Removal Rate Of Ciprofloxacin Research Articles

Three-dimensional electrochemical Fenton degradation of CIP by doping Ce and Cu in Jacaranda shell base as particle electrodes

Currently, ciprofloxacin (CIP) in water environments has attracted wide attention. In order to degrade CIP by electrocatalysis, it is very important to develop catalysts with high catalytic activity as particle electrodes. In this study, Jacaranda shell was made into biochar (BC) by calcination, Ce and Cu modified BC (Ce-Cu/BC) was prepared by a simple impregnation and calcination method as a particle electrode in a three-dimensional electro-Fenton (3D/EF) system to degrade CIP. Characterization of the Ce-Cu/BC particle electrodes was conducted using SEM, XRD, and XPS, revealing the porous structure of the calcined jacaranda shell base, confirming successful loading of Ce and Cu. Optimal operating conditions for CIP removal were determined to be 4 g/100 mL particle electrodes dosage, initial pH of 5, 8 V voltage, and 2 mM Fe2+ concentration, resulting in a maximum CIP removal rate of 84.97% with an energy consumption of 1.32 W•h. Stability tests demonstrated the robustness of Ce-Cu/BC, while comparative tests and radical extinction experiments highlighted the high electrocatalytic activity of the 3D/EF system, primarily attributed to the indirect oxidation of •OH, an active substance generated within the system LC-MS and UV full-band scanning analyses were employed to propose potential CIP degradation pathways.

Construction of stable photo-Fenton system with efficient removal capability of ciprofloxacin by accelerating in-situ photoreduction of Fe3+ in MIL-100(Fe)

ABSTRACT Well-dispersed MIL-100(Fe) nanoparticles were synthesized under mild conditions and used to construct a photo-Fenton system (VMH system) with the assistance of visible-light irradiation and hydrogen peroxide. In such a VMH system, the MIL-100(Fe) has a high specific surface area and provides numerous Fe3+ active sites, thus accelerating the reaction of Fe3+ with photo-generated electrons under visible-light irradiation and generates Fe2+, and then the acquired Fe2+ can activate H2O2 to generate ⋅OH, accompanying with the oxidation of Fe2+ to Fe3+. Hence, the in-situ recycling of Fe2+/Fe3+ promotes the generation of ·OH, thus making the VMH system exhibits promising photocatalytic activity. The removal rate of ciprofloxacin in the VMH system is as high as 95.2% within 120 min photo-Fenton reaction, which is about 26 times higher than that of the Visible light/MIL-100(Fe) system. Moreover, the VMH system also exhibits strong degradation ability to other typical antibiotics, such as tetracycline, norfloxacin and cephalexin, and maintains high cyclic stability, revealing great practical application potential in the purification of antibiotic wastewater.

A comprehensive study on the co-removal of Cr (VI) and ciprofloxacin via microbial-photocatalytic coupling: Mechanistic insights and performance evaluation

The increasing contamination of water systems by antibiotics and heavy metals has become a growing concern. The intimately coupled photocatalysis and biodegradation (ICPB) approach offers a promising strategy for the effective removal of mixed pollutants. Despite some prior research on ICPB applications, the mechanism by which ICPB eliminates mixed pollutants remains unclear. In our current study, the ICPB approach achieved approximately 1.53 times the degradation rate of ciprofloxacin (CIP) and roughly 1.82 times the reduction rate of Cr (VI) compared to photocatalysis. Remarkably, after 30 days, the ICPB achieved a 96.1% CIP removal rate, and a 97.8% reduction in Cr (VI). Our investigation utilized three-dimensional fluorescence analysis and photo-electrochemical characterization to unveil the synergistic effects of photocatalysis and biodegradation in removal of CIP and Cr (VI). Incorporation of B–Bi3O4Cl (B-BOC) photocatalyst facilitated electron-hole separation, leading to production of ·O2−, ·OH, and h+ species which interacted with CIP, while electrons reduced Cr (VI). Subsequently, the photocatalytic products were biodegraded by a protective biofilm. Furthermore, we observed that CIP, acting as an electron donor, promoted the reduction of Cr (VI). The microbial communities revealed that the number of bacteria favoring pollutant removal increased during ICPB operation, leading to a significant enhancement in performance.

