Degradation Of Ciprofloxacin Research Articles

Highly efficient CoAl-LDH/(110) facet-exposed BiOBr catalysts: Promotional effect of Z-type heterojunction and oxygen vacancies in photocatalytic ciprofloxacin degradation

Photocatalysis has received extensive attention as a sustainable technology. Herein, a 2D/2D CoAl-LDH/(110) facet-exposed BiOBr Z-type heterojunction photocatalyst enriched with oxygen vacancies (OVs) and Lewis acid sites was prepared by deposition-precipitation method. Results show that the removal of ciprofloxacin by the optimal heterojunction achieves 88 % within 10 min and 98.6 % within 95 min under visible light. Characterization and DFT calculation reveal that CoAl-LDH induces high-energy (110) crystal plane exposure of BiOBr, resulting in the generation of surface OVs and Lewis acid sites. OVs contribute to the adsorption of dissolved oxygen in water, thereby facilitating the generation of •O2−. And Bi(3−x)+ Lewis acid sites promote the adsorption and degradation of reactant molecules. The charge transfer recombination mechanism of the heterojunction enhances the utilization of photogenerated electrons and holes, improving the catalyst photostability. This work provides a simple method for constructing efficient and stable Z-type heterojunctions with defects for photocatalytic water treatment.

Graphitic carbon nitride-modified cerium ferrite: an efficient photocatalyst for the degradation of ciprofloxacin, ampicillin, and erythromycin in aqueous solution

Incomplete removal of antibiotics by most known wastewater treatment plants is a global challenge. Therefore, graphitic carbon nitride-modified cerium ferrite (CeFe2O4@g-C3N4) was synthesized to remove antibiotics (ampicillin, ciprofloxacin and erythromycin) from water. CeFe2O4@g-C3N4 showed activity in the visible light with a Tauc plot revealing the bandgap energy (2.46 eV). The scanning electron micrograph (SEM) result revealed the surface of CeFe2O4@g-C3N4 to be heterogeneous, while the transmission electron micrograph (TEM) image confirmed a flaky with rod and oval shaped surface (average particle size of 42.22 nm). CeFe2O4@g-C3N4 exhibited a 100% removal of all the studied antibiotics from aqueous solution in a photocatalytic degradation that is described by pseudo-1st-order kinetics. CeFe2O4@g-C3N4 demonstrated a high regeneration capacity, which is above 90% at the 12th cycle of treatment without any observable changes in its phase structure which suggests a promising chemical stability and reusability. CeFe2O4@g-C3N4 compared favourably with some selected antibiotic degradable photocatalysts suggesting the economic viable of CeFe2O4@g-C3N4 as photocatalyst for the purification of antibiotics-contaminated water.Graphical

Cu-Doped V-Based MOF Derivative VO2@Cu-VMOF as a Cathodic Catalyst for Electro-Fenton Degradation of Antibiotics.

In this study, the VO2@5%Cu-VMOF/graphite felt (GF) is prepared as an electro-Fenton cathode via hydrothermal process and low-temperature carbonization for efficient antibiotics degradation. The VO2@5%Cu-VMOF/GF cathode exhibit great ciprofloxacin (CIP) degradation performance over the pH range of 2.1-7.2, and CIP removal reached 98.1% within 60min at a pH of 3.4, with corresponding total organic carbon (TOC) removal of 68.7%. The cathode also showed desired catalytic performance toward various antibiotics decomposition. The great catalytic activity of the VO2@5%Cu-VMOF/GF cathode is attributed to lattice strain induced by Cu doping, and the elimination of the overpotential difference between the optimal oxygen reduction potential (OP ORR) and optimal metal reduction potential (OP MRR). Density Function Theory (DFT) calculations showed that Cu doping facilitated electrons accumulation around V atoms, and thus increased the content of low-valence metals in the cathode material. Four possible degradation pathways for CIP are proposed and intermediate toxicity is evaluated. This work advances the design and application of MOF derivatives as electro-Fenton cathodic materials for emerging contaminants degradation.

