /MIL-100(Fe) composites could absorb visible light to conduct photocatalytic and heterogeneous photo-Fenton reactions simultaneously. For the TiO 2 /MIL-100(Fe) composites (TF15-18), the individual kinetics analysis of removing organic dyes, including dark adsorption and light reaction, belonged to the pseudo-second-order model with the rate constants of 1.682 and 7.702 g·mg−1·min−1, respectively. The completed dye removal was achieved under 90 min dark adsorption and 180 min light reaction under the best conditions of pH=3.5 and 40 μL H 2 O 2 addition in 150 mL MB solution. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Utilization of density functional theory (DFT) and time-dependent DFT calculations to achieve significant NIR absorption. • Discovery of a significant red-shift in dyes based on isoindigo derivatives with thiophene as the π-spacer. • Identification of fluorene as an effective donating group in dyes, which reduces charge recombination rates. In this study, we employed density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations to optimize near-infrared (NIR) harvesting dyes, gaining deeper insights into their structure–property relationship, particularly for dye-sensitized solar cells (DSSCs). Our focus was on fine-tuning electron-donating and withdrawing groups within D-π-A metal-free organic dyes to enhance NIR absorption and achieve visually transparent DSSCs. Our research revealed a significant redshift in dyes based on isoindigo derivatives, with thiophene (TII) as the π-spacer. Dyes incorporating fluorene as the donor group effectively mitigated charge recombination rates, a key challenge in low-bandgap molecules. Notably, the TII1 dye, combining a fluorene donor with a TII π-spacer, exhibited maximum absorption at 654 nm and transmitted substantial visible light (500–600 nm), making it suitable for use in visually transparent DSSCs. These findings underscore the potential of the TII1 dye in significantly advancing the development of visibly transparent DSSCs. [ABSTRACT FROM AUTHOR]

• 3D hollow ZIF-67 MOF based photocatalyst with excellent photo-catalytic performance was synthesized. • The H-ZIF-67@PDA@TiO 2 sample exhibited strongest photo-current intensity. • The photodegradation kinetic follows the Langmuir-Hinshelwood (L-H) model. • Superoxide free radicals (•O 2 −) and hydroxyl radicals (•OH) were the primary and secondary reactive species during photo-degradation. Photocatalytic technology is considered the most promising green technology for the degradation and removal of organic pollutants. In this paper, an innovative multifunctional photocatalytic material has been successfully prepared. The zeolitic-imidazolate-framework-67 (ZIF-67) was first synthesized by an easy and green approach. Then, a polydopamine (PDA) mid-layer was incorporated on its surface via dopamine self-polymerization, which not only serves as a stable linking agent, but also increases the amount of visible light captured and reduces the recombination of photogenerated electron-hole pairs. After the hydrolysis and hydrothermal process of tetrabutyl orthotitanate, the TiO 2 nanoparticles were uniformly grafted on the surface, and finally, the hollow ZIF-67@PDA@TiO 2 was successfully obtained. The prepared H-ZIF-67@PDA@TiO 2 photocatalyst was characterized by various techniques, and further used for the photo degradation of a variety of dyes in wastewater in the presence of visible light. A degradation rate of almost 100% was achieved for Acid Fuchsin and Congo Red within 40 min, followed by Erythrosine B and Rose Bengal with a 99% degradation rate within 150 min. Moreover, the ZIF-67-based photocatalyst exhibited high stability and recyclability and maintained an excellent photocatalytic performance during continued cycling. Furthermore, the superoxide radical (•O 2 −) and the hydroxyl radical (•OH) were the primary and secondary reactive species during photodegradation. Overall, the excellent performance of this simple photocatalyst was clearly demonstrated, and its numerous advantages, such as low energy consumption, low cost, non-toxicity, and environmental friendliness, showing promising potential for its practical implementation. [Display omitted] [ABSTRACT FROM AUTHOR]

• Uniform and smooth Cu(0)-loaded polymeric fibers were prepared by one-step electrospinning. • Microwave Ar plasma treatments allowed to generate Cu/Cu 2 O nanostructures on fibers. • Various morphologies of Cu/Cu 2 O nanostructures were modulated by plasma treatments. • The plasma treated fibers displayed the highest photocatalytic activity toward methyl orange and 4-NP under visible light. Self-standing photocatalytic materials based on transition-metal decorated electrospun fiber mat have attracted considerable attention for photodegradation of toxic refractory organic pollutants in the environment. In this study, poly(N-vinylpyrrolidone)/copper(II) nitrate fibers (Cu/PVP-F) were prepared by electrospinning of PVP/Cu(NO 3) 2 solution followed by crosslinking using microwave-induced argon plasma (MAP) to produce Cu/Cu 2 O composites on the surface of fibers. The optimization for the electrospinning fibers was conducted such that the optimized electrospun composite fibers exhibited excellent visible light photocatalytic activity, corresponding to the narrowest band gap energy based on photoluminescence analyses. Moreover, the experimental results showed that the electro-spinning Cu/PVP-F fibers treated with MAP revealed the highest rate of photodegradation efficacy toward methyl orange (MO) and 4-nitrophenol (4- NP), that could be employed in the subsequent photocatalysis cycles with good recovery. [ABSTRACT FROM AUTHOR]

