Initial Ciprofloxacin Concentration Research Articles

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.

Fabrication of mesoporous Sm-Nd2O3/Thymine doped gC3N4 nanocomposite for the adsorption and photodegradation of ciprofloxacin under visible light

The ciprofloxacin (CIP) antibiotic was degraded using Sm-Nd2O3 decorated Thymine doped gC3N4 (Sm-Nd2O3/T-gC3N4) nanocomposite under visible light irradiation. The oxygen-containing component like thymine doped in the gC3N4 significantly improves the active sites of the catalyst and its ability to absorb light, which highly influences the adsorption and photocatalytic activity. The chemical and morphological analysis of the nanocomposite were studied utilizing the XRD, FTIR, HRSEM, HRTEM, EDAX, UV-DRS, XPS, BET, and PL. The photocatalytic activity was investigated under several factors such as pH, initial concentration of CIP, catalyst dosage, inorganic anions, and real lake water sample, to optimize and enhance the photocatalytic efficiency of Sm-Nd2O3/T-gC3N4 nanocomposite, as a result, the degradation efficiency achieved to 99.65 % within 120 min with the rate constant of 0.0472 min−1. The Z-scheme mechanism of the Sm-Nd2O3/T-gC3N4 photocatalyst was proposed based on the Mott-Schottky and trapping experiments. Further, the degradation pathway of CIP was postulated based on the intermediates, identified by the LC-MS analysis

Antibiotics pollutants in agricultural soil: Kinetic, sorption, and thermodynamic of ciprofloxacin

The entry of antibiotics, as pollutants, into the environment has created great concerns. Environmental dynamics of antibiotics based on soil chemical properties need to be a better understanding of their chemical behavior. This research is focused on studying the adsorption behavior and kinetic mechanisms of ciprofloxacin (CIP) in an agricultural soil. For this purpose, a batch experiment was conducted at different times (5 min–24 h), and using initial concentrations of CIP (0–1 mmol L−1) in the soil. The adsorption processes as affected by pH and ionic strength were assessed based on the modeling with response surface methodology (RSM). According to the results, the sorption equilibrium was found within 240 min, and the pseudo second-order model was the best for describing the data. Increasing the initial CIP concentration increased CIP adsorption, but increases in ionic strength and pH had an inverse effect. Based on RSM modeling, the CIP adsorption was 7.31 and 7.03 (mg g−1) in the presence of NaCl and CaCl2 electrolytes, respectively, in the optimized conditions (pH 6.5 and ionic strength 0.01 mol L−1). The spontaneous nature of CIP adsorption was determined based on thermodynamic calculations (ΔG° = −10.8 to −12.4 kJ mol−1). The interaction of pH and ionic strength was described with the quadratic model. The obtained results contribute to understanding the CIP fate in the soil environment and facilitate decisions regarding entry and controlling soil contamination due to this antibiotic.

Adsorption of ciprofloxacin from aqueous solutions using cellulose-based adsorbents prepared by sol-gel method

Ciprofloxacin (CIP) is one of the most widely used antibiotics to treat bacterial infections. Consequently, there is concern that it may contaminate water resources due to its high usage level. It is therefore necessary to monitor, trace, and reduce exposure to these antibiotic residues. In the current study, the extraction of CIP from water was performed using a green adsorbent material based on cellulose/polyvinyl alcohol (PVA) decorated with mixed metal oxides (MMO). This cellulose/MMO/PVA adsorbent was synthesized using a simple sol-gel method. The prepared adsorbent materials were then characterized using a range of methods, including scanning electron microscopy, energy-dispersive X-ray spectroscopy, gas adsorption analysis, X-ray diffraction, and Fourier Transform infrared. The impact of pH, adsorbent dose, contact time, and CIP concentration on ciprofloxacin extraction were examined. The equilibrium and kinetic adsorption data were well described using the Freundlich model (R2 = 0.965). The optimum conditions for CIP adsorption were: pH = 4.5; adsorbent dosage = 0.55 g·L−1; contact time = 83 min; and initial CIP concentration = 2 mg·L−1. The adsorption capacity of the cellulose/MMO/PVA adsorbent for CIP removal was ∼19 mg·g−1 (CIP removal = 86.48 %). This study shows that cellulose/MMO/PVA adsorbents have potential for removing contaminants from aqueous environments.

