Degradation Rate Of Ciprofloxacin Research Articles

A novel dual S-scheme heterojunction photocatalyst KBCN/t-BiVO4/m-BiVO4 induced by phase-transformed bismuth vanadate for highly efficient degradation of ciprofloxacin in full-spectrum: Degradation pathway, DFT calculation and mechanism insight

A novel KBr-g-C3N4/t-BiVO4/m-BiVO4 (15KBCN/mtBVO-P, P means PVP) heterojunction photocatalyst is synthesized using a hydrothermal method with the assistance of surfactant polyvinylpyrrolidone (PVP). Field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and X-ray powder diffraction (XRD) confirm the formation of the heterostructure and changes in the crystal structure. Under sunlight illumination, 15KBCN/mtBVO-P exhibits the strongest photocatalytic degradation performance for ciprofloxacin (CIP), reaching 95.3 % within 240 min, the apparent kinetic constant is approximately 3.4, 2.4, and 3.3 times higher than CN, t-BVO, and m-BVO. The outstanding CIP degradation rate is observed under simulated solar and visible light, with over 93.0 % and 85.8 % in 60 min and 120 min. The enhanced photocatalytic performance is attributed to the in-situ generation of the mixed-phase BiVO4 by precise crystal phase regulation. Furthermore, the charge transport and photocatalytic degradation mechanism of 15KBCN/mtBVO-P is revealed. Degradation pathways and ecotoxicity of CIP and its degradation products were elucidated through LC-MS/MS technology, DFT calculations, and QSAR models. This study presents a pioneering perspective on the fabrication and development of g-C3N4-based dual S-scheme heterojunction photocatalysts for practical application.

Facile fabrication of CeO2/L-Bi2O2CO3 composite photocatalyst for removal of ciprofloxacin under visible light irradiation

The application of semiconductor photocatalytic technology to degrade antibiotics in water has been proved to be a promising technology CeO2/L-Bi2O2CO3 composite photocatalyst was efficiently prepared by a facile room temperature precipitation technique and employed in the photocatalytic degradation of ciprofloxacin (CIP). When the concentration of ciprofloxacin was 20 mg/L and the dosage of catalyst was 1.0 g/L, the degradation rate of CIP was 89.96 % after 120 min reaction with optimal catalyst. The addition of L-cysteine not only changed the crystallinity of Bi2O2CO3, but also broadened its visible light absorption range. Additionally, the combination of CeO2 and L-Bi2O2CO3 creates a heterojunction interface accelerates the electron transfer, thereby improving the photocatalytic activity. The degradation process was confirmed to involve the significant participation of O2– and h+ through free radical capture experiments. HPLC-MS analysis detected the intermediates of CIP degradation, leading to the proposition of two potential degradation pathways. Moreover, an electron transfer mechanism was suggested by analyzing the Mott-Schottky (M−S) curve and Taut-plot curves. This work provides new paradigm for the rational design of modified Bi2O2CO3-based photocatalysts and the treatment of contain CIP wastewater.

S-type heterojunction enhance the photocatalytic activity of TiO2/AgBr/Ag using loofah sponge as template towards ciprofloxacin degradation

Photocatalyst TiO2/AgBr/Ag (TBA) composites using loofah sponge as a template were successfully prepared for the first time. The photocatalytic activities of the TBA composites were evaluated by removing ciprofloxacin (CIP) under visible light. The PDOS shows that the valence band edge of TBA-30 is primarily composed of Ti 3d atom states, with small contributions from O 2p atom states. The conduction band edge is dominated by Ag 4d and O 2p atom states, with minor contributions from Br 4p atom states. TBA-30 composites demonstrate outstanding photocatalytic performance, degrading 87% of the target within 180 min. The degradation rate of CIP decreased to 70.19% after five runs, Furthermore, the TOC removal efficiency of CIP reached 84.2% in the end. CIP intermediates and degradation pathway were determined by GC-MS. Three-dimensional excitation-emission matrix fluorescence spectra (3D EEM) were used to study the degradation of CIP molecules. Trapping experiments and electron paramagnetic resonance (EPR) characterisation identified superoxide (·O2-) and photogenerated holes (h+) as the primary active radicals. Furthermore, formed S-type heterojunction and Ag as the electron capture site enhanced the separation efficiency of photoinduced electron-hole pairs. The DFT calculation was used to study the electron transport performance of TBA-30 by calculating the charge density difference.

