photo-Fenton Degradation Research Articles

Synergistic adsorption&photo-Fenton degradation of meloxicam and tetracycline by hollow nanoflower-like S-scheme FeWO4/ZnIn2S4 heterojunction: Mechanism, toxicity assessment, and potential applications

The rational construction of materials with dual rapid adsorption&photo-Fenton oxidative degradation functions holds great significance in the field of removing difficult-to-degrade organics. A late-model S-scheme heterojunction photocatalyst FeWO4/ZnIn2S4 was prepared by solvothermal method in this paper. The FeWO4 nanoparticles were distributed on the surface of the hollow nanoflowers assembled by ZnIn2S4, forming heterojunction structures. Representative drug residues, tetracycline (TC) and meloxicam (MLX), were selected as targets to systematically explore the removal properties of FeWO4/ZnIn2S4. This photocatalyst exhibited suitable adsorption ability, excellent photocatalytic performance, and good photo-Fenton ability for both targets. The removal efficiency of tetracycline and meloxicam by 20-FW/ZIS reached 92.9 % and 98.7 %, respectively, through a combination of adsorption&photo-Fenton degradation, with these remarkable properties being maintained after four consecutive cycles. Based on the detection of active species and the analysis of degradation intermediates, an adsorption&photo-Fenton removal mechanism and possible degradation pathway were proposed. Escherichia coli (E. coli) inhibition experiments, combined with Toxicity Estimation Software Tool (T.E.S.T.) simulated toxicity analysis, showed that the toxicity of TC and MLX decreased significantly following the photocatalytic reaction. In brief, the newly developed multifunctional photocatalyst 20-FW/ZIS, as prepared in this paper, demonstrates great potential for effectively treating organic matter in wastewater, with promising applications for practical use.

Porous fluorine-cerium nanosheets anchored with FeOOH quantum dots for synergistic enhanced visible-light-driven photo-Fenton degradation of phenol

The utilization of two-dimensional (2D) materials to construct heterogeneous catalysts provides opportunities for environmental remediation, while the incorporation of porous structures can further enhance catalytic performance. In this work, a porous 2D FeOOH/fluorine-cerium (F-Ce) nanosheet composite was designed and synthesized by a simple impregnation-precipitation method. The unique 2D porous structure of F-Ce promoted the high dispersion of FeOOH quantum dots (QDs) (∼1.4 nm) and their tight integration to form S-scheme heterojunctions. This structure offered a greater number of active sites, and significantly improved the capacity of light absorption and the separation and migration efficiency of photogenerated carriers, thus improving catalytic activity. This catalyst achieved a phenol removal rate of 98.1 % within 20 min during the photo-Fenton reaction, which significantly surpasses pure FeOOH (32.9 %) and F-Ce (21.7 %) alone. In particular, the optimized 14FeOOH/F-Ce catalyst achieved more than 95.0 % degradation efficiency within a remarkably short period of 5 min. Mott Schottky and in situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) studies demonstrated that the S-scheme charge transfer mechanism of this heterojunction synergistically enhanced the catalytic activity of the Fenton-like reaction. This study provides valuable insights for designing efficient 2D porous heterojunction catalysts for visible-light-driven Fenton applications.

Construction of a novel Z-scheme FeTiO3/MOF-derived In2S3 catalyst for visible-light-driven photo-Fenton degradation of pollutants

The rapid recombination rate of photoexcited carriers for iron titanate (FeTiO3) is still limited the process performance of photo-Fenton. This article reports the successful synthesis of the highly efficient Z-scheme FeTiO3/MOF-derived In2S3 photocatalyst using the hydrothermal method, compensating for the susceptibility of FeTiO3 photo-generated carriers to complexation to a certain extent. A series of characterization have been carried out to explore the structure, morphology and composition of FeTiO3/MOF-derived In2S3 heterostructure. The 0.5 FeTiO3/MOF-derived In2S3 exhibits the excellent photo-Fenton performance for TCH, Cr6+ and OTC, the degradation rate constants (k2) are up to 0.6297 L·mg−1·min−1, 1.332 L·mg−1·min−1, and 0.427 L·mg−1·min−1, respectively. Active species capture experiments and electron paramagnetic resonance (EPR) spectra show that photo-generated holes (h+) and superoxide radicals (·O2-) are present in the photo-Fenton system. The superior photo-Fenton performance is mainly manifested in the following: the MOF-derived In2S3 micro-floral carrier extends the reaction interface of 0.5 FM-I; FeTiO3 effectively enhances the photo-absorption ability of 0.5 FM-I in visible range; the construction of Z-scheme FeTiO3/MOF-derived In2S3, forming the new carriers transport channels and enhancing the generation of ·O2- and ·OH. This experimental exploration provided a reasonable experimental basis for the preparation of efficient photocatalysts.

