Magnetic Photocatalyst Research Articles

Novel Carbon@BaMoZrFe12O19 photocatalytic peroxymonosulfate activation for ibuprofen removal

This study reports a successful synthesis of a novel Carbon@BaMoZrFe12O19 M-hexaferrite photocatalyst (NPs) using the coprecipitation method. Afterthat, the NPs were used as an activator for peroxymonosulfate (PMS) to remove ibuprofen (IBU) from water. NPs were subjected for a thorough characterization process utilizing various analytical techniques including XRD, FTIR, UV, PL TEM, SEM/EDS, and X-ray photoelectron spectroscopy (XPS). Significantly, the utilization of NPs for PMS activation demonstrated a notable improvement in the elimination of IBU under visible light. The research conducted a thorough investigation into the effects of various parameters, such as activating systems, initial pH, inorganic salts, IBU contents, and water matrix on the efficiency of IBU degradation. The significance of reactive oxygen species, such as sulfate and hydroxyl radicals, as well as singlet oxygen, in the removal of IBU, was clarified by chemical quenching tests. In addition, NPs exhibited competent magnetic separation and reprocessing capacities. The magnetic NPs revealed excellent constancy and recyclability, by sustaining degrading productivity after five consecutive cycles. Therefore, the present study offers a significant contributions to the understanding of photocatalytic degradation for organic pollutants through the utilization of magnetic photocatalysts.

Surfactant-driven modifications to AlFeO3 for degradation of emerging antibiotic contaminants

We show that residues of unused antibiotics Sulfamethoxazole (SMZ) and tetracycline (TC) in wastewater can be treated by photocatalytic degradation. Here, a magnetic photocatalyst known as aluminum ferrite (AlFeO3) is employed to assess the degradation of SMZ and TC under visible light conditions. The structural and functional properties of co-precipitated AlFeO3 with four different surfactants are examined. The little-known relevance of surfactant usage in AlFeO3 synthesis, its characteristics, and its impact on emergent particle morphology for SMZ and TC degradation is reported. The results indicate that the catalyst can completely (100 %) degrade SMZ and TC in ∼60 mins. We propose a distinct degradation pathway for the same. Significantly, AlFeO3 can decompose TC and SMZ to yield rather small compounds (m/z ∼ 60), thereby showing potential for practical use. Also, the use of different surfactants indicates that surface potential plays a significant role in photocatalytic degradation. Despite the large size and low surface area, AlFeO3 performed well due to the surface potential of the catalyst. Findings suggest that using bulk catalysts with adjusted surface potentials offers sufficient performance, thereby bypassing the need for nano-sizing and concern about nano-toxicity. Further, the magnetic property of AlFeO3 facilitates the recovery and reuse of the catalyst post-degradation.

Magnetic and visible light-induced novel green synthesized magnetic Co3O4 photocatalysts via sunflower seed meal extract for anionic and cationic dye removal by adsorption assisted photocatalytic degradation

This study was aimed at the preparation of m-Co3O4 NPs (magnetic Co3O4 nanoparticles) from sunflower seed meal (SFSM) which is the waste of sunflower seed oil factories, and their application as a photocatalyst for the adsorption assistant photocatalysis degradation of methylene blue (MB), and direct yellow-50 (DY-50) under the visible irradiations. Also, the photocatalytic performance of m-Co3O4 NPs was evaluated in synthetic wastewater. The produced m-Co3O4 NPs were ferromagnetic with a saturation magnetization value of 4.3 emu g−1 and the degradation of cationic MB and anionic DY-50 dyes by 100% and 93% in 20 min and 35 min, respectively, by adsorption-assisted photocatalytic process under visible light was achieved. The reactions were found to be pseudo-second-order equation for the adsorption-assisted photocatalytic process for both dyes. The photocatalytic activity of m-Co3O4 NPs decreased slightly even after five repeated cycles. These results show that the m-Co3O4 NPs can be used successfully in dye treatment in wastewater with their adsorption-assisted photocatalytic properties, activation by visible light, magnetic separability, and low-cost production.

Insight into efficient photocatalytic degradation of norfloxacin over a simple, economical biochar-based magnetic photocatalyst under solar illumination: a statistical and experimental approach.

