Fenton Photocatalyst Research Articles

Development and testing of alginate/C3N4porphyrin bead as a self-initiated Fenton photocatalyst for highly efficient atrazine removal

Fenton reaction has been widely used for efficient treatment of organic wastewater. However, its applications are limited by such key factors as pH < 3. In this study, we developed, tested, and optimized an alginate/C3N4porphyrin bead (C3N4por-SA) as a recyclable photocatalyst in a photocatalysis-self-Fenton process to overcome these limitations. Porphyrin-modified C3N4 (C3N4por) was used as the H2O2 donator, while Fe(III) nodes served as the Fenton reagent. The as-prepared floating alginate/C3N4por bead utilized the light source as a driving force for the catalysis. Under visible light irradiation for 6 h, the model pollutant atrazine was degraded by 70.96 % by the optimized photocatalyst (named as C3N4por-SA-Fe1Ca5), demonstrating better photocatalytic performance than alginate/C3N4 beads. This improvement was attributed to the higher H2O2 yield from C3N4por. The alginate/C3N4por bead showed better photocatalytic activity even after several consecutive cycles and could easily be recovered for reuse. Furthermore, Fe(III)/Ca(II) bimetallic alginate bead exhibited better photocatalytic activity and a higher content of •OH radicals than the Ca(II) monometallic alginate beads, due to the ability of Fe(III) nodes to serve as a Fenton reagent. The influences of light sources, and commonly existing matters (namely SO42−, Cl−, CO32−, NO3−, and humic acid) were investigated. Moreover, the alginate/C3N4por bead demonstrated good photocatalytic performance in a simulated natural environment without the addition of extra H2O2, with an atrazine removal percentage of up to 96.3 % after 3-h irradiation. These findings indicated the great potential of alginate/C3N4por bead in practical applications.

Enhanced photo-Fenton catalytic activity over Cu-doped Bi12O17-xCl2 nanotube for tetracycline degradation: Oxygen vacancies-induced mixed valent Cu

Fenton photocatalyst constructed by transition metal-doped semiconductor material seems to be a promising alternative to classic Fenton catalysts. A series of Cu-doped tubular Bi12O17Cl2 with sufficient oxygen vacancies (ov) was successfully prepared through a hydrothermal method. The formation of ov in the Bi12 crystal lattice can favor the Fenton reaction not only by serving as a reaction site and increasing the charge density in the photocatalyst but also by partially reducing the dopant Cu2+ to Cu+, which consequently enhances the H2O2 activation to a significantly higher rate. Notably, Cu-doped Bi12O17Cl2 ov with an optimal dopant proportion of 4 % exhibited a preferable Fenton catalytic rate 4.5 times higher than pure photocatalytic degradation. This work investigates the mutual promotion of oxygen vacancies and dopant ions in the Fenton reaction and provides a novel development scheme for the advanced oxidation process.

3D hierarchical Fe-doped Bi4O5I2 microflowers as an efficient Fenton photocatalyst for tetracycline degradation over a wide pH range

Fenton reaction is proved to be an efficient method for degrading organic pollutants in wastewater. However, the narrow pH range greatly restricts the application of Fenton reaction. Herein, the 3D hierarchical Fe-doped Bi4O5I2 microflowers have been synthesized via a hybrid solvothermal-calcination method and applied in a photo-Fenton system for efficient removal of tetracycline (TC). The optimized Fe-doping Bi4O5I2 (11Fe-BOI) microflowers present more than 90% degradation efficiency over the pH range of 3.0–9.0 in Fenton system under visible light irradiation, and the reaction rate constant in 11Fe-BOI/H2O2/Vis system is 2.79 × 10−2 min−1, which is 19.11, 1.85 and 7.71 times higher than that of H2O2/Vis (1.46 × 10−3 min−1), 11Fe-BOI/Vis (1.51 × 10−2 min−1) and 11Fe-BOI/H2O2 (3.61 × 10−3 min−1) systems, respectively. The synergy effect of photocatalysis and Fenton reaction plays a pivotal role for the TC degradation process via accelerating the separation of carriers and the generation of reactive oxygen species. The scavenging experiments and EPR results manifest that O2– and OH are dominant active species during the TC degradation process. This work provides great prospect to fabricate an efficient non-noble metal photocatalyst for photo-Fenton degradation of antibiotics.