Enhanced Photocatalytic Degradation of Ciprofloxacin Antibiotics using Fe3O4-SiO2-EN@Zn-Al Layered Double Hydroxide Nanocomposites under the COVID-19 pandemic

A novel layered double hydroxide nanocomposite, Fe3O4-SiO2-EN@Zn-Al-LDH, was synthesized and employed as a photocatalyst for the degradation of ciprofloxacin (CIP) in aqueous solutions. Characterization of the photocatalyst was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) techniques. The results indicated successful synthesis of particle with specific surface area of 28.67 m²/g, pore size of 1.64 nm, and pore volume of 6.58 cm³/g. Optimal degradation of CIP was observed under the following conditions: pH 5, photocatalyst dosage of 0.6 g/L, initial CIP concentration of 25 mg/L, and an irradiation duration of 60 minutes. Comparative experiments demonstrated that incorporating Zn-Al LDH with core-shell nanoparticles (Fe3O4-SiO2-EN) enhanced removal efficiency by 2.5 to 6 times compared to individual materials. The composite exhibited efficient activation under UV, visible light, and solar radiation, resulting in 100% degradation of CIP under UV, 100% under visible light, and 81.4% under solar radiation. Biodegradability, indicated by the BOD5/COD ratio, increased from 0.28 to 0.73 after 120 minutes of photocatalytic oxidation under visible light, with 80.83% COD removal and 74.17% TOC removal. Reactive species generation, such as •OH, •O2-, and h+, was confirmed by introducing scavengers (TBA, BQ, and TEOS) into the reaction medium. The photocatalytic activity of the nanocomposite was slightly decreased over 5 consecutive CIP treatment cycles. Toxicity assessment of treated wastewater using E. coli and Daphnia magna bioassays revealed a significant decrease in E. coli growth inhibition rate with prolonged treatment time. The EC50 percentage improved from 1.27% to 97.4% after 4 hours of CIP treatment under visible light. In conclusion, the development of the Fe3O4-SiO2-EN@Zn-Al-LDH presents a noteworthy advancement in photocatalysis for the degradation of CIP in aqueous solutions.

A novel RuO₂@ZnO-Alginate-Halloysite composite for the effective degradation of Eosin Yellow dye and Ciprofloxacin drug

This research explores the synthesis and application of a novel RuO₂@ZnO-Alginate-Halloysite composite to effectively mitigate Eosin Yellow (EY) and Ciprofloxacin (CIP). The composite exhibited a predominant zinc oxide (ZnO) phase with added ruthenium oxide (RuO₂), alginate, and halloysite components, confirmed through X-ray diffractogram (XRD), Raman, and Fourier Transform Infrared Spectroscopy (FTIR). The addition of RuO₂ did not alter the crystal structure significantly. Still, it impacted the optical properties, with the band gap energies ranging from 3.281 to 3.252 eV, indicating a redshift associated with increased RuO₂ concentration. The composites were tested for EY and CIP photocatalytic degradation under UV light. The composites containing 2 and 3% of RuO2 presented impressive photocatalytic performance, achieving up to 82.53% degradation of CIP and 68.68% of EY under UV irradiation respectively, highlighting its potential as a robust solution for environmental remediation. The study employed a series of scavenger tests to identify the primary reactive species involved in the photocatalytic degradation of ciprofloxacin drug and eosin yellow dye. The introduction of benzoquinone led to a significant decrease in photocatalytic activity, indicating that superoxide (•O₂⁻) and hydroxyl radicals (•OH) are the dominant species in the photocatalytic degradation of CIP and EY, respectively. The synergistic effects of these reactive species contribute significantly to the photocatalytic performance of the composite material. Finally, the composites showed good recyclability, maintaining substantial degradation performance over multiple cycles. The significance of this study is underscored by the urgent need to find effective methods for removing hazardous compounds from wastewater, a growing concern due to their harmful impact on aquatic ecosystems and human health.

