Search Results (36)

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

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

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 concentration of antibiotics in natural water poses a significant threat to society’s sustainable development due to water pollution. Photocatalytic technology is an efficient and environmentally friendly approach to environmental purification, offering great potential for addressing pollution and attracting significant attention from scholars worldwide. TiO₂, as a representative semiconductor photocatalytic material, exhibits strong oxidation ability and excellent biocompatibility. However, its wide band gap and the rapid recombination of photo-generated electron–hole pairs significantly limit its photocatalytic applications. Recent studies indicate that constructing heterojunctions with synergistic plasmonic effects is an effective strategy for developing high-performance photocatalysts. In this study, Bi metal nanoparticles and (BiO)₂CO₃ nanosheets were simultaneously grown on TiO₂ nanofibers via an in situ hydrothermal method, successfully forming a Bi@(BiO)₂CO₃/TiO₂ composite fiber photocatalyst with synergistic plasmonic effects. The surface plasmon resonance (SPR) effect of Bi nanoparticles combined with the (BiO)₂CO₃/TiO₂ heterojunction enhances sunlight absorption, facilitates efficient separation of photo-generated carriers, and significantly strengthens the photo-oxidation and reduction abilities. This system effectively generates abundant hydroxyl (·OH) and superoxide (·O²⁻) radicals under sunlight excitation. Consequently, Bi@(BiO)₂CO₃/TiO₂ exhibited outstanding photocatalytic performance. Under simulated sunlight for 60 min, the photodegradation efficiencies of the quinolone antibiotics lomefloxacin, ciprofloxacin, and norfloxacin reached 93.2%, 97.5%, and 100%, respectively. Bi@(BiO)₂CO₃/TiO₂ also demonstrates excellent stability and reusability. This study represents a significant step toward the application of TiO₂-based photocatalyst materials in environmental purification. Full article

Optimization of the efficiency of the photocatalytic degradation of organic and pharmaceutical pollutants represents a matter of fundamental and practical interest. The present experimental and DFT study deals with evaluation of OH radical binding energy as a simple computational descriptor of the catalytic activity of d-metal-decorated TiO₂ photocatalysts for the photodegradation of the widely used antibiotic ciprofloxacin. Five d-metals commonly used in catalytic materials (Zr, Pt, Pd, Fe, and Cu) were deposited on the TiO₂ surface, and the obtained photocatalysts were characterized experimentally (XRPD, ICP-OES, and SEM) and theoretically (DFT). Attention was also paid to the mechanistic insights and degradation byproducts (based on UV-Vis spectrometry and LC/MS analysis) in order to obtain systematic insight into their structure/performance relationships and confirm the proposed model of the degradation process based on OH radical reactivity. Full article

A novel and highly efficient photocatalyst of a AgBiO₃/BiOCl heterojunction has been developed via a facile water bath and in situ precipitation method. The photocatalytic activities of the catalysts were investigated by the degradation of ciprofloxacin (CIP) under visible-light irradiation (>420 nm). The experiment results revealed that the photocatalytic performance of the optimized AgBiO₃/BiOCl heterojunction was much higher than pure AgBiO₃ and BiOCl. The degradation efficiency of the as-prepared AgBiO₃/BiOCl heterojunction (ABC-30) for CIP could reach 88% within 160 min, with 2.89 and 3.76 times higher activity than pure AgBiO₃ and BiOCl, respectively. The improved photocatalytic performance of AgBiO₃/BiOCl was attributed to the synergistic effect of the enhanced light absorption range and effective separation and transfer of the photo-induced charge carrier. The optimized heterojunction showed broad-spectrum catalytic activities towards various organic contaminants. The degradation efficiencies varied with the nature of the pollutant and decreased in the following order: Lanasol Red 5B (100%) > methyl orange (99%) > methylene blue (98%) > tetracycline (92%) > ciprofloxacin (88%) > ofloxacin (85%) > norfloxacin (78%) > rhodamine B (59%) > metronidazole (43%) > phenol (40%) > carbamazepine (20%). Furthermore, the trapping experiments and ESR indicated that superoxide radicals and holes were the main reactive species. Full article

