Synthesis and characterizations of a novel CoFe2O4@CuS magnetic nanocomposite and investigation of its efficiency for photocatalytic degradation of penicillin G antibiotic in simulated wastewater

Green and environmentally friendly architecture of starch-based ternary magnetic biocomposite (Starch/MIL100/CoFe2O4): Synthesis and photocatalytic degradation of tetracycline and dye

The presence of tetracycline and dye as organic contaminants has led to the poisoning of wastewater. The aim of this study is to synthesize a novel biocomposite material by decorating natural starch polymer granules with metal-organic framework (MIL100) and cobalt ferrite magnetic (CoFe2O4) nanoparticles. The synthesized ternary magnetic biocomposite (Starch/MIL100/CoFe2O4) was used for the photocatalytic degradation of methylene blue (MB) and tetracycline (TCN) using LED visible light. The synthesis of the biocomposite was confirmed through comprehensive analyses (XRD, SEM, FTIR, BET, EDX, MAP, DRS, pHzpc, TGA, and Raman). The evaluation examined the influence of initial pollutant concentration, catalyst dosage, pH, and the impact of anions on pollutant removal. The results show that the pollutant degradation ability of biocomposite has been significantly improved, so that the base biopolymer, starch, achieved 18% tetracycline degradation, but when decorated with MIL100 and cobalt ferrite, it increased to 91.2%. It was observed that the degradation for methylene blue improved from 12% for starch to 96.6% for the magnetic biocomposite. The tetracycline degradation decreased by more than 20% in the presence of NaCl, NaNO3, and Na2SO4. The finding shows that the biocomposite adheres to first-order kinetics for both pollutants. The scavengers test identified hydroxyl radicals as the most effective active species in the degradation process. High stability, even after passing 5 cycles of recycling was observed for the biocomposite. The results indicated that the facile and green synthesized Starch/MIL100/CoFe2O4 magnetic biocomposite could be used as an effective photocatalyst for the degradation of Tetracycline and dye at room temperature.

Unique effect of bromide ion on intensification of advanced oxidation processes for pollutants removal: A systematic review

Advanced oxidation processes (AOPs) have been developed to decompose toxic pollutants to protect the aquatic environment. AOP has been considered an alternative treatment method for wastewater treatment. Bromine is present in natural waters posing toxic effects on human health and hence, its removal from drinking water sources is necessary. Of the many techniques advanced oxidation is covered in this review. This review systematically examines literature published from 1997 to April 2024, sourced from Scopus, PubMed, Science Direct, and Web of Science databases, focusing on the efficacy of AOPs for pollutant removal from aqueous solutions containing bromide ions to investigate the impact of bromide ions on AOPs. Data and information extracted from each article eligible for inclusion in the review include the type of AOP, type of pollutants, and removal efficiency of AOP under the presence and absence of bromide ion. Of the 1784 documents screened, 90 studies met inclusion criteria, providing insights into various AOPs, including UV/chlorine, UV/PS, UV/H2O2, UV/catalyst, and visible light/catalyst processes. The observed impact of bromide ion presence on the efficacy of AOP processes, alongside the AOP method under scrutiny, is contingent upon various factors such as the nature of the target pollutant, catalyst type, and bromide ion concentration. These considerations are crucial in selecting the best method for removing specific pollutants under defined conditions. Challenges were encountered during result analysis included variations in experimental setups, disparities in pollutant types and concentrations, and inconsistencies in reporting AOP performance metrics. Addressing these parameters in research reports will enhance the coherence and utility of subsequent systematic reviews.

Biodegradation of penicillin G sodium by Sphingobacterium sp. SQW1: Performance, degradation mechanism, and key enzymes

Biodegradation is an efficient and cost-effective approach to remove residual penicillin G sodium (PGNa) from the environment. In this study, the effective PGNa-degrading strain SQW1 (Sphingobacterium sp.) was screened from contaminated soil using enrichment technique. The effects of critical operational parameters on PGNa degradation by strain SQW1 were systematically investigated, and these parameters were optimized by response surface methodology to maximize PGNa degradation. Comparative experiments found the extracellular enzyme to completely degrade PGNa within 60 min. Combined with whole genome sequencing of strain SQW1 and LC-MS analysis of degradation products, penicillin acylase and β-lactamase were identified as critical enzymes for PGNa biodegradation. Moreover, three degradation pathways were postulated, including β-lactam hydrolysis, penicillin acylase hydrolysis, decarboxylation, desulfurization, demethylation, oxidative dehydrogenation, hydroxyl reduction, and demethylation reactions. The toxicity of PGNa biodegradation intermediates was assessed using paper diffusion method, ECOSAR, and TEST software, which showed that the biodegradation products had low toxicity. This study is the first to describe PGNa-degrading bacteria and detailed degradation mechanisms, which will provide new insights into the PGNa biodegradation.

Congregating Ag into γ-Bi2O3 coupled with CoFe2O4 for enhanced visible light photocatalytic degradation of ciprofloxacin, Cr(VI) reduction and genotoxicity studies