Investigating the Z-scheme mechanism on the optimized oxygen vacancies ZnO/Co3S4 photocatalyst for the efficient photocatalytic removal of ciprofloxacin

The waste of human and animal antibiotics is an inescapable problem and a severe threat to the continuation of human life. A logical strategy to face the challenge of antibiotic contamination is to design active, stable, environmentally friendly, and economical photocatalysts. Hence, oxygen vacancies ZnO/Co3S4 (ZnO-OV/Co3S4) photocatalyst was successfully fabricated for the first time and used for the photocatalytic removal of ciprofloxacin (CIP) as a widely used antibiotic under visible light. Several techniques were engaged in exploring the crystallinity, morphology, structure, chemical and elemental composition, and electrochemical and optical properties of the constructed nanocomposites. The band gap of ZnO-OV and Co3S4 nanoparticles was determined at 2.95 and 1.58 eV by evaluating the optical properties and using the Tauc plots. To optimize the conditions of the photocatalytic process, factors such as the weight percentage of the nanocomposite components, the photocatalyst dosage, the initial concentration of CIP, the pH of the test solution, and the presence of bubbled oxygen were varied. The optimal degradation rate constant (0.0720 min−1) was obtained for ZnO-OV/Co3S4 (15 %) nanocomposite at pH 9, nanocomposite dosage of 1.5 g/L, and 10 mg/L of CIP in the visible spectrum. The experimental and characterization outcomes indicated that the significantly boosted photocatalytic activity of the ZnO-OV/Co3S4 composite was chiefly attributed to the oxygen vacancies, retard charge carriers recombination by the construction of heterojunction between the ZnO-OV and Co3S4. Finally, the possible Z-scheme mechanism was proposed to illuminate the migration of charge carriers.

Red mud supported on rice husk biochar as sono-photo-Fenton catalysts for degradation of ciprofloxacin in water

To develop efficient methods to reuse red mud and rice husk waste to remove ciprofloxacin (CIP) in water, a simple and efficient Fenton catalyst based on red mud/rice husk biochar composite (RMR) was prepared using ultrasonic-assisted impregnation method. The effects of initial solution pH, initial CIP concentration, contact time, and catalyst dose on the removal of CIP in water were studied. The results showed that at pH 3, RMR dose of 1.0 g/L, CIP concentration of 20 mg/L, treatment time of 180 min, and temperature of 50 °C, the degradation efficiency was the highest at 75.97 % for sono-Fenton (SF) and 95.65 % for sono-photo-Fenton (SPF) with in situ generation of H2O2 during processes, indicating RMR has a great potential application in the treatment of organic pollution in actual wastewater. Other factors such as the co-existing anions (NO3–, SO42−, Cl−) or water matrices and other antibiotics were also investigated to prove the good removal of CIP by RMR for practical applications.

EFFECT OF CALCINATION TEMPERATURE VARIATION ON GREEN SYNTHESIS OF CADMIUM SULFIDE FOR CIPROFLOXACIN PHOTODEGRADATION

The green synthesis method has been successfully carried out to CdS with tea leaf extract and calcination temperature variation for the application of photocatalytic degradation of ciprofloxacin antibiotic. Variations in calcination at temperatures of 500, 600, and 700 ℃ were carried out to determine the effect of temperature on morphology and elemental composition, crystal structure and size, functional groups, and band gap energy by SEM-EDX, XRD, FTIR, and UV-DRS Spectrophotometer. The SEM-EDX image of the synthesized CdS is smooth and spherical and there is agglomeration with an even distribution of elements. The results of XRD and FTIR characterization showed the CdS peaks. The size of the CdS crystal increased with increasing temperature, namely CdS-600 at 64 nm and CdS-700 at 81.58 nm. The band gap energy value is influenced by the calcination temperature during synthesis with the band gap energy values of CdS-600 2.3 eV and CdS-700 2.38 eV. The percentage of CdS effectiveness with variations in calcination temperature in ciprofloxacin photodegradation is CdS-500 at 32.18%, CdS-600 at 48.72%, and CdS-700 at 8.73%. The optimum condition of CdS synthesis in degrading ciprofloxacin by photocatalytic process occurs at a temperature of 600℃ with a photocatalytic irradiation time under visible light for 120 minutes, a CdS mass of 10 mg, and an initial concentration of ciprofloxacin of 25 ppm. This result demonstrates the potential of an environmentally friendly method that can be applied in wastewater treatment.

