Heterogeneous photo-Fenton Research Articles

Synthesis, characterization, and photocatalytic applications of novel sword-like copper oxide microparticles

• Novel CuO microparticles in sword-like morphology were prepared by microemulsion and calcination. • The major composition of the prepared materials was confirmed by XRD and EDS. • The photocatalytic property of the CuO microparticles was established using methylene blue model dye compound. • The degradation of methylene blue dye followed first-order kinetic model according to the general Langmuir–Hinshelwood mechanism. This letter aimed to synthesize novel copper oxide (CuO) microparticles via the microemulsion method followed by calcination. The synthesized material was characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometry, and diffuse reflectance spectroscopy techniques; and subsequently applied for the degradation of methylene blue (MB) using the heterogeneous photo-Fenton method. SEM images revealed the formation of homogeneous sword-like CuO microparticles. The XRD pattern and EDS spectrum confirmed that the main part of the material was CuO with the formation of Na 8 Cu 5 O 10 as an impurity. The photocatalytic degradation of MB followed the first-order kinetic model according to the general Langmuir–Hinshelwood mechanism. The as-prepared materials can be successfully applied in the visible-light-induced photocatalytic degradation of hazardous organic compounds and industrial wastewaters.

Mg-Fe-Al-O spinel: Preparation and application as a heterogeneous photo-Fenton catalyst for degrading Rhodamine B.

It is an urgent need to develop new environmentally friendly spinel ferrites with high catalytic efficiency. In this work, a series of Mg-Fe-Al-O spinels with different ratios of Mg/Al were successfully synthesized by the reaction sintering method and were used as a heterogeneous photo-Fenton catalyst for degradation of Rhodamine B (RhB). The effect of different ratios of Mg/Al on the properties of Mg-Fe-Al-O spinel was characterized and analyzed through a range of advanced characterization techniques and DFT calculations. The influence factors on the photo-Fenton reaction catalyzed by Mg-Fe-Al-O spinels were systematically investigated. The results showed that the prepared Mg-Fe-Al-O spinels had larger lattice parameters, wider bandgap, and stronger magnetism, with the Mg content increased. Among them, Mg-9 (Mg0.88Fe1.88Al0.23O4) had the best catalytic performance in the photo-Fenton reaction. The degradation efficiency of RhB reached 98.45%, and the TOC removal efficiency was 83.47%. The elemental valence and PDOS of Mg-9 (Mg0.88Fe1.88Al0.23O4) spinels were closer to MgFe2O4. The photo-generated holes could directly oxidize water and hydroxyl to generate reactive oxygen species ·OH, improving the catalytic activity.

Construction of 3D/2D ZnFe2O4/g-C3N4 S-scheme heterojunction for efficient photo-Fenton degradation of tetracycline hydrochloride

Heterogeneous photo-Fenton catalytic reaction is a promising advanced oxidation technology for environment remediation. Herein, 3D/2D ZnFe2O4/g-C3N4 heterojunctions were successfully fabricated and applied in photo-Fenton degrading tetracycline hydrochloride (TC). The crystalline phases, morphologies, microstructures, specific surface areas and optical properties of as-prepared catalysts were investigated by multiple inspect techniques. After comparison and optimizing, the ZFO/NCN-2 (4.8 wt% ZnFe2O4/g-C3N4) heterojunction displayed the best photo-Fenton catalytic activity for TC degradation, with the degradation efficiency of 94.4 % in 40 mins. The implementation of active species trapping tests, photoluminescence (PL) spectra, electron spin resonance (ESR) measurements and density functional theory (DFT) calculations not only confirmed that the hydroxyl radicals (·OH), superoxide radicals (·O2–) and holes (h+) were all participated in the photo-Fenton reaction, but also evidenced an S-scheme photogenerated charge transfer route. The effective charge separation and accelerated Fe3+/Fe2+ cycles were responsible for the outstanding photo-Fenton activity. Additionally, the plausible degradation pathways of TC were reasonably proposed in view of the high-performance liquid chromatography mass spectrometry (HPLC-MS) analytic results. The current work presented a potentially efficient photo-Fenton catalyst for the decontamination of antibiotic wastewater.