Rapid room temperature synthesis of CuBi2O4 via ball-milling strategy boost light-driven persistent activation of hydrogen peroxide

Photo-Fenton technology with the superiorities of photocatalysis and traditional Fenton catalysis can improve the catalytic efficiency of photocatalytic materials and thus achieve efficient degradation for organic pollutants. However, exploring a low-cost catalyst with excellent catalytic performance using a simple method remains a challenge. In this work, CuBi2O4 photocatalyst synthesized by a mechanical ball-milling strategy (M-CuBi2O4) was exploited and used for tetracycline (TC) degradation. The impact of solution pH and H2O2 dosage on the photo-Fenton degradation efficiency of M-CuBi2O4 towards TC was investigated. M-CuBi2O4 exhibited significant 85.1% of photo-Fenton catalytic activity for TC removal, which was 9.35 times higher than that of CuBi2O4 synthesized by hydrothermal method (H-CuBi2O4). The enhanced catalytic performance of M-CuBi2O4 was due to the superior charge carrier separation efficiency, wider photo-response range and increased generation of active species. The primary active substances involved in the photo-Fenton reaction for TC degradation were determined to be hydroxyl radicals (•OH), superoxide radicals (•O2-), and singlet oxygen (1O2). This study provides a streamlined and rapid approach for macro preparation of high-performance photocatalysts for dealing with antibiotic-contaminated wastewater.

Strong evidence for interface-field-induced photocarrier separation in new AgFeO2-BiVO4 heterostructures and their efficient photo-Fenton degradation of ciprofoxacin

Deep elucidation of photocarrier transfer and separation mechanism is scientifically significant for developing new photocatalysts in pollutant elimination. In this study, we have immobilized AgFeO2 (AFO) nanoparticles on the surface of BiVO4 (BVO) nanobricks to construct new BVO-AFO heterostructured photocatalysts. Multiple advanced characterization techniques combined with theoretical calculations corroborate substantial evidence for the formation of built-in electric field at the BVO-AFO heterojunction interface and efficient photocarrier transfer/separation behavior and mechanism. Simulated-sunlight-driven photodegradation of ciprofoxacin (CIP) demonstrates an important enhanced photocatalysis of the heterostructure photocatalysts; particularly, the BVO-15 %AFO exhibits a photodegradation performance with η(30 min) = 89.9 % and kapp = 0.06659 min−1, which is enhanced by 4.2 (or 3.4) times over that of bare BVO (or AFO). The heterostructure-enhanced photocatalysis is benefited from the interface-field-facilitated transfer and separation of photocarriers, thus extending their lifetime and making them more probable to participate in the photocatalytic reactions. Furthermore, the BVO-AFO heterostructured photocatalysts demonstrate an important activation of peroxymonosulfate (PMS) or H2O2 to generate additional •OH and •SO4− reactive species, thus further promoting the CIP degradation. This work provides an important scientific basis for designing excellent heterostructured photocatalysts.

Integrated fiber paper-based composites enabling photo-Fenton synergistic degradation and switchable adsorption for efficient and multitasking pollutants removal

Single catalytic systems have received wide attention for eradicating pervasive contaminants in water but lack multifunctional integrated biobased capturing and purifying system (bio-CPs). In this work, a universal design of integrated bio-CPs with layered structure driven from fiber filtering paper (FP) was demonstrated for multitasking environmental remediation. Fe-rich composite catalysts (Fe-BiOBr/TiO2) and polyphenol-modified lignin system (PLPR) were herein first developed for the full decoration of FP substrates, achieving the facile construction of layered structure with highly active surface and photocatalytic layer. Profiting from this, a photo-Fenton synergetic degradation system on composites was designed, facilitating a remarkable degradation capability (99.24 % for MEB) and full-time operation ability. Driven by highly enhanced interfacial interactions mediated by polyphenol, this material was capable of efficient capture pollutants (165.29 mg·g-1 for Cr (VI)). And assisted with well-maintained high water flux feature, this bio-CPs that efficient remove pollutants by flowthrough capture were realized, showing the switchable application. Significantly, the convenience of surface deposition and self-assembly supported the potential applications in real system based on extended preparation of such bio-CPs. This work provided a novel and universal strategy to develop the universal and multifunctional integrated bio-CPs to support for large-scale, cost-effective, and sustainable wastewater remediation engineering.