Pig manure biochar in soil forms catalytic system with endogenous H2O2 to degrade ciprofloxacin in purple soil

Biochar might improve ciprofloxacin (CIP) removal in soil, but little was known about how it goes on in purple soil. Thus, we investigated the variations of CIP in soil amended with pig manure (PM) derived biochar generated at 300℃ and 600℃ (PMC3 and PMC6). Compared with CK, PM, PMC3 and PMC6 decreased residual CIP by 42.3%, 48.8%, and 46.1%, respectively, confirming the enhancement of PM, PMC3 and PMC6 on CIP dissipation and indicating a higher performance of PMC3 and PMC6 in CIP removal than that of PM. Signal of persistent free radicals (PFRs) was observed in PMC3 and PMC6, which was contributed to the formation of O2·- and H2O2. Compared to PM, the secretion of H2O2 by microbe in PMC3 and PMC6 were enhanced by 71.5%-97.5% and 57.4%-79.5%, respectively. Meanwhile, catalase contents in PMC3 and PMC6 were reduced by 18.7%-68.6% and 8.4%-59.7%, respectively. These results suggested that H2O2 accumulated much easily in PMC3 and PMC6 than that in CK, which was benefited to the ·OH formation through the reaction between H2O2 and PFRs. Pearson correlation analysis identified that ·OH was the major contributor for 72.2%-80.2% of CIP removal in soil. In addition, degradation products were identified using UPLC-Q-TOF analysis. The results showed that the quinolone ring and piperazinyl ring were the main CIP degradation products. Under the action of ·OH, the piperazinyl ring in the CIP was completely destroyed. The phytotoxicity analysis was evaluated by bioreporter and Estimation Programs Interface (EPI) Suite. This study implies that biochar is a useful material for controlling CIP contamination through forming catalytic system with endogenous H2O2. These process insights have important implications for the pathway for CIP dissipation by biochar.

Response surface optimization of ciprofloxacin degradation using UV/O3 oxidation process

Response surface optimization of ciprofloxacin degradation using UV/O3 oxidation process

Dysprosium chromite nanoparticles: A promising photocatalyst for the remediation of ciprofloxacin and methylene blue from wastewater

A facile sol-gel synthesis method was employed to synthesize dysprosium chromite (DyCrO3) nanoparticles (NPs), which were subsequently calcined at 750 ∘C to investigate their structural, optical, and photocatalytic properties. Rietveld refinement of powder X-ray diffraction patterns revealed a single-phase orthorhombic structure for the DyCrO3 NPs, exhibiting good crystallinity and belonging to the Pbnm space group. Furthermore, Field Emission Scanning Electron Microscopy and Transmission Electron Microscopy imaging revealed a promising morphology with an average particle size of 30 ± 7 nm. Optical assessments indicated an energy band gap of 2.72 eV, suggesting potential for solar light harvesting as a photocatalyst. Mott-Schottky plots confirmed the n-type semiconductor behavior of the DyCrO3 NPs, and valence band X-ray photoelectron spectroscopy analysis supported these findings. Electronic band structure calculations showed a substantial conduction band minimum and a positive valence band maximum, essential for promoting oxygen reduction and oxidation reactions, respectively, which are crucial for photocatalytic activity. Moreover, the synthesized DyCrO3 NPs demonstrated significant potential as efficient photocatalysts, effectively decomposing the antibiotic ciprofloxacin (CIP) under solar light. Notably, the DyCrO3 NPs achieved 83 % degradation of CIP within 240 min of solar irradiation. Similarly, under identical conditions, the DyCrO3 NPs photocatalyst showed promise in degrading 70 % of the colored organic pollutant methylene blue (MB). Interestingly, during the first 120 min, the degradation of CIP was approximately 25 % greater than that of MB. The ability of DyCrO3 NPs to efficiently degrade both colored and colorless pollutants highlights the catalyst’s inherent photocatalytic nature, rather than merely relying on dye-sensitization effects. Furthermore, the presence of DyCrO3 NPs reduced the activation energy for CIP degradation from 31.657 kJ mol−1 K−1 to 20.846 kJ mol−1 K−1, providing additional evidence of their true catalytic efficacy. Apparent quantum yield values of 40 % for CIP and 35 % for MB degradation further illustrate their superior solar energy harvesting ability. A comprehensive mechanism was developed to explain the impressive photocatalytic performance of the synthesized NPs, highlighting their potential in degrading pharmaceutical antibiotics.