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.

Anodic oxidation of ciprofloxacin antibiotic and real pharmaceutical wastewater with Ti/PbO2 electrocatalyst: Influencing factors and degradation pathways

This study investigated the impact of operational variables including current density, solution pH, sodium sulfate electrolyte concentration, initial pollutant concentration, and reaction time on ciprofloxacin (CIP) anodic oxidation and its COD removal by Ti/PbO2 electrocatalyst. Ti/PbO2 anode was prepared by electrochemical method and its characteristics were determined using SEM, EDX-map, XRD, and linear sweep voltammetry (LSV) techniques. Under optimal conditions, the removal rate of CIP and COD at the initial concentration of 15 mg/L of the pollutant after 75 min of reaction was 92 % and 88.8 %, respectively. CIP mineralization was confirmed by evaluating its UV–vis spectra and cyclic voltammetry (CV) curves during the process. Considering the degradation intermediates identified by LC-MC analysis, the main reactions in CIP mineralization pathways were discussed in detail. Finally, the improvement of biodegradability of pharmaceutical wastewater during anodic oxidation treatment was evaluated. The results indicated that the biodegradability of wastewater significantly increased from BOD/COD = 0.18 for raw wastewater to BOD/COD = 0.42 for treated wastewater. The results showed that anodic oxidation with Ti/PbO2 electrocatalyst can be a practical method of treating wastewater that contains resistant and toxic pharmaceutical compounds.

Efficient degradation of ciprofloxacin in wastewater by CuFe2O4/CuS photocatalyst activated peroxynomosulfate

In this study, CuFe2O4/CuS composite photocatalysts were successfully synthesized for the activation of peroxynomosulfate to remove ciprofloxacin from wastewater. The structural composition and morphology of the materials were analyzed by XRD, SEM, TEM, and Raman spectroscopy. The electrochemical properties of the samples were tested by an electrochemical workstation. The band gap of the samples was calculated by DFT and compared with the experimental values. The effects of different catalysts, oxidant PMS concentrations, and coexisting ions on the experiments were investigated. The reusability and stability of the photocatalysts were also investigated. The mechanism of the photocatalytic degradation process was proposed based on the free radical trapping experiment. The results show that the p-p heterojunction formed between the two contact surfaces of the CuFe2O4 nanoparticle and CuS promoted the charge transfer between the interfaces and inhibited the recombination of electrons and holes. CuFe2O4-5/CuS photocatalyst has the best catalytic activity, and the removal rate of ciprofloxacin is 93.7%. The intermediates in the degradation process were tested by liquid chromatography-mass spectrometry (LC-MS), and the molecular structure characteristics of ciprofloxacin were analyzed by combining with DFT calculations. The possible degradation pathways of pollutants were proposed. This study reveals the great potential of the photocatalyst CuFe2O4/CuS in the activation of PMS for the degradation of ciprofloxacin wastewater.

Highly efficient adsorption of antibiotic ciprofloxacin hydrochloride from aqueous solution by diatomite-basic zinc chloride composites.