The work attempts to construct a highly effective γ-Bi2O3/CoFe2O4/Ag visible active photocatalyst for the enhanced degradation of ciprofloxacin (CIP) and Cr(VI) reduction. γ-Bi2O3/CoFe2O4/Ag photocatalyst was prepared by simple solid phase and co-precipitation methods. The nanosphere shaped CoFe2O4 photocatalyst are embedded on top of γ-Bi2O3 nanotriangle. The addition of Ag into γ-Bi2O3/CoFe2O4 heterojunction primitively facilitates the photocatalytic activity in higher rate. The quantitative analysis of photocatalyst possesses to have lower e-/h+ recombination rate compared to its counterparts. The prepared γ-Bi2O3/CoFe2O4/Ag photocatalyst showed 96.6% degradation of CIP in 220 min and 99.2% reduction of Cr(VI) in 120 min. Additionally, γ-Bi2O3/CoFe2O4/Ag showed outstanding recyclability and long-term stability with a degradation efficiency of 96.5% even after six cycles. The intermediate products formed were identified and the degradation pathway was elucidated by gas chromatography-mass spectrometry analysis. Total organic carbon measurement was carried over to assess the efficiency of complete degradation and the removal percentage was found to be 98%. The end product toxicity study towards bacteria was proven to have less toxicity level when compared to parent compound. Lastly, the genotoxicity of γ-Bi2O3/CoFe2O4/Ag photocatalyst was tested in Allium cepa and the results confirmed to have no cause of toxicity impacts. Overall, the work not only tends to provide a highly visible active γ-Bi2O3/CoFe2O4/Ag photocatalyst, but also attributes to have no further negative imprints in the environment.

Application of a novel composite of Fe3O4@SiO2/PAEDTC surrounded by MIL-101(Fe) for photocatalytic degradation of penicillin G under visible light

The novel photocatalyst of Fe3O4@SiO2/PAEDTC@MIL-101(Fe) was prepared based on the sol-gel method, and its structure and morphology were determined by SEM mapping, TEM, XRD, FTIR, and N2 adsorption-desorption analyses. The photocatalytic activity of nanocomposite was evaluated in comparison with other particles as well as adsorption and photolysis processes. The effect of operating parameters showed that the complete degradation of penicillin G (PNG) can be provided at a photocatalyst dosage of 0.6 g/L, radiation intensity of 36 W, pH of 5, and time of 60 min. In the optimum condition, 84% TOC removal was attained and the BOD5/COD rate for the treated effluent was above 0.4, which was representative of the high biodegradability of the treated effluent compared to the raw sample. The findings of energy consumption showed that PNG can be easily and effectively treated by the photocatalytic process based on magnetic MIL-101(Fe) with electrical energy per order between 10 and 20.87 kWh/m3. Due to the excellent interaction between the MIL-101(Fe) and Fe3O4@SiO2/PAEDTC, the photocatalyst stability test showed a recyclability of the particles for 5 consecutive reaction cycles with a minimum reduction of 7%. Solution treated with photocatalyst under UV and visible light sources explained that the toxicity of the effluent after treatment is significantly reduced with the growth of Escherichia coli. Scavenging experiments showed that •OH radical and hole (h+) are the main agents in degrading PNG to CO2, H2O, and biodegradable and low-toxicity products. Finally, the findings of the diagnostic analysis and comparative experiments proved that with the interaction of Fe3O4@SiO2, NH2, and MIL-101(Fe), a lower band gap can be prepared for more absorption of photons and pollutant and also more and faster production of active radicals.

Synthesis and characterization of rGO/Fe0/Fe3O4/TiO2 nanocomposite and application of photocatalytic process in the decomposition of penicillin G from aqueous

In this study, we synthesized rGO/Fe⁰/Fe₃O₄/TiO₂ nanocomposite according to Hummer's, and straightforward sol-gel method. The FESEM, EDX, TEM, FT-IR, XRD, BET, UV spectra, and VSM analysis were applied to determine the catalyst properties. Optimization of influence parameters on photocatalytic process performance to penicillin G degradation in aqueous media. pH (4-8), nanocomposite dose (10-20 mg/L), reaction time (30-60 min), and penicillin G concentration (50-100 mg/L) were optimized via central composite design. In the optimum condition of PCP, supplementary studies were done. As a result of the analysis, the nanocomposite was well synthesized and displayed superior photocatalytic properties for degrading organic pollutants. In addition to being magnetically separable, the synthesized rGO/Fe⁰/Fe₃O₄/TiO₂ nanocomposite exhibits high recyclability up to 5 times. The quadratic model of optimization is based on the adjusted R²(0.99), and predicated R²(0.97) suggested. According to the analysis of variance test, the model was significant (F-Value = 162.95, P-Value = 0.0001). Photocatalytic process is most efficiently decomposed at pH = 6.5, catalyst dose = 18.5 mg/L, reaction time = 59.1 min, and penicillin G concentration = 52 mg/L (efficiency = 96%). The chemical oxygen demand and total organic carbon decrease were 78, and 65%. The photolysis and adsorption mechanism as a single mechanism had lower performance in penicillin G degradation. Benzocaine had the greatest effect on reducing the efficiency of the process as a radical scavenger. The °OH, h^+, and O₂^●- were the main reactive oxidant species in penicillin G removal. Phenoxyacetaldehyde, Acetanilide, Diacetamate, Phenylalanylglycine, N-Acetyl-l-phenylalanine, Diformyldapsone, and Succisulfone were the main intermediates in penicillin G degradation. The results indicated the photocatalytic process with rGO/Fe⁰/Fe₃O₄/TiO₂ nanocomposite on a laboratory scale has good efficiency in removing penicillin G antibiotic. The application of real media requires further studies.

Mesoporous Polymeric Ionic Liquid via Confined Polymerization for Laccase Immobilization towards Efficient Degradation of Phenolic Pollutants

Laccase immobilization is a promising method that can be used for the recyclable treatment of refractory phenolic pollutants (e.g., chlorophenols) under mild conditions, but the method is still hindered by the trade-off limits of supports in terms of their high specific surface area and rich functional groups. Herein, confined polymerization was applied to create abundant amino-functionalized polymeric ionic liquids (PILs) featuring a highly specific surface area and mesoporous structure for chemically immobilizing laccase. Benefiting from this strategy, the specific surface area of the as-synthesized PILs was significantly increased by 60-fold, from 5 to 302 m2/g. Further, a maximum activity recovery of 82% towards laccase was recorded. The tolerance and circulation of the immobilized laccase under harsh operating conditions were significantly improved, and the immobilized laccase retained more than 84% of its initial activity after 15 days. After 10 cycles, the immobilized laccase was still able to maintain 80% of its activity. Compared with the free laccase, the immobilized laccase exhibited enhanced stability in the biodegradation of 2,4-dichlorophenol (2,4-DCP), recording around 80% (seven cycles) efficiency. It is proposed that the synergistic effect between PILs and laccase plays an important role in the enhancement of stability and activity in phenolic pollutant degradation. This work provides a strategy for the development of synthetic methods for PILs and the improvement of immobilized laccase stability.