Durable fluorinated cobalt oxyhydroxide/calcium alginate hydrogels for activating peroxymonosulfate to enable nearly 100% degradation of ciprofloxacin.

Peroxymonosulfate (PMS) activation by solid catalysts for ciprofloxacin (CIP) removal is a promising method for decontaminating wastewater. However, mainstream catalysts suffer from efficiency and durability issues due to mechanical fragility and structural instability. Here, we have developed a durable calcium alginate hydrogel encapsulating fluorinated cobalt oxyhydroxide (FCO/CAH), fabricated by a simple hydrogen-bond-assisted cross-linking reaction, to enhance PMS activation for complete CIP removal. The optimized 2-FCO/CAH could generate abundant singlet oxygen (1O2) and sulfate radicals (SO4˙-) with PMS, resulting in 0.433 min-1 kinetic constant and approximately 100% CIP degradation within 10 minutes. This exceptional degradation efficiency is due to the even distribution of 2-FCO, which maximizes catalytic sites for PMS activation, and the multichannel cavity structure of CAH, which effectively enriches both PMS and CIP. Furthermore, the durability of 2-FCO/CAH was proved by its negligible decay in CIP removal efficiency (∼100%) and good microstructure retention after 6 consecutive cycles, facilitated by a stable surface reconstructed interphase on the 2-FCO surface and the strong mechanical property of 2-FCO/CAH. Our work showcases a facile approach to constructing durable hydrogel catalysts that improve PMS-mediated antibiotic degradation.

Effective photocatalytic hydrogen generation and degradation for single cobalt and tungsten metal atom oxide anchored on titanium dioxide-bismuth molybdate-reduced graphene oxide

A simple hydrothermal method was used to prepare the single-metal atom oxide (SMAO) catalyst. The prepared dual Cobalt and tungsten (CoW) single metal atom oxide anchored on the TiO2-Bi2MoO6-reduced graphene oxide (rGO), an interstitial atomic line of tungsten and cobalt. The prepared photocatalyst showed good photocatalytic hydrogen (H2) evolution and organic contaminant degradation. As co-catalysts, surface-dispersed CoW sites were created using a Co mono-substituted hetero-polyacid (HPA-Co). A larger quantity of single atoms were uniformly decorated on the TiO2-Bi2MoO6-Ethylenediamine (ED)-rGO catalyst. The presence of the CoW species was verified employing extended X-ray absorption near edge structure (XANES), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and extended X-ray absorption fine structure (EXAFS) analyses after a TiO2-Bi2MoO6-CoW-ED-rGO composite synthesized. The findings demonstrate that TiO2-Bi2MoO6-CoW-ED-rGO catalysts were more capable of producing hydrogen and degrading Ciprofloxacin (CIP) (21.46 mmol/g/h, 97.2%) than other bare and binary catalysts. Furthermore, it showed remarkable stability and reusability after five consecutive CIP photodegradation and H2 production cycles. Gas chromatography/mass spectroscopy (GC/MS) techniques were used to identify the intermediates in the photodegradation process. The prepared photocatalyst was significantly increased, and the separation of charge carriers was further boosted, thanks to the CoW material and the synergistic effect. A possible Z-scheme mechanism was proposed for the photocatalytic H2 production activity. More electrons can contribute to the reduction of H2 evolution because of the processability of the Z-scheme. This work created a recyclable, inexpensive, highly effective, and non-toxic catalytic material for H2 generation and CIP degradation.

Boosting ciprofloxacin and indigo carmine dye photodegradation using S-scheme plate-like BiOI@sulfated TiO2 heterojunctions: An understanding of the performance, the degradation route, and DFT computation