The antibiotic ciprofloxacin (CIP) is used to treat a variety of bacterial infections, yet it poses significant health risks to aquatic environments. While adsorption is a promising technique for CIP removal, current adsorption capacities remain limited. In this study, we introduce a diatomite and basic zinc chloride composite (ZnHC-Dt) prepared using a straightforward deposition method, with the ability to achieve highly efficient ciprofloxacin removal. ZnHC-Dt is characterized using field emission scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), and the Brunauer-Emmett-Teller method (BET). We also assess the zeta potential. The optimized ZnHC-Dt adsorbent, achieved at a mass ratio of 0.45 with ZnHC/(ZnHC+Dt), is adopted with a CIP adsorption capacity of 831.96 mg/g at 25 °C, broad pH adaptability (within 3.0-10.0), rapid adsorption rate (reaching equilibrium in 4 h), and stable performance under Na+ ionic strength. The CIP adsorption process follows pseudo-second-order kinetics and aligns well with the Langmuir adsorption model. The high adsorption capacity of ZnHC-Dt can be attributed to electrostatic attraction, hydrogen bonding, surface complexation, and available adsorption sites. During the desorption process, the CIP removal rate retains 65.33% effectiveness after five cycles. The results suggest that ZnHC-Dt holds significant potential for CIP removal in aqueous solutions.

An integrated approach for soluble and insoluble pollutants: Surface performance regulation of Co2CO3(OH)2@Ni foam for effective ciprofloxacin removal and oil/water separation

Effectively removing both soluble antibiotics and insoluble oils from wastewater is a significant challenge. To address both the problems, we synthesized a three-dimensional (3D) porous water treatment material. It can be converted from antibiotic removal mode to oil removal mode by simple surface performance regulation. This approach achieved a high removal rate for ciprofloxacin (CIP) and good separation efficiency for oil/water mixtures. Initially, Co2CO3(OH)2 nano-needles were fixed on Ni foam to synthesize Co2CO3(OH)2@Ni foam-1, which had a high CIP removal rate (93.59 % at pH 7.0) and a certain anti-interference ability. To assess the CIP removal performance, the environmental impact, economic benefit and energy consumption (3E) triangle model was established and the optimal operating point was selected. Characterization experiments demonstrated that the removal of CIP was attributed to the mechanisms of surface complexation, electrostatic attraction, cation bridging, precipitation and flocculation. Subsequently, Co2CO3(OH)2@Ni foam-2 was obtained by hydrophobic modification, which exhibited separation efficiencies above 93.5 % for a series of different oil/water mixtures. Co2CO3(OH)2@Ni foam series materials are easy to prepare and possess effective pollutants treatment efficiency, thus providing a new strategy for developing multi-functional water treatment materials and a novel approach for the treatment of soluble antibiotics and insoluble oils in wastewater.

Exploring the adsorption potential of Na2SiO3-activated porous carbon materials from waste bamboo biomass for ciprofloxacin rapid removal in wastewater

Effective utilization of biomass waste has become a key focus in achieving a sustainable future, considering the substantial amount of waste generated globally. This study investigates the characterization and evaluation of Na2SiO3-activated carbon derived from moso bamboo at various temperatures (500–900 °C) and residence time periods (30, 90, and 120 mins at 900 °C) for ciprofloxacin removal in aqueous solutions at initial concentrations of 50–250 mg/L. The activated carbons were characterized using N2 adsorption isotherms, revealing a combined Type I and Type IV behavior. The specific surface area (SBET) and total pore volume increased with increasing activation temperature, ranging from 157.3 m2/g to 381.6 m2/g. Regarding residence time, the SBET followed the sequence: Na2SiO3-60 (381.6 m2/g) > Na2SiO3-90 (333.8 m2/g) > Na2SiO3-120 (323.6 m2/g) > Na2SiO3-30 (312.7 m2/g). XRD analysis indicated a distinct peak at 23°, corresponding to the (002) plane of amorphous carbon, while Raman spectroscopy confirmed the presence of the D band and G band, indicating an amorphous carbon structure (ID/IG > 1). The adsorption performance of ciprofloxacin (CIP) on the activated carbons was evaluated at 298 K. The highest CIP removal rate of 89.2% was achieved within one hour using Na2SiO3-900, followed by Na2SiO3-800, Na2SiO3-700, Na Na2SiO3-600, and Na2SiO3-500, consistent with the SBET trend. The Langmuir adsorption isotherm model provided the best fit for analyzing the adsorption process, indicating predominantly monolayer adsorption, while the Freundlich model was suitable for ACs with different residence times. The maximum adsorption capacity of CIP was recorded for Na2SiO3-30 AC (17.12 mg/g). In conclusion, the synthesized activated carbons show promising potential as adsorbents for ciprofloxacin removal from water.

