Search Results (155)

Photocatalysis has been shown to be a promising and ecofriendly approach to the removal of contaminants of emerging concern (CECs). However, preventing the recombination of photogenerated charge carriers and achievement of suitable band edge positions are still major challenges to ensuring better performance. Herein, we report the preparation of surface-decorated BiVO₄ with both a noble metal (Ag) and transition metal (Fe). The structural, morphological, and semiconducting features of the material were examined employing various techniques (XRD, SEM, UV-DRS, PL, and photoelectrochemical tests). The band gap of surface-modified BiVO₄ is slightly narrower compared to pristine material, which is further validated by HOMO-LUMO gaps obtained through theoretical modeling approaches. The recombination of photogenerated charges was successfully reduced in the case of Ag–Fe–BiVO₄, as proven by lower PL intensity and increased current density. The comparative photocatalytic degradation of the CECs ciprofloxacin (CIP) and perfluorooctanoic acid (PFOA) was conducted employing pristine BiVO₄ and its two surface-modified analogues (Ag–BiVO₄, and Ag–Fe–BiVO₄) under solar light. Ag–Fe–BiVO₄ was shown to be the most efficient; however, its effectiveness differed depending on CEC type. Under the same process conditions, degradation of CIP reached 93.9%, while PFOA was degraded only partially (22.9%). Full article

Polymeric scaffolds are promising in tissue engineering due to their structural similarity to extracellular matrix components. This study aimed to design freeze-dried hydrogels based on chitosan (CHT) and hyaluronic acid (HA). Chitosan-based gels were crosslinked with oxidized maltodextrin (MDo) before the freeze-drying step, resulting in spongy porous scaffolds. Based on the state-of-the-art, our hypothesis was that crosslinking would increase scaffold stiffness and delay the degradation of the CHT:HA resorbable scaffolds swelled in a hydrated physiological environment. The physicochemical and mechanical properties of crosslinked CHT- and CHT:HA-based scaffolds were analyzed. Hygroscopic and swelling behavior were assessed using dynamic vapor sorption analysis and batch studies. Degradation was evaluated under different conditions, including in phosphate-buffered saline (PBS), PBS with lysozyme, and lactic acid solutions, to investigate scaffold resistance against enzymatic and acidic degradation. The porosity of the spongy materials was characterized using scanning electron microscopy, while dynamic mechanical analysis provided information on the mechanical properties. Crosslinked scaffolds showed reduced swelling, slower degradation rates, and increased stiffness, confirming MDo as an effective crosslinking agent. Scaffolds loaded with ciprofloxacin (CFX) demonstrated their ability to deliver therapeutic agents, as the CFX loading capacity was promoted by CHT–CFX interactions. Microbiologic investigation confirmed the results. Finally, cytotoxicity tests displayed no toxicity. In conclusion, MDo-crosslinked CHT and CHT:HA scaffolds exhibit enhanced stability, functionality, and mechanical performance, making them promising for cartilage tissue engineering. Full article

The development of efficient and stable photocatalysts is critical for addressing water pollution challenges caused by persistent organic contaminants. However, single-component photocatalysts often suffer from rapid photogenerated carrier recombination and limited visible-light absorption. In this study, a two-dimensional lamellar stacked Bi₂O₃/CeO₂ type-II heterojunction photocatalyst (BC) was successfully synthesized in situ by a topological transformation strategy induced by high-temperature oxidation of monolithic Bi. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses confirmed the uniform distribution of Bi₂O₃ nanosheets on CeO₂ surfaces, forming an intimate interfacial contact that enhances charge separation and transfer efficiency. Photoluminescence (PL) spectroscopy, UV–visible diffuse reflectance spectroscopy (DRS), and electrochemical characterization revealed extended visible-light absorption (up to 550 nm) and accelerated electron migration in the heterojunction. Under simulated sunlight, the optimized BOC (3:1) composite exhibited a ciprofloxacin (CIP) degradation rate constant 2.30 and 5.63 times higher than pure Bi₂O₃ and CeO₂, respectively. Theoretical calculations validated the type-II band alignment with conduction and valence band offsets of 0.07 eV and 0.17 eV, which facilitated efficient spatial separation of photogenerated carriers. This work provides a rational strategy for designing heterojunction photocatalysts and advancing their application in water purification. Full article

