Preparation of novel flower-like BiVO4/Bi2Ti2O7/Fe3O4 for simultaneous removal of tetracycline and Cu2+: Adsorption and photocatalytic mechanisms

Amino-functionalized cellulose composite for efficient simultaneous adsorption of tetracycline and copper ions: Performance, mechanism and DFT study

A novel cellulose composite (denoted as PEI@MMA-1) with porous interconnected structure was prepared by adsorbing methyl cellulose (MC) onto microcrystalline cellulose (MCC) and cross-linking polyethyleneimine (PEI) with MCC by the action of epichlorohydrin, which had the excellent adsorption property, wettability and elasticity. The performances of PEI@MMA-1 composite for removing tetracycline (TC), Cu2+ and coexistent pollutant (TC and Cu2+ mixture) were systematically explored. For single TC or Cu2+ contaminant, the maximum adsorption capacities were 75.53 and 562.23 mg/g at 30 °C, respectively, while in the dual contaminant system, they would form complexes and Cu2+ could play a "bridge" role to remarkably promote the adsorption of TC with the maximum adsorption capacities of 281.66 and 253.58 mg/g for TC and Cu2+. In addition, the adsorption kinetics, isotherms and adsorption mechanisms of single-pollutant and dual-pollutant systems have been thoroughly investigated. Theoretical calculations indicated that the amide group of TC molecule with the assistance of Cu2+ interacted with the hydroxyl group of PEI@MMA-1 composite to enhance the TC adsorption capacity. Cycle regeneration and fixed bed column experiments revealed that the PEI@MMA-1 possessed the excellent stability and utility. Current PEI@MMA-1 cellulose composite exhibited a promising application for remediation of heavy metals and antibiotics coexistence wastewater.

Contamination distribution and non-biological removal pathways of typical tetracycline antibiotics in the environment: A review

While the occurrence and removal technologies of tetracyclines in the environment have been reported, a comprehensive systematic summary and analysis remain limited, especially for new generations compounds such as doxycycline. In this review, the latest information regarding the distribution of various tetracyclines in different countries over the past seven years (2017-2023) reveals a notable absence of research reports in North America and Oceania. With China as the representative country, the investigation indicates that the maximum concentrations of TCs exceed 5 µg/L. The maximum concentration of tetracyclines in feces (26.22 µg/L) can reach one order of magnitude higher than that in other media. Furthermore, advanced oxidation technologies, such as Fenton processes, electrochemical oxidation, photolysis, ozonation, etc., were also examined, and the median degradation rate achieved 91.9-97.67%. Reactions such as methylation, demethylation, hydroxylation, dehydration, ring cleavage, and oxidation were observed during degradation. The most common intermediate product was identified as m/z = 461 (C22H25N2O9). This review indicates that future efforts should emphasize understanding the occurrence and fate of new-generation tetracyclines in the environment.

Repeated fluctuation of Cu2+ concentration during photocatalytic purification of SMZ-Cu2+ combined pollution: Behavior, mechanism and application

Although the effect of Cu²⁺ on antibiotic removal during photocatalytic reaction has been studied in depth, there is less known about the effect of antibiotics on Cu²⁺ removal. In this study, we report for the first time that, during the photocatalytic purification of sulfamerazine (SMZ) and Cu²⁺ combined pollution, Cu²⁺ concentration showed an obvious five-stage fluctuation, which was completely different from the simple promotion or inhibition reported in previous studies. By employing HPLC-MS analysis and density functional theory (DFT) calculation, the repeated fluctuation of Cu²⁺ concentration was found to be closely related to the SMZ degradation process, mainly resulting from solution pH drop and formation of Cu-containing intermediates which acted as sacrificial agents for Cu²⁺ reduction. In addition, compared with the SMZ-free system, the presence of SMZ can greatly enhance the deep removal of Cu²⁺ (minimum Cu²⁺ concentration was only 0.17 mg/L vs. 1.28 mg/L without SMZ), and there was a wide time interval to ensure the efficient recovery of Cu metal. More interestingly, the in-situ obtained Cu-decorated TiO₂ photocatalyst performed well in water splitting, nitrogen fixation and bacterial sterilization. Results of this study confirmed the great potential of photocatalytic technology in purifying antibiotic-heavy metal combined pollution.