Efficient removal of ciprofloxacin from aqueous solution using Zn–C battery derived graphene oxide enhanced by hydrogen bonding, electrostatic and π-π interaction

In this study, graphene oxide (GO) derived from waste Zinc–Carbon (Zn–C) batteries was proposed for the efficient removal of antibiotics from the aqueous solution. Ciprofloxacin (CIP) antibiotic was selected as a typical contaminants. GO was prepared via an economical and environment-friendly route by using carbon rods from waste Zn–C batteries as the precursor. Characterization techniques were applied to determine the properties of as prepared GO. Effects of pH, contact time, and adsorbent dose on the adsorption were explored, and an optimum condition was established. Adsorption equilibrium was established in just 20 min for maximum removal of CIP (99.0%) at pH 5.7 for the adsorbent dose of 20 mg L−1 and at the initial concentration of CIP 2.0 mg L−1. The rapid and efficient removal of CIP was greatly influenced by the electrostatic attractions, pi-pi interactions and hydrogen bonding on the surface and edge of GO which was also proved by density functional theory (DFT). Langmuir model showed the best fit among the isotherm models and the calculated maximum adsorption capacity (qm) was 419.62 mg g−1 at 30°C. The kinetic studies also revealed that the adsorption process followed the pseudo-second-order model. The endothermic and spontaneous nature of adsorption was evaluated in thermodynamic studies.

Solar photocatalytic degradation of ciprofloxacin using biochar supported zinc oxide- tungsten oxide photocatalyst.

Ciprofloxacin (CIP) is an antibiotic used to treat bacterial infections. It is not completely broken down during conventional wastewater treatment processes and can persist in the environment, leading to the development of antibiotic-resistant bacteria. This study focuses on the solar photocatalytic degradation CIP using biochar-supported photocatalysts. The photocatalysts developed by combining ZnO and WO3 in different ratios (1:2, 1:1, 2:1) were supported on hemp herd biochar. The photocatalyst made with a ratio of 2:1:1 of ZnO:WO3:biochar (Z2W1H) reported the highest CIP degradation efficiency of 87.3% and TOC removal efficiency of 43.1% at a catalyst dosage of 2g/L, initial CIP concentration of 3mg/L, and treatment time of 150min. Subsequently, the effects of operating parameters on CIP degradation were investigated using central composite design (CCD). About 85.4% degradation efficiency of CIP was obtained at optimum conditions (pH ∼8.4, initial CIP concentration ∼4.4mg/L, catalytic dosage ∼3.4g/L) within 90min. A quadradic model was developed to interpret the linear and interactive effect of operating parameters on the CIP degradation efficiency with 2.24-4.59% error. The adsorption-desorption study showed around 42.21% of adsorbed CIP was desorbed from Z2W1H. Scavenger studies demonstrated that the CIP breakdown was notably done by the superoxide radical (O2•-). The mechanism of CIP degradation was adsorption on biochar and subsequent degradation by photocatalyst. The prevalent degradation reactions such as C-N bond cleavage, decarboxylation, decarbonylation, defluorination, and ring opening lead to formation of various intermediates. The Z2W1H reusability test showed ~ 4.2% decrease in CIP removal efficiency after three cycles.

Efficient removal of ciprofloxacin and ofloxacin from aqueous solutions using a novel nano-scale adsorbent: Modeling, optimization, and characterization

In the fascinating realm of water purification, our study unveils the remarkable potential of a cutting-edge nano-scale adsorbent—combining graphene oxide (GO), chitosan (CS), and polydopamine (PDA)—in efficiently remove ciprofloxacin (CPF) and ofloxacin (OFL) from aqueous solutions. Our exploration delves deep into the adsorbent's character, utilizing a range of analytical techniques including SEM, RAMAN, FTIR, TGA, BET, XRD, and Zeta potential analyses provided insights into the adsorbent's properties. Modeling the adsorption process with Response Surface Methodology (RSM), Artificial Neural Network (ANN) and General Regression Neural Network (GRNN) indicated excellent predictions by GRNN, with RMSE = 0.0200 and 0.0166, MAE = 0.0082 and 0.0092, as well as AAD = 0.0002 and 0.0006, highlighting its modeling power.Optimization using genetic algorithm (GA) revealed maximum CPF removal efficiency of approximately 95.20% under pH = 6.3, sonication time = 9.0 min, adsorbent dosage = 2.10 g L⁻1, temperature = 45 °C and initial CPF concentration = 90.0 mg L⁻1. Similarly, OFL removal reached about 95.50% under pH = 6.30, sonication time = 8.0 min, adsorbent dosage = 2.0 g L⁻1, temperature = 45 °C and OFL concentration = 115.0 mg L⁻1. RSM optimization closely aligned with GA results. Pseudo-second-order (PSO) kinetic model and Langmuir isotherm model best fitted the experimental data for both antibiotics. Thermodynamic analysis indicated a favorable and spontaneous adsorption process for CPF and OFL. The study concludes that the proposed adsorbents show effectiveness in removing CPF and OFL at lower doses and shorter sonication times compared to various reported adsorbents.