Mn doping accelerates regeneration of Fe2+ in FeOOH and promotes efficient H2O2 activation for degradation of As(III)

In this study, a carbonized aerogel (CA) decorated with Mn-FeOOH hybrid nanoparticles was prepared and has been used as a better heterogeneous photo-Fenton catalyst. Mn doping accelerated the regeneration of Fe2+ and promoted the decomposition of H2O2 while producing many hydroxyl radicals (·OH), which solved the mass transfer problem in the traditional heterogeneous Fenton system. The amount of·OH in the Mn-FeOOH@CA/H2O2 system within 40 min was 2.4 times higher than that in the FeOOH@CA/H2O2 system, which further indicates that·OH was the main active species. High-porosity CA has been designed as an electron transport channel. During photocatalysis, electron transfer occurred between the Mn-FeOOH composite material and CA. The Fe2+ could be used as reaction sites to promote the activation of H2O2 on the surface of 1-Mn/FeOOH, and achieved 100 % As(III) degradation efficiency within 25 min. The catalyst maintained more than 80 % of its original oxidation capacity after five cycles of experiments, which indicates that it has good durability. This work is expected to provide rational design of heterometallic doped materials with oxygen vacancies to treat arsenic pollution.

Facile and scalable synthesis of Fe-based metal organic frameworks for highly efficient photo-Fenton degradation of organic contaminants

Fe-based metal organic frameworks (Fe-MOFs) being a newly developed photo-Fenton catalyst, have gained ever-increasing attention for environmental remediation, but have been limited by high synthesis cost (high energy-consumption and low yield). In this work, economical and scalable synthesis of Fe-BDC1 (BDC denotes as terephthalic acid) was achieved via facile stirring under ambient condition, and its adsorptive, photocatalytic, Fenton-like and photo-Fenton performances were comprehensively explored against contaminants removal. In comparison, synthesized Fe-BDC2 with the common solvothermal method, the yield of Fe-BDC1 increased 3.4 times. Also, its adsorption capacity towards Rhodamine B (Rh. B) increased about 5.85 times. Moreover, the significantly improved degradation of Rh. B was observed in the Fenton-like and photo-Fenton systems with the increased reaction rate constants up to 4.90 and 2.33 times, respectively. This enhanced catalytic performance of Fe-BDC1 was mainly attributed to the enlarged specific surface area (SSA) and favorable electron separation and migration, resulting into the accelerated ≡Fe(II)/≡Fe(III) cycle and increased yield of reactive oxidative species (ROSs). Additionally, the unique light-induced adsorption enhancement further strengthened the contaminants removal. Fe-BDC1 as photo-Fenton catalyst was found superior over conventional catalysts in terms of advantages including: low dose requirement of catalysts (decrease in an order of magnitude) and H2O2, wide pH working range (3.0–9.0), excellent reusability and stability, universal removal behavior against all organic pollutants, and remarkable synergism between photocatalysis and Fenton-like process with synergistic factor of 77.23%. Moreover, the Fe coordinative unsaturated sites (Fe CUSs) and ·OH were determined as the active sites and the main ROSs, respectively, responsible for highly efficient pollutant degradation. This work gives a feasible solution for the preparation of Fe-MOFs with low synthesis cost and high yield, paving ways for their practical mass application in heterogeneous photo-Fenton oxidation.

High-activity and excellent-reusability γ-Fe2O3/SiO2 coating on TC4 titanium alloy by plasma electrolytic oxidation for enhanced photo-Fenton degradation.