Sustainable BiOI/sulfated TiO2 nanocomposites were created for the present study utilizing the environmentally friendly dispersion-ultrasonication technique. Then, their ability to degrade the medication ciprofloxacin (CIP) and indigo carmine coloring (IC) in aquatic water was evaluated. The optimized catalyst 10%BiOI/ST, denoted as 10BOST together with 5BOST, is subjected to thorough characterization together with that of sulfate-free TiO2 (10BOT) to assess their physiochemical, morphological, textural, structural, and elemental composition properties. It is noteworthy that the 10BOST composite achieves remarkable degradation and performs exceptionally well in photocatalytic IC and CIP degradation. In 35 min, it degrades IC to 100%, with a rate constant of 0.066 min−1, which is superior to that of 10BOT (0.054 min−1) in the incidence of visible light and without an oxidizing agent. In CIP, 10BOST yields 85.6% degradation with a rate constant of 0.027 min−1 preceding 0.024 min−1 for 10BOT when potassium persulfate oxidizing agent is present. This exceptional performance is ascribed to the composite's diminished particle diameter, largest pore radius, hydrophilicity, improved light absorption, and the developed heterojunction between ST and BiOI, as demonstrated by XPS, TEM, XRD, EDX and IR data. The effect of sulfation concentration, pH, Ti3+/Ti4+ ratio, and pollutant concentration were studied together with the active species determinations, which revealed that active radicals like SO4•−, •OH, and h+ were well participated in the pollutant's decomposition. Testing for toxicity shows that during CIP breakdown, innocuous hazardous intermediates evolve with a notable 70% mineralization rate in their TOC. Furthermore, 10BOST showed strong stability and reusability. Using DFT simulations, profound insights into the principles underlying the adsorption sites of pollutants, their chemical reactivity, and the arrangement of their electrical charges, and how these factors affect the reaction mechanism on BOST photocatalysts.

Novel insights into revealing the intrinsic degradation mechanism of ciprofloxacin by Chlorella sorokiniana: Removal efficiency, pathways and metabolism

Microalgae-mediated biodegradation of antibiotics has attracted increasing interest. However, the exact degradation mechanism behind it remains elusive, which is crucial for improving its efficiency and large-scale implementation. Therefore, this study aims to thoroughly investigate how Chlorella sorokiniana (C.sorokiniana) degrades ciprofloxacin (CIP) from the molecular level to elucidate its complicated degradation mechanism. Results show that C.sorokiniana exhibited an impressive removal rate of 38.05–74.29 % for CIP, the synergistic effect of biosorption and biodegradation was the main removal mechanism of CIP. The content of EPS increased by 11.84–103.31 %, acting as a carrier to increase the bioavailability of CIP. Enzyme activity analysis identified POD, CYP450, and GST as the major catalytic enzymes responsible for the biotransformation process of CIP with increases of 6–41.2 %, 18.78–102.1 % and 3.53–58.15 %, respectively. Molecular docking further revealed that the binding affinity of 146.24 μM, 27.71 μM and 16.33 μM was observed for POD,CYP450, and GST, respectively, indicating the high metabolic efficiency of CIP by CYP450. Finally, DFT calculations elucidated the enzyme-mediated biodegradation pathway of CIP, including hydroxylation, decarboxylation, and ring opening. These findings are expected to further fill the knowledge gap on the catalysis mechanism of CIP degradation by enzymes and improve the practical application of microalgae to antibiotic wastewater.

Degradation of ciprofloxacin by hydrogen peroxide activated with pyrite under simulated sunlight

Ciprofloxacin (CIP) residues in the environment pose risks to both human health and ecosystems. In this study, we explored the effect of hydrogen peroxide (H2O2) on CIP degradation, activated by pyrite (FeS2) under simulated sunlight. XRD, XRF, EDS, XSP, DRS, and PL tests confirmed the high purity of FeS2 and its photocatalytic properties. With [CIP] = 30 μM, [FeS2] = 0.2 g/L, [H2O2] = 0.2 mM, CIP removal reached 87.6 %. The removal rate of TOC reached 55.3 % after 60 min of light exposure, and hydroxyl radicals (OH) contributed 72.7 % to the process. H2O2 utilization was 67.5 %, and the system operated effectively across a pH range of 2.00 to 8.00. CIP removal in river water reached 87.9 % after 3 h of light exposure, though the degradation was slower than in ultrapure water. Cl−, SO42−, and NO3− had little effect on degradation, whereas H2PO4−, CO32−, and HCO3− significantly inhibited the process as their concentrations increased. In livestock wastewater, the simulated sunlight-FeS2/H2O2 system was less effective, but after diluting the wastewater 100 times, CIP removal reached 87.6 % after 60 min. The degraded solutions showed no significant toxicity. These findings suggest that FeS2, combined with simulated sunlight, can effectively catalyze low concentrations of H2O2 to produce OH radicals, removing antibiotics from livestock wastewater.