Nanocomposite-based ceramic membrane with microbubble is an emerging hybrid technology for treating recalcitrant organics in wastewater. The current work is based on the synergistic effect of photocatalyst, microbubble, and membrane separation for enhanced degradation of Bismarck brown R, which is otherwise very low in the standalone process. In this study, we have fabricated a bench-scale membrane set up of submerged type, modified tubular membrane with the novel Zeolite A@ZnO 1−X nanocomposite, and detailed analytical characteristics are investigated. The thin layer coating (average thickness 24.6 µm) of oxygen-deficient ZA@ZnO 1−X photocatalyst gives a high photocatalytic efficiency under visible light without hampering the rejection rate. Here, we have treated Bismarck brown R contaminated wastewater in our prototype setup with simulated and natural wastewater collected from a local dying factory. The operational parameters such as Bismarck brown R concentration, solution pH, temperature, and flux are varied and analyzed optimized reaction conditions favorable for actual wastewater treatment. The hybrid ZA@ZnO 1−X nanocomposite-based tubular membrane improved the degradation of natural wastewater to 95.4 % decolorization and 94 % COD removal in 90 mins at pH 8.15, solution flux 120 ml/min and temperature 30 °C. The scavenging experiment resolved responsible reactive species for organic dye degradation: holes and HO•. The tentative mechanistic degradation pathway involved homolytic cleavage of the azo bond followed by phenyl radical generation to a small intermediate of hydroxyquinol. This work represents an efficient alternative to conventional membrane technology with lesser membrane fouling tendency and enhanced catalytic efficiency in assistance with microbubbles simultaneously. [Display omitted] [ABSTRACT FROM AUTHOR]

• Bi 2 S 3 /BiOCl 0.5 Br 0.5 heterojunction composites were prepared. • Tested in photocatalytic degradation of organics and reduction of Cr6+. • An optimal amount of Bi 2 S 3 was identified for photocatalytic oxidation. • The photocatalytic reduction activity increases with the Bi 2 S 3 content. • Possible photocatalytic mechanisms were discussed. Bi 2 S 3 /BiOCl 0.5 Br 0.5 heterojunction composites were prepared by hydrothermally treating BiOCl 0.5 Br 0.5 in thioacetamide (TAA) solutions with different concentrations. The compositions, morphologies, and structures of the resulting samples were studied via various characterization methods. The samples were tested in photocatalytic degradation of aqueous antibiotics and organic dyes as well as photocatalytic reduction of aqueous Cr6+. The introduction of an optimal amount of Bi 2 S 3 to BiOCl 0.5 Br 0.5 can expand the light absorption range effectively and lead to more photogenerated carriers. However, the presence of excess Bi 2 S 3 on BiOCl 0.5 Br 0.5 can inhibit the generation of •OH, thus leading to decreased activity in photocatalytic degradation of aqueous antibiotics and organic dyes. In contrast, the activity of the samples in photoreduction of aqueous Cr6+ increases with the increase of Bi 2 S 3 content, because more electrons can be excited under the same irradiation. Possible photocatalytic mechanisms are discussed. [ABSTRACT FROM AUTHOR]

In this work, we synthesized cobalt oxide loaded Rh/Sb:SrTiO 3 -nanocube (NC) photocatalysts for organic dye degradation and bacterial inactivation. Firstly, we synthesized Rh/Sb-doped SrTiO 3 NC nanocomposite and further loaded cobalt oxide (2 wt%) via wet impregnation and followed by hydrogen-reduction treatments. Interestingly, after hydrogen heat treatment cobalt oxide-loaded photocatalysts convert into metallic Co/CoO x -Rh/Sb:SrTiO 3 NCs. The hydrogen-treated Co/CoO x -Rh/Sb:SrTiO 3 NCs (red) photocatalyst shows significantly high degradation efficiencies and good recyclability for Orange II dye (90.1%) and bisphenol A (99.1%) under visible-light irradiation (λ ≥ 420 nm) within 30 min. Additionally, the bacterial inactivation efficiency of Co/CoO x -Rh/Sb:SrTiO 3 NCs (red) photocatalyst reaches about ∼97% for both Staphylococcus aureus and Escherichia coli under visible light. The enhanced photocatalytic dye degradation and bacterial inactivation activity of Co/CoO x -Rh/Sb:SrTiO 3 NCs (red) photocatalyst was due to the delayed photogenerated charge-recombination process, generation of oxygen vacancies, and the synergistic effect of a metallic Co/CoO x phase. Further, radical trapping experiments confirmed that the degradation of Orange II was governed by the major species, •O− 2 and h+. In last, the possible charge-transfer mechanisms of the photocatalytic degradation of organic pollutants, as well as the inactivation of bacteria over the Co-Rh/Sb: SrTiO 3 (red) NC photocatalyst, are presented in detail. [Display omitted] • Co/CoO x -Rh/Sb:SrTiO 3 -NC photocatalysts were synthesized via wet impregnation method and hydrogen-reduction treatments. • Hydrogen annealing create oxygen vacancies in Co/CoO x -Rh/Sb:SrTiO 3 -NC photocatalysts. • Optimum Co/CoO x -Rh/Sb:SrTiO 3 -NC photocatalysts show 90.1% Orange II dye and 99.1% BPA degradation under visible light. • Charge transfer mechanisms during organic dye degradation and bacterial inactivation are well proposed. [ABSTRACT FROM AUTHOR]