The immobilized coatings as a kind of promising Fenton-like catalysts with excellent performance and reusability for the efficient degradation of antibiotics and phenol under solar light irradiation is investigated. Herein, the porous γ-Fe2O3/SiO2 immobilized ceramic coating on TC4 titanium alloy as photo-Fenton catalyst was prepared via plasma electrolytic oxidation technology. The as-obtained immobilized coating manifested a remarkable catalytic activity that the removal efficiencies of phenol and various antibiotics could reach more than 92% within 90min, and presented excellent reusability after six runs in phenol removal. The high activity and excellent reusability of γ-Fe2O3 were attributed to the synergistic effect of multiple pathways to jointly produce abundant •OH, and the combination of γ-Fe2O3 and SiO2 in the coating could effectively reduce iron leaching during the heterogeneous photo-Fenton process, respectively. This work provides a novel strategy for the synthesis of high-performance photo-Fenton catalysts to dispose of wastewater in the future.

Magnetic porphyrin-based metal organic gel for rapid RhB removal and enhanced antibacterial activity by heterogeneous Photo-Fenton reaction under visible light.

Nanomaterials with visible light-driven catalytic ability are beneficial in controlling environmental pollutants. Porphyrin-based metal organic gel (MOG) was herein synthesized in one step and magnetic metal organic gel (MMOG) was successfully prepared via in-situ reaction of MOG and Fe3O4. This MMOG was developed as a novel visible light assisted Fenton-like catalyst. The catalytic experiments showed the high photo-Fenton activity of MMOG in the degradation of Rhodamine B (RhB) in the presence of visible light and H2O2 with a RhB degradation efficiency of 94.2% within 40min. Notably, the obtained MMOG can kill E. coli and S. aureus with high killing rate (>99.999%) under visible light. Importantly, the MMOG can be recovered simply by an external magnetic field due to the unique magnetic property. This easily synthesized MMOG with photo-Fenton activity under visible light and magnetic property makes MOG based on the photo-Fenton reaction a prospective material for the environmental and biomedical applications.

Synergistic improving photo-Fenton and photo-catalytic degradation of carbamazepine over FeS2/Fe2O3/organic acid with H2O2in-situ generation

Herein, a heterogeneous photo-Fenton and photo-catalytic system was constructed using oxide pyrite (FeS2/Fe2O3) mineral and organic acids including tartaric acid (TA), ascorbic acid (AA), and citric acid (CA). In the proposed system, FeS2/Fe2O3 can be successfully activated through irradiation to generate photogenerated carriers, which generated H2O2in-situ through the reduction reactions between e- and O2. The addition of organic acids enhanced the dissolution of iron from FeS2/Fe2O3. Based on the iron and in-situ generated H2O2, •OH was produced through a photo-Fenton reaction. Furthermore, h+, e-, and •O2−, which were generated through the photo-catalytic activation of FeS2/Fe2O3, also played a certain role in the degradation of carbamazepine (CBZ). Therefore, the synergistic photo-Fenton and photo-catalytic reaction improved the degradation of CBZ, with the degradation efficiencies of 86%, 62%, and 68% in FeS2/Fe2O3/TA, FeS2/Fe2O3/AA, and FeS2/Fe2O3/CA systems, respectively. This investigation provides an innovative strategy for the removal of organic pollutants using natural minerals.

Oxygen vacancies and interfacial iron sites in hierarchical BiOCl nanosheet microflowers cooperatively promoting photo-Fenton

Controllable active site construction, crystal structure regulation and efficient charge separation are core issues in heterogeneous photo-Fenton. Herein, abundant oxygen vacancies and well-dispersed interfacial iron sites are simultaneously constructed in hierarchical nanosheet-assembled BiOCl microflowers. The composites exhibit superior performance in photo-Fenton oxidation of carbamazepine (10 mg L−1) with a low H2O2 concentration (1.3 mM). The high performance highly depends on the synergistic effects between oxygen vacancies and iron species. Rather than modulating the valence band, the involvements of oxygen vacancies and iron species could modify the conduction band of BiOCl. The presence of oxygen vacancies promotes the migration of photo-generated electrons and accelerates the redox cycling of ≡Fe(III)/≡Fe(II) to boost the activation of H2O2 to generate hydroxyl radicals, and oxygen vacancies can be well preserved after cyclic use. This work provides understanding on efficient utilization of oxygen vacancies and interfacial iron sites to assist photo-Fenton and the underlying electron transfer mechanism.