Magnetic Fe3O4/CeO2/g-C3N4 composites with a visible-light response as a high efficiency Fenton photocatalyst to synergistically degrade tetracycline

Magnetic Fe3O4/CeO2/g-C3N4 (FCG) composites with a visible-light response were successfully synthesized and characterized as a heterogeneous Fenton-like catalyst for tetracycline hydrochloride (TCH) degradation. The optimal mass ratio, pH value, catalyst addition, H2O2 concentration, and temperature were explored. Photodegradation studies showed the best activity when the mass ratio of the composite was 1:0.75:0.75 (F1C0.75G0.75) and the removal rate of TCH by F1C0.75G0.75 reached 96.63% after 180 min. The first order kinetic constant of the reaction system was 0.0533 min−1. According to the test of free radical scavenger and metal leaching tests, the Fenton-like degradation of TCH by F1C0.75G0.75 composite was analyzed. g-C3N4 effectively reduced the leaching of Fe and the location where TCH was attacked by hydroxyl radicals was mainly on the surface of the catalyst. The reusability of the F1C0.75G0.75 composites was also studied after five cycles.

Bimetallic iron-copper oxide nanoparticles supported on nanometric diamond as efficient and stable sunlight-assisted Fenton photocatalyst

Bimetallic iron and copper oxide nanoparticles (NPs) supported on hydroxylated diamond (D3) exhibits an improved activity for the heterogeneous Fenton phenol degradation under natural or simulated sunlight irradiation with respect to analogous monometallic samples or than analogous FeCu NPs on graphite, activated carbon and P25 TiO2 semiconductor. FeCu/D3 catalyst exhibits good recyclability and stability especially working at pH 6. Overall, the high activity of the Fe20Cu80(0.2 wt%)/D3 catalyst is mainly due to the combination of the high activity of reduced copper species decomposing H2O2 to HO· radical, while Fe2+ allows the regeneration of these reduced copper species.

Synergetic effect of Fe2O3 and BiVO4 as photocatalyst nanocomposites for improved photo-Fenton catalytic activity

Photo-Fenton reactions and the related functional nanomaterials have been widely studied for applications in wastewater treatment industry. Herein, visible-light-responsive Fe2O3 nanoparticle-decorated BiVO4 nanoplates were designed and successfully prepared through a one-pot hydrothermal route. The as-prepared Fe2O3/BiVO4 nanocomposites exhibit excellent photo-Fenton catalytic activity toward the discoloration of methylene blue (MB) and Rhodamine B (RhB) dye molecules in the presence of H2O2. The experimental results indicate that nearly 100% of MB (100 mL, 10 mg L−1) and RhB (100 mL, 5 mg L−1) dye molecules are degraded in the presence of 1 g L−1 Fe2O3/BiVO4-1 (FB-1) photo-Fenton catalyst and 0.5 mL of H2O2 within 20 min. The Fe2O3/BiVO4 Fenton photocatalyst also demonstrates high reusability under visible light irradiation with λ ≥ 420 nm. The photoinduced electrons on the conduction band of BiVO4 nanoplates can move toward the surface of Fe2O3/BiVO4 to accelerate the reduction of Fe3+; then, the as-formed Fe2+ ions on the surface of the catalyst greatly enhance the decomposition of H2O2 to form reactive ·OH species for the use in photodegradation of MB and RhB dye molecules. The synergetic effect of Fe2O3 and BiVO4 reported in this work might provide more opportunity to fabricate other novel semiconductor-based Fenton nanocomposites for contamination treatments in wastewater.

Green and cost-effective carboxylic acid Fe complex functionalized cotton fabrics: sunlight-driven catalytic and antibacterial activities, mechanical and thermal properties

Polycarboxylic acid (PCA) modified cotton fiber Fe complex (Fe-PCA-Cotton) was created by the surface modification of cotton fabric with tartaric acid (TA), citric acid (CA) or 1,2,3,4-butanetetracarboxylic acid (BTCA) and subsequent Fe(III) ion coordination to meet the “4-E” criteria: efficient, economical, environmentally friendly and easily-produced. Effect of PCA structure on sunlight-driven catalytic and antibacterial activities, mechanical and thermal properties of the obtained Fe-PCA-Cotton was investigated, which showed that Fe-TA-Cotton had higher photocatalytic ability than other two complexes under different weather conditions. The best antibacterial activity was achieved when CA was used for the complex preparation. Increasing their Fe contents over critical values led to the complexes with excellent catalytic and mechanical performance. A little difference in thermal property between three complexes was found. This study indicated that Fe-CA-Cotton is possibly one of the few solar-driven heterogeneous Fenton photocatalyst that can be produced and applied in industrial scale.