Synergistic removal of organic pollutants from water by CTF/BiVO4 heterojunction photocatalysts

Herein, a series of covalent triazine framework/bismuth vanadate (CTF/BiVO₄) heterojunction catalysts were prepared using the hydrothermal method. The mechanism of the CTF/BiVO₄ heterojunction photocatalyst in the system was examined to provide a theoretical basis for constructing a high-efficiency photocatalysis composite system for removing organic pollutants from water. Compared with CTF and BiVO₄ catalysts alone, composite materials have been shown to have significantly higher degradation efficiencies against organic pollutants in water. Moreover, the degradation effect was found to be optimal when the mass ratio of CTF to BiVO₄ was 1:1 (1-CTF/BiVO₄). On the basis of physicochemical characterization results, it was concluded that the effective construction of CTF/BiVO₄ composite photocatalyst material systems and the formation of type II heterojunction structures between CTF and BiVO₄ effectively promote the separation of photogenerated carriers and increase the interface charge transfer efficiency.

Preparation of BiFeO3 and photodegradation of tetracycline pollutant in the UV-heterogeneous Fenton-like system

Surplus tetracycline in the water body causes damage to the ecology balance and human health. Therefore, this work established an efficient strategy, namely, the BFO-based UV-heterogeneous Fenton-like system, to eliminate TC pollution. The photocatalytic oxidation system has been integrated with the heterogeneous Fenton-like system, cooperated with the photolysis of H₂O₂. These synergistic effects could boost the generation of reactive species for the TC degradation and mineralization, due to the reduction of Fe(III) to Fe(II) by photogenerated electrons and the separation of photogenerated electron-hole pairs. The prepared BFO was stable with no secondary pollution, and could be recovered by an extra magnet to reuse. Compared with other single oxidation systems, this coupled system showed an outstanding performance in TC disposal, and TC and TOC removal efficiencies could reach 100% and 74.92%, respectively. Moreover, the mechanisms for TC degradation involved that TC was degraded by oxidation species, such as superoxide radicals, hydroxyl radicals, and positive holes, and intermediate products in the TC degradation process mainly were products at m/z = 459, m/z = 445, and m/z = 134. The promising TC disposal efficiency achieved by the integration between BFO-based photocatalytic and heterogeneous Fenton-like system sheds light on applying BFO to control water pollution.

Recent development on core-shell photo(electro)catalysts for elimination of organic compounds from pharmaceutical wastewater

Pharmaceutical organics are a vital milestone in contemporary human research since they treat various diseases and improve the quality of human life. However, these organic compounds are considered one of the major environmental hazards after the conception, along with the massive rise in antimicrobial resistance (AMR) in an ecosystem. There are various biological and catalytic technologies existed to eliminate these organics in aqueous system with their limitation. Advanced Oxidation processes (AOPs) are used to decompose these pharmaceutical organic compounds in the wastewater by generating reactive species with high oxidation potential. This review focused various photocatalysts, and photocatalytic oxidation processes, especially core-shell materials for photo (electro)catalytic application in pharmaceutical wastewater decomposition. Moreover, we discussed in details about the design and recent developments of core shell catalysts and comparison for photocatalytic, electrocatalytic and photo electrocatalytic applications in pharmaceutical wastewater treatment. In addition, the mixture of inorganic and organic core-shell materials, and metal-organic framework-based core-shell catalysts discussed in detail for antibiotic degradation.

Synthesis of magnetic nanocomposite Fe3O4@ZIF-8@ZIF-67 and removal of tetracycline in water

We prepared a double-layer magnetic nanocomposite Fe₃O₄@ZIF-8@ZIF-67 by layer-by-layer self-assembly. Fe₃O₄@ZIF-8@ZIF-67 was used to remove tetracycline from an aqueous solution via a combination of adsorption and Fenton-like oxidation. Depending on the outstanding porous structure of the Fe₃O₄@ZIF-8@ZIF-67, a high adsorption capacity for tetracycline was 356.25 mg g^-1, with > 95.47% removal efficiency within 100 min based on Fenton-like oxidation. To better understand the mechanisms involved in integrated adsorption and Fenton-like oxidation, various advanced characterization techniques were used to monitor the changes in morphology and composition of Fe₃O₄@ZIF-8@ZIF-67 before and after removal of tetracycline. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) all supported adsorption and Fenton oxidation of tetracycline. This study extends the application of Fe₃O₄@ZIF-8@ZIF-67 for environmental remediation.