Synthesis and characterization of g-C3N4-CoFe2O4-ZnO magnetic nanocomposites for enhancing photocatalytic activity with visible light for degradation of penicillin G antibiotic

Nowadays, antibiotic water pollution is an increasingly dangerous environmental threat. Thus, water treatment is essential for their reduction and removal. In recent decades, photocatalysts have attracted much attention due to their influential role in solving this issue. The photocatalytic process, which is one of the green processes and part of advanced oxidation processes, can be a good choice for treating contaminated water containing non-degradable organic matter. However, the design of high-performance photocatalysts under free sunlight can be challenging. In this study, g-C₃N₄-Ca, Mg codoped CoFe₂O₄-ZnO (gCN-CFO-ZnO) nanocomposite photocatalyst was applied in removing penicillin G (PENG) from drug effluents. Also, the effects of contaminant concentration, initial pH, irradiation time, and zinc oxide ratio in the nanocomposites were investigated. The hydrothermal method was carried out to prepare the appropriate composites. Then, the obtained products were characterized by powder X-Ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), Raman, field-emission scanning and transmission electron microscope (FE-SEM&TEM), energy dispersive X-Ray (EDX), diffuse reflectance spectroscopy (DRS), vibrating sample magnetometer (VSM) and Photoluminescence (PL) techniques. According to the findings, the degradation of PENG in an acidic environment occurred remarkably; under the same conditions, with decreasing pH from 9 to 5 in the gCN-CFO-ZnO (33.33%) nanocomposite, the degradation efficiency grew from 47% to 74%. Also, the degradation rate of PENG in gCN-CFO-ZnO (16.66%) and gCN-CFO-ZnO (50%) nanocomposites under optimal conditions (pH = 5, PENG the concentration of 10 ppm, and irradiation time of 120 min) was achieved 52% and 60%, respectively. Further, gCN-CFO-ZnO (33.33%) nanocomposite showed higher efficiency in PENG degradation compared to the other two nanocomposites.

Synthesis of CoFe2O4 magnetic nanoparticles for application in photocatalytic removal of azithromycin from wastewater

Azithromycin is one of the most widely used antibiotics in medicine prescribed for various infectious diseases such as COVID-19. A significant amount of this drug is always disposed of in hospital effluents. In this study, the removal of azithromycin using Cobalt-Ferrite magnetic nanoparticles (MNP) is investigated in the presence of UV light. For this purpose, magnetic nanoparticles are synthesized and added to the test samples as a catalyst in specific proportions. To determine the structural and morphological properties of nanoparticles, characterization tests including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), and Energy-dispersive X-ray spectroscopy (EDX) are performed. 27 runs have been implemented based on the design of experiments using the Box-Behnken Design (BBD) method. Parameters are the initial concentration of azithromycin (20-60 mg/L), contact time (30-90 min), pH (6-10), and the dose of magnetic nanoparticles (20-60 mg/L). The obtained model interprets test results with high accuracy (R² = 0.9531). Also, optimization results by the software show that the contact time of 90 min, MNP dosage of 60 mg/L, pH value of 6.67, and azithromycin initial concentration of 20 mg/L leads to the highest removal efficiency of 89.71%. These numbers are in the range of other studies in this regard.

Facile Construction of Bi2Sn2O7/g-C3N4 Heterojunction with Enhanced Photocatalytic Degradation of Norfloxacin

To mitigate antibiotic residues in the water environment, Bi2Sn2O7/g-C3N4 (BSCN) heterojunction was fabricated by a facile ultrasound-assisted hydrothermal method. The microstructure, morphology, and optical properties of Bi2Sn2O7/g-C3N4 heterojunction was studied by XRD, FTIR, XPS, SEM, TEM, UV–Vis DRS, and PL. The degradation rate of 20 mg/L norfloxacin (NOR) under visible light for 3 h was adopted as one of the indexes to evaluate the photocatalytic performance of Bi2Sn2O7/g-C3N4 heterojunction. Embellished with 20% Bi2Sn2O7 (BSO), the Bi2Sn2O7/g-C3N4 heterojunction decomposed 94% NOR in the experimental solution, which was 2.35 and 3.03 times as much as pristine g-C3N4 and bare Bi2Sn2O7, respectively. In addition, the Bi2Sn2O7/g-C3N4 heterojunction still eliminated 89% of NOR after five cycles, portending outstanding stability and cyclability of photocatalytic activity. A possible photocatalytic mechanism of Bi2Sn2O7/g-C3N4 heterojunction for NOR degradation is proposed.

A BaTiO3/WS2 composite for piezo-photocatalytic persulfate activation and ofloxacin degradation

Piezoelectric fields can decrease the recombination rate of photogenerated electrons and holes in semiconductors and therewith increase their photocatalytic activities. Here, a BaTiO₃/WS₂ composite is synthesized and characterized, which combines piezoelectric BaTiO₃ nanofibers and WS₂ nanosheets. The piezo-photocatalytic effect of the composite on the persulfate activation is studied by monitoring Ofloxacin (OFL) degradation efficiency. Under mechanical forces, LED lamp irradiation, and the addition of 10 mM persulfate, the OFL degradation efficiency reaches ~90% within 75 min, which is higher than efficiencies obtained for individual BaTiO₃, WS₂, or TiO₃, widely used photocatalysts in the field of water treatment. The boosted degradation efficiency can be ascribed to the promotion of charge carrier separation, resulting from the synergetic effect of the heterostructure and the piezoelectric field induced by the vibration. Moreover, the prepared composite displays good stability over five successive cycles of the degradation process. GC-MS analysis is used to survey the degradation pathway of OFL during the degradation process. Our results offer insight into strategies for preparing highly effective piezo-photocatalysts in the field of water purification.