Ciprofloxacin adsorption onto CNT loaded Pumice: Adsorption Modelling, kinetics, equilibriums and reusability studies

A novel CNT-derived Pumice adsorbent (P-CNT3) was successfully synthesized as an efficient adsorbent for Ciprofloxacin (CIP) removal from aqueous solutions. In present study, P-CNT3 composite synthesized by hydrothermal technique was loaded with multiwalled carbon nanotube (CNT) using sonification to remove CIP antibiotic. P-CNT3 composite were characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses. Adsorption performance was studied by adjusting the pH, contact time, initial CIP concentration, temperature and adsorbent dosage in a batch reactor to obtain the maximum adsorption capacity (qm). The maximum adsorption capacity (qm) was achieved in 240 min at pH ≤ 5).The adsorption process of P-CNT3 followed the pseudo-first-order kinetic model (R2 = 0.989) and sips isotherm model (R2 = 0.991), and qm to adsorb CIP was 28.6 mg/g. The illustrated adsorption mechanism shows that hydrophobic interactions, electrostatic and non-electrostatic interactions, suggests CIP adsorption. Over the temperature range of 298–318 K, the thermodynamic parameters ΔG°, ΔS° and ΔH° were calculated. The adsorption reactions were shown to be spontaneous and endothermic. Furthermore, activation energy suggested a physisorption mechanism for P-CNT3. In addition, regeneration study shows that the P-CNT3 can be reused five times with excellent results in CIP adsorption. Based on these findings, P-CNT3 can be considered a feasible low-cost adsorbent for CIP removal. Hence, the prepared P-CNT3 composite can be used as an inexpensive and a promising adsorbent for the removal of other pharmaceutical compounds.

Application of CuFeLDH-NCNT in ultrasound-assisted-Fenton-like process for removing ciprofloxacin from aqueous solutions.

In this study, the mesoporous material NCNT was prepared by treating carbon nanotubes (CNT) with hydrazine and subsequently loaded with Cu-Fe layered double hydroxide (CuFeLDH) to create a multiphase catalyst (CuFeLDH-NCNT). Its application as a multiphase catalyst was investigated in an ultrasound-assisted Fenton process for ciprofloxacin (CIP) degradation in aqueous solution. In addition, the impacts of catalyst dosage, ultrasonic power, H2O2 dosage, and beginning pH on CIP removal efficiency were carefully evaluated to maximize the removal efficiency of CIP. The findings indicated that the elimination rate of the initial CIP concentration of 20 mg/L surpassed 94.66% after a mere 100 min, while the TOC degradation rate was 70.4%. The high removal rate was due to the synergistic action between the nanoparticles, H2O2, and ultrasonography. The degradation intermediates of CIP were examined, and putative degradation pathways and mechanisms were postulated.

Synthesis of Ag/ZnO/BiOCl Composite Material and Its Photodegradation Performance on Ciprofloxacin

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.

Photocatalytic degradation of ciprofloxacin from water with waste polystyrene and TiO2 composites

Ciprofloxacin (CIP) is one of the widely used antibiotics with a broad antimicrobial spectrum in the fluoroquinolone type. Its concentration in water bodies has increased over the years due to its frequent use. Since ciprofloxacin in the aquatic ecosystem adversely affects human health as well as other organisms, it must be removed from wastewater.The aim of this study was to develop Polystyrene (PS) and Titanium dioxide (TiO2) composites that can be used as catalysts in CIP removal by photocatalytic process. Waste PS (obtained from disposable cutlery) was used in the synthesis of these composites. In this study, PS-TiO2 composites with different PS content (C20, C50, C80; the numbers in the names indicate the PS percentage in the composite by weight) were synthesized. This is important in terms of the use of one waste in the removal of another waste.This process was optimized using Box-Behnken design, one of the response surface method. Parameters such as the amount of polymer in the composite, pH and initial CIP concentration were studied and their effects on CIP removal were found. The validity and adequacy of the selected model were evaluated according to the relevant statistical data. These are R2 = 0.9751, adjusted R2 = 0.9565, the model's p-value <0.05 and the lack of fit-value 0.246. Optimum conditions for CIP removal were obtained when the C50 was used, with a pH value of 3 and an initial CIP concentration of 5 mg/L.In the process carried out under these conditions, the CIP removal was found to be 95.01 % at the end of 180 min. This value was predicted as 94.37 % in the model. According to these results, C50 composite synthesized with waste PS can be used effectively for CIP removal.