Degradation of ciprofloxacin by persulfate activated by Fe(III)-doped BiOCl composite photocatalyst.

Fe-BOC-X photocatalyst was successfully prepared by solvothermal method. The photocatalytic activity of Fe-BOC-X was determined by ciprofloxacin (CIP), a typical fluoroquinolone antibiotic. Under sunlight irradiation, all Fe-BOC-X showed better CIP removal performance than original BiOCl. In comparison, the photocatalyst with iron content of 50 wt% (Fe-BOC-3) has excellent structural stability and the best adsorption photodegradation efficiency. The removal rate of CIP (10mg/L) by Fe-BOC-3 (0.6g/L) reached 81.4% within 90min. At the same time, the effects of photocatalyst dosage, pH, persulfate, persulfate concentration, and combinations of different systems (PS, Fe-BOC-3, Vis/PS, Vis/Fe-BOC-3, Fe-BOC-3/PS, and Vis/Fe-BOC-3/PS) on the reaction were systematically discussed. In reactive species trapping experiments, electron spin resonance (ESR) signals revealed that the photogenerated holes (h+), hydroxyl radical (•OH), sulfate radical (•SO4-), and superoxide radical (•O2-) played an important role in CIP degradation; hydroxyl radicals (•OH) and sulfate radicals (•SO4-) play a major role. Various characterization methods have demonstrated that Fe-BOC-X has larger specific surface area and pore volume than original BiOCl. UV-vis DRS indicate that Fe-BOC-X has wider visible light absorption and faster photocarrier transfer and provides abundant surface oxygen absorption sites for effective molecular oxygen activation. Accordingly, a large number of active species were produced and participated in the photocatalytic process, thus effectively promoting the degradation of ciprofloxacin. Based on HPLC-MS analysis, two possible decomposition pathways of CIP were finally proposed. The main degradation pathways of CIP are mainly due to the high electron density of piperazine ring in CIP molecule, which is mainly attacked by various free radicals. The main reactions include piperazine ring opening, decarbonylation, decarboxylation, and fluorine substitution. This study can better open up a new way for the design of visible light driven photocatalyst and provide more ideas for the removal of CIP in water environment.

Z-scheme cobalt-iron oxide/perylene diimide supermolecule heterojunction for high-efficiency ciprofloxacin removal in a photocatalysis-self-Fenton system

Fenton technology has been famous on antibiotics removal, but seriously restricted by the extra addition of H2O2 and low mineralization efficiency. Herein, we develop a novel cobalt-iron oxide/perylene diimide organic supermolecule (CoFeO/PDIsm) Z-scheme heterojunction under photocatalysis-self-Fenton system, in which the holes (h+) of photocatalyst can mineralize organic pollutants and the photo-generated electrons (e−) are used to in-situ H2O2 production with high efficiency. The CoFeO/PDIsm exhibits superior in-situ H2O2 production at a rate of 281.7 µmol g−1 h−1 in contaminating solution, correspondingly of total organic carbon (TOC) removal rate of ciprofloxacin (CIP) is 63.7 %, far exceeding current photocatalysts. The high H2O2 production rate and remarkable mineralization ability are ascribed to great charge separation in Z-scheme heterojunction. This work provides a novel Z-scheme heterojunction with photocatalysis-self-Fenton system for environmental-friendly removing the organic containment.