A metal-organic frameworks (MOFs) matrix of MIL-100(Fe) loading N-doped TiO 2 (N-TiO 2 ) nanoparticles as a novel photocatalyst was successfully synthesized by a facile two-step strategy including preparation of neutral N-TiO 2 sol and caging N-TiO 2 nanoparticles. The as-synthesized samples were characterized by a series of techniques including XRD, ICP, BET, UV–vis, XPS and TEM. Photocatalytic activity of the samples was assessed based on degradation of methylene blue or rhodamine B dye in model wastewater under visible-light irradiation. The as-synthesized samples essentially maintain the typical MOFs structure and porous property of MIL-100(Fe), which exhibits well confinement effect on TiO 2 nanoparticles. A significant finding is that the quantum dots-like N-TiO 2 nanoparticles (<2 nm) with an appropriate mass percentage of 32% highly disperse in cages of MIL-100(Fe) with 1.9 nm of pore size and obtain narrowed band gap. But agglomeration of N-TiO 2 nanoparticles occurs as TiO 2 content increases to 50%. Meanwhile, nitrogen atoms are successfully incorporated into the TiO 2 lattice. The optimal catalyst obtains 99.1% and 93.5% of final removal rate, respectively for methylene blue and rhodamine B, presenting the enhanced photocatalytic performance by comparison with the pure MIL-100(Fe). The composite exhibits more excellent sedimentation efficiency and reusability than pure N-TiO 2 . A possible mechanism of the photocatalysis process is presented in detail. [ABSTRACT FROM AUTHOR]

The effective separation of oil-water emulsion and the degradation of organic dyes are significant for solving the problem of environmental pollution. In this view, porphrin-cored with siloxane-poly(amido amine) dendrimer(PP-Si-PAMAM) blending PVDF composite membrane (PP-Si-PAMAM/PVDF) was successfully prepared by using simple non-solvent-induced phase inversion method. After introducing PP-Si-PAMAM into PVDF membrane matrix, the porosity, hydrophilicity and mechanical properties of the composite membrane were significantly improved. The resultant membrane exhibits admirable separation performance (above 99.1%) and high permeation flux (830–1471 L∙m−2∙h−1∙bar−1) for a series of oil-water emulsions. After 10 cycles of separation, the separation efficiency of the PP-Si-PAMAM/PVDF membrane is still more than 99%, and it still maintains excellent separation efficiency and permeability after extreme chemical environment treatment. Moreover, PP-Si-PAMAM/PVDF membrane has excellent degradation effect on organic dyes RhB and MB under visible light, and the degradation efficiency reaches 88% and 90% respectively in a short time. This work has huge potential applications in wastewater treatment with its combined advantages of oil-water emulsion separation and catalytic degradation of organic dye contaminants. In this work, we innovatively doped porphrin-cored with siloxane-poly(amido amine) dendrimer (PP-Si-PAMAM) into the PVDF matrix to prepared PP-Si-PAMAM/PVDF membrane by a facile non-solvent-induced phase conversion method for oil-water separation and catalyze the degradation of water-soluble dyes. The resultant membrane exhibits admirable oil/water separation performance and dye catalytic degradation performance. [Display omitted] • A novel PVDF membrane was fabricated via incorporating PP-Si-PAMAM. • The PP-Si-PAMAM/PVDF composite membrane has dual functions of catalytic degradation and separation. • The PP-Si-PAMAM/PVDF composite membrane has excellent permeability and recovery performance. [ABSTRACT FROM AUTHOR]