Global water scarcity and antimicrobial resistance (AMR) represent two escalating crises that urgently demand integrated and effective solutions. While wastewater reuse is increasingly promoted as a strategy to alleviate water scarcity, conventional treatment processes often fail to eliminate persistent contaminants and antibiotic-resistant microorganisms. Cold plasma (CP), a non-thermal advanced oxidation process, has demonstrated the strong potential to simultaneously inactivate pathogens and degrade micropollutants. CP generates a diverse mix of reactive oxygen and nitrogen species (ROS and RNS), as well as UV photons and charged particles, capable of breaking down complex contaminants and inducing irreversible damage to microbial cells. Laboratory studies have reported bacterial log reductions ranging from 1 to >8–9 log₁₀, with Gram-negative species such as E. coli and Pseudomonas aeruginosa showing higher susceptibility than Gram-positive bacteria. The inactivation of endospores and mixed-species biofilms has also been achieved under optimized CP conditions. Viral inactivation studies, including MS2 bacteriophage and norovirus surrogates, have demonstrated reductions >99.99%, with exposure times as short as 0.12 s. CP has further shown the capacity to degrade antibiotic residues such as ciprofloxacin and sulfamethoxazole by >90% and to reduce ARGs (e.g., bla, sul, and tet) in hospital wastewater. This perspective critically examines the mechanisms and current applications of CP in wastewater treatment, identifies the operational and scalability challenges, and outlines a research agenda for integrating CP into future water reuse frameworks targeting AMR mitigation and sustainable water management. Full article

Photocatalytic degradation has the advantages of high efficiency and stability compared with traditional antibiotic treatment. Therefore, the development of efficient and stable photocatalysts is essential for antibiotic degradation in water treatment. In this study, layered g-C₃N₄/flower-like ZnO heterojunction loaded with different amounts of CQDs (C_x%CNZO (x = 1, 2, 3, 4)) were precisely synthesized at room temperature. The as-prepared photocatalyst showed enhanced performance in degrading ciprofloxacin (CIP). The heterojunction with CQDs loaded at 3 wt% (C_3%CNZO) achieved a 91.0% removal rate of CIP at 120 min under a sunlight simulator illumination, and the photodegradation reaction data were consistent with the first-order kinetic model. In addition, cycling experiments confirmed that the C_3%CNZO heterojunction had good reusability and photocatalytic stability after four cycles. According to the experimental results, superoxide radical (•O₂⁻) was the main active species involved in CIP degradation. Furthermore, C_3%CNZO was found to conform to a type II electron transfer pathway. Finally, the possible degradation pathways of CIP were analyzed. This work may provide an effective strategy for the removal of various antibiotics in water treatment. Full article

Molecularly imprinted polymers (MIPs) are emerging as efficient materials for environmental remediation due to their dual functionality in selective pollutant adsorption and catalytic degradation. This review examines recent advances in MIP-based technologies, focusing on their role in photocatalysis and advanced oxidation processes. Experimental findings highlight impressive degradation efficiencies, such as 95.8% methylene blue degradation using ZnO/CuFe₂O₄ MIPs and a 60% improvement in refractory organic degradation with TiO₂-MIPs. Adsorption studies show high uptake capacities, including 273.65 mg/g for ciprofloxacin with MOF-supported MIPs and 2350.52 µg/g for rhodamine B using magnetic MIPs. Despite these advancements, several challenges remain, including issues with long-term stability, scalability, and economic feasibility. Future research should prioritize optimizing polymer synthesis, integrating MIPs with high-surface-area matrices like MOFs and COFs and enhancing recyclability to ensure sustained performance. MIPs hold significant potential for large-scale water treatment and pollution control, provided their stability and efficiency are further improved. Full article