Symmetry-Engineered BINOL-Based Porous Aromatic Frameworks for H2O2 Production via Artificial Photosynthesis and In Situ Degradation of Pharmaceutical Pollutants.

Accomplishing visible light-driven H2O2 production at millimolar concentrations is practically challenging, particularly for organic semiconductors. In this context, achieving a maximum H2O2 production rate of 31.60 mmol·g-1·h-1 by using porous aromatic frameworks (PAFs) represents a significant accomplishment. We report the unusual photoactivity of tetraphenylmethane-BINOL-linked PAFs in triplet oxygen activation to facilitate the generation of reactive oxygen species (ROS), as confirmed by their optical and electrochemical responses, despite the absence of a conventional chromophoric moiety. Moreover, an in situ BINOL formation strategy was used to synthesize these PAFs during polymerization in contrast to the reported protocols involving chiral BINOLs as precursors. The as-synthesized polymers had a capsule-like morphology (for TPM-BINOL-6), high thermal stability up to 348 °C, and a high Brunauer-Emmett-Teller (BET) surface area of up to 1382 m2/g (for TPM-BINOL-4). Interestingly, they showed sunlight-driven production of H2O2 via an oxygen reduction reaction of up to 17.05 mmol·g-1·h-1 in 1:10 isopropanol in water for TPM-BINOL-6, which was quantified by titration with ceric sulfate. It also exhibited exemplary photocatalytic efficiency with an H2O2 production rate of 6.65 mmol·g-1·h-1 in seawater. Interestingly, the H2O2 production rate reached a maximum of 18.03 mmol·g-1·h-1 with an SCC efficiency of 4.5% under an AM 1.5G solar simulator and apparent quantum yield (AQY) of 15.8% (at λ = 456 nm) for TPM-BINOL-6 in ethanol:water = 1:10. Moreover, the exceptionally high H2O2 production rate of 31.60 mmol·g-1·h-1 was achieved in 1:1 ethanol in water under 50 W blue LED light. Furthermore, these PAFs generated adequate ROS, which were utilized in the photocatalytic degradation of tetracycline via the superoxide intermediate. Additionally, the as-formed H2O2 was further channelized in the pollution abatement catalytic system for the fast degradation of ciprofloxacin (within 4 h) and the reduction of toxic oxometallate Cr(VI) within 10 min, which is one of the earliest reports of utilizing photosynthesized H2O2 for environmental detoxification.

Dual-active-group co-modification of BiOBr for boosting photocatalytic CO2 reduction coupled with ciprofloxacin oxidation

Coupling CO2 photoreduction with ciprofloxacin (CIP) oxidation presents a promising strategy for achieving not only the complete utilization of photoexcited carriers but also the win–win goals of energy conversion and environmental remediation. In this study, we utilized an aminated BiOBr catalyst with surface hydroxyl groups (NH2/BOB–OH) for efficient photocatalytic CO2 reduction coupled with CIP oxidation. In this process, hydroxyl (OH) and amino groups (NH2) adsorbed and activated CIP (an organic pollutant) and CO2 molecules, respectively, promoting the overall photocatalytic redox activity. Remarkably, 0.5NH2/BOB–OH exhibited excellent photocatalytic redox performance for CO2 reduction coupled with CIP oxidation, with the CO yield and CIP degradation efficiency being 6.85 and 1.08 times higher, respectively, than those achieved using BiOBr without any active groups. Moreover, a series of in situ experimental characterizations and theoretical simulations revealed that these two opposing active groups not only accelerated carrier separation but also boosted the surface reactivity of the catalyst. These findings provide helpful insights into the dual-active-group functionalization of semiconductors, leading to their high photoredox activity for energy conversion along with environmental remediation.