Photocatalytic degradation of ciprofloxacin by using tannin-doped BaTiO3 catalyst

The aim of this study is to highlight the significance of ciprofloxacin degradation, a commonly used antibiotic in healthcare and agriculture, by synthesizing tannin-doped BaTiO3 (T-Ba) photocatalysts at various tannin amounts (0–50 wt%) and investigating their photocatalytic activity under both UV-A light and visible light irradiation. The impact of several parameters, including the initial concentration of ciprofloxacin, photocatalyst dosage, initial solution pH, and scavengers effect, on the photocatalytic activity was explored. The photocatalysts were characterized by FTIR, SEM, XRD, XPS, TEM, BET, PL and UV-DRS analysis. In the conducted studies, it was observed that the highest efficiency was achieved at 96 % under appropriate parameters. The kinetic study was conducted based on the Langmuir-Hinshelwood equations. According to stability tests, ciprofloxacin degradation was found as 92 % after the second cycle, while it was 50 % after the fifth cycle.

Electrochemical degradation of ciprofloxacin from water: Modeling and prediction using ANN and LSSVM

Ciprofloxacin is a widely used antibiotic that is also a persistent contamination that causes major health and environmental risks. This study investigated the electrochemical removal of ciprofloxacin using a boron-doped diamond anode and a non-supportive electrode to get an accurate understanding of the anode's performance. The effects of current density, initial ciprofloxacin concentration, time, pH, and electrolyte concentration on the removal efficiency of ciprofloxacin were investigated. Additionally, ANN and LSSVM models were used to predict ciprofloxacin removal. The results showed that the BDD anode was effective in removing ciprofloxacin from water, with complete removal of 10 mg L−1 CIP in less than 45 min with electrolyte concentration of 25 g L−1, a current density of 20 mA cm−2, and a pH value of 3. The removal efficiency was found to increase with increasing current density and time because it increases the concentration of active species. The removal efficiency was also found to be higher at acidic pH values and higher electrolyte concentrations. The ANN model was found to be more accurate in predicting ciprofloxacin removal than the LSSVM model, with an R2 of 0.9982 and an AARE% of 2.68%, compared to R2 of 0.9978 and an AARE% of 3.85%. The models were validated using a new set of data, and the results showed that the ANN model was able to accurately predict ciprofloxacin removal under a variety of conditions.

Ciprofloxacin antibiotic removal from aqueous solutions by ZnO nanoparticles coated on ACA: modeling and optimization.

Antibiotics are one of the most widely used drug groups. The presence of antibiotics in urban water sources and sewage creates many environmental and medical risks for humans and other living organisms. In this study, the potential of zinc oxide (ZnO) coated on almond shell activated carbon (ACA-ZnO) in removing ciprofloxacin (CIP) from aqueous solutions was investigated. Almond shell was used to make activated carbon. Zinc oxide nanoparticles were prepared by the sol-gel method, and finally, ZnO nanoparticles were bonded to activated carbon. The effect of independent parameters pH, contact time, adsorbent dose, and initial CIP concentration on CIP removal efficiency using ACA-ZnO was investigated by response surface methodology. Optimal removal was obtained at pH = 5.4, CIP initial concentration = 7.4 mg/L, adsorbent dose = 0.82 g/L, and reaction time = 67.3 min. This study followed a quadratic model (R2 = 0.958). The best model of adsorption isotherm fits with the Freundlich model (R2 = 0.9972) and the maximum capacity was 251.42 mg/g adsorption kinetics, and pseudo-second-order kinetic model (R2 = 0.959). The results of this study showed that ACA-ZnO as an adsorbent is very efficient, without environmental side effect and cost-benefit.