Copper(II) phosphate as a promising catalyst for the degradation of ciprofloxacin via photo-assisted Fenton-like process

This work aims to unravel the potential of copper(II) phosphate as a new promising heterogenous catalyst for the degradation of ciprofloxacin (CIP) in the presence of H2O2 and/or visible light (λ > 400 nm). For this purpose, copper(II) phosphate was prepared by a facile precipitation method and fully characterized. Of our particular interest was the elucidation of the kinetics of CIP degradation on the surface of this heterogeneous catalyst, identification of the main reactive oxygen species responsible for the oxidative degradation of CIP, and the evaluation of the degradation pathways of this model antibiotic pollutant. It was found that the degradation of the antibiotic proceeded according to the pseudo-first-order kinetics. Copper(II) phosphate exhibited ca. 7 times higher CIP degradation rate in a Fenton-like process than commercial CuO (0.00155 vs. 0.00023 min−1, respectively). Furthermore, the activity of this metal phosphate could be significantly improved upon exposure of the reaction medium to visible light (reaction rate = 0.00445 min−1). In a photo-assisted Fenton-like process, copper(II) phosphate exhibited the highest activity in CIP degradation from among all reference samples used in this study, including CuO, Fe2O3, CeO2 and other metal phosphates. The main active species responsible for the degradation of CIP were hydroxyl radicals.

High potential of the vacuum UV-activated peracetic acid (VUV/PAA) process in eliminating recalcitrant contaminants and waterborne pathogens: Assessing the efficacy of annular and helical reactor configurations

The effectiveness of VUV/PAA in degrading Ciprofloxacin (CIP) and inactivating E. coli was studied. VUV was more efficient than UVC in activating PAA. The VUV/PAA process degraded CIP twice as fast as the VUV process under similar conditions and was more effective in acidic or neutral solutions than in alkaline solutions. The hydroxyl radicals formed were key to the degradation, whereas the R-C species played a lesser role. Furthermore, the VUV/PAA process achieved a satisfactory CIP degradation rate in spiked tap water. Operating the reactors in batch mode, completely degraded CIP in 30 min, and 86.5 % TOC removal was achieved in 120 min of a 40 mg/L CIP solution. In addition, VUV/PAA inactivated a 6.5-log of 1.2 × 109 CFU/mL of E. coli in only 5 min. Moreover, the VUV/PAA process was compared in a helical (HPR) and annular photoreactor (APR); the HPR led to approx. x3 higher ▪OH generation and superior CIP degradation rate. The VUV/PAA process improved CIP degradation in both the APR and HPR with longer hydraulic residence times, where the HPR outperformed the APR in degrading CIP. Overall, the VUV/PAA@HPR system is an effective method for enhancing the degradation of recalcitrant organics and waterborne pathogens in contaminated water, including in the flow-through mode, making it a promising process for water treatment.

Zinc-Doped BiOBr Hollow Microspheres for Enhanced Visible Light Photocatalytic Degradation of Antibiotic Residues.

Photocatalysis represents an effective technology for environmental remediation. Herein, a series of Zn-doped BiOBr hollow microspheres are synthesized via one-pot solvothermal treatment of bismuth nitrate and dodecyl ammonium bromide in ethylene glycol along with a calculated amount of zinc acetate. Whereas the materials morphology and crystal structure remain virtually unchanged upon Zn-doping, the photocatalytic performance toward the degradation of ciprofloxacin is significantly improved under visible light irradiation. This is due to the formation of a unique band structure that facilitates the separation of photogenerated electron-hole pairs, reduced electron-transfer resistance, and enhanced electron mobility and carrier concentration. The best sample consists of a Zn doping amount of 1%, which leads to a 99.2% degradation rate of ciprofloxacin under visible photoirradiation for 30 min. The resulting photocatalysts also exhibit good stability and reusability, and the degradation intermediates exhibit reduced cytotoxicity compared to ciprofloxacin. These results highlight the unique potential of BiOBr-based photocatalysts for environmental remediation.