Efficient degradation of orange II by core shell CoFe2O4-CeO2 nanocomposite with the synergistic effect from sodium persulfate

Novel core shell CoFe₂O₄-CeO₂ (CoFe-Ce) nanocomposite was synthesized and investigated as an efficient photocatalyst to activate sodium persulfate (Na2S2O8, PS) for orange Ⅱ (OⅡ) degradation. The CoFe-Ce nanocomposite was successfully designed and synthesized by a facile hydrothermal reaction followed by calcination and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), and vibrating sample magnetometer (VSM). Compared with pure CoFe₂O₄ and CeO₂, the photocatalytic efficiency of CoFe-Ce nanocomposite was significantly improved. Under the irradiation of visible light, the catalytic degradation efficiency of orange II could reach to 98.5% within 60 min. Additionally, the as-prepared material could be recycled for at least five times using magnetic separation ability of the nanocomposite, and during the cycling the dye degradation rate was almost unchanged. The active species produced during the degradation were studied by classical quenching experiments, and the different types of free radicals produced in the system were further confirmed by electron paramagnetic resonance (EPR) spectroscopy. This novel nanocomposite is expected to have potential application for degradation of organic pollutants in wastewater by utilizing solar energy.

Reaction of the anammox granules to various antibiotics and operating the anammox coupled denitrifying reactor for oxytetracycline wastetwater treatment

The anaerobic ammonium oxidation (anammox) basedtechnology has been considered as an economic and efficient way to remove nitrogen. However, the anammox bacteria could be strongly inhibited by antibiotics. In present research, inhibiting properties of oxytetracycline, penicillin and polymyxin sulfate upon the anammox activity were investigated through batch experiment. The results implied that anammox activity was significantly inhibited by oxytetracycline and polymyxin sulfate. The non-competitive inhibiting model showed that the inhibiting constants (Ki) of oxytetracycline and polymyxin sulfate were 188.5 and 17.7 mg/L, respectively. Meanwhile, the anammox process was not suppressed while the concentration of penicillin reached 3000 mg/L. In long-run experiment, the influent oxytetracycline concentration of the anammox coupled denitrifying reactor was operated at 20 mg/L. It was observed that the anammox performance completely deteriorated, while the NO₂^--N removing efficiency reached 15.8%. The obtained findings could provide important instruction for the treatment of antibiotic contaminated wastewater.

Photocatalytic degradation of Penicillin G in aqueous solutions: Kinetic, degradation pathway, and microbioassays assessment

The photocatalytic degradation of pharmaceutical micropollutants of Penicillin G (PG) was investigated in a photoreactor at a laboratory scale. The impact of type of catalyst, pH, and initial concentration of PG were studied. Maximum removal efficiency was obtained at pH = 6.8, [ZnO]₀ = 0.8 g L^-1, and [PG]₀ = 5 mg L^-1 and reaction time of 150 min. The addition of persulfate sodium (PPS) enhanced the efficiency of the photocatalytic reaction. The efficiency of photolysis process in the presence of PPS was significantly improved to 72.72% compared to the classical photocatalysis system (56.71%). Optimum concentration of PPS to completely degraded PG was found to be 500 mg L^-1. The QuEChERS extraction, GC-MS/MS method, and concentration technique showed favorable performance identification of the possible mechanism of PG degradation pathway. Toxicity of PG and its by-products were evaluated using microbioassays assessment based on nine selected bacterial strains. Results confirmed the effectiveness of the implemented system and its safe use via the bacteria Bacillus subtilis, which has illustrated significant activity. Due to the high efficiency, facility benefits, and low-cost of the suggested process, the process can be considered for the degradation of various pharmaceutical contaminants in pharmaceutical industry treatment under the optimal conditions.

Recent advances in structural modifications of photo-catalysts for organic pollutants degradation - A comprehensive review

Over the last few years, industrial and anthropogenic activities have increased the presence of organic pollutants such as dyes, herbicides, pesticides, analgesics, and antibiotics in the water that adversely affect human health and the environment worldwide. Photocatalytic treatment is considered a promising, economical, effective, and sustainable process that utilizes light energy to degrade the pollutants in water. However, certain drawbacks like rapid recombination and low migration capability of photogenerated electrons and holes have restricted the use of photo-catalysts in industries. Hence, despite the abundance of lab-scale research, the technology is still not much commercialized in the mainstream. Several structural modifications in the photo-catalysts have been adopted to enhance the pollutant degradation performance to overcome the same. In this context, the present review article outlines the different advanced heterostructures synthesized to date for improved degradation of three major organic pollutants: antibiotics, dyes, and pesticides. Moreover, the article also emphasizes the degradation kinetics of photo-catalysts and the publication trend in the past decade along with the roadblocks preventing the transfer of technology from the laboratory to industry and new age photo-catalysts for the profitable implications in industrial sectors.