Simultaneous decontamination of multi-pollutants: A promising approach for water remediation

Water remediation techniques have been extensively investigated due to the increasing threats of soluble pollutants posed on the human health, ecology and sustainability. Confronted with the complex composition matrix of wastewater, the simultaneous elimination of coexisting multi-pollutants remains a great challenge due to their different physicochemical properties. By integrating multi-contaminants elimination processes into one unit operation, simultaneous decontamination attracted more and more attention under the consideration of versatile applications and economical benefits. In this review, the state-of-art simultaneous decontamination methods were systematically summarized as chemical precipitation, adsorption, photocatalysis, oxidation-reduction, biological removal and membrane filtration. Their applications, mechanisms, mutual interactions, sustainability and recyclability were outlined and discussed in detail. Finally, the prospects and opportunities for future research were proposed for further development of simultaneous decontamination. This work could provide guidelines for the design and fabrication of well-organized simultaneous decontaminating system.

A critical review on bismuth oxyhalide based photocatalysis for pharmaceutical active compounds degradation: Modifications, reactive sites, and challenges

Pharmaceutical active compounds (PhACs), as a kind of widely used pharmaceutical drugs, has attracted much attention. The bismuth oxyhalides (BiOX)-based photocatalysis can remove PhACs efficiently due to its unique layered structure, optical and electronic properties. Nevertheless, the rapid recombination of photogenerated electron-hole pairs, and the inherent instability of structure have limited its practical application. In order to solve these problems, recent modification studies tend to focus on facet control, elemental doping, bismuth-rich strategies, defect engineering and heterojunction. Therefore, the objective of this review is to summarize the recent developments in multiply modified strategies for PhACs degradation. The synthesis methods, photocatalytic properties and the enhancement mechanism are elaborated. Besides, based on theoretical calculation, the reactive sites of typical PhACs attacked by different reactive oxygen species were also proposed. Subsequently, challenges and opportunities in applications are also featured which include factors, viz., dissolution of halogen ions, instability under visible light, applications of real water/wastewater, intermediates and byproducts toxicity analysis of BiOX-based photocatalysis. Finally, the perspectives of BiOX-based photocatalysis for PhACs photodegradation in actual water applications are highlighted.

Effective tetracycline removal from liquid streams of dairy manure via hierarchical poly (vinyl alcohol-co-ethylene)/polyaniline metal complex nanofibrous membranes

Antibiotic residues from animal wastes enter underground and surface water streams, posing high risks to public health. Novel technologies capable of removing the residues from the matrix of concern such as animal waste should be developed. This research investigates the development of nanofiber absorbent for removing tetracycline (TC) antibiotic residues from liquid streams of dairy manure produced in a typical dairy farm. Hierarchically structured nanofibrous adsorbent was developed through growing a uniform polyaniline (PAni) nanodots on poly (vinyl alcohol-co-ethylene) (EVOH) nanofiber membrane (NFM). Moreover, Cu²⁺ ions were chelated on the developed EVOH/PAni-Cl NFM to improve TC adsorption efficiency and selectivity. The TC adsorption capacities of EVOH/PAni-Cl-Cu²⁺ and EVOH/PAni-Cl) NFM were 1100 mg g^-1 and 600 mg g^-1 within 120 min., respectively. The NFMs adsorption efficiency was investigated using dairy wastewater. Initial TC concentrations in dairy wastewater sample varied between 20 and 50 ppm. The EVOH/PAni-Cl-Cu²⁺ NFM showed TC removal of 86% from dairy manure samples at 25 ppm initial TC concentration within 60 min. during batch mode treatment. Results showed that the dynamic binding efficiency of 450 mg g^-1 can be achieved at an initial TC concentration of 50 ppm. Furthermore, the NFM displayed efficient chemical and physical stability even after 8 cycles of reusing without significant changes in its performance or hazardous Cu²⁺ leaching.