The transformation of residual agricultural solid waste into an efficient value-added carbon product has been an ongoing strategy for solid waste management and a sustainable economy. Meanwhile, the upsurgence of antibiotic contamination in water bodies due to their inadvertent use poses a serious threat to human health and leads to antimicrobial resistance. Hence, to neutralize two evils in one stroke simultaneously, a simple, easy, and cost-effective pea shell-based magnetic photocatalyst (PSMC) has been synthesized and characterized by XRD (X-ray diffraction), VSM (vibrating sample magnetometer), XPS (X-ray photoelectron spectroscopy), TGA (thermogravimetric analysis), and FTIR (Fourier-transform infrared) spectroscopy techniques. Batch experimental studies revealed that PSMC efficiently eliminates norfloxacin (91.3%) within 180min from wastewater and mineralizes it into innocuous products at optimum parameters of norfloxacin concentration of 20mg/L, catalyst dosage of 15mg, and pH 3.5. Additionally, statistical parameters for the photodegradation of NX obtained from ANOVA by applying the Box-Behnken design are in close agreement with batch experiment parameters. PSMC has surplus advantages of facile recovery for recycling up to seven consecutive cycles by an external magnet and efficacy in natural solar light, making it cost-effective and economical. Radical scavenging studies revealed that O2•- and OH• were the potent reactive species in the photocatalytic degradation process.

Demonstrating Synergistic Activity of Magnetic Iron Oxide Nano Photocatalyst for C-H Activation in Heterogeneous Phase.

This report describes a dual catalytic approach for the versatile C‒H arylation of arenes under photo-excitation at room temperature. The cooperative catalysis utilizes iron oxide magnetic nanoparticles (which mostly contain Fe3O4 along with some γ-Fe2O3) as the potential photocatalyst, which merges with the Pd-catalyzed C‒H activation cycle for the reductive generation of aryl radical from aryl diazonium salt, revealing its photocatalytic activities. The method is applicable to a wide range of aryl coupling partners and different directing groups, demonstrating excellent productivity, nice co-operativity and recyclability. Adequate control experiments and mechanistic studies assisted in establishing the radical-based mechanism for the C‒H arylation occurring in the heterogeneous phase.

Graphitic carbon nitride (g-C3N4)-based magnetic photocatalysts for removal of antibiotics

Graphitic carbon nitride (g-C3N4)-based magnetic photocatalysts for removal of antibiotics

Novel synthesis organic–inorganic heterojunctions of protonated g-C3N4/Fe3O4/AgBr/AgCl/AgI quinary magnetic photocatalyst with enhanced visible-light photocatalytic degradation of methylene blue in water

A novel magnetic quinary nanocomposite, protonated g-C3N4/Fe3O4/AgBr/AgCl/AgI, was synthesized using a wet chemical method. The multi-heterojunction photocatalyst with multi-carrier source and multi-channel carrier transport is constructed to enhance the photocatalytic degradation performance of pure g-C3N4. The design of the quinary nanocomposite is also an effective approach to solve the chemical stability problem of silver halides. The photocatalytic degradation efficiency under visible light irradiation was analyzed for methylene blue (MB) as the target organic pollutant. The quinary nanocomposite with 10 % g-C3N4 displayed high photocatalytic performance, with 83 % of MB degraded under 6 h LED white light irradiation. The effective quinary nanocomposite has good magnetic properties and can be magnetically separated to prevent secondary pollution of the photocatalyst in water. Parameters such as initial concentration of pollutant, initial solution pH, and light source were studied. Zeta potential results showed that the quinary nanocomposite could disperse homogenously to decrease aggregation in the solution. The photocatalytic degradation mechanism was investigated, and the mineralization results were analyzed based on liquid chromatography-mass spectroscopy (LC-MS) and total organic carbon (TOC). It was found that the hydroxyl and superoxide radicals were major reactive species by scavenging experiments. Additionally, protonated g-C3N4/Fe3O4/AgBr/AgCl/AgI nanocomposite showed excellent reusability after magnetic separation and regeneration, thus suggesting it to be a promising photocatalyst for treating wastewater containing organic contaminants.