In situ heterojunction growth of CdS‐Bi2MoO6 microspheres for highly efficient photocatalytic degradation of Ciprofloxacin under visible light

AbstractIn‐situ synthesis was utilized to create a novel CdS‐Bi2MoO6 microspheres heterojunction photocatalyst for the degradation of Ciprofloxacin (CIP). Under visible light irradiation (> 420 nm), the prepared samples demonstrated effective photocatalytic activity, the highest CIP degradation rate can reach 87 % within 60 minutes. The apparent kinetic rate constant (0.0503 min−1) is 2.9 and 5.4 times greater than that of pure CdS (0.0173 min−1) and Bi2MoO6 (0.00929 min−1), respectively. XRD, FT‐IR, Raman, SEM, TEM, HRTEM, XPS, EIS, PL, and other techniques have been applied to analyze the composition and structure of the catalyst. Furthermore, various active substance capture experiments and EPR spectra were used to examine the potential photocatalytic mechanisms. ⋅ O2− and h+ have been proven to be the most active substances in the photocatalytic degradation of CIP. The prepared samples have excellent stability, and the photodegradation system positively impacts toxicity reduction. The effective treatment of antimicrobial wastewater is a possible use for the catalyst.

Degradation of Ciprofloxacin in Water by Magnetic-Graphene-Oxide-Activated Peroxymonosulfate.

Antibiotics are extensively applied in the pharmaceutical industry, while posing a tremendous hazard to the ecosystem and human health. In this study, the degradation performance of ciprofloxacin (CIP), one of the typical contaminants of antibiotics, in an oxidation system of peroxymonosulfate (PMS) activated by magnetic graphene oxide (MGO) was investigated. The effects of the MGO dosage, PMS concentration and pH on the degradation of CIP were evaluated, and under the optimal treatment conditions, the CIP degradation rate was up to 96.5% with a TOC removal rate of 63.4%. A kinetic model of pseudo-secondary adsorption indicated that it involves an adsorption process with progressively intensified chemical reactions. Furthermore, the MGO exhibited excellent recyclability and stability, maintaining strong catalytic activity after three regenerative cycles, with a CIP removal rate of 87.0%. EPR and LC-MS experiments suggested that •OH and SO4-• generated in the MGO/PMS system served as the main reactants contributing to the decomposition of the CIP, whereby the CIP molecule was effectively destroyed to produce other organic intermediates. Results of this study indicate that organic pollutants in the aqueous environment can be effectively removed in the MGO/PMS system, in which MGO has excellent catalytic activity and stabilization for being recycled to avoid secondary pollution, with definite research value and application prospects in the field of water treatment.

Construction of a porous pyrite cinder-supported Mn-doped BiFeO3 composite photocatalyst: Confined-space strategy, structure, and visible-light catalytic degradation toward ciprofloxacin

A series of novel confined visible-light catalysts, namely, Mn-doped BiFeO3 (MBFO) composite photocatalyst anchored on porous residue pyrite cinder (PR-PyC) after partial Fe extraction (PR-PyC/MBFO-φ, φ refers to the doped amount of Mn), was successfully constructed via confined-space strategy using the Fe extracted from PyC as Fe source for BiFeO3 (BFO) and the PR-PyC as the template and structure regulator for MBFO generation. The resulting PR-PyC/MBFO-5% is composed of relatively uniform nanoparticles anchored in the channels of PR-PyC matrix and interparticle interstices and has a specific surface area of 14.18 m2/g, an average pore size of 37.76 nm, and a pore volume 0.13 cm3/g. It has a type-II heterojunction with a band gap energy (Eg) of 1.95 eV and exhibits high visible-light catalytic degradation activity toward ciprofloxacin (CIP) and excellent recyclability. The CIP degradation rate of PR-PyC/MBFO-5% reached 96.41% with an apparent reaction rate constant kapp of 0.0265 min−1 under visible-light irradiation for 120 min, and the corresponding mineralization rate reached 77.42%. The active species produced during photocatalysis were h+ and •OH, in which h+ plays a major role. The doping of 5% Mn can effectively regulate the energy band structure and heterojunction type and the use of an appropriate amount of PR-PyC can effectively guide and regulate the structure and morphology of the as-prepared catalyst. This study presents an effective confined-space strategy for fabricating innovative high-efficiency photocatalysts for antibiotic degradation, thereby paving the way for the valuable resource utilization of PyC.