Insights into mesoporous MCM-41-supported titania decorated with CuO nanoparticles for enhanced photodegradation of tetracycline antibiotic

In this research, tetracycline photodegradation under UV light was investigated over bare TiO₂ and a series of MCM-41 supported CuO-TiO₂ heterojunctions varying in CuO content with the intent of exploring the effect of MCM-41 presence and especially, CuO addition. Several techniques including XRD, FESEM, EDX, DRS, BET, and PL were applied to characterize the physicochemical and photophysical properties of synthesized nanocomposites. It was found that the co-existence of MCM-41 and CuO enhances the surface dispersion of Ti species, leading to less number of agglomerates and smaller particle size of TiO₂, which it promoted photophysical properties and reinforced the interaction of surface species with the support and thereby, the photosite leachings were lessened. However, the excessive loadings alleviate the synergetic effect of CuO due to the significant decrease of surface area, the appearance of more number of agglomerations, and surface coverage of MCM-41. The results revealed that CuO addition not only enhances the photocatalytic activity of TiO₂/MCM-41 but also makes it reusable in further experiments. It was also observed that the highest photodegradation of tetracycline was obtained over TiO₂-CuO/MCM-41 nanocomposite containing 5 wt% CuO. It is attributed to less electron-hole recombination, appropriate band gap, smaller number of agglomerations, and more uniform dispersion of photosites. Following the obtained results, a possible reaction mechanism was also proposed.

Application of graphene-based materials for removal of tetracyclines using adsorption and photocatalytic-degradation: A review

Tetracyclines are extensively used to treat human and animal infectious diseases due to its effective antimicrobial activities. About 70-90% of its parent materials are released into the environment through urine and feces, implying they are the most frequently detected antibiotics in the environment with high ecological risks. Adsorption and photocatalysis have been promising techniques for the removal of tetracyclines due to effectiveness and efficiency. Graphene-based materials provide promising platforms for adsorptive and photocatalytic removal of tetracyclines from aqueous environment owning to distinctive remarkable physicochemical, optical, and electrical characteristics. Herein, we intensively reviewed the available literatures in order to provide comprehensive insight about the applications and mechanisms of graphene-based materials for removal of tetracyclines via adsorption and phototocatalysis. The synthesis methods of graphene-based materials, the tetracycline adsorption and photocatalytic-degradation conditions, and removal mechanisms have been extensively discussed. Finally concluding remarks and future perspectives have been deduced and recommended to stimulate further researches in the subject. The review study can be used as theoretical guideline for further researchers to improve the current approaches of material synthesis and application towards tetracyclines removal.

Sepiolite supported BiVO4 nanocomposites for efficient photocatalytic degradation of organic pollutants: Insight into the interface effect towards separation of photogenerated charges

Although the construction of clay-supported photocatalyst is a promising strategy to develop the low cost and high activity photocatalyst, only few works researched the effect of their interfaces on the photocatalytic performance. Herein, a monoclinic BiVO₄/sepiolite nanocomposite was fabricated as case to study the transport mechanism of photogenerated carries based on the interfaces effect. The obtained BiVO₄/sepiolite nanocomposites exhibited excellent visible light photocatalytic performance. The photocatalytic degradation rates of antibiotic tetracyclines (TCs) and methylene blue (MB) by the nanocomposites are 2 and 5.34 times higher than that by pure BiVO₄ under visible light irradiation. XPS and Raman spectra confirmed the strong interfaces effect existing between BiVO₄ and sepiolite clay. Moreover, PL and transient photocurrent response suggested that the strong interfaces effect effectively promoted the separation of photogenerated electron-hole pairs and further enhanced the photocatalytic performance. In addition, the results of trapping experiments revealed that the photo-induced holes (h⁺) were the dominant active species in the photocatalytic mechanism. This work illuminates the photocatalytic mechanism of monoclinic BiVO₄/sepiolite nanocomposites and provides a novel strategy for designing the clay-supported photocatalyst for degradation of organic pollutants.