FeCoNiMnCuTi high entropy amorphous alloys and M50Ti50 (M = Fe, Cu, FeCoNiMnCu) amorphous alloys: Novel and efficient catalysts for heterogeneous photo-Fenton decomposition of Rhodamine B

Traditional Fe based amorphous alloys (Fe-Si-B system) with good Fenton-like performance have attracted great attention in dye wastewater decomposition. However, their relative low catalytic stability, narrow pH working range and expensive constituent elements impede the corresponding application. In addition, discovering new application of high entropy alloys in catalytic degradation besides decolorization of azo dyes has already been a scientific research hotspot. Consequently, in this work, M50Ti50 (M = Fe, Ni, Cu, FeCoNiMnCu) amorphous alloys, FeCoNiMn high entropy alloys and FeCoNiMnCuTi high entropy amorphous alloys were prepared by one-step ball milling method and then used as Fenton-like catalysts. The average particle sizes of the prepared Fe50Ti50, Ni50Ti50, Cu50Ti50, (FeCoNiMnCu)50Ti50, FeCoNiMn and FeCoNiMnCuTi were measured to be 22.3, 27.8, 26.5, 17.1, 15.4 and 19.5 μm, respectively. Among them, Fe50Ti50, Cu50Ti50, (FeCoNiMnCu)50Ti50 and FeCoNiMnCuTi exhibited superior photo-Fenton performances: 4 min UV decomposition rates of RhB solution are up to 82.77%, 85.96%, 75.23% and 88.19%, respectively, which would be the promising Fenton-like catalysts for industrial dye wastewater treatment. In particular, this is the first report on dye degradation behavior of equiatomic high entropy amorphous alloys and Cu based amorphous alloys were firstly developed to be a photo-Fenton catalyst.

Visible light assisted Fenton degradation of oxytetracycline over perovskite ErFeO3/porous g-C3N4 nanosheets p-n heterojunction

Exploring effective approach to boost the removal efficiency has always been a critical challenge in the field of environmental contaminant treatment. In this study, p-n heterojunctions were precisely fabricated by incorporating perovskite ErFeO3 nanoparticles on porous g-C3N4 nanosheets and employed to degrade oxytetracycline and tetracycline through visible light assisted heterogeneous photo-Fenton technology. The built-in electric field at the interface of ErFeO3 and g-C3N4 provided an additional driving force for the separation of photoinduced electron-hole pairs, which accelerated the generation of e-, h+ and ROS. The addition of H2O2 and the present of Fe-based ErFeO3 induced the photo-Fenton reaction. Under visible light irradiation, 99.7% of oxytetracycline and 98.5% of tetracycline could be decomposed over ErFeO3/g-C3N4 p-n heterojunctions. The apparent rate constant of photo-Fenton degradation for oxytetracycline was about 194 times of photocatalytic degradation and 53 times of Fenton degradation, respectively. The ErFeO3/g-C3N4 p-n heterojunctions also had exceptional stability and adaptability. The structures of degradation intermediates, possible photo-Fenton degradation mechanism and pathways of oxytetracycline were proposed according to the HPLC-MS, ESR and free radical quenching experiments. This study provided an effective approach for effective treatment of refractory pollutant.