Nanoarchitectonics of Oxygen-Vacancy BiOCl@Bi4O5Br2 Z-Type Heterojunctions with Efficient Photocatalytic Degradation Performance

Searching for a stable and efficient photocatalyst still presents a variety of challenges, when photocatalytic technology is widely used today. In this paper, oxygen-vacancy BiOCl with different masses was loaded on Bi4O5Br2 nanosheets by a simple two-step method. The UV–Dis spectrum showed that the absorption range of the complex to visible light was larger than that of the two pure substances. In addition, the PL, [Formula: see text]–[Formula: see text] and EIS characterization prove that the formation of heterogeneous interface between the two materials accelerated the charge transfer in the semiconductor, eventually making photocatalytic efficiency significantly increased. The results showed that the 1 wt.% Ov-BOC@BOB has the best degradation performance, which was seven and four times than that of Ov-BOC and BOB within 120 min, respectively. Free radical capture experiment further confirmed that the charge transfer between oxygen-vacancy BiOCl and Bi4O5Br2 conforms to the Z-type transfer mechanism, such a charge-transfer mechanism would leave behind strongly reducing electrons and strongly oxidizing holes, respectively. The degradation rate of ciprofloxacin (CIP) was not significantly reduced after five cycles of experiments, indicating that the compound had good stability. This study provides a feasible idea for exploring stable and efficient photocatalysts.

CuCoFe-LDHs activated sodium percarbonate (SPC) for the degradation of ciprofloxacin

Sodium percarbonate (SPC) is widely used in Fenton-like technology for the organic wastewater treatment because of its low costs and convenient transportation. However, low utilization efficiency of hydrogen peroxide limits its application. In this work, a catalyst (CuCoFe-LDHs) was designed to activate SPC for degrading ciprofloxacin (CIP) effectively in heterogeneous Fenton system with higher H2O2 utilization rate (62 %) and higher stability (degradation rate of CIP decreased 5.6 % after five cycles). Since SPC was dissolved in water, H2O2 and CO32- were generated, and CO32- was transferred to HCO3- subsequently along with the variation of pH value. Plenty of •OH and •O2- was generated, and most of •OH was directly reacted with CIP. However, •O2-, was prone to react with HCO3- to form •CO3-, and then for degrading CIP. Compare with CuMgFe-LDHs catalyst, the electrochemical impedance spectroscopy (EIS) showed that CuCoFe-LDHs with stronger electron transfer ability. Therefore, the Co atom could facilitate the generation of specific free radical via enhancing electron transfer rate for the degradation of CIP in CuCoFe-LDHs. In summary, this study provides a cheap, recyclable, efficient and environmentally friendly wastewater treatment method for the degradation of refractory organic pollutants.

Preparation of sodium alginate gel microspheres catalysts and its high catalytic performance for treatment of ciprofloxacin wastewater

The discharge of the antibiotic wastewater has increased dramatically in our country with the development of medical science and wide application of antibiotic, resulting in serious harm to human body and ecological environment. In this work, ciprofloxacin (CIP) was selected as one of typical antibiotics and heterogeneous Fenton-like catalysts were prepared for the treatment of ciprofloxacin wastewater. The sodium alginate (SA) gel microspheres catalysts were prepared by polymerization method using double metal ions of Fe3+ and Mn2+ as cross-linking agents. Preparation conditions such as metal ions concentration, mass fraction of SA, polymerization temperature and dual-metal ions as crosslinking agent were optimized. Moreover, the effects of operating conditions such as initial concentration of CIP, pH value and catalyst dosage on CIP removal were studied. The kinetic equation showed that the effect of the initial concentration of CIP on the degradation rate was in line with second-order kinetics, and the effects of catalyst dosage and pH value on the degradation rate of CIP were in line with first-order kinetics. The SA gel microspheres catalysts prepared by dual-metal ions exhibited a high CIP removal and showed a good reusability after six recycles. The SA gel microspheres catalysts with an easy recovery performance provided an economical and efficient method for the removal of antibiotics in the future.