Pharmaceuticals and personal care products (PPCPs) which include antibiotics such as tetracycline (TC) and ciprofloxacin (CIP), etc., have attracted increasing attention worldwide due to their potential threat to the aquatic environment and human health. In this work, a facile sol-gel method was developed to prepare tungsten-doped TiO₂ with tunable W⁵⁺/W⁶⁺ ratio for the removal of PPCPs. The influence of solvents in the synthesis of the three different tungsten precursors doped TiO₂ is also taken into account. WCl₆, ammonium metatungstate (AMT), and Na₂WO₄●2H₂O not only acted as the tungsten precursors but also controlled the tungsten ratio. The photocatalyst prepared by WCl₆ as the tungsten precursor and ethanol as the solvent showed the highest photodegradation performance for ciprofloxacin (CIP) and tetracycline (TC), and the photodegradation performance for tetracycline (TC) was 2.3, 2.8, and 7.8 times that of AMT, Na₂WO₄●2H₂O as the tungsten precursors and pristine TiO₂, respectively. These results were attributed to the influence of the tungsten precursors and solvents on the W⁵⁺/W⁶⁺ ratio, sample crystallinity and surface properties. This study provides an effective method for the design of tungsten-doped TiO₂ with tunable W⁵⁺/W⁶⁺ ratio, which has a profound impact on future studies in the field of photocatalytic degradation of PPCPs using an environmentally friendly approach. Full article

Contamination of soil, water, and wastewater by pharmaceuticals, including antibiotics, is a global health problem. This work evaluated the use of a natural compound, curcumin (CUR), as a homogeneous photocatalyst, together with hydrogen peroxide (H₂O₂) as a benign oxidant, to promote the photodegradation of ciprofloxacin (CIP). Furthermore, we carried out theoretical calculations using density functional theory (DFT) to assess the chemical reactivity of ciprofloxacin. In addition, the intermolecular interaction patterns of two crystalline polymorphs of the antibiotic drug were analyzed through Hirshfeld surfaces. Finally, calculations using the TD-DFT formalism were carried out to understand the effects on the CIP molecule caused by the simultaneous presence of the CUR molecule and ultraviolet-visible light (UV-Vis). A photooxidative effect was observed in the presence of the CUR photocatalyst (CIP + CUR (1:0.5)), resulting in a degradation of CIP of up to 24.4%. However, increasing the concentration of the CUR photocatalyst (ciprofloxacin + curcumin (1:1)) decreased the photodegradation of CIP, which may be caused by competition between the CIP molecule and CUR for ROS generated in situ. Additionally, the calculation results showed that the electronic excitations caused by the associated CIP + CUR structures affect the CIP molecule, resulting in the effects observed experimentally. The results show that CUR, when applied as a photosensitizing catalyst, presents synergistic potential with H₂O₂ in the photocatalytic degradation of ciprofloxacin. This photocatalytic process can be applied to the environmental remediation of pharmaceutical micropollutants, a subject of ongoing studies. Full article

This research evaluates the efficacy of catalysts based on Co₃O₄-gC₃N₄@ZnONPs in the degradation of ciprofloxacin (CFX) and the photocatalytic production of H₂ through water splitting. The results show that CFX experiences prompt photodegradation, with rates reaching up to 99% within 60 min. Notably, the 5% (Co₃O₄-gC₃N₄)@ZnONPs emerged as the most potent catalyst. The recyclability studies of the catalyst revealed a minimal activity loss, approximately 6%, after 15 usage cycles. Using gas chromatography–mass spectrometry (GC-MS) techniques, the by-products of CFX photodegradation were identified, which enabled the determination of the potential degradation pathway and its resultant products. Comprehensive assessments involving photoluminescence, bandgap evaluations, and the study of scavenger reactions revealed a degradation mechanism driven primarily by superoxide radicals. Moreover, the catalysts demonstrated robust performance in H₂ photocatalytic production, with some achieving outputs as high as 1407 µmol/hg in the visible spectrum (around 500 nm). Such findings underline the potential of these materials in environmental endeavors, targeting both water purification from organic pollutants and energy applications. Full article