Catalytic activity of magnetite fish-scales and tea-waste as heterogeneous photo-Fenton catalysts for removal of methyl orange through Cu(Ⅱ) adsorption

In this study, magnetite fish scales and tea waste (MFS and MTW) were first used to adsorb Cu(Ⅱ) cations (Cu-MFS and Cu-MTW) and were then applied as heterogeneous photo-Fenton catalysts to degrade methyl orange (MO) from an aqueous solution. The morphological and structural properties of the fabricated catalysts were characterized via SEM, XRD, EDX/MAP, VSM, BET and FTIR techniques. The effects of pH, catalyst dosage, initial concentration of MO, and the initial concentration of H2O2 on the degradation efficiency of MO were investigated. The degradation efficiency of MO through the use of MFS, Cu-MFS, MTW, and Cu-MTW in the photo-Fenton process was achieved 82.6%, 97.2%, 89.1%, and 96.9%, respectively, under optimum condition (pH of 3, 0.2 g/L of MFS and Cu-MFS and 0.4 g/L of MTW and Cu-MTW, an H2O2 concentration of 0.5 mM within 200 min). Additionally, the rate of degradation reactions followed the first-order kinetics. Catalytic action was assigned to the formation of hydroxyl radicals (OH•) via the reaction between H2O2 and Fe(II) and Cu(II) on the surface of Cu-MFS and Cu-MTW during the photo-Fenton process. Furthermore, not only did Cu-MFS and Cu-MTW exhibit negligible iron and copper leaching, but they also indicated long-term stability after three consecutive cycles.

Metal-organic frameworks-derived CoFeN-NC materials with the enhanced catalytic activity and selectivity for the degradation of organic dyes via adsorption and heterogeneous photo-Fenton

Nanoscale iron-based materials are widely used as photocatalytic materials for catalytic oxidative degradation of organic dyes in water. Here, a series of MOFs derived nitrogen doped cobalt iron bimetallic carbon composite nanomaterials (CoxFe1-xN-NCs) were prepared by self-assembly and annealing treatment, and their application in the removal of organic dyes in water was investigated by the synergistic effect of adsorption and photo-Fenton. The study found that the Co0.8Fe0.2N-NC exhibit superior catalytic performance for different types of organic dyes. For example, when the concentration of MB was 40 mg L-1, the degradation rate constant was 3.88 × 10-2 min−1, which were 2.9 and 25.2 times the corresponding values of the Fenton-like and photocatalytic system, respectively. Meanwhile, compared with azo dyes Methyl Orange and Congo Red (MO and CR), Co0.8Fe0.2N-NC has obvious selective catalysis for non-azo dyes Methylene Blue, Malachite Green, Rhodamine B and Neutral Red (MB, MG, RhB and NR). Moreover, the reaction of cobalt iron active centers with hydrogen peroxide (H2O2) further promotes the generation of active substances (·OH, ·O2– and h+), speeding up the degradation of organic dyes. These results suggest that the synergistic effect of adsorption and photo-Fenton may provide new clues for the treatment of organic pollutants in wastewater.

Simultaneous Removal of Antibiotic Resistant Bacteria, Antibiotic Resistance Genes, and Micropollutants by FeS2@GO-Based Heterogeneous Photo-Fenton Process.

The co-occurrence of various chemical and biological contaminants of emerging concerns has hindered the application of water recycling. This study aims to develop a heterogeneous photo-Fenton treatment by fabricating nano pyrite (FeS2) on graphene oxide (FeS2@GO) to simultaneously remove antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs), and micropollutants (MPs). A facile and solvothermal process was used to synthesize new pyrite-based composites. The GO coated layer forms a strong chemical bond with nano pyrite, which enables to prevent the oxidation and photocorrosion of pyrite and promote the transfer of charge carriers. Low reagent doses of FeS2@GO catalyst (0.25 mg/L) and H2O2 (1.0 mM) were found to be efficient for removing 6-log of ARB and 7-log of extracellular ARG (e-ARG) after 30 and 7.5 min treatment, respectively, in synthetic wastewater. Bacterial regrowth was not observed even after a two-day incubation. Moreover, four recalcitrant MPs (sulfamethoxazole, carbamazepine, diclofenac, and mecoprop at an environmentally relevant concentration of 10 μg/L each) were completely removed after 10 min of treatment. The stable and recyclable composite generated more reactive species, including hydroxyl radicals (HO•), superoxide radicals (O2• -), singlet oxygen (1O2). These findings highlight that the synthesized FeS2@GO catalyst is a promising heterogeneous photo-Fenton catalyst for the removal of emerging contaminants.