Preparation of ZnO/Cu2O Composite Particles and Its Degradation of Ciprofloxacin: Analysis of Degradation Performance and Active Species

At present, the water pollution caused by antibiotics has seriously affected the ecological balance and human health. The development of a novel and efficient visible-light-responsive semiconductor photocatalysts is of great significance for the degradation of ciprofloxacin by visible light. In this study, solvothermal method was used to prepare ZnO and ZnO/Cu2O composite particles. The effects of ZnO addition on the microstructure, surface morphology and photoelectric properties of composite particles were studied by XRD, XPS, SEM, BET and UV-Vis techniques. The kinetics of photocatalytic degradation of ciprofloxacin by ZnO/Cu2O composite particles and the contribution of different active species in the degradation process were studied. The results show that the purity of the prepared product is high. ZnO/Cu2O has an octahedral morphology. Compared with Cu2O, ZnO/Cu2O has a clear difference, the absorbance is reduced, the band gap is increased, and the surface fitting resistance is significantly reduced. Among them, R3 sample has highest purity and degree of recombination, the surface fitting resistance is the smallest, the separation efficiency of photogenerated electrons and holes is improved, and the photocatalytic performance is improved. The degradation rate of ciprofloxacin by R3 sample is 80.4%, and the degradation of ciprofloxacin conforms to the first-order kinetic equation. After 5 repeated experiments, the ciprofloxacin degradation rate can still reach 75.3%, indicating that the composite material has good stability and reusability. Studies on active species in the process of degradation showed that ·OH played a major role in the degradation of ciprofloxacin.

Solar-driven hybrid photo-Fenton degradation of persistent antibiotic ciprofloxacin by zinc ferrite-titania heterostructures: degradation pathway, intermediates, and toxicity analysis.

Present work puts forward an efficient strategy to degrade one of the persistent antibiotic contaminants, ciprofloxacin (CIP). Hybrid advanced oxidation process (HAOP) is tailored with a synergy effect between photocatalysis and photo-Fenton catalysis on zinc ferrite-titania heterostructured composite (ZFO-TiO2). The ZFO-TiO2 heterostructured composite enables heterogenous surfaces for enhanced charge separation where HAOP is implemented for CIP degradation with the aid of class AAA solar simulator. The results reveal an enhanced degradation rate of CIP (kobs = 0.255min-1), noticeably higher than the conventional TiO2-based photocatalysis. The HAOP system strongly enhances the reaction rates showing five times higher performance as compared to TiO2-based photocatalysis. The substitution reactions for degradation of CIP into its intermediates were analyzed by LC-MS/MS, and the plausible degradation pathways have been graphically modeled identifying 3-phenyl-1-propanol and phenol molecules as less toxic end products. Toxicity of the photodegraded samples reveal 18.1 ± 1.24% inhibition of V. fischeri at the end of 60-min treatment indicating reduced toxicity of CIP contaminated samples. Antimicrobial inhibition studies on E. coli also corroborate an effective CIP removal (~ 100%) in less than 90min. The study puts forward a novel ZFO-TiO2 composite HAOP system for efficient and rapid mineralization of an antibiotic pollutant, extendable towards wide range of pharmaceutical drug degradation studies.

Efficient heterostructure of CuS@BiOBr for pollutants removal with visible light assistance