Fabrication of a double-layer membrane cathode based on modified carbon nanotubes for the sequential electro-Fenton oxidation of p-nitrophenol

To improve the electrocatalytic efficiency of the cathode and provide a wider pH range in the electro-Fenton process, N-doped multi-walled carbon nanotubes (NCNTs) and ferrous ion complexed with carboxylated carbon nanotubes (CNT-COOFe²⁺) were used to fabricate the diffusion layer and catalyst layer of a membrane cathode, respectively. The morphology, structure, and composition of CNT-COOFe²⁺ were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The oxygen reduction performance of NCNT was evaluated using cyclic voltammetry (CV) and the rotating disk electrode technique (RDE). In addition, a potential application of the cathode in sequential electro-Fenton degradation of p-nitrophenol (p-NP) was investigated. The results revealed that iron was successfully doped on the carboxylated carbon nanotubes in ionic complexation form and the content of iron atoms in CNT-COOFe²⁺ was 2.65%. Furthermore, the defects on the tube walls provided more reactive sites for the electro-Fenton process. A combination of CV and RDE data indicated that NCNT had better electrocatalytic H₂O₂ generation activity with a more positive onset potential and higher cathodic peak current response than CNT. A p-NP removal rate of 96.04% was achieved within 120 min, and a mineralization efficiency of 80.26% was obtained at 180 min in the sequential electro-Fenton process at a cathodic potential of - 0.7 V vs SCE and neutral pH. The activity of the used cathode was restored simply through electro-reduction at - 1.0 V vs SCE, and a p-NP removal rate of more than 70% was obtained at 60 min after six regeneration cycles.

Effects of divalent copper on tetracycline degradation and the proposed transformation pathway

To reveal the characteristics of tetracycline (TC) photocatalytic degradation under Cu(II) coexistence, effects of Cu(II) on TC photocatalytic degradation by ZnO nanoparticles (ZnO NPs) as a function of pH, humic acid (HA), and initial Cu(II) concentration were investigated. Interaction of TC with Cu(II) in the treatment process was analyzed by circular dichroism (CD) spectroscopy, while TC degradation pathway was investigated by high-performance liquid chromatography-mass spectrometry. Sixty-five percent and ninety-one percent TC degradation within 60 min in the absence and presence of Cu(II), respectively, was reported. Both adsorption and photocatalytic degradation of TC under Cu(II) coexistence increased with increasing pH from 3 to 6, while decreased with further increase in pH. HA inhibited the degradation of TC by ZnO NPs both in the presence as well absence of Cu(II), while TC degradation decreased from 91 to 73% and from 73 to 37% in the presence and absence of Cu(II), respectively. TC degradation by ZnO NPs first increased then decreased with increasing Cu(II). Maximum TC degradation (about 94%) was obtained in the optimum concentration range of Cu(II) (0.05-0.15 mmol/L). In addition, there was a lag effect between TC adsorption and degradation on ZnO NPs. TC degradation was improved via Cu(II)-TC surface complexation and followed N-demethylation and hydroxylation routes. This study could be of potential importance in extrapolating the transformation of TC or other antibiotics under the coexistence of heavy metals in water.

Degradation of antibiotics by advanced oxidation processes: An overview

Antibiotics are becoming emerging contaminants due to their extensive production and consumption, which have caused hazards to the ecological environment and human health. Various techniques have been studied to remove antibiotics from water and wastewater, including biological, physical and chemical methods. Among them, advanced oxidation processes (AOPs) have received increasing attention due to their fast reaction rate and strong oxidation capability, which are effective for the degradation of antibiotics in aquatic environments. In this review paper, a variety of AOPs, such as Fenton or Fenton-like reaction, ozonation or catalytic ozonation, photocatalytic oxidation, electrochemical oxidation, and ionizing radiation were briefly introduced, including their principles, characteristics, main influencing factors and applications. The current applications of AOPs for the degradation of antibiotics in water and wastewater were analyzed and summarized, the concluding remarks were given and their future perspectives and challenges were discussed.

Simultaneous and efficient photocatalytic reduction of Cr(VI) and oxidation of trace sulfamethoxazole under LED light by rGO@Cu2O/BiVO4p-n heterojunction composite

Antibiotics and heavy metals often coexist in polluted environment, and the harm of combined pollution is greater than that of single pollution. In this study, a series of graphene supported p-n heterojunction rGO@Cu₂O/BiVO₄ composites are synthesized with different Cu₂O doping for simultaneous detoxification of Cr(VI) and antibiotics. The obtained photocatalysts (rGO@Cu₂O/BiVO₄) with proper loading amount of Cu₂O shows the a high photocatalytic degradation activity for simultaneously efficient Cr(VI) reduction and sulfamethoxazole (SMZ) oxidation under LED light at neutral pH. The Cr(VI) was completely transformed to Cr(III) rather than simply Cr(VI) adsorbed on the surface of rGO@Cu₂O/BiVO₄. The photocatalytic activity of composites can be attributed to excellent electrical conductivity of rGO and the p-n heterojunction between Cu₂O and BiVO₄, which promotes the spatial separation of photogenerated charges at the heterojunction boundary and inhibits of the photogenerated h⁺ and e^- recombination. It's confirmed that h⁺, O₂^- and OH are the main reactive species for the photocatalytic SMZ oxidation, and the most important reactive species is h⁺. Finally, the tentative degradation pathways of SMZ are proposed based on the liquid chromatography-triple quadrupole mass spectrometry analysis. This work provides an effective approach for the treatment of water that contains SMZ and Cr(VI) under LED light.

