Wood-converted porous carbon decorated with MIL-101(Fe) derivatives for promoting photo-Fenton degradation of ciprofloxacin

In response to the escalating concerns over antibiotics in aquatic environments, the photo-Fenton reaction has been spotlighted as a promising approach to address this issue. Herein, a novel heterogeneous photo-Fenton catalyst (Fe3O4/WPC) with magnetic recyclability was synthesized through a facile two-step process that included in situ growth and subsequent carbonization treatment. This catalyst was utilized to expedite the photocatalytic decomposition of ciprofloxacin (CIP) assisted by H2O2. Characterization results indicated the successful anchoring of MIL-101(Fe)-derived spindle-like Fe3O4 particles in the multi-channeled wood-converted porous carbon (WPC) scaffold. The as-synthesized hybrid photocatalysts, boasting a substantial specific surface area of 414.90 m2·g-1 and an excellent photocurrent density of 0.79 μA·cm-2, demonstrated superior photo-Fenton activity, accomplishing approximately 100% degradation of CIP within 120 min of ultraviolet-light exposure. This can be attributed to the existence of a heterojunction between Fe3O4 and WPC substrate that promotes the migration and enhances the efficient separation of photogenerated electron-hole pairs. Meanwhile, the Fe(III)/Fe(II) redox circulation and mesoporous wood carbon in the catalyst synergistically enhance the utilization of H2O and accelerate the formation of •OH radicals, leading to heightened degradation efficiency of CIP. Experiments utilizing chemical trapping techniques have demonstrated that •OH radicals are instrumental in the CIP degradation process. Furthermore, the study on reusability indicated that the efficiency in removing CIP remained at 89.5% even through five successive cycles, indicating the structural stability and excellent recyclability of Fe3O4/WPC. This research presented a novel pathway for designing magnetically reusable MOFs/wood-derived composites as photo-Fenton catalysts for actual wastewater treatment.

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.

Activities of BiFeO3/carbon-dots catalysts in piezo-photocatalytic degradation of ciprofloxacin upon light/ultrasonic excitation

Designing catalysts that can effectively make use of renewable energy benefits to solve the current challenges of environmental pollution and increasing energy demands. Piezo-photocatalysis that can utilize solar energy and natural vibration-energy has emerged as a "green" technique. In this work, we fabricated BiFeO3/C nano composites that can harvest solar and vibration energies and degrade organic pollutants. The incorporated carbon quantum dots bring about more efficient visible light absorbance and separation of photoinduced electron-hole pairs. The piezoelectric polarization further suppresses the recombination of photoinduced electron-hole pairs. The catalysts own higher reaction rates in piezo-photocatalysis and the BiFeO3/C-0.12 shows the highest degradation efficiency (k-value of 0.0835 min-1).

Low temperature in situ fabrication of NiFe2O4/tetragonal-BiVO4/Bi2MoO6 ternary heterostructure: A conjugated step-scheme multijunction photocatalyst with synergistic charge migration for antibiotic photodegradation and H2 generation

Rational design of novel conjugated step-scheme (S-scheme) multijunction heterostructure with synergistic charge channelization, superior light harvesting efficiency and strong redox ability is a pioneering approach to mimic natural photosynthesis process. Herein, a mild cetyltrimethyl ammoniumbromide (CTAB) assisted one pot reflux synthesis route is designed for in situ integration of metal organic framework (MOF)-derived NiFe2O4 with tetragonal-BiVO4 (t-BiVO4) and γ-Bi2MoO6 to prepare NiFe2O4/t-BiVO4/Bi2MoO6 (NFO/BVO/BMO) ternary composites. Morphologically, fine dispersion of NiFe2O4 (NFO) quantum dots over γ-Bi2MoO6 (BMO) and t-BiVO4 (BVO) nanoplates yielded three types of microscopic heterojunctions among BMO-BVO, BVO-NFO and BMO-NFO phases. The ternary composites displayed important physicochemical attributes including high surface area, strong optical absorption, superior charge mobility and higher excited state lifetime which accounted for its improved photocatalytic activity towards ciprofloxacin degradation (>99% in 90 min) and H2 evolution (1.11 mmolh-1g-1, photon conversion efficiency 18.5%). Kinetics study revealed 12-55 fold higher ciprofloxacin photodegradation activity and 31-41 times higher H2 evolution rate for the ternary composite in comparison to the pure semiconductors. A conjugated S-scheme charge transfer mechanism has been deduced from comprehensive band position analysis and radical trapping study to explain the enhanced photocatalytic activity. This work for the first time demonstrated the rational construction of conjugated S-scheme heterostructures with potential application in water remediation and green H2 production.