Multifunctional ferrocene-based photo-Fenton membrane: An efficient integration of rejection and catalytic process

A novel ferrocene-based nanofiltration membrane is prepared to combine filtration and photo-Fenton reaction for water treatment. Membranes containing ferrocene groups are successfully fabricated via an integration of layer-by-layer interfacial polymerization and ion exchange reaction. Rejection performance towards bisphenol S (BPS) increases with the growth of the interfacial polymerization layer, and the optimal membrane shows the highest rejection rate of 98.1%. For the optimal photo-Fenton system with H2O2, UV and ferrocene-based membrane (PS/HTCC-3/FcSO3), the degradation rate of k is 0.092 min−1, which is 1.8 times higher than that of the system with only H2O2 and UV. Meanwhile, the salinity of BPS in the optimal system is 2 times higher than that of the system with H2O2 and UV. After the heterogeneous photo-Fenton process, PS/HTCC-3/FcSO3 can reject 65.6% of the BPS degradation by-products based on the variation of total organic carbon (TOC). In addition, quenching experiments prove that ·OH is the primary active radical, and the yield of ·OH in the optimal system is the highest compared with the system with H2O2 and UV. The outstanding performance of ferrocene-based membrane demonstrates its potential for micropollutants treatment.

Fabrication of MoS2/FeOCl composites as heterogeneous photo-fenton catalysts for the efficient degradation of water pollutants under visible light irradiation

The heterogenous photo-Fenton technology has been widely applied in the field of water treatment due to its characteristic of environment friendly and no generation of iron sludge. However, the unsatisfied photogenerated charge separation and transfer efficiency quite limited the catalytic activities of the photo-Fenton materials. Herein, the MoS2/FeOCl (MS/FOC) heterojunction was synthesized by ingenious ultrasonic method. The photo-Fenton catalytic activities were evaluated by the degradation of dye and antibiotic pollutants in the water. With the assistance of the MS, the MS/FOC performed the enhanced charge transfer efficiency compared with the pure FOC. As the result, more photogenerated electron could gathered on the FOC and further boosted Fenton reaction to generate more hydroxyl radical (•OH) for high-performance degradation of water pollutants. This work provides a new insight into the design and synthesis of the novel photo-Fenton catalyst for the high-efficiency water treatment in future.

Tunable Synthesis of Hematite Structures with Nanoscale Subunits for the Heterogeneous Photo-Fenton Degradation of Azo Dyes

Facile syntheses of branched hematite (α-Fe2O3) crystals with fine-tuning of their nanoscale subunit morphologies were reported. Starting from Prussian red and bisolvent systems with controlled temperature as the crucial parameters, fine-tuning of the nanoscale subunit morphologies in the context of controlling the anisotropic growth of branched α-Fe2O3 crystals was demonstrated. The systematic and optimized studies significantly improved the controlled synthesis of the hierarchical growth of nanoscale subunits, leading to the formation of branched dendritic leaflike (secD3D, tertD2D, and tertD3D) and hyperbranched (secS2D and hypB2D) α-Fe2O3 particles for their size-reduced variants used in photocatalysis. The kinetics of the photo-Fenton degradation of three azo dyes (chlorazol black, direct blue, and methyl orange) with five types of branched dendritic α-Fe2O3 particles were compared systematically.