Photothermal-assisted magnetic recoverable Cd0.9Zn0.1S/NiCoB heterojunction with extraordinary photocatalytic hydrogen evolution

Easily recyclable photocatalysts hold great potential in the field of photocatalysis. Guided by rational theoretical predictions, this study designs a novel tetrapod-like Cd0.9Zn0.1S/NiCoB (CZS/NCB) Schottky heterojunction with magnetic and photothermal properties, and demonstrates its excellent photocatalytic hydrogen evolution performance. Under the combined effects of the photothermal properties and the Schottky heterojunction, the photocatalytic hydrogen evolution rate extraordinarily reaches 108.39 mmol g−1 h−1 after 3 h of visible light irradiation, which is 4.69 times that of pure CZS. Additionally, photocatalytic hydrogen evolution tests conducted using infrared thermography and alternating visible and visible plus infrared light irradiation have confirmed the material’s outstanding photothermal properties. In-depth density functional theory (DFT) calculations reveal potential charge transfer pathways and confirm the formation of the Schottky heterojunction. This work provides guidance for the rational construction of magnetic recoverable photocatalysts with practical application.

Preparation and photocatalytic mechanism of magnetic Ag2S/CoFe1.95Dy0.05O4 Z‐scheme heterojunction

AbstractThe synthesis of high‐efficiency magnetic composite photocatalyst by doping magnetic cobalt ferrite and compounding single semiconductor photocatalyst is a promising strategy to improve the oxidation ability of photocatalytic systems. In this paper, CoFe1.95Dy0.05O4 (CFDO) was prepared by doping Dy element into magnetic CoFe2O4, and Ag2S (AS)/CFDO with high‐efficiency magnetic photocatalyst was synthesized by compounding AS with CFDO as the substrate. The photocatalytic samples were characterized by different advanced characterization methods, and their photocatalytic degradation of methylene blue (MB) was studied. The results show that AS/CFDO exhibits higher visible light response, excellent photogenerated charge separation ability and migration efficiency, and excellent catalytic performance in the catalytic degradation system. The photocatalytic activity of AS/CFDO was the highest, and its photocatalytic degradation kinetic constant K was 2.48 and 1.54 times that of AS and CFDO, respectively. In addition, the catalyst contained in the catalytically contaminated solution can be effectively separated by an external magnetic field to achieve multiple cycles of degradation and recycling. The cyclic degradation experiments showed that AS/CFDO exhibited high degradation stability during the photodegradation process. After the fifth reuse, the degradation efficiency was still more than 88.0%. Finally, the possible photocatalytic mechanism of the samples was discussed. Therefore, this work provides an effective solution for the construction of photocatalysts with high efficiency, magnetic recovery, and cyclic degradation stability and avoids the secondary pollution of catalysts to organic wastewater. It is of great significance to create an environmentally friendly catalytic method for efficient cyclic degradation of organic wastewater.

Catalyzing the metabolism through CoFe2O4 magnetic photocatalyst for photo fermentative biohydrogen production: Selectivity and recyclability across diverse strains

The interaction between the photo-induced charges from photo nanocatalysts (PNCs) and biohydrogen production strains plays a key role in controlling the metabolism mechanism in fermentative biohydrogen production from lignocellulosic biomass wastes. Thus, in the present study, two strains of Rhodopseudomonas palustris (PNSB) and a mixed consortium of HAU-M1 were evaluated for their biohydrogen production potential from corn stover (CS), whereas metabolism was catalyzed through photo-induced electrons from magnetic PNCs of cobalt ferrite (CoFe2O4). The threshold concentration of CoFe2O4 (400 mg/L) produced 428.62 mL and 373.30 mL biohydrogen in PNSB and HAU-M1, which is 129.0 % and 81.12 % higher as compared to respective control groups (CGs), respectively. The presence of PNCs provides the photo-induced electrons, which catalyze the metabolic processes as butyric acid increases by 96.29 % and 94.87 % in PNSB and HAU-M1, respectively, hence increasing hydrogen production. The results were supported by microbial community investigation, which showed that the incorporation of the appropriate concentration of PNCs effectively changes the bacterial community dynamics and diversifies the phyla (Firmicutes, Proteobacteria, and Bacteroidetes) and hydrogen-producing genus Clostridium. The recovered yield of CoFe2O4 PNCs from PNSB and HAU-M1 fermentative mediums in three consecutive cycles was (90.87 %, 88.94 %), (80.25 %, 72.25 %), and (69.75 %, 60.80 %) respectively showing potential for recycling catalysts during the fermentation process. Thus, selecting the right photocatalysts and strain can affect metabolism and biohydrogen production, while recyclability reduces environmental leaching.