Facile Synthesis of a Bi2WO6/BiO2−x Heterojunction for Efficient Photocatalytic Degradation of Ciprofloxacin under Visible Light Irradiation

In this work, a Z-scheme Bi2WO6/BiO2−x heterojunction was successfully prepared using a self-assembly strategy. Various characterization techniques demonstrated that the formation of the heterojunction not only accelerated the separation of photoinduced carriers but also weakened the recombination rate of photogenerated electron–hole pairs-. The Bi2WO6/BiO2−x composites had a wider absorption edge than Bi2WO6 in the range of 200–800 nm, which improved the photocatalytic performance of ciprofloxacin (CIP) degradation under xenon lamps. As a result, the Z-scheme heterojunction Bi2WO6/BiO2−x composite exhibited excellent photocatalytic activity. Catalyzed by the optimal 20% Bi2WO6/BiO2−x (0.5 g/L), the removal rate of CIP (10.0 mg/L) was 91.8% within 2 h irradiated by visible light, which was 2.37 times that of the BiO2−x catalyst. This work will provide a fresh perspective on the construction of visible-driven Z-scheme photocatalysts for wastewater treatment.

Efficient Removal of Ciprofloxacin from Contaminated Water via Polystyrene Anion Exchange Resin with Nanoconfined Zero-Valent Iron.

Ciprofloxacin (CIP), an important emerging contaminant, has been frequently detected in water, and its efficient removal has become an issue of great concern. In this study, a nanocomposite material nZVI/PA was synthesized by impregnating nanoscale zero-valent iron (nZVI) inside a millimeter-sized porous host (polystyrene-based anion exchange resin (PA)) for CIP removal. The nZVI/PA composite was characterized by field emission scanning electron microscopy coupled with energy-dispersive X-ray, transmission electron microscopy, X-ray diffraction, as well as X-ray photoelectron spectroscopy, and it was confirmed that nZVI was uniformly dispersed in PA with a small particle size. Furthermore, several key factors were investigated including initial solution pH, initial CIP concentration, co-existing ions, organic ligands, and dissolved oxygen. The experimental results indicated that the nZVI/PA composites exhibited a high removal efficiency for CIP under the conditions of initial pH 5.0, and initial CIP concentration 50 mg L-1 at 25 °C, with the maximum removal rate of CIP reaching 98.5%. Moreover, the nZVI/PA composites exhibited high efficiency even after five cycles. Furthermore, quenching tests and electron spin resonance (ESR) confirmed that CIP degradation was attributed to hydroxyl (·OH) and superoxide radicals (⋅O2-). Finally, the main degradation products of CIP were analyzed, and degradation pathways including the hydroxylation of the quinolone ring, the cleavage of the piperazine ring, and defluorination were proposed. These results are valuable for evaluating the practical application of nZVI/PA composites for the removal of CIP and other fluoroquinolone antibiotics.

Facile Preparation of Fe3O4@SiO2 Derived from Iron-Rich Sludge as Magnetic Catalyst for the Degradation of Organic Contaminants by Peroxymonosulfate Activation

Iron-rich sludge, generated during flocculation/sedimentation processes by using Fe-based coagulant in drinking water treatment plants, could be used as a precursor to prepare an effective peroxymonosulfate (PMS) activator (Fe3O4@SiO2) for the ciprofloxacin (CIP) degradation via facile hydrothermal treatment. The catalytic performances of raw iron-rich sludge and Fe3O4@SiO2 were evaluated. The removal rate of CIP in Fe3O4@SiO2/PMS system increased from 44.7% to 82.8% within 60 min compared with the raw iron-rich sludge. The effects of PMS, catalyst loadings, temperature, and initial pH on the CIP degradation were examined, demonstrating that acidic conditions and higher temperatures were beneficial for CIP degradation. Both sulfate radicals (SO4•−) and hydroxyl radicals (•OH) contributed to the CIP degradation, and SO4•− was predominated in the Fe3O4@SiO2/PMS system, which was confirmed by the result of electron paramagnetic resonance (EPR) analysis and radical quenching tests. The mechanisms of the PMS activation process by Fe3O4@SiO2 were elucidated, and the influencing factors were among which the role of the iron mineral phase was emphatically explored. This study provides a facile method to convert the recycled waste iron-rich sludge to magnetic heterogeneous catalysts for CIP degradation with PMS activation.