A novel heterogeneous Fenton photocatalyst prepared using waste wool fiber combined with Fe3+ ions for dye degradation

Wool fiber Fe complex (Fe-Wool) was prepared with waste wool fiber and Fe3+ ions by a simple exhaust method, and characterized using SEM, FTIR, XRD, XPS, and diffuse reflectance UV-vis spectroscopy. The activity of Fe-Wool was tested as a novel heterogeneous Fenton catalyst for dye degradation in a wide pH range. Effect of Fe content, incorporation of Cu2+ ions, and light irradiation on its catalytic activity was also examined. The results indicated that amino and carboxylic groups or disulfide crosslinks from wool fiber as the ligand sites could react with Fe3+ ions to form Fe-Wool, and the Fe content in Fe-Wool was highly dependent on Fe3+ initial concentration and temperature. Fe-Wool showed a better catalytic activity on the dye degradation under light irradiation than in the dark because it was activated in the UV and visible regions. Incorporation of Cu2+ ions could significantly increase catalytic activity of Fe-Wool for the dye degradation, especially in neutral and alkaline pH range.

Preparation of magnetic photocatalyst nanohybrid decorated by polyoxometalate for the degradation of a pharmaceutical pollutant under solar light.

Magnetic polyoxometalate nanohybrid was prepared by the surface modification of γ-Fe2O3/SrCO3 nanoparticles with PW 12 O 40 (3 -) polyoxometalate (POM) anions. The results of Fourier transform infrared (FTIR) and energy-dispersive X-ray (EDX) confirm the presence of POM on the surface of γ-Fe2O3/SrCO3 nanoparticles. TEM results revealed the ellipsoid-like structure of nanohybrid which was 23nm in length and 6nm in width. The activity of the photocatalyst was investigated by the photocatalytic degradation of ibuprofen (IBP) in an aqueous solution under solar light. It was found that in comparison with the γ-Fe2O3/SrCO3, the degradation of IBP after 2-h exposure to the solar light irradiation was significantly higher for POM-γ-Fe2O3/SrCO3 nanohybrids. The degradation of IBP was enhanced by the addition of H2O2 to the air saturated solution, while the addition of NaHCO3 and isopropanol restricted the degradation process. In the presence of H2O2, the Fenton photocatalyst degradation under solar light irradiation led to relatively complete degradation of IBP. Furthermore, the photocatalytic activity and magnetization properties of this magnetic photocatalyst nanohybrid provide a promising solution for the degradation of water pollutants and photocatalyst recovery. Graphical Abstract Schematic illustration for preparation of POM-γ-Fe2O3/SrCO3 nanohybrid and photocatalytic reaction of IBP on POM-γ-Fe2O3/SrCO3 nanohybrid.

Coaxial solution blowing of modified hollow polyacrylonitrile (PAN) nanofiber Fe complex (Fe-AO-CSB-HPAN) as a heterogeneous Fenton photocatalyst for organic dye degradation

The dyes degradation performance of the modified hollow polyacrylonitrile Fe complex (Fe-AO-CSB-HPAN) prepared by coaxial solution blowing (CSB).

Iron(III)–Alginate Fiber Complex as a Highly Effective and Stable Heterogeneous Fenton Photocatalyst for Mineralization of Organic Dye

Iron(III)–alginate fiber complex was prepared through the coordination of alginate fiber with Fe(III) ions and characterized using Fourier transform infrared, X-ray diffraction, X-ray photoelectron spectroscopy, and diffuse reflectance UV–vis spectra, respectively. Effect of Fe(III) initial concentration and reaction temperature on the Fe content of the obtained complex was also investigated. It was then tested as a heterogeneous Fenton photocatalyst for dye degradation with H2O2. The results indicated that the carboxyl groups from alginate fiber successfully reacted with Fe(III) ions to form the complex. Higher Fe(III) ion concentration or elevation of temperature led to a proportional increase in the Fe content of the complex. Moreover, Fe(III)–alginate fiber complex could effectively catalyze the dye mineralization in the dark or under light irradiation in a wide pH range of 3–9. Its catalytic activity was hardly affected by Na2SO4 or NaCl in wastewater. The stable catalytic performance was observed in its reuse processes.