Co-N3 site activated peroxymonosulfate for rapid degradation of ciprofloxacin: Synergistic effect of free radicals and nonfree radicals

Nitrogen-doped metal-organic framework (MOFs)-derived carbon materials (denoted as Co-MOF-74@N-T-x) were successfully fabricated by calcinating Co-MOF-74, utilizing the green precursor of melamine. Among these materials, Co-MOF-74@N-500-2 demonstrated superior catalytic performance in activating peroxymonosulfate (PMS), achieving over 95 % degradation of ciprofloxacin (CIP) within 15 min, with a rate constant that was 1.25 times greater than that of Co-MOF-74-500. The primary active species identified in this study were sulfate radicals (SO4•−) and singlet oxygen (1O2), with the latter playing an important role in the degradation of CIP in the Co-MOF-74@N-500-2/PMS system. Theoretical calculations confirmed that the enhanced catalytic activity primarily stemmed from the Co-N3 configuration, which was more effective in activating PMS than the other configurations were. Co-MOF-74@N-500-2/PMS showed excellent performance in oxidizing CIP across a broad pH range (3.0–9.0) and demonstrated stability over five cycles, along with impressive degradation performance capabilities for a wide range of pollutants including metronidazole (MNZ), oxytetracycline (OTC), nitrofurantoin (FNT), methylene blue (MB), and acid orange (OG). This study presents a viable strategy for developing efficient and durable catalytic systems aimed at degrading organic pollutants via PMS.

Photodegradation of ciprofloxacin and its interaction with Cu(II) in different water matrices: Insight into degradation pathways

Co-contamination of ciprofloxacin (CIP) and Cu(II) is common in marine aquaculture water. However, the transmission and transformation of these substances in natural water matrices are often overlooked. This study sought to assess the impact of Cu(II) on CIP degradation in distilled (DI) and simulated (SI) mariculture water, as well as to develop a relationship between Cu(II), CIP, and its degradation products. First, complexation assays and analog computations revealed that Cu (II) forms complexes by binding to the oxygen atoms of the carbonyl (C=O) and carboxyl (COOH) groups in the CIP molecule. Second, photodegradation experiments showed that Cu(II) significantly hindered the degradation effect of CIP in DI water, while Cu(II) did not significantly hinder the degradation of CIP in SI water. Furthermore, the effect of Cu(II) on the degradation mechanism of CIP was determined by combining quenching and EPR experiments, Materials Studio software calculations, and UPLC-MS results. It was demonstrated that Cu(II) enhanced the production of singlet oxygen (1O2), hydroxyl radicals (•OH), and superoxide radicals (•O2−) in DI water. In the presence of Cu(II), CIP undergoes hydroxylation and decarbonylation reactions, forming hydroxylated and nitroxylated products. Additionally, direct defluorination and cleavage of the piperazine ring occur, followed by complexation reactions with Cu(II). However, in SI water, the production of 1O2 depends on the indirect action of Cu(II) and the excited state transformation of organic matter. Experimental evidence has shown that CIP can create intermediate compounds that include O-O peroxide rings, with or without the presence of Cu(II). When Cu(II) is present, the cyclopropyl group of the CIP molecule is more prone to transformation and so degradation. Finally, the toxicity assessment results indicated that both Cu(II) and SI water increased the toxicity of the degradation products.

Charge separation by switching heterojunction system from Type-II to S-scheme for enhanced photocatalytic activity: Environmental detoxification and H2 production