Removal of organic dye-based impurities from water has been achieved traditionally by the use of photocatalysts. ZnO is a commonly used photocatalyst that works when irradiated by UV irradiation. Since the UV fraction in a solar spectrum is very small, there is a scope of utilizing the near-infrared and visible spectrum for the process of dye degradation. We synthesized a novel tri-dopant upconversion nanoparticle (NaYF 4 :Yb,Tm,Nd) system using a simplified microwave-assisted technique and combined it with ZnO particles for methylene blue dye degradation studies. We examined the role of neodymium (Nd3+) dopant on the efficiency of dye degradation when illuminated under an inexpensive tungsten halogen lamp source. X-ray diffraction studies revealed that the presence of Nd3+ in the crystal lattice leads to a reduction in the particle size due to shrinkage in the crystallite size. The presence of Nd3+ in upconversion nanoparticles revealed several characteristic absorption bands from 520 nm to 870 nm along with the characteristic 980 nm corresponding to (ytterbium) Yb3+. The power-dependent study at 980 nm confirmed the multi-photon process of upconversion. The degradation efficiency revealed up to 92% degradation for 5 mg L−1 of dye. The degradation efficiency of upconversion nanoparticles and ZnO system in the presence of Nd3+ was 72% and in the absence of Nd3+ was 58%, for a dye concentration of 10 mg L−1. The dye degradation rate constant was higher for NaYF 4 :Yb,Tm,Nd and ZnO system (0.0041 min−1) compared to NaYF 4 :Yb,Tm, and ZnO set (0.0029 min−1). Thus, the presence of Nd3+ widens the absorption spectra of UCNP in both the visible and near-infrared (NIR) range. [Display omitted] • Successful synthesis of Nd, Yb, Tm doped NaYF 4 upconversion nanoparticles • Successful dye degradation utilising the visible and NIR spectrum and triggering the photocatalysis process of ZnO • Presence of Nd dopant increases the dye degradation • Efficient dye removal of upto (72%) under illumination in simple halogen lamp [ABSTRACT FROM AUTHOR]

Ag/Mn 3 O 4 composites were synthesized with various concentrations of graphene using a sol–gel method followed by hydrothermal synthesis. The as-synthesized Ag/Mn 3 O 4 /graphene composites were characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (DRS), Raman spectroscopy, and nitrogen adsorption/desorption isotherm measurements. The photocatalytic performance of the Ag/Mn 3 O 4 /graphene composites was tested in organic dye pollutants in pure water as well as in complex mixtures of organic compounds. Therefore, the degradation of organic dyes was also evaluated in the presence of organic acid as common substances in natural water. The characterization results revealed that the Mn 3 O 4 nanoparticles exhibited an excellent stability and crystalline structure and were successfully connected with Ag nanoparticles and graphene. In the presence of organic acid, the degradation of organic dye increases in comparison with the dye degradation in the absence of organic acid. The strength of the synergic effect between photocatalysis and the presence of organic acids was not significantly related to the structure of the organic acid. The effectiveness in increasing the photocatalytic degradation of the organic dyes was as follows: ascorbic acid > oxalic acid > citric acid > formic acid > ethylenediaminetetraacetic acid > acetic acid > no acid > EDTA + ascorbic acid. The leached Mn and Ag species were found to be indirectly proportional to the photocatalytic performance trend. The highest concentrations of leached species were observed when ascorbic acid was present in the solution. [ABSTRACT FROM AUTHOR]

• A thin-layer boron-doped g-C 3 N 4 nanosheet with high and stable photocatalytic activity was prepared. • It can be used as photocatalyst for fast degrading various organic dyes under visible light irradiation. • The possible mechanism and route of various dyes degradation were also investigated. We herein prepared the boron-doped graphitic carbon nitride (B-g-C 3 N 4) nano-sheets with 1–5 monolayers and 50−200 nm size via heating the mixture of melamine and boron oxide. We demonstrated that the prepared thin-layer B-g-C 3 N 4 nano-sheets have a high and stable photo-catalytic activity for degrading various organic dyes with a high speed and efficiency under visible light irradiation. In the presence of 2 mg/mL of B-g-C 3 N 4 nano-sheets, Eosin Y (EY, heterocyclic dye), Rhodamine B (RhB, triarylmethane dye), Methylene blue (MB, thiazide dyes) and Methyl orange (MO, Azo dyes) can be completely degraded within 5, 10, 20 and 60 min respectively under visible light irradiation follow the first-order kinetics. The possible route and intermediate products of various dyes during photo-degradation over B-g-C 3 N 4 nano-sheets were also investigated. In comparison with other g-C 3 N 4 or g-C 3 N 4 -based materials, the prepared thin-layer B-g-C 3 N 4 nano-sheets have much higher photo-catalytic activity and can be used for visible light-driven degrading various organic dyes. The success of this study provides a promising method for economical, rapid and environmental-friendly treatment of dye-contaminated water. [ABSTRACT FROM AUTHOR]