Boosted visible-light-induced photo-Fenton degradation of organic pollutants over a novel direct Z-scheme NH2-MIL-125(Ti)@FeOCl heterojunction catalyst

Improving the charge separation, charge transfer, and effective utilization is crucial in a photocatalysis system. Herein, we prepared a novel direct Z-scheme NH2-MIL-125(Ti)@FeOCl (Ti-MOF@FeOCl) composite photocatalyst through a simple method. The prepared composite catalyst was utilized in the photo-Fenton degradation of Rhodamine B (RhB) and ciprofloxacin (CIP). The Ti-MOF@FeOCl (10FeTi-MOF) catalyst exhibited the highest catalytic performance and degraded 99.1 and 66% of RhB and CIP, respectively. However, the pure NH2-MIL-125(Ti) (Ti-MOF) and FeOCl catalysts achieved only 50 and 92% of RhB and 50 and 37% of CIP, respectively. The higher catalytic activities of the Ti-MOF@FeOCl composite catalyst could be due to the electronic structure improvements, photoinduced charge separations, and charge transfer abilities in the catalyst system. The composite catalysts have also enhanced adsorption and visible light-responsive properties, allowing for efficient degradation. Furthermore, the electron paramagnetic resonance (EPR) signals, the reactive species trapping experiments, and Mott-Schottky (M − S) measurements revealed that the photogenerated superoxide radical (•O2−), hydroxyl radical (•OH), and holes (h+) played a vital role in the degradation process. The results also demonstrated that the Ti-MOF@FeOCl heterojunction composite catalysts could be a promising photo-Fenton catalyst system for the environmental remediation.Environmental implicationsThe discharging of toxic contaminants such as organic dyes, antibiotics, and other emerging pollutants to the environment deteriorates the ecosystem. Specifically, the residues of organic pollutants recognized as a threat to ecosystem and a cause for carcinogenic effects. Among them, ciprofloxacin is one of antibiotics which has biological resistance, and metabolize partially in the human or animal bodies. It is also difficult to degrade ciprofloxacin completely with traditional treatment methods. Similarly, organic dyes are also toxic and a cause for carcinogenic effects. Therefore, effective degradation of organic pollutants such as RhB and ciprofloxacin with appropriate method is crucial.

Oxygen Vacancy Engineering and Constructing Built-In Electric Field in Fe-g-C3N4/Bi2MoO6 Z-Scheme Heterojunction for Boosting Photo-Fenton Catalytic Degradation Performance of Tetracycline.

A novel Fe-g-C3N4/Bi2MoO6 (FCNB) Z-scheme heterojunction enriched with oxygen vacancy is constructed and employed for the photo-Fenton degradation of tetracycline (TC). The 2% FCNB demonstrates prominent catalytic performance and mineralization efficiency for TC wastewater, showing activity of 8.20 times greater than that of pure photocatalytic technology. Density-functional theory (DFT) calculations and degradation experiments confirm that the formation of Fe-N4 sites induces spin-polarization in the material, and the difference in Fermi energy levels results in the formation of built-in electric field at the contact interface, which facilitates the continuous generation and migration of photogenerated carriers to address the issue of insufficient cycling power of Fe (III)/Fe (II).The reactive radicals persistently target the extremely reactive sites anticipated by the Fukui function, causing the mineralization of TC molecules into "non-toxic" compounds through processes of hydroxylation, demethylation, and deamidation. This work holds significant importance in the domain of eliminating organic pollutants from water.