Efficient photocatalytic degradation of ciprofloxacin by graphite felt-supported MnS/Polypyrrole composite: Dominant reactive species and reaction mechanisms

The accumulation of antibiotics in aquatic environments poses a serious threat to human health. Photocatalytic degradation is a promising method for removing antibiotics from water, but its practical implementation requires improvements in photocatalyst activity and recovery. Here, a novel graphite felt-supported MnS/Polypyrrole composite (MnS/PPy/GF) was constructed to achieve effective adsorption of antibiotics, stable loading of photocatalyst, and rapid separation of spatial charge. Systematic characterization of composition, structure and photoelectric properties indicated the efficient light absorption, charge separation and migration of the MnS/PPy/GF, which achieved 86.2% removal of antibiotic ciprofloxacin (CFX), higher than that of MnS/GF (73.7%) and PPy/GF (34.8%). The charge transfer-generated 1O2, energy transfer-generated 1O2, and photogenerated h+ were identified as the dominant reactive species, which mainly attacked the piperazine ring in the photodegradation of CFX by MnS/PPy/GF. The •OH was confirmed to participate in the defluorination of CFX via hydroxylation substitution. The MnS/PPy/GF-based photocatalytic process could ultimately achieve the mineralization of CFX. The facile recyclability, robust stability, and excellent adaptability to actual aquatic environments further confirmed MnS/PPy/GF is a promising eco-friendly photocatalyst for antibiotic pollution control.

Structural regulatory mechanism of phosphotungstate acid decorated graphene oxide quantum dots-chitosan aerogel and its application in ciprofloxacin degradation

Chitosan modified AGQD (amine modified graphene oxide quantum dots) and then combined with H₃PW₁₂O₄₀ to obtain CS_x@AGQD-HPW₁₂ via facile process and applied for CIP removal through pre-adsorption and photocatalytic processes. The application of chitosan could regulate the morphology and photoelectric properties effectively. CS_0.5@AGQD-HPW₁₂ was found to have the optimal CIP removal performance among all the products, the corresponding adsorption removal efficiency and pre-adsorption photocatalysis process were 72.1 % and 98.8 %, respectively. Results of toxicity assessment confirmed photocatalytic degradation process could mitigate the ecotoxicity of CIP effectively. The optimal TOC (total organic carbon) removal efficiency was about 52.1 %. Possible pathways for CIP degradation and reaction mechanism were proposed based on the results of intermediates analysis and trapping experiments. This demonstrated a novel approach to chitosan application and an eco-friendly way to remove CIP by adsorption-photocatalysis process.

Sunlight-driven photocatalytic degradation of ciprofloxacin and organic dyes by biosynthesized rGO-ZrO2 nanocomposites

Aquatic ecology has been greatly threatened by the discharge of effluents of textile and antibiotic industries into natural waters. Herein, an efficient and easily recycled reduced graphene oxide/zirconium oxide nanocomposite has been synthesized using banana peel extract (abbreviated as rGO-ZrO₂ in this work). The X-ray diffraction (XRD), field emission scanning electronic microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), UV-visible diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy were used to analyze the synthesized material. The as-prepared rGO-ZrO₂ nanocomposite was employed as a photocatalyst for the decomposition of rhodamine blue (RhB) and crystal violet (CV) dyes, and ciprofloxacin (CIP) antibiotic by illumination with direct sunlight. The RhB and CV were degraded to maximum extent of around 86 and 90%, respectively, over the rGO-ZrO₂ nanocomposite after exposure to direct sunlight for 120 min. On the other hand, the degradation of CIP was approximately 93.1% over the rGO-ZrO₂ nanocomposite in 240 min under same experimental conditions. Further studies were performed regarding the role of parameters like pH, catalyst dose, and scavengers, in order to understand the superiority of rGO-ZrO₂ nanocomposite in degrading organic pollutants. Moreover, the intermediate products and plausible CIP degradation mechanisms were examined using liquid chromatography-mass spectrometry (LC-MS). Moreover, the catalyst was easily separated from the solution and demonstrated good stability and reusability. The RhB, CV, and CIP removal efficiency were 80%, 83%, and 88%, respectively, after five cycles.