Synthesis of ZnFe2O4@Uio-66 nanocomposite for the photocatalytic degradation of metronidazole antibiotic under visible light irradiation

In this study, the application of ZnFe₂O₄, Uio-66 nanoparticles and ZnFe₂O₄@Uio-66 photocatalytic nanocomposites, with different ratios of each component was synthesized and applied for the photocatalytic degradation of metronidazole (MNZ) antibiotic. The samples were characterized with (FTIR), (XRD), (SEM), (DLS), (VSM), and UV-Vis spectroscopy. The photocatalytic process was performed under visible light in an aqueous solution. The optical studies revealed that the addition of ZnFe₂O₄ nanoparticles could stimulate the activation wavelength of the nanocomposite, effectively shifting it to the visible light region, and correspondingly reduce the bandgap. To evaluate the ability of ZnFe₂O₄@Uio-66 magnetic nanocatalyst to degrade metronidazole, effective parameters such as the initial concentration of MNZ in aqueous solution(10-90 mg/L), pH(2-10), the illumination and darkness time and photocatalyst dosage(0.01-0.05 g) were investigated and optimized. It was observed that when ZnFe₂O₄ concentration was twice that of Uio-66, the degradation efficiency increased. The optimum degradation conditions, at which 93.7% degradation efficiency was achieved, were determined at 120 min brightness, 40 min darkness, pH = 8, initial concentration of 10 ppm, and photocatalyst content of 0.03 g. Based on the results of photocatalytic degradation kinetics, all the samples followed the Langmuir-Hinshelwood pseudo-first-order kinetics model.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40201-021-00713-x.

Spinel ferrites (MFe2O4): Synthesis, improvement and catalytic application in environment and energy field

To develop efficient catalysts is one of the major ways to solve the energy and environmental problems. Spinel ferrites, with the general chemical formula of MFe₂O₄ (where M = Mg²⁺, Co²⁺, Ni²⁺, Zn²⁺, Fe²⁺, Mn²⁺, etc.), have attracted considerable attention in catalytic research. The flexible position and valence variability of metal cations endow spinel ferrites with diverse physicochemical properties, such as abundant surface active sites, high catalytic activity and easy to be modified. Meanwhile, their unique advantages in regenerating and recycling on account of the magnetic performances facilitate their practical application potential. Herein, the conventional as well as green chemistry synthesis of spinel ferrites is reviewed. Most importantly, the critical pathways to improve the catalytic performance are discussed in detail, mainly covering selective doping, site substitution, structure reversal, defect introduction and coupled composites. Furthermore, the catalytic applications of spinel ferrites and their derivative composites are exclusively reviewed, including Fenton-type catalysis, photocatalysis, electrocatalysis and photoelectro-chemical catalysis. In addition, some vital remarks, including toxicity, recovery and reuse, are also covered. Future applications of spinel ferrites are envisioned focusing on environmental and energy issues, which will be pushed by the development of precise synthesis, skilled modification and advanced characterization along with emerging theoretical calculation.

Photocatalytic Penicillin Degradation Performance and the Mechanism of the Fragmented TiO2 Modified by CdS Quantum Dots

In this study, a novel method was adopted to construct a CdS-TiO₂ heterostructure to degrade penicillin under sunlight. A potato extract was used during the synthesis process of CdS QDs as a stabilizer and a modifier. The CdS-TiO₂ composite with a heterostructure delivers high photocatalytic degradation efficiency. In detail, 0.6 mg/mL of CdS-TiO₂ can successfully decompose penicillin after 2 h, and 5‰ CdS-TiO₂ shows the optimal degradation efficiency with the degradation rate reaching 88%. Furthermore, the underlying mechanisms of the penicillin decomposition reaction were investigated by the EPR test and trapping experiment. It was found that the high photocatalytic degradation efficiency was attributed to the heterojunction of CdS-TiO₂, which successfully suppresses the recombination of the conduction band of CdS and the valence band of TiO₂. Moreover, it was confirmed that the reaction is the O₂-consuming process, and introducing O₂ can greatly accelerate the generation of a superoxide radical during the photocatalytic degradation process, which eventually improves the degradation of penicillin and shortens the degradation time. Finally, this work provides the possible penicillin degradation pathways, which will inspire the researchers to explore and design novel photocatalysts in the field of wastewater treatment in the future.

Fabrication of graphitic carbon nitride functionalized P-CoFe2O4 for the removal of tetracycline under visible light: Optimization, degradation pathways and mechanism evaluation

In this study, nano-sized CoFe₂O₄ composites were prepared through co-precipitation process. Then the phosphorus-doped strong magnetic graphitic carbon nitride hybrids composites (P-CoFe₂O₄@GCN) was stemmed from the CoFe₂O₄ composites via the thermal polymerization method. The TEM results show that the CoFe₂O₄ nanoparticles have been successfully embedded into the graphitic carbon nitride (GCN). The BET specific surface area of P-CoFe₂O₄@GCN-1 could reach 36.91 m²/g, which was 5.38 times higher than that of GCN. Thus, it provided sufficient reaction active sites to enhance the photocatalytic activity for tetracycline (TC) decomposition. The results from the photocatalytic experiments showed that the degradation efficiency of TC by P-CoFe₂O₄@GCN-1 could reach 96.2% within 60 min, which is 3.19 times higher than that of GCN. The h⁺, O₂•^- and •OH radicals detected by the electron spin resonance (ESR) were responsible for the TC decomposition in the photocatalytic reaction system. Persulfate (PS) can further activate the hybrid mixture system, and the fitting model predicted by the response surface methodology (RSM) indicated that the maximum tetracycline removal could reach 99.6% within 30 min. In addition, the degradation intermediates of TC were detected by HPLC-MS and the photodegradation mechanism was discussed.

Enzyme-catalyzed biodegradation of penicillin fermentation residues by β-lactamase OtLac from Ochrobactrum tritici

BACKGROUND

Biodegradation of antibiotics is a promising method for the large-scale removal of antibiotic residues in the environment. However, the enzyme that is involved in the biodegradation process is the key information to be revealed.