Z-scheme heterojunction WO3/BiOBr supported-single Fe atom for ciprofloxacin degradation via visible-light photocatalysis

Single-atom catalysts have drawn tremendous attention on account of their high activity, selectivity and stability. Z-scheme heterojunctions can effectively improve the utilization of optical energy due to the enhanced separation of photogenerated electrons and holes. In this work, several catalysts associated with single-atom Fe (FeSA) loaded on Z-scheme heterojunction WO3/BiOBr were prepared; their structure, morphology and photoelectric properties were analyzed; their photocatalytic degradation performance of Ciprofloxacin (CIP) was investigated; and the effects of initial pH, initial CIP concentration, catalyst dosage, light intensity, inorganic anions and humic acid on CIP removal rate were examined. Relevant results showed that the percentage of CIP removal by FeSA/WO3/BiOBr could reach 98.5% (120 min); the optimal conditions were pH= 9, [CIP]0 = 10 mg/L, [FeSA]0 = 0.8 g/L and Ilight= 500 W (100% degradation rate within 30 min);·O2- and h+ were the key active species. Results of the cyclic experiments suggested good stability of the catalyst. Furthermore, the mechanism of CIP photocatalytic degradation was proposed to be a synergistic mechanism of Z-scheme heterojunction migration and valence cycling between single-atom Fe2+ and Fe3+. Finally, the products and pathways of CIP degradation were analyzed.

Tunable Fe-deficiency modified sodium ferric silicate for improving photo-Fenton-like activity

Photo-Fenton-like process of the Fe-based semiconductors depends on the reversible Fe(III)-Fe(II) pair strongly, which is highly sensitive to their surface structure. Herein, a facile ball-milling method was developed to obtain a novel Fe-deficient sodium ferric silicate (SFS) by facilitating the breakage of weak Fe-O bonds. The released Fe3+ from lattice was found, leading to the formation of Fe-deficient structure at the surface of catalyst. Furthermore, the Fe-deficiency could be controlled by adjusting the milling conditions. In comparison with the pristine SFS, Fe-deficient SFS shows improved transfer efficiency of the photon-activated species and enhanced photo-Fenton-like catalytic performances. The introduced surface Fe-deficiency not only traps photogenerated electrons, but also provides more active sites in the photo-Fenton-like process. The removal rate of ciprofloxacin and Cr(VI) exhibited 5.12 and 2.83 folds superior to those of the pristine counterpart, respectively. Furthermore, Fe-deficient SFS showed an excellent photocatalytic sustainability for ciprofloxacin oxidation and Cr(VI) reduction. The possible degradation pathways and the intermediates of ciprofloxacin molecules were also investigated by liquid chromatograph-mass spectrometer. The surface Fe-deficient structure was attributed to facilitating carriers separation and active species production efficiently in this work.

Adsorption and oxidation of ciprofloxacin by a novel layered double hydroxides modified sludge biochar

In this study, biochar derived from municipal sludge (SBC) was modified by CoFe-Layered double hydroxides (CoFe-LDH), and used as adsorbent and oxidant for the removal of ciprofloxacin (CIP) for the first time. Under the optimal conditions, the CIP removal rate is increased by 24% compared with the single SBC, while the removal rates of total organic carbon and total nitrogen in the modified one are increased by 24% and 27%, respectively. Mechanism investigation suggested that the specific surface area and adsorption sites of modified biochar increased, and more CIP was adsorbed to the composite surface and then oxidized by more environmental persistent free radicals contained in the CoFe-LDH@SBC, when the adsorbed CIP molecules was oxidized and degraded, the adsorption sites can be freed and thus new CIP could be adsorbed to the CoFe-LDH@SBC. In addition, the plausible degradation pathways of CIP were proposed according to high-performance liquid chromatography-mass spectrometry and density functional theory calculation. It not only reveals that CoFe-LDH@SBC has the high ability of adsorption and oxidation for CIP removal but also sheds novel insight into the application of biochar.