Dual redox cycles of Mn(Ⅱ)/Mn(III) and Mn(III)/Mn(IV) on porous Mn/N co-doped biochar surfaces for promoting peroxymonosulfate activation and ciprofloxacin degradation

Mn and N co-doped biochar (Mn-N-TS) was prepared as an effective catalyst to activate peroxymonosulfate (PMS) for ciprofloxacin (CIP) degradation. As opposed to Mn-TS and N-TS, Mn-N-TS had more active sites containing N and Mn, as well as a greater specific surface area (923.733 m² g^-1). The Mn-N-TS exhibited excellent PMS activation ability. In the Mn-N-TS/PMS system, the CIP removal efficiency was 91.9% in 120 min. Mn and N co-doping could accelerate electron transfer between CIP and PMS molecules. Simultaneously, defect sites, graphitic N, pyridinic N, C═O groups, and Mn(II)/Mn(III)/Mn(IV) redox cycles acted as active sites to activate PMS and generate free radicals (OH, SO₄^- and ¹O₂). Furthermore, the Mn-N-TS/PMS system could effectively degrade CIP in a wide pH range, background substances, and actual water. Finally, a probable mechanism of PMS activation by Mn-N-TS was proposed. In conclusion, this work gave a novel direction for the rational design of Mn and N co-doped biochar.

Constructed wetland-microbial fuel cells enhanced with iron carbon fillers for ciprofloxacin wastewater treatment and power generation

In this study, the following three experimental devices were operated for 70 days for the treatment of ciprofloxacin pollutants in wastewater: constructed wetlands (CW), constructed wetland-microbial fuel cells (EG), and constructed wetland-microbial fuel cells with new iron-carbon fillers (TPFC). The water quality, power generation capacity, microbial community structure, and changes in the resistance gene qnrs were studied. The efficiency of removal of total phosphate in the TPFC (97.1% ± 2.5%) was significantly higher than that in the EG (51.6% ± 4.8%) and the CW (68.1% ± 2.9%). The efficiency of removal of ciprofloxacin was also significantly higher (TPFC: 91.2% ± 3.4%, EG: 82.1% ± 2.3%, and CW: 75.1% ± 5.6%) (P < 0.05). The voltage of TPFC reached 300.16 ± 12.12 mV, which was apparently greater than that of EG (180.36 ± 16.73 mV) (P < 0.05), possibly because of the higher abundance of microorganisms such as Burkholderiaceae, Hydrogenophaga, and Proteobacteria. There were more copies of the resistance gene qnrs (TPFC: 7.74/μL, EG: 5.52/μL, and CW: 2.65/μL), which may be associated with stronger resistance; therefore, the efficiency of removal of ciprofloxacin was higher in the TPFC. TPFCs are a promising way to remove ciprofloxacin in wastewater.

Efficient photocatalytic degradation of emerging ciprofloxacin under visible light irradiation using BiOBr/carbon quantum dot/saponite composite

The use of visible-driven photocatalysts has fascinated attention as a capable and sustainable approach for wastewater remediation. In this work, BiOBr/carbon quantum dot (CQDs)/saponite composites (CQDs/Clay@BiOBr) were fabricated via hydrothermally using two different CQDs/Clay precursors (in-situ synthesis (IS) and physical mixing (PM)). The obtained products were characterized, and the photocatalytic performances of the prepared samples were evaluated in the photocatalytic decomposition of emerging ciprofloxacin (CIP) pharmaceutical waste. The highest CIP mineralization performance was achieved when a combination of BiOBr and CQDs/Clay (IS) with the appropriate proportion because the strong adhesion between CQDs and clay generate a great heterojunction in the composite. The stronger interaction of CQDs and better distribution of CQDs on the surface of clay in the CQDs/Clay (IS) enhanced the interaction of BiOBr and CQDs, and avoided the re-agglomeration of excess of CQDs on surface of BiOBr which reduce the active surface to receive the light and react with CIP. The ultrafast degradation rate of the optimized CQDs/Clay@BiOBr composite was better compared to others. The significant improvement in the CIP degradation efficiency of the CQDs/Clay@BiOBr composite was attributed to the excellent separation and transportation of photogenerated electrons and holes, as confirmed by photoluminescence, photocurrent density, and electrochemical impedance spectroscopy results. Moreover, the photocatalytic degradation mechanism of CIP in the CQDs/Clay@BiOBr composite was proposed based on the electronic states of each material in the composite and on a scavenger test. Thus, the proposed CQDs/Clay@BiOBr composite can be employed as a potential visible-light-driven photocatalyst for the decomposition of organic contaminants in wastewater.