Intercalation of novel Ocimum Sanctum leaves derived carbon dots between g-C3N4/CoFe2O4 Z-scheme heterojunction system for boosting the radicals’ generation in photo-Fenton degradation and synchronized electrochemical sensing of sulfamethoxazole antibiotic

Deeming about incessant consumption and disposal of pharmaceutical antibiotics in natural water bodies, this study demonstrates the synthesis of a novel Tulsi leaves (Ocimum Sanctum) derived carbon dots modified Z-scheme g-C3N4/CoFe2O4 heterojunction system. Characterization techniques namely XRD, FT-IR, XPS, FE-SEM, HR-TEM and EDX supported composite formation. Fabricated catalysts presented excellent photocatalytic performance towards removal of sulfamethoxazole (SMX). UV–vis DRS, PL and EIS findings suggested the augmented visible light absorption capability, suppression of electron-hole pairs recombination and effective separation of charge carriers which were accountable for degradation process. Probable mechanistic pathway for SMX removal was photo-Fenton assisted with Z-scheme separated electron-hole pairs via activation of H2O2, where hydroxyl radicals (•OH) were main reactive species. Additionally, the prepared material was employed as electrochemical sensor for individual as well as simultaneous detection of SMX and trimethoprim with quite impressive detection limits of 0.042 µM and 0.047 µM, respectively.

Effect of solvothermal reaction time on adsorption and photocatalytic activity of spinel ZnFe2O4 nanoparticles

The present investigation explored the impact of solvothermal reaction time on the adsorption properties of synthesized spinel ZnFe2O4 Nanoparticles (ZF NPs) and their photocatalytic activity for the degradation of congo red (CR) dye. The structure, morphology and chemical composition is identified for the synthesized ZF NPs. The reaction times for the solvothermal synthesis of ZF NPs were investigated at time intervals of 6 hrs and 18 hrs which are denoted as ZF-6 h and ZF-18 h respectively. The XRD confirms the formation of spinel-type ZF-6 h and ZF-18 h with crystallite size of 5.50 nm and 8.36 nm for ZF-6 h and ZF-18 h respectively. The FESEM image of ZF-6 h exhibits microspheres, whereas in ZF-18 h NPs, the microspheres undergoes deformation. TEM analysis of ZF-6 h revealed that the microspheres were consists of 8–10 nm size ZF-NPs. Raman spectroscopy and XPS studies indicates, the reaction time influence the occupancy with 64 % and 32 % of inversion of Zn2+ cations from tetrahedral to octahedral sites in ZF-6 h and ZF-18 h, respectively. The surface area of mesoporous ZF-6 h and ZF-18 h are 138.29 m2/g and 128.41 m2/g respectively as confirmed using BET and BJH techniques. The CR dye adsorption capacity of 123.73 mg/g for ZF-6 h is higher compared to ZF-18 h (99.93 mg/g). The maximum dye removal efficiency evaluated for ZF-6 h NPs and ZF-18 h NPs was 87.33 % and 73.09 % respectively upon exposure of natural sunlight. The recyclability study identifies that ZF-6 h NPs remain stable for three degradation cycles. These results indicate that reaction time in solvothermal synthesis is sensitive to the morphology and physicochemical properties of ZF NPs. The enhanced performance of such ZF NPs is attributed to the synergistic effect of adsorption followed by photocatalytic (photo-Fenton) degradation of dyes.

Heterogeneous Photo-Fenton Degradation of Azo Dyes over a Magnetite-Based Catalyst: Kinetic and Thermodynamic Studies

Textile wastewater containing dyes poses significant environmental hazards. Advanced oxidative processes, especially the heterogeneous photo-Fenton process, are effective in degrading a wide range of contaminants due to high conversion rates and ease of catalyst recovery. This study evaluates the heterogeneous photodegradation of the azo dyes Acid Red 18 (AR18), Acid Red 66 (AR66), and Orange 2 (OR2) using magnetite as a catalyst. The magnetic catalyst was synthesized via a hydrothermal process at 150 °C. Experiments were conducted at room temperature, investigating the effect of catalyst dosage, pH, and initial concentrations of H2O2 and AR18 dye. Kinetic and thermodynamic studies were performed at 25, 40, and 60 °C for the three azo dyes (AR18, AR66, and OR2) and the effect of the dye structures on the degradation efficiency was investigated. At 25 °C for 0.33 mmolL−1 of dye at pH 3.0, using 1.4 gL−1 of the catalyst and 60 mgL−1 of H2O2 under UV radiation of 16.7 mWcm−2, the catalyst showed 62.3% degradation for AR18, 79.6% for AR66, and 83.8% for OR2 in 180 min of reaction. The oxidation of azo dyes under these conditions is spontaneous and endothermic. The pseudo-first-order kinetic constants indicated a strong temperature dependence with an order of reactivity of the type OR2 > AR66 > AR18, which is associated with the molecular size, steric hindrance, aromatic conjugation, electrostatic repulsion, and nature of the acid–base interactions on the catalytic surface.