Activation of peroxymonosulfate for ciprofloxacin degradation by a novel oxygen-deficient CoTiO3/TiO2NTs/Ti composite catalytic membrane:Electron transfer pathway and underlying mechanism

The technique of activating peroxymonosulfate (PMS) by enriching oxygen vacancies (Vo) in heterogeneous catalysts has gained extensive attentions in the removal of emerging contaminants, e.g., antibiotics from wastewater. In this study, a Vo-CoTiO3/TiO2NTs/Ti (Vo-CTNs) catalytic membrane with rich oxygen vacancies was prepared and employed for the activation of PMS in degrading ciprofloxacin (CIP) in a continuous flow reactor. The averaged degradation efficiency of CIP in the Vo-CTNs/PMS system could reach 97.3 %, significantly higher than that in the CoTiO3/TiO2NTs/Ti (CTNs) system (91.1 %). Quenching experiments and electron paramagnetic resonance analysis collectively confirmed the presence of •OH, SO4•−, O2•− and 1O2 during the CIP degradation process. The results of the electrochemical experiments demonstrated that in the presence of oxygen vacancies, the mutual conversion between Co2+ and Co3+ was facilitated, resulting in a lower transfer resistance. At an initial CIP concentration of 10 mg/L and a membrane flux of 600 LMH, the degradation efficiency and mineralization rate of CIP could reach 95.2 % and 51.1 % after 12 h of operation, respectively. Meanwhile, limited leaching of cobalt ions (52 μg/L) from the catalytic membrane was observed during treatment. Theoretical calculations revealed that Vo engineering can modulate the surface electronic states, thereby enhancing binding energy and electron transfer for PMS activation. The degradation of CIP is mainly achieved through the ring opening reactions in the piperazine, quinolone, and cyclopropyl groups attacked by reactive oxygen species. In this work, we built cobalt-based composite nanomaterials to promote effective electron transfer and minimize leaching of cobalt ions, and providing a new method for activating PMS in a continuous flow system by enriching the oxygen vacancies in the catalytic membrane. This method has potentials to be applied in treating wastewater containing antibiotics such as CIP.

Highly conductive Ti3C2 MXene reinforced g-C3N4 heterojunction photocatalytic for the degradation of ciprofloxacin: Mechanism insight

The extensive use of ciprofloxacin (CIP) poses a great threat to aquatic ecosystem, due to its potentially serious inhibitory effect on the microbial activity and low natural degradation rate. Photocatalytic degradation has emerged as a feasible method for treating CIP pollution. In this study, Ti3C2 reinforced g-C3N4 heterojunction material (MX/CN) was prepared using solvent drying method. The heterojunction composite accelerated the electron transfer rate, and the resulting MX/CN exhibited superior photocatalytic activity against CIP under visible light driving. The MX/CN sample achieved higher CIP photocatalytic removal rate of 97.8 %, 1.23 times higher than CN. Moreover, 6 %-MX/CN showed the best photocatalytic activity at pH = 7 when the initial concentration of CIP was 10 mg/L. Under neutral condition, the presence of Cl−, NO3−, and HCO3− reduced the degradation of CIP, where the addition of HCO3– caused a competed redox reaction with •OH in the system, resulting in a reduction of the CIP degradation efficiency to 30.9 %. The photocatalytic mechanism involving MX/CN was proposed according to the trapping experiments of active species, which confirmed that •O2− was the primary active component in photocatalytic degradation of CIP and h+ and •OH also played significant roles. Finally, cycling experiments using MX/CN showed that the CIP degradation efficiency maintained more than 90 % after five cycles.

Adsorptive removal of ciprofloxacin from simulated wastewater using crosslinked starch ester: Isotherms, kinetics, thermodynamics, modeling, and simulation for continuous operation

The rise in fluoroquinolone concentrations in wastewater caused significant concern due to their potential acute toxicity to living organisms. A novel eco-friendly adsorbent, crosslinked potato starch ester, was used to remove ciprofloxacin from a simulated aqueous solution by a batch adsorption process and used its obtained parameters to solve mathematical modeling. With a maximum adsorption capacity of 243.90 mg/g, the ciprofloxacin adsorption on crosslinked potato starch ester was suitable for the Langmuir isotherm model. The kinetics of ciprofloxacin adsorption showed that the pseudo-first-order kinetic model was a good fit for the adsorption process. Thermodynamic parameters exhibited that ciprofloxacin adsorption onto crosslinked potato starch ester was exothermic, achievable, and spontaneous. Finally, the process is simulated under various operating conditions using the mathematical model of a fixed bed continuous adsorption column. According to the results, under optimal operation conditions of inlet fluid velocity, particle size, bed height, and initial ciprofloxacin concentration with values 0.002 m/s, 1.2 mm, 0.2 m, and 143.4 mg/L, respectively, the highest dynamic adsorption capacity was 18.75 mg/g.