RESULTS

In this study, the beta-lactamase from Ochrobactrum tritici that mediates the biodegradation of penicillin V was identified and characterized. When searching the proteins of Ochrobactrum tritici, the β-lactamase (OtLac) was identified. OtLac consists of 347 amino acids, and predicted isoelectric point is 7.0. It is a class C β-lactamase according to BLAST analysis. The coding gene of OtLac was amplified from the genomic DNA of Ochrobactrum tritici. The OtLac was overexpressed in E. coli BL21 (DE3) and purified with Ni2+ column affinity chromatography. The biodegradation ability of penicillin V by OtLac was identified in an in vitro study and analyzed by HPLC. The optimal temperature for OtLac is 32 ℃ and the optimal pH is 7.0. Steady-state kinetics showed that OtLac was highly active against penicillin V with a Km value of 17.86 μM and a kcat value of 25.28 s-1 respectively.

CONCLUSIONS

OtLac demonstrated biodegradation activity towards penicillin V potassium, indicating that OtLac is expected to degrade penicillin V in the future.

Kinetic Modeling for Photo-Assisted Penicillin G Degradation of (Mn0.5Zn0.5)[CdxFe2-x]O4 (x ≤ 0.05) Nanospinel Ferrites

Penicillin G is an old and widely used antibiotic. Its persistence in the environment started to appear in many environmental samples and food chains. The removal of these emerging pollutants has been a challenging task for scientists in the last decades. The photocatalytic properties of Cd²⁺ doped Manganese- Zinc NSFs with chemical formula (Mn_0.5Zn_0.5)[Cd_xFe_2−x]O₄ (0.0 ≤ x ≤ 0.05) NSFs are herein evaluated. The Manganese- Zinc N.S.F.s nanomaterials were deeply characterized, utilizing UV-Vis (reflectance) spectroscopy, X-ray diffraction, N₂ adsorption isotherm measurements, and S.E.M., SEM-EDX mapping, and T.E.M. The Kinetic model for the photodegradation of penicillin G (as a model molecule) is investigated using visible light as a source of energy. The kinetic study shows that our results fit well with the modified pseudo-first-order model. The Pen G degradation are 88.73%, 66.65%, 44.70%, 37.62% and 24.68% for x = 0.5, 0.4, 0.3, 0.2 and 0.1, respectively, against 14.68% for the free Cd spinel sample. The pseudo-rate constant is bandgap dependent. From the intra-diffusion rate constant (K_d), we developed an intra-diffusion time (τ) model, which decreases exponentially as a function of (x) and mainly shows the existence of three different domains versus cadmium coordination in spinel ferrite samples. Hence, Cadmium’s presence generates spontaneous polarization with a strong opportunity to monitor the charge separation and then open the route to a new generation of “assisted” photocatalysts under visible light.

Fabrication of novel magnetic CuS/Fe3O4/GO nanocomposite for organic pollutant degradation under visible light irradiation

The magnetic nanocomposites composed of copper sulphide, iron oxide, and graphene oxide (CuS/Fe₃O₄/GO) were synthesized through a facile sol-gel combined with hydrothermal techniques for photodegradation of methylene blue (MB) as a model organic pollutant. The as-prepared samples were characterized by powder X-ray diffraction (XRD), vibrating sample magnetometer (VSM), differential reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray analysis (EDX) and results confirmed successful synthesis of magnetic nanocomposite. Presence of Fe₃O₄ and GO in nanocomposite induced a synergistic effect in CuS performance as CS₈₈F₆G₆ (i.e. 88% CuS, 6% Fe₃O₄, and 6% GO). The photocatalytic degradation efficiency of MB reached up to 90.3% after exposure to visible light irradiation for 80 min. The composite nanosheets are photostable, reusable, and magnetically recoverable, revealing potential application in removal of organic pollutants.

Efficient removal of levofloxacin from different water matrices via simultaneous adsorption and photocatalysis using a magnetic Ag3PO4/rGO/CoFe2O4 catalyst

A magnetic Ag₃PO₄/rGO/CoFe₂O₄ ternary catalyst was firstly prepared and used for removing levofloxacin (LVF) from different water matrices via simultaneous adsorption and photocatalysis. Compared with Ag₃PO₄ and Ag₃PO₄/CoFe₂O₄, Ag₃PO₄/rGO/CoFe₂O₄ shows a superior adsorption-photocatalysis performance for LVF elimination since rGO component not only improves the adsorption ability but also enhances the charge separation efficiency of the catalyst. About 90.7% of LVF in distilled water (10 mg/L) was removed by the ternary catalyst after adsorption for 0.5 h and photocatalysis for 1.0 h, and the removal of LVF performed well in the pH range of 3.51-9.47. Singlet oxygen (¹O₂) was the major reactive oxygen species for LVF degradation in Ag₃PO₄/rGO/CoFe₂O₄ system under visible light, as confirmed by the quenching experiments and ESR study. Based on the detected intermediates in the photocatalytic process, the possible LVF degradation pathways were well-established. As-synthesized Ag₃PO₄/rGO/CoFe₂O₄ can also efficiently remove LVF from the different real water matrices (river water, lake water and secondary effluent) via simultaneous adsorption and photocatalysis. Moreover, magnetic Ag₃PO₄/rGO/CoFe₂O₄ can be easily recovered and effectively reused for the removal of LVF in actual water bodies.

Emerging Hybrid Nanocomposite Photocatalysts for the Degradation of Antibiotics: Insights into Their Designs and Mechanisms

The raising occurrence of antibiotics in the global water bodies has received the emerging concern due to their potential threats of generating the antibiotic-resistive and genotoxic effects into humans and aquatic species. In this direction, the solar energy assisted photocatalytic technique offers a promising solution to address such emerging concern and paves ways for the complete degradation of antibiotics with the generation of less or non-toxic by-products. Particularly, the designing of hybrid photocatalyticcomposite materials has been found to show higher antibiotics degradation efficiencies. As the hybrid photocatalysts are found as the systems with ideal characteristic properties such as superior structural, surface and interfacial properties, they offer enhanced photoabsorbance, charge-separation, -transfer, redox properties, photostability and easy recovery. In this context, this review study presents an overview on the recent developments in the designing of various hybrid photocatalytic systems and their efficiency towards the degradation of various emerging antibiotic pharmaceutical contaminants in water environments.