Enhanced photo-Fenton degradation of tetracycline hydrochloride by 2, 5-dioxido-1, 4-benzenedicarboxylate-functionalized MIL-100(Fe)

Heterogeneous photo-Fenton technology has drawn tremendous attention for removal of recalcitrant pollutants. Fe-based metal-organic frameworks (Fe-MOFs) are regarded to be superior candidates in wastewater treatment technology. However, the central metal sites of the MOFs are coordinated with the linkers, which reduces active site exposure and decelerates H2O2 activation. In this study, a series of 2, 5-dioxido-1, 4-benzenedicarboxylate (H2DOBDC)-functionalized MIL-100(Fe) with enhanced degradation performance was successfully constructed via solvothermal strategy. The modified MIL-100(Fe) displayed an improvement in photo-Fenton behaviors. The photocatalytic rate constant of optimized MIL-100(Fe)-1/2/3 are 2.3, 3.6 and 4.4 times higher compared with the original MIL-100(Fe). The introduced H2DOBDC accelerates the separation and transfer in photo-induced charges and promotes Fe(II)/Fe(III) cycle, thus improving the performance. •OH and •O2− are main reactive radicals in tetracycline (TCH) degradation. Dealkylation, hydroxylation, dehydration and dealdehyding are the main pathways for TCH degradation.

Cl-based functional group modification MIL-53(Fe) as efficient photocatalysts for degradation of tetracycline hydrochloride

MIL-53(Fe) catalyst has been widely used to treat the pollutants in water. However, the limited number of electrons in MIL-53(Fe) catalyst has always affected the rate at which Fe3+ can be reduced to Fe2+. We modulated iron-based metal–organic frameworks (MOFs) using organic ligands modified with chlorine functional groups. The characterization results indicate that the 2Cl-MIL-53(Fe) catalyst exhibited the optimal photoelectric properties while maintaining the original structural characteristics. The experimental analyses and the first-principles study suggest that the introduction of a chlorine functional group not only reduced the band gap width and enhanced the visible-light absorption capacity, but also significantly enhanced the electron cloud density of Fe–O clusters. This could further accelerate the redox cycle of Fe(III)/Fe(II), beneficial for H2O2 activation. The constructed Cl-MIL-53(Fe) catalyst exhibited a 3.8 times higher reaction rate constant than pure MIL-53(Fe) catalyst. The specific TCH degradation pathway and mechanism of 2Cl-MIL-53(Fe) treatment are proposed. This study provides a new strategy for iron-based MOFs as a heterogeneous photo-Fenton catalyst to degrade pollutants in water.

Photo-Fenton degradation of sulfamethoxazole using MIL-53(Fe) under UVA LED irradiation and natural sunlight

The MOF MIL-53(Fe) was synthesized, activated and evaluated in photo-Fenton reactions assisted by UVA LED irradiation and natural sunlight using the antibiotic sulfamethoxazole (SMX) as a degradation target molecule. A 23 full factorial design of experiments was carried out in order to determine the effects of several parameters' influence on the degradation of SMX. The effect of different operational parameters such as pH, hydrogen peroxide and catalyst concentration was analyzed, and tests of reuse of the catalyst were performed. Likewise, the dissolved organic carbon (DOC), iron leached from the MIL-53(Fe) structure and H2O2 consumption were monitored, and the degradation products of the reaction were identified. The use of MIL-53(Fe) as a heterogeneous photo-Fenton catalyst using natural sunlight as an irradiation source allowed the degradation of 96% of the SMX in solution in just 120 min under near-neutral conditions. Likewise, removal of 30% of the DOC in solution was achieved, being the leached iron concentration less than 0.20 mg L−1, a value within the quality standard of water intended for human consumption imposed by the European Union (Directive 98/83/CE). Efficiency and stability after multiple cycles postulate the MOF MIL-53(Fe) as a potential heterogeneous catalyst to be considered in the development of alternative water purification systems based on the photo-Fenton process. An appropriate combination of solid-state characterization and chemical analysis techniques were applied, including PXRD, DRS, ZP, SEM, FTIR, HPLC-DAD, HPLC-MS/MS, and UV-Vis, which provided the experimental evidence that supports this study.