The Z-scheme heterojunction photocatalyst CuS@BiOBr was fabricated by precipitating BiOBr on CuS nanoparticles. The experimental results showed that CuS@BiOBr system showed high efficiency in the photocatalytic degradation of ciprofloxacin (CIP) compared with BiOBr and CuS. Catalyst application in realistic wastewater: CIP of removal ratio was 86.49%, 76.95%, 78.58% and 75.11% in DI water, tap water, lake water (longitude123.701077, latitude 41.453335) as well as river water (longitude 123.701710, latitude 41.453070), separately. These results show that CuS@BiOBr-700 can be effectively used for the photocatalytic removal of ciprofloxacin contaminants in the environment. • Composite catalyst of CuS@BiOBr was synthesized through a two-step hydrothermal method. • The CuS@BiOBr exhibited enhanced activity for CIP oxidation under visible-light. • Visible light response enhancement effect of CuS was demonstrated. • Composite catalyst of CuS@BiOBr has superior durability. Constructing the Z-scheme photocatalyst has been seen as an effective strategy to facilitate the removal of antibiotic contamination by photocatalysts. We constructed the Z-type heterojunction photocatalyst CuS@BiOBr by precipitating BiOBr on CuS nanoparticles. The experimental results showed that the CuS@BiOBr in comparison to BiOBr and CuS system exhibited highly efficient photocatalytic degradation of ciprofloxacin (CIP). The degradation rate of CIP under CuS, BiOBr and CuS@BiOBr-700 heterojunction were 19.28%, 53.26% and 86.49%, respectively. The structure, morphology, porosity, optical performance and photoelectrochemical properties of CuS@BiOBr were characterized by multifarious characterization methods. The influence of environmental factors (different water sources and initial pH) on the degradation of ciprofloxacin (CIP) was investigated. A Z-scheme charge transfer mechanism was confirmed by free radical trapping experiments, which demonstrated that the photoexcited holes (h + ) and superoxide radicals (⋅O 2 ¯ ) were the major active species.

Ultralow Fe doping induced high photocatalytic activity toward ciprofloxacin degradation and CO2 reduction

TiO2 is one of the most ideal photocatalytic materials, but its application is limited by many problems (e.g., wide band gap, easy carrier recombination). Co-catalyst with changes in valence could efficiently overcome the disadvantages above. Herein, a Fe species (Fe, Fe2O3)/TiO2 was designed to fully utilize photogenerated charges and holes. The degradation rate of ciprofloxacin can reach 99.97%. In addition, its methane generation from photoreduction of CO2 is 12.9 times than that of pure TiO2. These results are attributed to the well-designed catalyst including the combination of TiO2 and FeOx as photocatalysts and oxygen buffers, and the dispersion of single-atom Fe clusters as cocatalysts and electron trap sites. The effect mechanism of Fe species on TiO2 was verified by PBE DFT calculation. Finally, following a concept of thermodynamic-kinetic synergy, a new design strategy for photocatalysts is accordingly proposed, as such, the prepared catalyst is expected to be applied in the environmental remediation.

Simple tactic polycondensation synthesis of Z-scheme quasi-polymeric g-C3N4/CaFe2O4 composite for enhanced photocatalytic water depollution via p-n heterojunction

Ferrites are promising photocatalysts as they absorb a considerable fraction of visible light. Herein, a novel in-situ simple tactic polycondensation method was used to produce n-type porous graphitic carbon nitride nanosheets over p-type CaFe2O4 particles resulting in a “quasi-polymeric” heterojunction. An interfacial electron trap state was created, as represented by an energy-resolved distribution of electron trap patterns in the g-C3N4/CaFe2O4, which traps excited electrons and prevents charge carrier recombination. When the CaFe2O4 precursor content in the g-C3N4/CaFe2O4composite was optimized, the degradation rates of ciprofloxacin and phenol are 2.3 and 2.1-fold higher in comparison to pristine g-C3N4, respectively. The g-C3N4/CaFe2O4 composite efficiently absorbed visible light and could separate and transport charge carriers through the p-n heterojunction. The efficient interfacial charge transport and separation achieved in the composite were validated using photoluminescence spectra and photoelectrochemical characterizations. Based on scavenger studies and electron spin resonance analysis, the most active radical species for the aforementioned pollutant degradation are holes and superoxide anion radicals. Mott-Schottky measurements and X-ray photoelectron spectroscopy confirmed the photocatalytic reaction mechanism is a Z-scheme charge carrier transport route based on the p-n heterojunction. Therefore, the g-C3N4/CaFe2O4 heterojunction offers a lot of promise for pollutant degradation that is both efficient and long-term.

Construction of PDIsa/BiOBr type-I scheme heterojunction for efficient ciprofloxacin photocatalytic degradation.