The development of highly efficient photocatalysts is essential for harnessing solar energy for pollutant degradation and hydrogen (H2) production. This study provides a novel ternary S-scheme photocatalyst (Fe2O3/Bi2O3/g-C3N4), prepared from optimized binary 20-Bi-C via a simple electrostatic self-assembly method for the first time. Using various methods including UV–vis DRS, PL, ESR, photocurrent, Mott-Schottky, XPS, XRD, FTIR, SEM, TEM, and BET, the optical, structural, and morphological characteristics of the produced materials were fully studied. The photocatalytic performance of as-manufactured materials was evaluated through the degradation of the Ciprofloxacin (CIP) and H2 production. Under optimized conditions determined by the RSM method, a maximum CIP degradation of 97.20 % was achieved at a rate of 0.053 min−1, with the catalyst dosage: 0.44 g/l, CIP concentration: 26.07 mg/l, pH: 6.29 and Time: 63.01. The optimized heterojunction exhibited an exceptional photocatalytic H2 generation rate of 2428 μmol·g−1·h−1 within 2 h, surpassing the binary 20-Bi-C photocatalyst by 1.3 times. Furthermore, after five continuous cycles, the 5-Fe2O3/Bi-C photocatalyst showed good chemical stability and reusability, sustaining a degradation rate of over 96 % and a TOC removal of 80 %. Experiments on the identification of free radicals have demonstrated the important roles that O2−, h+, and OH species play in the photocatalytic process. The enhancement mechanism of 5-Fe2O3/Bi-C involves the successful synthesis of Fe2O3/Bi-C photocatalyst with well-aligned positions of band gap edges, enabling the facile charge transfer through S-Scheme mechanism. Furthermore, the study investigates the impact of environmental factors, including solution pH, water matrices, and the efficiency of the synthesized photocatalyst on other organic pollutants. The photocatalytic degradation behavior of CIP is predicted using LC-MS analysis. This work provides a new method for building S-scheme heterojunctions by creatively converting the type-II heterojunction system to an S-scheme by metal oxide doping.

Layered bismuthene forming the interfacial pathway for rapid charge transfer in CuNb13O33/g-C3N5 photocatalyst for enhancing ciprofloxacin degradation

The objective of the present research was to examine the usefulness of the photocatalytic degradation process in removing the ciprofloxacin drug from wastewater, which is difficult to remove from waterbodies. To tackle this difficulty, a ternary copper niobium oxide/carbon nitride/layered bismuthene heterostructure (CuNb13O33/g-C3N5-L-Bi) composite was developed by an intuitive solvothermal process. layered bismuthene (L-Bi) was prepared using a unique ball milling approach. According to the results of the characterization, adding L-Bi and g-C3N5 with a low band gap to the original band structure of CuNb13O33 makes it more efficient. After 120 min of irradiation, the modified CuNb13O33/g-C3N5-L-Bi sample significantly improved ciprofloxacin degradation, resulting in a degradation rate of 98 %. In addition, the impact of the catalyst that has been created on the removal of ciprofloxacin at various pH, catalyst dosages, and scavengers was also examined, demonstrating the catalyst’s suitability for purifying natural water environments. A detailed study of the steps used to break down ciprofloxacin has shown that many active species are involved, with a focus on the important roles played by reactive oxidative species (ROS). Thus, this study introduces a novel combination of layered bismuthene photocatalysts for environmentally friendly degradation of antibiotics.

Fabrication of boron modified bi-functional air diffusion electrode for ciprofloxacin degradation: In-situ H2O2 generation and self-activation

In order to improve H2O2 in-situ generation in electrochemical system, a boron (B) modified air diffusion electrode (B@ADE) was fabricated in the present study. Carbon black (CB) doped by B was deposited on ADE surface as catalytic layer. Performance of B@ADE with different B/C mass ratios has been investigated and 0.3 was identified as the optimal one·H2O2 yield can be achieved 204.85 mg L-1 within 45 min at 0.3-B@ADE, which was 1.51 times for that of ADE. Meanwhile, H2O2 self-activation on B@ADE surface was observed and effects of different operating parameters on •OH formation have been analyzed. XPS analyzation demonstrated that BC2O, BC2O and C=O/O-C=O were related to H2O2 generation. DFT calculation revealed that BCO2 was benefit for O2 adsorption, while BC2O promoted *OOH desorption with lower free energy barriers for H2O2 and •OH generation. Quenching experiments for ciprofloxacin (CIP) demonstrated that •OH, O2•- and 1O2 were co-existed in the system with their contribution quantified. Four possible degradation pathways were proposed through active sites identification by DFT calculation and intermediates detection by HPLC-MS/MS. Bio-toxicity analyzation results showed that the toxicity of most intermediates was lowered than CIP. These results proved that electrochemical oxidation system with B@ADE enhanced in-situ H2O2 generation and self-activation, with great potential for practical application.