PVA/CS and PVA/CS/Fe gel beads' synthesis mechanism and their performance in cultivating anaerobic granular sludge

Biomass washout from high-speed anaerobic suspended bed bio-reactors is still a challenge to their stable operation. Preserving active biomass to efficiently retain biomass in the reactor is one of the solutions to this problem. Herein, two carriers (polyvinyl alcohol/chitosan (PVA/CS) and PVA/CS/Fe gel beads) were prepared using the cross-linking method. The fourier transform infrared (FTIR) and ¹³C nuclear magnetic resonance (¹³C NMR) analyses showed that PVA/CS gel beads formed mainly through hydrogen-bonds (NH₂OH^-). Furthermore, FTIR, ¹³C NMR, energy dispersive spectrum (EDS), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) analyses showed that PVA/CS/Fe gel beads formed mainly through chelate bond (NH₂-Fe^M+OH^-). The scanning electron microscope (SEM) results affirmed that the gel beads had rough and well-developed porous structure for the attachment of microbes. Furthermore, the abilities of gel beads on the cultivation of granular sludge in an up-flow anaerobic sludge bed (UASB) reactor were effectively demonstrated while treating wastewater polluted with glucose and alkali lignin. The results showed that the gel beads-assisted reactors had a higher performance than those without the gel beads. The cultivation of granules in these reactors was accelerated, while the granules became bigger and exhibited better settling velocities. The reactor with gel beads was easier to withstand a higher organic loading rate due to dense microbial aggregates, which were caused by more humic-like substance. Particularly, the reactor with PVA/CS/Fe gel beads was able to improve the overall robustness of the system due to stronger mechanical properties of gel beads, and also prevented cells detachment.

Visible-light photocatalytic performance, recovery and degradation mechanism of ternary magnetic Fe3O4/BiOBr/BiOI composite

The ternary magnetic Fe₃O₄/BiOBr/BiOI (x : 3 : 1) photocatalysts were successfully synthesized by a facile solvothermal method. The samples were characterized by XRD, SEM, EDS, ICP-AES, XPS, UV-vis DRS, PL and VSM. Nitrogen-containing dye RhB was used as a degradation substrate to evaluate the photocatalytic degradation activities of the samples. The photocatalytic performance of Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) is superior to other Fe₃O₄/BiOBr/BiOI (x : 3 : 1). Compared with binary magnetic Fe₃O₄/BiOBr (0.5 : 1) prepared in our previous work, the Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) has obvious advantages in photocatalytic activity and adsorption capacity. And the specific surface area (48.30 m² g⁻¹) is much larger than that of the previous report (Fe₃O₄/BiOBr/BiOI (0.5 : 2 : 2)) synthesized by a co-precipitation method. Besides, after 25 s of magnetic field, Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) can be rapidly separated from water. After eight recycling cycles, the magnetic properties, photocatalytic activity, crystallization and morphology of the Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) catalyst remain good. The possible photocatalytic degradation mechanism of RhB under Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) photocatalyst was also proposed. The results indicate that the ternary magnetic Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) composite with high photocatalytic degradation efficiency, good magnetic separation performance and excellent recyclability and stability has potential application prospect in wastewater.

The ternary magnetic Fe₃O₄/BiOBr/BiOI (x : 3 : 1) photocatalysts were successfully synthesized by a facile solvothermal method.

Metal-free SERS substrate based on rGO–TiO2–Fe3O4 nanohybrid: contribution from interfacial charge transfer and magnetic controllability

We proposed a new ternary nanohybrid rGO–TiO₂–Fe₃O₄ as a magnetically controllable, ultra-sensitive SERS substrate with ultra-high SERS activity and applicability.