Synthesis and characterization of CuCoFe2O4@GA/AC as a bio-based matrix magnetic nano-heterogeneous photocatalyst for ceftriaxone degradation from aqueous media

Emerging contaminants such as ceftriaxone are a significant issue in the environment. They have led to a series of ecological, environmental, and health issues, and it is urgent to find a green and secure method to remove antibiotics from water effectively. In this research, the CuCoFe2O4@Gum Arabic (GA)/Activated Carbon (AC) as an innovative bio-based matrix magnetic nanocatalyst was synthesized for the efficient degradation of ceftriaxone from aqueous media. The structure of CuCoFe2O4@GA/AC was characterized via FESEM, EDS, Mapping, XRD, FTIR, VSM, and DRS analyses. The structural analysis of the catalyst revealed its synthesis at the nanometer scale (40–50 nm), exhibiting high magnetic strength (Ms: 5.38 emu/g) and favorable optical properties with a bandgap of 3.6 eV. Under optimized conditions, including a pH of 5, 60 min of irradiation time, 0.24 g/L photocatalyst dose, and ceftriaxone concentration of 5 mg/L, the removal efficiency from synthetic and real samples was 94.43% and 62.5%, respectively. The photocatalytic degradation process of ceftriaxone followed pseudo-first-order and Langmuir–Hinshelwood kinetic models. Furthermore, analysis of the process mechanism indicated a prominent role of the superoxide radical. The catalyst had a high recovery capability and chemical stability. The photocatalytic degradation of ceftriaxone by CuCoFe2O4@GA/AC showcased remarkable efficiency, indicating its potential utility in the treatment of wastewater contaminated with antibiotics.

Mesoporous g-C3N4/ZnFe2O4/TCPP nanocomposite for selective liquid-phase oxidation of alcohols to aldehydes under visible light irradiation

This study provides a viable strategy for the production of aromatic benzaldehydes by a three-component magnetic recoverable photocatalyst. The novel photocatalyst was fabricated by modification of Graphitic carbon nitride (g-C3N4) using ZnFe2O4 magnetic nanoparticles and Tetrakis(4-carboxyphenyl)porphyrin (TCPP) and labeled as CFP where C is the carbonic substrate, F shows the magnetic component and P demonstrated TCPP porphyrin. The optimized CFP photocatalyst demonstrated approximately 96 % conversion and 99 % selectivity for the oxidation of benzyl alcohol to benzaldehyde. The photocatalytic reaction carried out in the presence of acetonitrile and H2O2 as solvent and oxidant under LED lamp (15 W) irradiation. The results reveal that the values of conversion and selectivity of various types of benzylic alcohols are attributed to the aromaticity and position of substituents on the benzene ring. The reusability of CFP photocatalyst was investigated up to the fourth cycle, and it revealed any significant loss of photocatalytic oxidation activity, which is related to high structural stability of photocatalyst.

Production of magnetic photocatalysts from TiO2, Fe(NO3)3 and sucrose and their application for the degradation of model organic contaminants