Sonocatalytic degradation of ciprofloxacin using hydrogel beads of TiO2 incorporated biochar and chitosan

Pharmaceuticals are necessary to be removed from environment. Herein TiO₂ incorporated biochar made from pyrolysis of agricultural wastes was encapsulated into chitosan to obtain a novel hydrogel beads. This hydrogel beads executed a dual role as both adsorbent and sonocatalyst, which proved to be suitable for the removal of antibiotic ciprofloxacin (CIP) from water. The results showed that adsorption of CIP followed pseudo first order kinetics model and Langmuir adsorption isotherm model, having maximum adsorption at pH 9. Whereas the degradation was more efficient at pH 6 due to greater standard potential for ^•OH/H₂O in acidic media. The degradation was maximum at 150 W of ultrasonic power, then decreased in presence of dissimilar electrolytes and even reduced to 0 in presence of Na₃PO₄. Different quenchers such as benzoquinone (BQ), Triethanolamine (TEA) and isopropyl alcohol (IPA) reduced degradation efficiency (DE) and mineralization efficiency (ME). The DE was decreased from 85.23% to 81.50% (BQ), 74.27% (TEA), and 61.77% (IPA) within 25 min. The prepared sonocatalyst was capable of regeneration with DE, remaining sufficiently high (62%) even after four regeneration steps. These results indicate that titanium-biochar/chitosan hydrogel beads (TBCB) are durable and effective for long-term CIP removal.

Photocatalytic degradation of persistent organic pollutants by Co-Cl bond reinforced CoAl-LDH/Bi12O17Cl2 photocatalyst: mechanism and application prospect evaluation

The widespread distribution of persistent organic pollutants (POPs) in natural waters has aroused global concern due to their potential threat to the aquatic environment. Photocatalysis represents a promising mean to remediate polluted waters with the simple assistance of solar energy. Herein, we fabricated a Co-Cl bond reinforced CoAl-LDH/Bi₁₂O₁₇Cl₂ heterogeneous photocatalyst to investigate the feasibility of photocatalysis to treat POPs-polluted water under environmental conditions. The optimum CoAl-LDH/Bi₁₂O₁₇Cl₂ (5-LB) composite photocatalyst exhibited excellent photocatalytic performance, which could degrade 92.47 % of ciprofloxacin (CIP) and 95 % of bisphenol A (BPA) with 2h of actual solar light irradiation in Changsha, China (N 28.12 °, E 112.59 °). In view of the synergistic influence of water constituents, various water matrices greatly affected the degradation rate of CIP (BPA), with the degradation efficiency of 82.17% (84.37%) in tap water, 69.67% (71.63%) in wastewater effluent, and 44.07% (67.7%) in wastewater inflow. The results of electron spin resonance, and chemical trapping experiment, HPLC-MS and density functional theory calculation reflected that the degradation of CIP was mainly attributed to h⁺ and ¹O₂ attacking the active atoms of CIP molecule with high Fukui index. Furthermore, the non-toxicity of both 5-LB photocatalyst and treated CIP solution was proved by E.coli and B.subtilis cultivation, which further demonstrated the feasibility of the 5-LB to treat POPs in real water under irradiation of solar light.

Highly effective and stable MWCNT/WO3 nanocatalyst for ammonia gas sensing, photodegradation of ciprofloxacin and peroxidase mimic activity

The present study discusses the ammonia (NH₃) sensing characteristics, photocatalytic degradation of emerging pollutants, and peroxidase mimic activity of multifunctional multi-walled carbon nanotube-tungsten oxide nanocomposite (MWCNT/WO₃) prepared by conventional solvothermal method. The prepared MWCNT/WO₃ nanocomposites were characterized by various analytical techniques like XRD, Raman, XPS, N₂ adsorption, FESEM with elemental analysis and diffuse reflection spectroscopy. The prepared 1% MWCNT/WO₃ nanocomposite showed better gas sensing performance for the NH₃ vapors at 10-100 ppm than the pristine WO₃ and the response and recover time of about 13 and 15s towards 20 ppm of ammonia (NH₃) was achieved. The photocatalytic activity of MWCNT/WO₃ towards organic dyes such as Rhodamine-B (Rh.B) methylene blue (MB) and pharmaceutical compound ciprofloxacin (CIP) were studied and achieved above 90% degradation at 160 min for CIP and 60 min for MB and Rho-B respectively. The radicle scavenging activity for MWCNT/WO₃ nanocomposite showed the predominant formation of hydroxyl (OH^•) and superoxide radicle (^•O^2-). Further, the MWCNT/WO₃ nanocomposite showed peroxidase mimic activity and exhibit the limit of detection (LOD) of about 321 nM. From the overall analysis, MWCNT/WO₃ hybrid seems to have potential characteristics that can be explored for multiple functional applications.