Photocatalytic and Antibacterial Properties of Ag-CuFe2O4@WO3 Magnetic Nanocomposite

This study aimed to synthesize a new magnetic photocatalytic nanosystem composed of Ag-CuFe2O4@WO3 and to investigate its photodegradation efficiency for two drug pollutants of Gemfibrozil (GEM) and Tamoxifen (TAM) under Ultraviolet (UV) light irradiation. In this regard, the effect of pH, catalyst dosage, and drug concentration was thoroughly determined. The largest photodegradation level for GEM (81%) and TAM (83%) was achieved at pH 5, a photocatalyst dosage of 0.2 g/L, drug concentration of 5 mg/L, and contact time of 150 min. The drug photodegradation process followed the pseudo first-order kinetic model. In addition to the photodegradation effect, the nanocomposites were proved to be efficient in terms of antibacterial activity, proportional to the Ag doping level. The Ag-CuFe2O4@WO3 nanocomposite exhibited a stable, efficient performance without an obvious catalytic loss after five successive cycles. Taken together, the developed magnetic photocatalyst is able to simultaneously disinfect wastewater streams and to degrade pharmaceutical contaminants and thus shows a promising potential for purification of multi-contaminant water systems.

Copper sulfide nanoparticles with potential bifunctional properties: supercapacitor and photocatalysis

Pure hexagonal CuS nanoparticles with stable high capacitance and photocatalytic activity were obtained by a mild solvothermal method.

Metal–organic complex-derived 3D porous carbon-supported g-C3N4/TiO2 as photocatalysts for the efficient degradation of antibiotic

g-C₃N₄/TiO₂/CNOT heterojunction photocatalysts exhibit efficient synergistic adsorption–photocatalysis performance for the removal of chlortetracycline hydrochloride (CTC-HCl).

Functionalized magnetic PAMAM dendrimer as an efficient nanocatalyst for a new synthetic strategy of xanthene pigments

A green protocol has been developed for preparation of the wide variety of colored xanthene derivatives using a new efficient magnetic solid acid catalyst bearing polyamidoamine dendrimer moiety as a nanoscopic compound. Dendrimers, highly symmetric molecules around a core and 3D spherical morphology, show interesting traits based on their functionalized groups on the branched surface. They can be designed to provide water soluble structures or pseudo-active sites of biomolecules. The catalyst was assembled via a polyamidoamine dendrimer immobilized on the surface of γ-Fe₂O₃ followed by the sulfonylation of the amine groups by chlorosulfonic acid resulting in γ-Fe₂O₃@PAMAM-SO₃H. Herein, PAMAM dendrimer with repeating amine/amide branches as catchable sites of sulfonic acid groups was introduced as transformer of homogeneous to heterogeneous acidic catalysts. The physicochemical properties of synthesized catalyst were studied using by FT-IR, FE-SEM, XRD, VSM, EDS, TGA/DTG, and TEM. Finally, the catalytic activity of γ-Fe₂O₃@PAMAM-SO₃H was evaluated for the preparation of xanthene derivatives via a one-pot, three components reaction of aromatic aldehydes with i) β-naphthol, ii) cyclic 1,3-dicarbonyl, iii) β-naphthol and cyclic 1,3-dicarbonyl compounds, iv) 2-hydroxy-1,4-naphthoquinone, leading to the eco-riendly preparation of the target compounds in good to excellent yields. The catalyst could be easily recycled for at least five consecutive runs without significant loss in its catalytic activity.

Assessing short-term effects of magnetite ferrite nanoparticles on Daphnia magna

Magnetic nanoparticles (MNPs) are used in a wide range of sectors ranging from electronics to biomedicine, as well as in eutrophicated lake restoration due to their high P, N, and heavy metal adsorption capacity. This study assessed the effects of MNPs on mortality and morphometric changes of D. magna. According to the SEM, the synthesised MNPs were found to have spherical nanoparticles, be uniformly distributed, and have a homolithic size distribution of 50-110 nm. The EDX spectra confirmed the elemental structure and purities of these MNPs. A total of 396 neonates were used for short-term bioassays (96 h) through the MNPs in the laboratory (16:8 photoperiod). Experiments were applied in triplicate for each concentration of CuFe2O4, CoFe2O4, and NiFe2O4 MNPs and their respective control groups. Mortality and morphological measurements of each individual were recorded every 24 h. In the probit analysis, the 96-h LC50 (p < 0.05) for CuFe2O4, CoFe2O4, and NiFe2O4 MNPs was calculated to be 1.455 mg L-1, 39.834 mg L-1, and 21.730 mg L-1, respectively. CuFe2O4 MNPs were found to be more toxic than the other two MNPs. The concentrations of CuFe2O4, CoFe2O4, and NiFe2O4 MNPs drastically affected life span and morphologic growth of D. magna as a result of a short time exposure. The results of this study are useful for assessing what risks they pose to freshwater ecosystems.