AbstractBACKGROUNDPhotocatalysis is an efficient method for the removal of organic contaminants in wastewater. In this study, different magnetic photocatalysts for the degradation of organic compounds were prepared.RESULTSTi/C/Fe photocatalysts were prepared by supporting TiO2 (20, 40 and 60% w/w) on a carbon/iron oxide (C/Fe) magnetic carrier. Characterization via Raman spectroscopy, X‐ray diffractometry, thermal analysis, X‐ray fluorescence, scanning electron microscopy and energy‐dispersive X‐ray spectroscopy/elemental mapping and magnetic property analysis by vibrating‐sample magnetometry confirmed the presence of TiO2, Fe3O4, Fe3C and char in the photocatalysts as well as their magnetic properties. The results of specific surface area analysis showed that the C/Fe support had a surface area of 183 m2 g−1 and that this area decreased with an increasing amount of supported TiO2, reaching up to 129 m2 g−1. Diffuse reflectance spectroscopy characterization revealed that the bandgap values obtained for the photocatalysts (Ti/C/Fe) were lower than 3.2 eV. The prepared photocatalysts showed high efficiency in degrading the contaminants Remazol Black (RB5) (99%), paracetamol (77%) and phenol (90%). Recovery and reuse experiments using RB5 showed that after the fourth reaction, the photocatalytic efficiency was reduced by 50%, and the recovery reached up to 70%. Sedimentation kinetics showed that while only 6% of the TiO2 was deposited, up to 89% of the photocatalysts were deposited.CONCLUSIONSThese results indicate that the photocatalysts showed excellent photocatalytic efficiency for different contaminants and can be easily and quickly separated from the reaction medium by magnetic separation. © 2024 Society of Chemical Industry (SCI).

Optimisation of nickel ferrite production conditions for the preparation of magnetic composite photocatalysts

Ferrites of non-ferrous metals are promising magnetic catalysts that can be easily separated from the reaction mixture after use by applying a magnetic field. However, these materials have a fast electron-hole relaxation time, which reduces their activity in photoreactions. This problem is overcome by creating hybrid nanostructures based on ferrites, for example with zinc oxides. The catalytic activity of such structures depends highly on the method of their synthesis. In this work, the alkaline co-precipitation of Fe2+ and Ni2+ ions, which have similar values for hydroxides, was used to obtain stoichiometric and homogeneous nickel ferrite precursors. The influence of the reaction parameters on the purity of the nickel ferrite phase and the size of the particles was studied using the experimental design technique. Spherical nanoparticles 15.9 ± 1.1 nm in diameter were produced under the optimal conditions identified. Based on the obtained material, NiFe2O4/ZnO magnetic composites of different quantitative compositions were prepared. The photocatalytic activity of the hybrid structures was demonstrated by photodegradation of crystal violet dye.

Magnetic composite photocatalyst NiFe₂O₄/ZnIn₂S₄/biochar for efficient removal of antibiotics in water under visible light: Performance, mechanism and pathway

The widespread presence of antibiotics in aquatic environments, resulting from excessive use and accumulation, has raised significant concerns. A NiFe₂O₄/ZnIn₂S₄/Biochar (NFO/ZIS/BC) magnetic nanocomposite was successfully synthesized, demonstrating significantly enhanced electron-hole separation properties. Comprehensive investigations were conducted to evaluate the impact of various parameters, including catalyst mass, pH, and the presence of co-existing ions on the composite's performance. The nanoparticles of NiFe₂O₄ (NFO) and ZnIn₂S₄ (ZIS) were found to improve the surface stability and sulfamethoxazole removal capabilities of porous biochar, while also demonstrating high total organic carbon removal efficiencies. •O₂⁻ and h⁺ were identified as the predominant reactive oxygen species (ROS) in NFO/ZIS/BC-4 during the degradation process. The degradation outcomes of sulfamethoxazole under natural sunlight and water conditions were consistent with laboratory findings, affirming the robust applicative potential of NFO/ZIS/BC. Density functional theory (DFT) calculations were performed to elucidate the photocatalytic mechanism and identify potential intermediate products. Additionally, the types of heterojunctions present in the system were characterized and discussed. After multiple iterations, NFO/ZIS/BC-4 maintained effective photodegradation capabilities through five cycles. This study presents an effective method for the treatment of antibiotics in aquatic environments, offering significant potential for environmental applications.