Electrochemical-assisted ultraviolet light coupled peroxodisulfate system to degrade ciprofloxacin in water: Kinetics, mechanism and pathways

The persulfate advanced oxidation is an emerging and efficient pollutant treatment method, but usually requires the help of other materials or energy to catalyze and produce highly oxidizing active substances. In this paper, electrochemical-assisted ultraviolet light coupled peroxodisulfate system (E-UV-PDS) was used to degrade ciprofloxacin (CIP), and it was determined that electrolysis and ultraviolet photolysis were synergistic by calculation. The effects of initial pH, voltage, peroxodisulfate dosage, CIP concentration and coexisting anions on the degradation process were explored. The quenching experiments showed that ¹O₂, ⋅OH and SO₄^-⋅ were the main active oxygen species. Under the following conditions, ultraviolet light = 6 W, voltage = 4 V, [peroxodisulfate] = 20 mM, [pH]₀ = 7 and [CIP] = 100 mgL^-1, the degradation rate of CIP reached about 100% after 120 min, and the influence of inorganic anions was also discussed. Several intermediate products were identified by LC-MS, and three degradation pathways were speculated for CIP degradation. Finally, economic evaluation of the E-UV-PDS system was made, and it was useful to construct environmentally friendly and low-cost catalytic processes for the efficient degradation of organic pollutants.

Efficient degradation of ciprofloxacin by magnetic γ-Fe2O3-MnO2 with oxygen vacancy in visible-light/peroxymonosulfate system

In this work, the magnetic γ-Fe₂O₃-MnO₂ bifunctional catalyst with oxygen vacancy was synthesized for peroxymonosulfate (PMS) activation under visible light. The activity of γ-Fe₂O₃-MnO₂ was investigated by ciprofloxacin (cipro) degradation. Results showed that 98.3% of cipro (50 μM) was removed within 30 min in visible-light/PMS system mediated by γ-Fe₂O₃-MnO₂ (2:1) with fine-tuned oxygen vacancy. The cipro degradation data fitted well with pseudo-first-order kinetic model with the highest kinetic constant of 0.114 min^-1. Besides, the γ-Fe₂O₃-MnO₂ exhibited stability, recyclability and practicability. High selectivity for cipro degradation was observed with coexisting anions in visible-light/γ-Fe₂O₃-MnO₂/PMS system. Furthermore, the enhanced mechanism of PMS activation under visible light with γ-Fe₂O₃-MnO₂ was proposed. The appropriate oxygen vacancy enhanced the separation of photo-induced carriers and Z scheme heterostructure maintained the highest redox potential. Accordingly, the synergistic effect of photocatalysis and PMS activation enhanced cipro degradation. Free radical and non-radical species including , h⁺, ¹O₂, •OH and co-existed in the coupled system. Impressively, this study provides a handy approach for oxygen vacancy regulation in metallic oxides composite and an easily recycled catalyst with high-activity in coupled oxidation system towards antibiotic degradation.

Synergetic effect of nano zero-valent iron and activated carbon on high-level ciprofloxacin removal in hydrolysis-acidogenesis of anaerobic digestion

Ciprofloxacin is the most commonly prescribed antibiotic, and its widespread use poses threat to environmental safety. The removal of ciprofloxacin from contaminated water has remained a major challenge. The present study investigated adding nanoscale zero-valent iron (NZVI) and activated carbon (AC) on high-level ciprofloxacin removal in hydrolysis-acidogenesis stage of anaerobic digestion. The results showed that the degradation rate of ciprofloxacin increased from 22.61% (Blank group) to 72.41% after adding NZVI/AC with concentration of ciprofloxacin in effluent decreasing from 8.25 mg L^-1 to 3.48 mg L^-1. The volatile fatty acids (VFAs) yield increased by 173.7% compared with the Blank group. In addition, the NZVI/AC group achieved the highest chemical oxygen demand (COD) removal rate and acidogenesis rate. The microbial community analysis presented that hydrolytic and acidogenic bacteria and microorganisms related to degrading ciprofloxacin were obviously improved in the NZVI/AC group. Moreover, eleven transformation products and the main degradation pathways were proposed based on mass spectrometry information. In summary, the NZVI/AC addition supplied promising approach for ciprofloxacin wastewater treatment.