Sustainable Water Treatment: Harnessing Mining Waste as Catalysts for Sicomet Green Degradation

This paper presents a novel circular economy approach to water remediation that focuses on creating sustainable systems by utilizing mining waste from El-Ouenza, Tebessa, in the east of Algeria. Waste materials are employed as catalysts in Fenton and photo-Fenton processes. Two cases were studied: the conventional and the modified heterogeneous photo-Fenton at a pH of 3 and under modified pH conditions for degrading Sicomet Green food dye ZS120. Catalysts were characterized through various analyses. Catalyst performance and dye degradation were examined for raw and calcined waste at 500°C. Parameters like catalyst amount, sodium sulfite concentration, oxalic acid, and pH were optimized for both systems, with and without ligand. The first system achieved 91.5% mineralization using 0.15 g L-1 catalyst, pH of 3, and 0.45 mM Na2SO3 in 90 minutes under sunlight. The second reached 78.5% efficiency with variable conditions. Kinetic models demonstrated a first-order model for both photo-Fenton degradation and mineralization under sunlight. These findings guide eco-friendly dye degradation via mining waste-based catalysts in photo-Fenton systems, supporting sustainable wastewater treatment.

Fe(III)-incorporated UiO-66(Zr)–NH2 frameworks: Microwave-assisted scalable production and their enhanced photo-Fenton degradation catalytic activities

In this work, the photocatalytic feasibility of UiO-66(Zr)–NH2 was tuned by combining a scalable producing approach and incorporating Fe3+. Different contents of Fe3+ were effectively incorporated into the UiO-66(Zr)–NH2 frameworks utilizing a microwave-assisted continuous flow tubular reactor within 10 min. It was observed that with increasing the Fe3+ content from 0.5 to 1.0, 2.0 and 3.0 M %, the production rate diminished from ∼ 1.72 to 1.65, 1.55, and 1.46 g/h, respectively. The hybrid Fe@UiO-66-NH2 (Fe@UON) showed enhanced light absorption and charge carrier separation efficiency owing to the newly formed heterostructures, Zr-O-Fe linkages, and –H2N:→ Fe3+ chelating. The optimal Fe@UON catalyst achieved the highest photo-Fenton degradation efficiency of ∼ 96 % towards tetracycline (TC) under energy-saving visible LED light (VLEL) conditions. The photodegradation was predominantly governed by the photo-induced species of ·O2–, h+, and •OH and facilitated by the Fe3+/Fe2+ cycles. At the same time, LC/MS analyses detailedly revealed the reaction pathways for the degradation. After several consecutive tests, the constructed hybrid Fe@UiO-66-NH2 catalysts maintained good catalytic durability, and there was an insignificant Fe leak to the environment. The findings showed that hybrid Fe3+@UiO-66(Zr)–NH2 derived from energy-effective, environmental and scalable methods could be a good material for treating antibiotic-polluted effluents.

Fe-MOFs nanosheets for photo-Fenton degradation of carbamazepine

Iron(II)-based metal organic framework (Fe(II)-MOF) nanosheets have emerged as promising candidates for photo-Fenton catalysis. However, efficiently synthesizing Fe(II)-MOF nanosheets remains a significant challenge. Here, a bottom-up synthesis strategy is proposed to prepare two-dimensional Fe-MOF nanosheets (TFMN) with micrometer lateral dimensions and nanometer thickness, featuring Fe(II) as the metal nodes. The application of TFMN in the photo-Fenton degradation of carbamazepine (CBZ) demonstrates remarkable CBZ degradation performance and excellent efficiency across a wide range of pH values. The electron density and density of states are further calculated by density functional theory. Mechanism analysis identifies h+, •OH and •O2− as the predominant active species contributing to the catalytic oxidation process in the Vis/TFMN/H2O2 system.