Antibiotic-based wastewaters seriously endanger human health and damage the ecological environment, and photocatalytic degradation is a desirable strategy for eliminating these contaminants in water. Therefore, developing a proper catalyst for the photodegradation of antibiotics, including ciprofloxacin (CIP), is of great importance. In this study, novel Ag₂S/Zn²⁺-decorated graphitic carbon nitride (AZCN for short) type-II heterojunctions are constructed through a precipitation–calcination procedure. The high porosity with a specific surface area of 133.5 m² g⁻¹, as well as the positive synergy between Ag₂S- and Zn²⁺-decorated graphitic carbon nitride (abbreviated as ZCN), enhance incident light harvesting, increase the adsorption capacity for reactant molecules, favor mass transfer and promote the separation and transport of photoinduced carriers, therefore improving the degradation efficiency of CIP. Specifically, the degradation efficiency of CIP (50 mL, 10 mg L⁻¹) over 2.5% AZCN (10 mg) is 18.1%, 43.1% and 55.7% within 60 min of irradiation using near-infrared light, visible light and simulated solar light, respectively. Moreover, it displays satisfactory recycling stability and excellent universality. This research not only develops a promising heterojunction photocatalyst but also offers some valuable insights in water remediation. Full article

Organic pollutants present a substantial risk to both ecological systems and human well-being. Activation of peroxymonosulfate (PMS) have emerged as an effective strategy for the degradation of organic pollutants. Bi-based heterojunction is commonly used as a photocatalyst for reductively activating PMS, but single-component Bi-based heterojunction frequently underperforms due to its restricted absorption spectrum and rapid combination of photogenerated electron–hole pairs. Herein, BiVO₄ was selected as the oxidative semiconductor to form an S-type heterojunction with CuBi₂O₄—x-CuBi₂O₄/BiVO₄ (x = 0.2, 0.5, and 0.8) for PMS photoactivation. The built-in electric field (BEF) in x-CuBi₂O₄/BiVO₄ promoted electron transfer to effectively activate PMS. The x-CuBi₂O₄/BiVO₄ heterojunctions also demonstrate stronger adsorption of the polar PMS than pure CuBi₂O₄ or BiVO₄. In addition, the BEF prompts photoelectrons able to reduce O₂ to •O₂⁻ and photogenerated holes in the valence band of BiVO₄ able to oxidize H₂O to generate •OH. Therefore, under visible light irradiation, 95.1% of ciprofloxacin (CIP) can be degraded. The 0.5-CuBi₂O₄/BiVO₄ demonstrated the best degradation efficiency and excellent stability in cyclic tests, as well as a broad applicability in degrading other common pollutants. The present work demonstrates the high-efficiency S-type heterojunctions in the coupled photocatalytic and PMS activation technology. Full article

The rational design of BiOBr photocatalysts with optimized surface properties and enhanced photooxidative capacities is crucial. This study proposes a synergistic strategy combining hydroxyl-rich solvents with polyvinylpyrrolidone (PVP) surfactants to modulate the structural and electronic properties of BiOBr through a solvothermal approach. The resulting self-assembled microspheres demonstrated exceptional efficiency in degrading ciprofloxacin (CIP), methyl orange (MO), and rhodamine B (RhB). Among the synthesized variants, BiOBr-EG-PVP (fabricated with ethylene glycol and PVP) exhibited the highest photocatalytic activity, achieving near-complete removal of 20 mg/L CIP and RhB within 10 min under visible light irradiation, with degradation rates 60.12–101.73 times higher than pristine BiOBr. The structural characterization revealed that ethylene glycol (EG) not only induced the formation of self-assembled microspheres but also introduced abundant surface hydroxyl groups, which simultaneously enhanced the hole-mediated oxidation capabilities. The incorporation of PVP further promoted the development of hierarchical honeycomb-like microspheres and synergistically enhanced both the hydroxyl group density and photooxidative potential through interfacial engineering. Density functional theory (DFT) calculations confirmed that the enhanced photooxidative performance originated from an increased surface oxygen content. This work elucidates the synergistic effects of hydroxyl-rich solvents and surfactant modification in the fabrication of advanced BiOBr-based photocatalysts, providing new insights for high-performance photocatalysis for environmental remediation. Full article