This study focuses on synthesizing a composite material of Ag/ZnO/BiOCl using Ag, ZnO, and BiOCl as raw materials. The material was prepared by loading Ag and BiOCl onto ZnO nanofilms, aiming to enhance the photocatalytic degradation of ciprofloxacin (CIP). Optimization of the photocatalytic degradation process through single-factor experiments revealed that under conditions of an initial CIP pH of 9, an Ag/ZnO/BiOCl dosage of 1 g/L, and an initial CIP concentration of 5 mg/L the conversion efficiency of CIP reached 98.79% after 150 min of exposure to a 250 W xenon lamp simulating sunlight. Furthermore, the composite material maintained a conversion efficiency of 86.17% for CIP even after five cycles of reuse, demonstrating its excellent stability. The optical properties, elemental composition, valence state, crystallinity, and morphology of the samples were analyzed using techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), UV–visible diffuse reflectance spectroscopy (UV-vis DRS), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results indicate that the introduction of Ag expanded the light response range of ZnO, while the addition of BiOCl improved the separation efficiency of electron–hole pairs in the composite nanomaterial. The photocatalytic mechanism was further elucidated through radical scavenging experiments, confirming that ·OH and h⁺ are the main active species in the degradation process. Full article

The presented work studies the processes of synthesis of ZnO microstructures using atmospheric-pressure microwave nitrogen plasma and investigates their photocatalytic activity in the processes of degradation of 2,4-dinitrophenol and the antibiotic ciprofloxacin when irradiated with sunlight. The work proposes an effective method for formation of photosensitive ZnO powders. Due to the features of plasma treatment in the open atmosphere of zinc metal microparticles, ZnO structures are formed with sizes from hundreds of nanometers to several micrometers with various micromorphologies. The lattice parameters of ZnO structures are characteristic of a hexagonal unit with a = 3.258 Å and c = 5.21 Å, volume 47.95 ų. The size of the crystallites is 48 nm. The plasma treatment was performed by means of a 2.45-GHz plasmatron at a power input of 1 kW in nitrogen flow at a rate of 1–10 L/min. Zn microparticles were injected into the microwave plasma at a mass rate of 20 g/min. High photoactivity was demonstrated (rate constants 0.036 min⁻¹ and 0.051 min⁻¹) of synthesized ZnO structures during photo-degradation of 2,4-dinitrophenol and ciprofloxacin, respectively, when exposed to solar radiation. Photo-active structures of ZnO synthesized using microwave plasma can find application in processes of mineralization of toxic organic compounds. Structures of ZnO synthesized using microwave plasma can find application in processes of mineralization of toxic organic compounds, and also in scintillation detectors, phosphors. Full article

Emerging contaminants and pollution are environmental problems threatening public health. Antibiotic ciprofloxacin and methylene blue dye are pollutants frequently detected in water systems worldwide. Photocatalysis is a process for water treatment. TiO₂-based catalysts synthesized with natural gums show improved photocatalytic properties. Here, the sol–gel method synthesized TiO₂/Arabic gum for photocatalytic performance. The innovation of this work was synthesized at 400 °C and investigated their photocatalytic proprieties using methylene blue and ciprofloxacin as model pollutants. XRD showed that the photocatalyst was in the anatase phase. The result showed that TiO₂ with a band gap of 3.29 eV was achieved at a calcination temperature of 400 °C. Corresponding FTIR results suggest only the existence of functional groups related to TiO₂. The SEM and BET method characterization indicated that TiO₂/Arabic gum were spherical-shaped nanoparticles arranged in clusters with a mesoporous structure, contributing to photocatalytic performance. In addition, photocatalytic studies showed that the methylene blue dye and ciprofloxacin antibiotic degradation rates reached 99% and 94% under UV light, respectively. The hole (h⁺) and $\mathrm{O}\mathrm{H}_{}^{\mathrm{⦁}}$ radicals are essential in photodegradation. The synthesized material showed excellent photostability and maintained almost the same degradation percentage in the three consecutive cycles tested on the different pollutants. The TiO₂/Arabic gum is an excellent candidate for future use in treating contaminants in aqueous media using photocatalysis. Therefore, TiO₂/Arabic gum nanoparticles are a promising material for wastewater treatment. Full article