BioTemplated Fe3+-Doped g-C3N4 Heterojunction Micromotors for the Degradation of Tetracycline through the Photo-Fenton Reaction

The excessive discharge of antibiotics into aquatic systems is a major issue in many countries worldwide and poses a threat to human health and the sustainable development of society. Hence, developing efficient treatment methods and purification technologies to degrade antibiotics is essential. Herein, we present the synthesis of low-cost, self-propelled tubular Fe3+-incorporated graphitic carbon nitride (g-C3N4-Fe@KF) micromotors using kapok fibers (KFs) as templates and their application as photo-catalysts for the photo-Fenton degradation of tetracycline (TC) under visible-light irradiation. The g-C3N4-Fe@KF micromotors moved rapidly when being propelled by oxygen bubbles generated in a hydrogen peroxide (H2O2) solution as a result of a photo-assisted Fenton reaction. The motion behavior of the g-C3N4-Fe@KF micromotors was dependent on the concentration of H2O2 and the length of the micromotors. The propulsion mechanism was discussed in detail. The micromotors efficiently degraded antibiotics via the photo-Fenton process. Photo-Fenton degradation efficiency was attributed to the synergistic effects of the doped Fe3+ and g-C3N4 under visible-light irradiation and self-propulsion of the micromotors. In addition, the micromotors possessed good reusability, thereby efficiently realizing multiple cycles of degradation. The current work offers an avenue for the design of micromotors, using inexpensive approaches, for various potential environmental applications.

Experimental and theoretical study of the photo-Fenton and photoelectrochemical properties of Ni doped FeOCl

In this work, Ni doped FeOCl (Ni-FeOCl) was synthesized by simple calcination method and used as a non-homogeneous phase catalyst for the photo-Fenton degradation of tetracycline (TC). Photo-Fenton experiments showed that the degradation of TC by Ni-FeOCl-10 was 93.3 % in 60 min under neutral solution, room temperature and visible light conditions. The incorporation of Ni led to lattice defects on the surface of FeOCl, which was favorable for the separation efficiency of the photogenerated electron-hole pairs (in agreement with the density-functional theory calculations). In addition, the TC removal efficiency decreased from 93 % to 82 % in five consecutive cycles, showing good structural stability. Finally, a possible mechanism for the degradation of TC by Ni-FeOCl catalysts was proposed on the basis of free radical trapping experiments. This research contributes fresh perspectives to the development of photo-Fenton catalysts and the treatment of antibiotic organic wastewater.

Construction of Bi2S3/FeWO4 Z-Scheme heterojunction for efficient photo-Fenton degradation of antibiotics: Performance and degradation mechanism

Herein, the Bi2S3/FeWO4 (BS/FWO) nanocomposite with excellent photo-Fenton activity was successfully prepared by dispersing FeWO4 nanoparticles onto the Bi2S3 nanorods using the hydrothermal method. Upon optimizing the ratio of Bi2S3 to FeWO4 in the BS/FWO photocatalyst, the degradation rate constants for tetracycline hydrochloride (TCH) and oxytetracycline (OTC) reach as high as 1.597 and 1.289 L·mg−1·min−1, respectively. These values were 5.4 and 6.1 times higher than those of pure FeWO4. The enhanced degradation performance of the BS/FWO composite could be attributed to the formed Z-scheme heterojunction, which facilitated the directional carrier transfer and inhibited the electron-hole recombination, thereby increasing the production of more reactive species. Active species capture experiments and electron paramagnetic resonance (EPR) analysis indicated that the BS/FWO heterojunction could generate superoxide radicals (·O2-) and hydroxyl radicals (·OH), which play a crucial role in the degradation of organics. Furthermore, the BS/FWO composite exhibited excellent stability across multiple reuse cycles. These findings propose a novel approach for wastewater treatment.

Photo-Fenton-Active MIL-88A/CNT-Based PVA Hydrogel for Solar-Driven Water Evaporation and Simultaneous Volatile Organic Compound Removal.

Solar-driven interfacial water evaporation (SIWE) has emerged as a promising avenue for cost-effective freshwater production from seawater or wastewater. However, the simultaneous evaporation of volatile organic compounds (VOCs) presents a limitation for the widespread implementation of this technique. Thus, developing dual-functional evaporators capable of both desalining seawater and degrading VOCs is challenging. Herein, we fabricated an iron-based metal-organic framework MIL-88A/carbon nanotubes (CNTs) poly(vinyl alcohol) hydrogel (MCH) evaporator via the conventional freezing method for solar-driven seawater desalination and simultaneous photo-Fenton VOC degradation. Because of the superior photothermal conversion capability of CNTs, reduced thermal conductivity and water evaporation enthalpy within the hydrogel, and the photo-Fenton activity of rod-shaped MIL-88A, the MCH evaporator exhibits a higher evaporation rate of 2.26 kg m-2 h-1 under 1 sun illumination with simultaneous VOC degradation. The higher hydrophilicity and vertical channels in the MCH evaporator enable its self-salt cleaning ability, facilitating consistent seawater desalination, even in high salt concentrations up to 10 wt %. The synergistic effects of localized heating from CNTs and hydrogen peroxide activation through reactive sites of MIL-88A allow the MCH evaporator to degrade more than 93% of the added phenol during evaporation. This work presents a sustainable and efficient approach for solar-driven seawater desalination, offering simultaneous VOC degradation.