This study synthesized graphene oxide (GO)/zinc oxide (ZnO)/silver (Ag) composite materials and investigated their photocatalytic degradation performance for ciprofloxacin (CIP) under visible light irradiation. GO/ZnO/Ag composites with different ratios were prepared via an impregnation and chemical reduction method and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results demonstrated that under optimal conditions (20 mg/L CIP concentration, 15 mg catalyst dosage, GO/ZnO-3%/Ag-doping ratio, and pH 5), the GO/ZnO/Ag composite exhibited the highest photocatalytic activity, achieving a maximum degradation rate of 82.13%. This catalyst effectively degraded ciprofloxacin under light irradiation, showing promising potential for water purification applications. Full article

Defects and heteroatom doping are two refined microstructural factors that significantly affect the performance of photocatalytic materials. Coupling defect and doping engineering is a powerful approach for designing efficient photocatalysts. In this research, we successfully construct dual defect-engineered BiVO₄ nanosheets (BVO-N-OV) by introducing N doping and oxygen vacancies through ammonium oxalate-assisted thermal treatment of BiVO₄ nanosheets. Due to the combined enhancement of band structure and surface properties from N doping and oxygen vacancies, the obtained BVO-N-OV nanosheets demonstrate improved visible light absorption, effective charge transfer efficiency, and increased active sites. As a result, the constructed BVO-N-OV/PMS system demonstrates significantly enhanced ciprofloxacin (CIP) removal performance under visible light illumination. The highest rate constant for CIP degradation over BVO-N-OV/PMS system is 7.9, 1.9, and 6.6 times greater than pristine BiVO₄ (BVO), oxygen vacancy-enriched BiVO₄ (BVO-OV), and N-doped BiVO₄ (BVO-N), respectively. Even in a broad pH range (3.0–11.0) with various anions, the BVO-N-OV/PMS/Vis system still demonstrates stable and excellent CIP removal performance. This study seeks to provide valuable insights into the interaction between defect and doping engineering in photocatalytic activation of PMS, thereby proposing new strategies for designing effective photocatalyst/PMS systems for wastewater treatment. Full article

Cd_xMn_1−xS solid solutions were synthesized by incorporating Mn²⁺ into CdS and the optimal ratio of Mn²⁺ to Cd²⁺ was explored via photocatalytic degradation performance for tetracycline (TC). Subsequently, the composite catalyst C@Cd_xMn_1−xS was prepared by loading Cd_xMn_1−xS onto the biomass gasification carbon residue (C) by hydrothermal method and characterized by various characterization tests. The optimal TC photodegradation condition and degradation mechanism catalyzed by C@Cd_xMn_1−xS was investigated. The results showed Cd_0.6Mn_0.4S had the optimal photocatalytic degradation efficiency, which is about 1.3 times that of CdS. The TC photodegradation efficiency by C@Cd_0.6Mn_0.4S prepared at the mass ratio of C to Cd_0.6Mn_0.4S of 1:2 was the best, which was 1.24 times that of Cd_0.6Mn_0.4S and 1.61 times that of CdS. Under the optimal conditions (visible light irradiation for 60 min, C@Cd_0.6Mn_0.4S of 20 mg, 40 mL TC solution of 40 mg/L), the TC degradation efficiency was 90.35%. The degradation efficiencies of 20 mg/L levofloxacin, ciprofloxacin, and 40 mg/L oxytetracycline catalyzed by C@Cd_0.6Mn_0.4S range from 89.88% to 98.69%. In the photocatalytic reaction system, •O₂⁻ and h⁺ are the dominant active species, which directly participate in the photocatalytic degradation reaction of TC, and •OH contributes little. The work provides a strategy to improve the photocatalytic performance of CdS for photocatalytic degradation antibiotics, and opens an interesting insight to deal with solid waste from biomass gasification. Full article