Pumice-loaded rGO@MnO2 nanomesh photocatalyst with visible light response for rapid degradation of ciprofloxacin

The agglomeration and recycling of nano-photocatalytic materials are still a big problem restricting the practical application of photocatalytic technology. Natural porous pumice with adsorption capacity provides an innovative approach to this challenge. Herein, the pumice supported reduced graphene oxide and MnO2 (PS@rGO@MnO2) was designed as a visible-light-driven solid photocatalyst. The PS@rGO@MnO2 possessed good photocatalytic performance, and the removal rate of ciprofloxacin (CFX) reached 80.00% with simulated solar irradiation for 6 h, and the degradation rate constant was 4.2 times that of blank pumice. The degradation rates of CFX in secondary effluent, lake water, and river water can reach 62.15%, 68.33%, and 67.63%, respectively. Hole (h+) and superoxide radical (O2−) are the main reactive oxygen species. The material test results revealed that the enhanced photocatalytic performance of PS@rGO@MnO2 was due to the improvement of light utilization rate, the reduction of electron-hole pair recombination rate, and the improvement of charge separation efficiency and transfer efficiency. ECOSAR model predictions indicate that CFX can effectively reduce toxicity in photocatalytic reactions. The removal performance of actual natural water verified that the material was of great practical application potential.

Efficient decontamination of ciprofloxacin at neutral pH via visible light assisted Fenton–like process mediated by Fe(III)–GLDA complexation

This work demonstrated a novel N,N-bis(carboxymethyl)glutamic acid (GLDA) modified visible (vis) light assisted Fenton–like system which could effectively removal ciprofloxacin (CIP) at neutral pH. The removal rate of CIP in the GLDA/Fe(III)/H2O2/vis system was 97.9% within 120 min and was approximately twice as high as that in the Fe(III)/H2O2/vis system. GLDA could significantly accelerate the Fe(III)/Fe(II) cycle under visible light irradiation. Radical scavenging experiments demonstrated that 74.2% of the Fe(II) in the GLDA/Fe(III)/H2O2/vis system originated from the ligand–to–metal charge transfer reaction between Fe(III) and GLDA. The hydroxyl radical was the dominant species for CIP degradation. H2O2 utilization kinetic modeling exhibited that 90.1% of H2O2 was used for CIP mineralization. The effects of experimental parameters and coexisting substances on the removal of CIP in the Fe(III)/GLDA/H2O2/vis system were investigated in detail. The intermediate products of CIP were explored via the high–performance liquid chromatography-mass spectrometry.

Effects of different carbon sources on the removal of ciprofloxacin and pollutants by activated sludge: Mechanism and biodegradation

This research investigated the effects of ciprofloxacin (CIP) (0.5, 5, and 20 mg/L) on SBR systems under different carbon source conditions. Microbial community abundance and structure were determined by quantitative PCR and high-throughput sequencing, respectively. The biodegradation production of CIP and possible degradation mechanism were also studied. Results showed that CIP had adverse effects on the nutrient removal from wastewater. Compared with sodium acetate, glucose could be more effectively used by microorganisms, thus eliminating the negative effects of CIP. Glucose stimulated the microbial abundance and increased the removal rate of CIP by 18%–24%. The mechanism research indicated that Proteobacteria and Acidobacteria had a high tolerance for CIP. With sodium acetate as a carbon source, the abundance of nitrite-oxidizing bacterial communities decreased under CIP, resulting in the accumulation of nitrite and nitrate. Rhodanobacter and Microbacterium played a major role in nitrification and denitrification when using sodium acetate and glucose as carbon sources. Dyella and Microbacterium played positive roles in the degradation process of CIP and eliminated the negative effect of CIP on SBR, which was consistent with the improved removal efficiency of pollutants.