Fabrication of heterojunction photocatalysts is a promising strategy for enhancing photocatalytic activity. However, the study about traditional type-I heterojunction still remains to be developed. Herein, a PDIsa/BiOBr traditional type-I heterojunction was constructed by electrostatic self-assembly method, which owned improved light absorption capacity and photogenerated charge separation efficiency. The interfacial electric field and the polarization electric field of PDIsa impelled the separation of excitons. The degradation rate of ciprofloxacin (CIP) was improved by 3.2 times over the optimal PDIsa/BiOBr composite than pure BiOBr. In addition, the TOC removal efficiency reached 67.34% within 120min. Trapping experiments and electron spin resonance (ESR) tests showed that superoxide radical (•O2-) was the most active species, and singlet oxygen (1O2) and hole (h+) played a secondary role. The work may furnish a new reference for designing BiOBr-based type-I heterojunction.

Z-scheme heterojunction composed of Fe doped g-C3N4 and MoS2 for efficient ciprofloxacin removal in a photo-assisted peroxymonosulfate system

Herein, a series of Z-type heterojunctions FexCN@MoS2-Y were synthesized by a combination of calcination and hydrothermal methods for the removal of ciprofloxacin (CIP) by peroxymonosulfate (PMS) activation under visible light. It was optimized that Fe3CN@MoS2-4 exhibited excellent photocatalytic performance, with the degradation rate of CIP 84 % within 140 min. Besides, its rate constants were 23.74, 3.59, and 3.98 times higher than those of pure g-C3N4, Fe3CN, and MoS2, respectively. Furthermore, the Fe3CN@MoS2-4/PMS/vis system could efficiently degrade other antibiotics (enrofloxacin (ENRO), metronidazole (MNZ) and tetracycline (TC)). The quenching experiments and electron paramagnetic resonance (EPR) characterization showed that reactive substances such as 1O2, h+ and Ovs played a dominant role in this system. We deeply explore the possible mechanisms and CIP degradation pathways for the enhanced CIP degradation efficiency in the Fe3CN@MoS2-4/PMS/vis system. Among them, the exposed Mo (IV) and Fe (II) sites on the catalyst surface accelerated the electron transfer, while the S2- therein promoted the cycling between ions, thus increasing the reaction rate. Finally, Fe3CN@MoS2-4 maintained appreciable performance even after 5 cycles. This study may provide a new approach for the development of metal-doped g-C3N4-based complexes.

Mesoporous titania accommodated with In2O3 nanoparticles as a superior photocatalyst for degradation ciprofloxacin antibiotic

• Sol-gel process was utilized for synthesizing a novel In 2 O 3 /TiO 2 photocatalyts. • Ciprofloxacin (CIP) was utilized to estimate the photocatalytic performance. • The optimum 1.5% In 2 O 3 /TiO 2 indicated the highest efficiency ∼100% within 60 min. • The mechanism of the In 2 O 3 /TiO 2 photocatalyst was proposed according to S-scheme. • In 2 O 3 /TiO 2 photocatalyst exhibited high stability for five consecutives cycles. Antibiotics are emanating pollutants due to their wide consumption and production, which causes hazards to human health and the ecological environment. Herein, the sol-gel process was utilized for synthesizing novel mesoporous In 2 O 3 /TiO 2 photocatalysts employing a soft template. The photocatalytic ability of the In 2 O 3 /TiO 2 nanocomposites was assessed through ciprofloxacin (CIP) degradation over visible light exposure. It could be found that 1.5% In 2 O 3 /TiO 2 nanocomposite exhibited the highest CIP degradation rate compared with bare TiO 2 nanoparticles (NPs). The 1.5% In 2 O 3 /TiO 2 nanocomposites indicated strengthening the photocatalytic performance ∼100% within 120 min to degrade CIP compared with the bare TiO 2 NPs (10%) because of the construction of heterojunctions, which could be reinforced the separation efficiency of photoinduced electrons-holes. The apparent rate constant of 1.5% In 2 O 3 /TiO 2 photocatalyst was determined to be about 0.013 min −1 , 13 folds larger than bare TiO 2 NPs (0.001 min −1 ). The photocatalytic ability was kept after recycling five times without depletion. The fostered photocatalytic ability was referred to as the transport of photoinduced electrons-holes between In 2 O 3 and TiO 2 , verified by photocurrent response and photoluminescence measurement. The photocatalytic reactions of the In 2 O 3 /TiO 2 photocatalyst were proposed according to the S-scheme mechanism. This work provides a favourable way to construct heterojunction photocatalysts for practical application in the destruction of organic contaminants.