Formula omitted] supported on amidoximated PAN fiber as effective catalyst for the photodegradation of organic dye under visible light irradiation

A novel heterogeneous Fenton photocatalyst was prepared by supporting Fe(bpy)32+ onto amidoximated polyacrylonitrile (PAN) fiber and then used for the degradation of organic dye under visible irradiation. FTIR, XPS and UV–vis diffuse reflectance spectroscopy analyses suggest that the Fe(bpy)32+ molecules were distorted during their immobilization onto the fiber support, and the OH groups in amidoxime group had interacted with Fe(bpy)32+. Upon visible light irradiation, the catalyst was found to be highly effective for the degradation and mineralization of Rhodamine B at a neutral pH and could be easily recycled without any loss of activity. The interaction of OH groups with Fe(bpy)32+ groups was considered to be responsible for the high catalytic performance since the Fe(bpy)32+ supported on unmodified PAN fiber did not show any photoactivity. The OH groups in conjunction with 2,2′-bipyridine ligands may provide a flexible bifunctional coordination environment for iron (II/III) ions. ESR studies indicate that hydroxyl radicals are involved in this photocatalysis process, and a possible mechanism is proposed.

A facile synthesis of iron functionalized hierarchically porous ZSM-5 and its visible-light photocatalytic degradation of organic pollutants

The hierarchically porous and iron-functionalized zeolite ZSM-5 has been fabricated as a Fenton photocatalyst by a facile post-treatment process, which exhibits an excellent visible-light catalytic property in the adsorption/degradation of organic pollutants under mild reaction conditions.

Photodegradation of Phenol over a Hybrid Organo-Inorganic Material: Iron(II) Hydroxyphosphonoacetate

Water treatment is a hot topic, and it will become much more important in the decades ahead. Advanced oxidation processes are being increasingly used for organic contaminant removal, for example using photo-Fenton reactions. Here we report the use of an organo-inorganic hybrid, Fe[HO3PCH(OH)COO]·2H2O, as Fenton photocatalyst for phenol oxidation with H2O2 under UVA radiation. Preactivation, catalyst content, and particle size parameters have been studied/optimized for increasing phenol mineralization. Upon reaction, iron species are leached from the catalyst making a homogeneous catalysis contribution to the overall phenol photo-oxidation. Under optimized conditions, the mineralization degree was slightly larger than 90% after 80 min of irradiation. Analysis by X-ray photoelectron spectroscopy revealed important chemical modifications occurring on the surface of the catalyst after activation and phenol photodegradation. The sustained slow delivery of iron species upon phenol photoreaction is advantageous ...

Preparation and photocatalytic performance of Fe (III)-amidoximated PAN fiber complex for oxidative degradation of azo dye under visible light irradiation

Polyacrylonitrile (PAN) fiber was modified with hydroxylamine hydrochloride to introduce amidoxime groups onto the fiber surface. These amidoxime groups were used to react with Fe (III) ions to prepare Fe (III)-amidoximated PAN fiber complex, which was characterized using SEM, XRD, FTIR, XPS, DMA, and DRS respectively. Then the photocatalytic activity of Fe–AO–PAN was evaluated in the degradation of a typical azo dye, C. I. Reactive Red 195 in the presence of H 2O 2 under visible light irradiation. Moreover, the effect of the Fe content of Fe–AO–PAN on dye degradation was also investigated. The results indicated that Fe (III) ions can crosslink between the modified PAN fiber chains by the coordination of Fe (III) ions with the amino nitrogen atoms and hydroxyl oxygen atoms of the amidoximation groups to form Fe (III)-amidoximated PAN fiber complex, and the Fe content of which is mainly determined by Fe (III) ions and amidoximation groups. Fe (III)-amidoximated PAN fiber complex is found to be activated in the visible light region. Moreover, Fe (III)-amidoximated PAN fiber complex shows the catalytic activity for dye degradation by H 2O 2 at pH = 6.0 in the dark, and can be significantly enhanced by increasing light irradiation and Fe content, therefore, it can be used as a new heterogeneous Fenton photocatalyst for the effective decomposition of the dye in water. In addition, ESR spectra confirm that Fe (III)-amidoximated PAN fiber complex can generate more OH radicals from H 2O 2 under visible light irradiation, leading to dye degradation. A possible mechanism of photocatalysis is proposed.