Synthesis of superparamagnetic Fe3O4–graphene oxide-based material for the photodegradation of clonazepam

The global concern over water pollution caused by contaminants of emerging concern has been the subject of several studies due to the complexity of treatment. Here, the synthesis of a graphene oxide-based magnetic material (GO@Fe3O4) produced according to a modified Hummers’ method followed by a hydrothermal reaction was proposed; then, its application as a photocatalyst in clonazepam photo-Fenton degradation was investigated. Several characterization analyses were performed to analyze the structure, functionalization and magnetic properties of the composite. A 23 factorial design was used for the optimization procedure to investigate the effect of [H2O2], GO@Fe3O4 dose and pH on clonazepam degradation. Adsorption experiments demonstrated that GO@Fe3O4 could not adsorb clonazepam. Photo-Fenton kinetics showed that total degradation of clonazepam was achieved within 5 min, and the experimental data were better fitted to the PFO model. A comparative study of clonazepam degradation by different processes highlighted that the heterogeneous photo-Fenton process was more efficient than homogeneous processes. The radical scavenging test showed that O2·-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${O}_{2}^{\\cdot -}$$\\end{document} was the main active free radical in the degradation reaction, followed by hydroxyl radicals (•OH) and holes (h+) in the valence layer; accordingly, a mechanism of degradation was proposed to describe the process.

Synthesis, structural characterization, DFT and molecular dynamics simulations of dinuclear (μ-hydroxo)-bridged triethanolamine copper(II) complexes: efficient candidates towards visible light-mediated photo-Fenton degradation of organic dyes.

Multinuclear (di/tri) copper(II) complexes bridged through hydroxyl groups are very interesting coordination complexes owing to their potential applications in various fields. In this work, three novel dinuclear (μ-hydroxo)-bridged copper(II) complexes in the crystal form, namely, [Cu2(3,5-DIFLB)2(H2tea)2](H2O) (1), [Cu2(4-ClB)2(H2tea)2](H2O) (2), and [Cu2(4-ETHB)2(H2tea)2](H2O)2 (3) (where DIFLB = difluorobenzoate, CLB = chlorobenzoate, ETHB = ethoxybenzoate, and H3tea = triethanolamine), were isolated at room temperature using methanol and water in a 4 : 1 v/v ratio as a solvent. Furthermore, all three complexes (1-3) were characterised using spectroscopic (UV-vis, DRS, and FT-IR), electrochemical (CV) and single-crystal X-ray diffraction techniques. Structural insights gained by packing analysis revealed the role of steric constraints of substituents and various non-covalent interactions in lattice stabilization, which were indeed supported by theoretical and molecular electrostatic potential illustrations. Hirshfeld surface analysis provided quantitative verification about various non-covalent interactions (interatomic contacts) involved in the packing of molecules. Interestingly, as a potential application, complexes 1-3 all exhibited remarkable visible light-mediated photo-Fenton degradation of approximately 98% for 50 ppm concentration of organic dyes (fuchsin basic (FB) and methyl orange (MO)) in 90 minutes with the optimized conditions of 1 mg mL-1 of dye solution. In all the cases, dye degradation by these materials was ascribed to the symbiotic relations among the molecular structures of complexes 1-3, which were endowed with various electron-withdrawing and electron-releasing substituents and ionic strength, with respect to the structure, shape and interacting patterns of dye molecules. The adsorption mechanism indicates that various weak interactions between the donor and acceptor groups of complexes and dyes, such as electrostatic, hydrogen bonding, and direct coordination to metal sites, play a crucial role, which is confirmed by molecular dynamics (MD) simulations. Theoretical studies by DFT-based descriptors, molecular electrostatic potentials, and band gaps provided deep insights into various electronic and reactivity parameters. For subsequent processes of dye degradation, complexes 1-3 were stable and recoverable. The successful integration of experimental and theoretical approaches sheds light on copper-based dinuclear stable coordination complexes, showcasing a significant step towards the development of novel heterogeneous photo-Fenton catalysts.