The increasing presence of various organics poses significant threats to aquatic ecosystems and living organisms. Conventional water treatment methods are often insufficient, necessitating the development of powerful and sustainable alternatives. This study addresses this challenge by exploring the synthesis of ZnO nanoparticles using green tea leaves extract—an eco-friendly approach—for the sunlight-activated removal of organics in agri-food wastewater. The research examined different conditions for the removal of clomazone (CLO), tembotrione (TEM), ciprofloxacin (CIP), and zearalenone (ZEA). Nitrate-derived ZnO synthesized in a water medium (N-gZnO_w) exhibited the highest photocatalytic activity, removing 98.2, 95.8, 96.2, and 96.6% of CLO, TEM, CIP, and ZEA. Characterization techniques (XRD, Raman spectroscopy, SEM, zeta potential measurements, UV–visible spectroscopy) confirmed the synthesis of N-gZnO_w, with an average particle size of 14.9 nm, an isoelectric point of 9.9, and a band gap energy of 2.92 eV. Photocatalytic experiments identified 0.5 mg/cm³ as an optimal catalyst loading, while a higher initial pollutant concentration reduced degradation efficiency. LC-ESI-MS/MS measurements confirmed the efficient pollutant degradation and the formation of degradation intermediates. Hence, this study demonstrates that green tea extract-synthesized ZnO nanoparticles offer a promising, sustainable solution for removing herbicides, pharmaceuticals, and mycotoxins from wastewater, paving the way for eco-friendly water purification technologies. Full article

The excessive use of ciprofloxacin, an antibiotic, has led to environmental challenges such as drug resistance and severe water pollution, necessitating effective mitigation strategies. Piezo-photocatalytic technology offers a sustainable solution. In this study, BiVO₄, recognized for its exceptional visible light absorption and conductivity, was embedded within polyvinylidene fluoride (PVDF) nanofibers to address issues of secondary water pollution and enhance material recovery. The addition of peroxymonosulfate (PMS) further improved the degradation process by generating highly reactive sulfate radicals (•SO₄⁻), which acted synergistically with piezoelectric effects to enhance pollutant breakdown. Under the combined effects of stir, illumination, and PMS activation, BiVO₄ achieved a 40% higher ciprofloxacin degradation efficiency compared to mechanical stir alone. This improvement is attributed to the generation of polarization charges at both ends of the material and the •SO₄⁻, which promoted efficient electron-hole separation and oxidative degradation. This study introduces a novel approach to piezo-photocatalytic water treatment using flexible BiVO₄ membrane materials with PMS enhancement. Full article

Anaerobic digestion (AD) is a waste-to-energy strategy that leverages natural microbiological processes. It is increasingly used in farms to treat manure, resulting in biogas for energy production and digestate as fertiliser. However, animal manure often contains antibiotic (AB) residues, raising concerns about their impact on AD efficiency and their potential spread through digestate use. This multidisciplinary study evaluated the effects of an AB mixture (enrofloxacin, ciprofloxacin and sulfamethoxazole) on CH₄ production, microbial community (Fungi, Bacteria and Archaea) dynamics and antibiotic resistance gene (ARG) presence. The experiment used a cattle manure/digestate ratio of 1:35, typical of real digesters, with AB concentrations set at low (2.5 mg kg⁻¹ each) and high (7.5 mg kg⁻¹ each) levels. The ABs affected cumulative CH₄ production (ranging from 5939 to 6464 mL) only at the highest concentration. After 51 days, sulfamethoxazole reached residual levels, while enrofloxacin and ciprofloxacin were only partially degraded (<50%), but ARGs were significantly reduced. The microbial community, particularly prokaryotes, exhibited resilience, maintaining efficient CH₄ production. Overall findings strongly suggest that AD is an effective treatment for producing energy and good fertiliser, also reducing AB and ARG content as well as mitigating CH₄ emissions into the atmosphere. Full article