A model study by using polymeric molecular imprinting nanomaterials for removal of penicillin G

We aimed to develop a molecularly imprinted polymeric systems with using penicillin G as a template molecule for removal of the antibiotic residues from environmental samples. Firstly, Pen-G-imprinted poly (2-hydroxyethyl methacrylate-N-methacryloyl-L-alanine) [p(HEMA-MAAL)] nanopolymers were synthesized by surfactant-free emulsion polymerization method. Then, template molecule (Pen-G) was extracted from nanopolymers. Synthesized nanopolymers were characterized by different methods such as Fourier-transform infrared spectroscopy (FTIR), elemental and zeta-size analysis, scanning electron microscope (SEM), and surface area calculations. Nanopolymers have 60.38 nm average size and 1034.22 m²/g specific surface area. System parameters on Pen-G adsorption onto Pen-G imprint nanopolymers were investigated at different conditions. The specific adsorption value (Q_max) of molecularly impirinted p(HEMA-MAAL) nanopolymers was found 71.91 g/g for Pen-G in 5 mg/mL Pen-G initial concentration. Pen-G adsorption of molecularly imprinted nanopolymers was 15 times more than non-imprinted polymer. It is shown that obtained p(HEMA-MAAL) nanopolymer was a reuseable product which protected its adsorption capacity of 98.9% after 5th adsorption-desorption cycle. In conclusion, we suggest a method to develop a nanostructure, selective, low-cost molecularly imprinted polymeric systems with using penicillin G as a template molecule for removal of the antibiotic residues.

Bridging and synergistic effect of the pyrochlore like Bi2Zr2O7 structure with robust CdCuS solid solution for durable photocatalytic removal of the organic pollutants

Herein, a strong redox ability photocatalyst of CdCuS solid solution composited with pyrochlore like Bi₂Zr₂O₇ has been fabricated by the simple hydrothermal method. The robust CdCuS solid solution materials perform the supporting role to the Bi₂Zr₂O₇ nano materials. The structural, optical, valence and vibrational states of the prepared heterostructure materials were analyzed using various characterization techniques. The photocatalytic activity of the as-synthesized Bi₂Zr₂O₇/CdCuS heterostructure has been verified under direct solar light and ambient conditions. The synthesized Bi₂Zr₂O₇/CdCuS nano combination exhibits a better photocatalytic activity for the removal of methylene blue and 4-nitrophenol organic probe molecules. The heterostructure formation between the samples is confirmed by HRTEM analysis. The improved rate of the photocatalytic reaction of the samples is attributed to the formation of heterostructures at the interface. The close interfacial contact between the two materials discloses the effective charge transfer, which leads to suppressed charge carrier recombination. The enhanced photo catalytic activity of redox-mediator-free-Bi₂Zr₂O₇/CdCuS heterostructure, possibly will be credited to the robust redox ability and the several charge transfer channels in the tight contact. The chief radicals produced in the catalytic reduction reaction have been predicted by the scavenger trapping methods and the results are discussed in detail. The obtained information from this study on Bi₂Zr₂O₇/CdCuS delivers some new visions for the design of active photocatalysts with multiple benefits.

Photocatalytic degradation mechanism for CdCuS solid solution supported pyrochlore like Bi₂Zr₂O₇.

The practical utility of the synthesis FeNi3@SiO2@TiO2 magnetic nanoparticles as an efficient photocatalyst for the humic acid degradation

Humic acid (HA) compounds in drinking water and wastewater disinfection processes are viewed as precursors of highly toxic, carcinogenic, and mutagenic disinfection by-product chemicals. In recent times, these compounds have gained considerable attention of scientists for their successful removal from aqueous solutions to permissible limits. To achieve this aim, the present study investigated, for the first time, the photocatalytical performance of the synthesis FeNi₃@SiO₂@TiO₂ nanoparticles for the HA degradation under different environmental conditions. The photocatalytic reactions were performed using ultraviolet (UV) radiation, whose intensity was fixed at 2500 μW/cm² throughout the experimental study. The characterization study performed, using specific diagnostic techniques, revealed the presence of several good morphological, magnetic, and catalytic specifications of the synthesized nanoparticles. The use of the simplified form of the Langmuir-Hinshelwood equation sufficiently describes the experimental data of the HA kinetic degradation, as it shows a high coefficient of regression values. Furthermore, the complete HA degradation was reached under conditions of pH = 3; initial HA concentration = 10 mg/L; FeNi₃@SiO₂@TiO₂ nanoparticles dosage = 0.01 g/L; and reaction time >30 min. Thus, the results obtained from this research suggested that the catalyst of FeNi₃@SiO₂@TiO₂ nanoparticles was an attractive, novel, and effective agent, which could be used for the degradation of HA in the photocatalytic processes.

Magnetic recyclable CoFe2O4@PPy prepared by in situ Fenton oxidization polymerization with advanced photo-Fenton performance

Here we present a magnetic recyclable photo-Fenton catalyst CoFe₂O₄@PPy with uniform morphology and excellent dispersibility prepared via simple in situ Fenton oxidization polymerization. The CoFe₂O₄ core provides good magnetic recyclability for the catalysts as well as the ion source for catalyzed decomposition of H₂O₂ in PPy coating. The optimal catalytic effect can be obtained by adjusting the ratio of CoFe₂O₄ and PPy. Methylene blue, Methyl orange and Rhodamine B (RhB) employed as model pollutants certificated that the catalyst exhibits a wide range of photodegradability. The decoloration rates reach nearly 100% in the photodegradation of 10 mg L⁻¹ RhB after 2 h visible-light irradiation and only low toxicity small molecules are detected by LC-MS. Moreover, the catalytic activity remains after 5 cycles with decoloration rates up to 90%. The degradation measurement in the presence of scavengers of reactive species reveals that the positive holes (h⁺) and hydroxyl radical (·OH) are the main reactive oxygen species in the CoFe₂O₄@PPy system. The performance enhancement may be attributed to the combination of improved Fenton activity by coordinated Fe²⁺ and PPy redox pairs and photo-catalytic activity by broaden adsorption and photo-generated charge separation.

Here we present a magnetic recyclable photo-Fenton catalyst CoFe₂O₄@PPy with uniform morphology and excellent dispersibility prepared via simple in situ Fenton oxidization polymerization.