Enhanced Photocatalytic Methylene Blue Degradation and Chromium(VI) Photoreduction under Sunlight by Fe3O4@rGO@CeO2/Nd2O3 as Magnetic Recyclable Photocatalyst

Enhanced Photocatalytic Methylene Blue Degradation and Chromium(VI) Photoreduction under Sunlight by Fe3O4@rGO@CeO2/Nd2O3 as Magnetic Recyclable Photocatalyst

Fabrication and characterization of a novel magnetic recyclable ternary photocatalyst Dy(OH)3/ZnO/SrFe12O19

In this work, a novel magnetic photocatalyst Dy(OH)3/ZnO/SrFe12O19 (DZS) was prepared by simple hydrothermal method. Especially, 15-DZS-5 (Dy(OH)3 15 %, SrFe12O19 5 %) had the highest photocatalytic activity, and could completely degrade RhB when exposed to simulative sunlight for 70 min. Furthermore, 15-DZS-5 has the widest photoresponse range, the narrowest band gap, the lowest electron hole recombination rate and the best conductivity due to the photosensitization effect of SrFe12O19 and Dy(OH)3 successfully separating the electrons and holes of ZnO by photoelectron capture. In addition, the saturation magnetization of 15-DZS-5 is 3.9 emu/g, and the degradation of RhB is over 88 % after five cycles, showing good magnetic recovery and stable photocatalytic activity. ·OH and ·O2− were the chief active groups in the photocatalytic RhB with 15-DZS-5 sample, and the influence of ·OH was more significant.

Enhanced photocatalytic performance of NiFe2O4/ZnIn2S4 p-n heterojunction for efficient degradation of tetracycline

The persistent release of tetracycline into the environment significantly endangers both ecosystems and human health. Zinc indium sulfide (ZnIn2S4) capable to degrade tetracycline pollutants under visible light irradiation has attracted extensive attentions and great effort has been devoted to augment its catalytic efficacy. In this work, we synthesized a p-n heterojunction, NiFe2O4/ZnIn2S4, to enhance the carrier migration rate and explained the intrinsic mechanism by density functional theory. When the heterojunction was formed, carriers traversed from the n-type NiFe2O4 to the p-type ZnIn2S4, instigating the emergence of a built-in electric field to facilitate the separation of carriers. 2 %-NiFe2O4/ZnIn2S4 exhibited excellent photocatalytic efficiency in tetracycline (TC) degradation and total organic carbon (TOC) removal. Compared to pure ZnIn2S4 and NiFe2O4, the TC degradation rates of 2 %-NiFe2O4/ZnIn2S4 were 2.0 times and 16.9 times higher, respectively. Additionally, 2 %-NiFe2O4/ZnIn2S4 had a saturation magnetization intensity of 3.05 emu/g, allowing for rapid recovery of the catalyst under a magnetic field. Superoxide radicals (O2−) and holes (h+) were the primary active species driving the degradation process. Furthermore, potential reaction pathways of tetracycline in this photocatalytic process were determined and bioconcentration factor and developmental toxicity of the intermediate products were accessed. This work held great potentials for wastewater treatment and provided a pathway for the development of magnetic recyclable photocatalysts.

Photothermal-enhanced magnetic Cd0.9Zn0.1S/CoB Schottky heterojunction toward photocatalytic hydrogen evolution

The construction of heterojunctions effectively suppresses the undesired recombination of photogenerated charge carriers. This work presents the rational design and preparation of a novel Cd0.9Zn0.1S/CoB (CZS/CoB) Schottky heterojunction tailored for photothermal-assisted photocatalytic hydrogen evolution with the aid of the predictions of density functional theory (DFT). Under visible light irradiation, the hydrogen evolution rate of CZS/CoB reaches 2.56 times that of pure CZS, due to the formed Schottky heterojunction and photothermal properties, effectively inhibiting electron-hole recombination and boosting the photocatalytic reaction. Notably, with the help of the excellent magnetic properties of CoB, the as-synthesized CZS/CoB exhibits excellent magnetic separation property, which is crucial for practical application. The charge transfer pathways in the Schottky heterojunction were confirmed by experimental results and verified by DFT calculation results. This study presents a feasible strategy for the design and preparation of magnetic recyclable Schottky Heterojunction photocatalyst for photocatalytic hydrogen evolution.

Optimization of Nickel Ferrite Production Conditions for the Preparation of Magnetic Composite Photocatalysts

Optimization of Nickel Ferrite Production Conditions for the Preparation of Magnetic Composite Photocatalysts