The design and synthesis of composite materials with new structures/properties have important practical significance for the degradation of organic pollutants in aquatic environments. On this basis, five new supramolecular materials {[L1]₂·[Cu₄I₈]}(1), {[L1]₂·[Ag₄I₈]}(2), {[L2]·[ZnBr₄]}(3), {[L3]₂·[AgI₅]}(4), {[L3]·[CdBr₃Cl]}(5) were synthesized by introducing an amino group into a series of nitrogen-containing cationic ligands (L1–L3) through the reaction of polybromomethylbenzene with 4-aminopyridine. The degradation effect of catalysts 1–5 on ciprofloxacin (CIP) under visible light was studied using their potential catalytic properties. The results showed that compounds 1 and 4 had better degradation effects compared to other compounds. Moreover, compounds 1 and 4 were proved to be excellent catalysts for the photocatalytic degradation of CIP with cyclic experiments. Through further exploration, it was found that neutral conditions and 20 mg compound dosage were more conducive to the photodegradation of CIP by the compound. Through free radical capture experiments, it was found that ·OH played a major role in the photodegradation of CIP. Full article

The design and synthesis of efficient photocatalysts that promote the degradation of organic pollutants in water have attracted extensive attention in recent years. In this work, CdS nanoparticles are grown in situ on Co@C derived from metal–organic frameworks. The resulting hierarchical CdS/Co@C nanostructures are evaluated in terms of their adsorption and photocatalytic ciprofloxacin degradation efficiency under visible-light irradiation. The results show that, apart from offering a large surface area (55.69 m²·g⁻¹), the prepared material can effectively suppress the self-agglomeration of CdS and enhance the absorption of visible light. The CdS/Co@C-7 composite containing 7% wt Co@C has the highest photodegradation rate, and its activity is approximately 4.4 times greater than that of CdS alone. Moreover, this composite exhibits remarkable stability after three successive cycles of photocatalysis. The enhanced photocatalytic performance is largely ascribed to the rapid separation of electron–hole pairs and the effective electron transfer between CdS and Co@C, which is confirmed via electrochemical experiments and photoluminescence spectra. The active substance capture experiment and the electron spin resonance technique show that h⁺ is the main active entity implicated in the degradation of CIP, and accordingly, a possible mechanism of CIP photocatalytic degradation over CdS/Co@C is proposed. In general, this work presents a new perspective on designing novel photocatalysts that promote the degradation of organic pollutants in water. Full article

Active pharmaceutical ingredients (APIs) can be assured to be safe and effective with the help of stability-indicating procedures. An accurate comparison comprising the utilization of capillary zone electrophoresis (CZE) and ultra-performance liquid chromatography (UPLC) for the sensitive and accurate measurement of ciprofloxacin (CPF) in the presence of its major photo-degradation product was conducted. The CZE and UPLC working conditions were optimized to obtain the best pattern of separation for CPF and its photo-degradant. The linearity range of the cited techniques was confirmed to be 0.5 to 50 µg/mL. A thorough validation scheme according to the ICH-Q2B criteria was performed, including linearity, accuracy, precision, robustness, detection, and quantification limits. Selective quantification of CPF in the presence of up to 90% of its main photo-degradant was carried out using the proposed methods. For the analysis of CPF in tablet and intravenous (I.V.) solution forms, the CZE and UPLC procedures were applied. The suggested methods can be applied to keep an eye on the safety and efficacy of CPF in either bulk or dosage forms. Full article