Fabrication and characterization of ternary sepiolite/g-C3N4/Pd composites for improvement of photocatalytic degradation of ciprofloxacin under visible light irradiation

The development of high-quality photocatalytic materials for the degradation of organic pollutants under visible light irradiation is a vital field of research. In the present study, a composite of natural sepiolite clay and synthetic graphitic carbon nitride (CN) mixed with dispersed palladium nanoparticles was developed for the efficient photocatalytic degradation of ciprofloxacin (CIP) under visible light irradiation. The sepiolite, CN, and composite materials were characterized by several techniques. The sepiolite/CN composite (SC30%) displayed superior activity than pristine sepiolite and CN, resulted from the generation of new electron trap states in the interfacial contract between sepiolite and CN to suppress the charge recombination of CN. Furthermore, the well-dispersed of 1 wt% Pd-nanoparticles in the SC30% composite collectively enhanced CIP degradation by avoiding the recombination of photogenerated electrons and holes. Additionally, the electron trap states on the surface of all samples were studied using novel reversed double-beam photoacoustic spectroscopy to understand electron transfer in the composites related to the photocatalytic degradation mechanism of CIP. The developed sepiolite/CN/Pd(0) composite can act as a potential catalyst for the degradation of organic pollutants in wastewater under visible light irradiation.

Plasma-catalytic degradation of ciprofloxacin in aqueous solution over different MnO2 nanocrystals in a dielectric barrier discharge system

The α-MnO₂, β-MnO₂ and γ-MnO₂ samples were prepared by the hydrothermal method and were used for the degradation of ciprofloxacin (CIP) wastewater in a combined DBD-catalytic process. The physical and chemical properties of the samples were systematically studied by several analytical techniques including BET, XRD, SEM, HRTEM, XPS, and H₂-TPR. The combination of DBD with α-MnO₂ showed the highest CIP degradation efficiency, and the efficiency could reach 93.1% after 50 min, which was 10.8% and 18.1% higher, respectively, than those of β-MnO₂ and γ-MnO₂ catalysts in the plasma-catalytic system. According to the model of response surface methodology, the contribution of key experimental parameters on the CIP degradation decreased in the order: peak voltage > air flow rate > initial concentration > initial pH. The optimum operating parameters were peak voltage 17 kV, air flow rate 2.5 L min^-1, an initial concentration 5 mg L^-1 and an initial pH 6.9. The quenching experiments of active species showed that OH and O₂^- were critical to the CIP degradation. The generated O₃ might be adsorbed by the α-MnO₂ catalyst and resulted in more OH generation. The intermediate products of CIP degradation in DBD+α-MnO₂ system were analyzed by LC-MS, and three possible degradation pathways were proposed. This research provides an insight into the use of the crystallographic structures in discharge plasma system for antibiotics in water.

Different methods of incorporating ciprofloxacin in soil affect microbiome and degradation of ciprofloxacin residue

Antibiotic residues in swine manure when entered the soil would most likely affect the complex composition and functions of the soil microbiome, which is also responsible for degrading these antibiotics. Three different methods of adding ciprofloxacin (CIP), a common antibiotic used in the swine industry, to the soil were used to investigate the effects of CIP on the soil microbiome and the degradation of CIP. Results of the study showed that the microbiome could promote the degradation of CIP in the soil when CIP was incorporated into the soil together with manure. However, the CIP degradation time was prolonged when adding the manure of swine fed with diet containing CIP in the soil. All treatments did not affect the copy number of the resistance genes, except for aac(6')-Ib-cr, as compared with the initial numbers of each treatment. MiSeq Illumina sequencing and Biolog-ECO microplates results showed that CIP had a significant effect on the abundance, structure, and function of the soil microbiome, but different addition methods resulted in distinct effects. Results of the present study demonstrated that the microbiome and fate of CIP responded differently to the different methods of adding CIP to the soil.

Enhanced simultaneous PEC eradication of bacteria and antibiotics by facilely fabricated high-activity {001} facets TiO2 mounted onto TiO2 nanotubular photoanode

Biohazards and coexisted antibiotics are two groups of emerging contaminants presented in various aquatic environments. They can pose serious threat to the ecosystem and human health. As a result, inactivation of biohazards, degradation of antibiotics, and simultaneous removal of them are highly desired. In this work, a novel photoanode with a hierarchical structured {001} facets exposed nano-size single crystals (NSC) TiO2 top layer and a perpendicularly aligned TiO2 nanotube array (NTA) bottom layer (NSC/NTA) was successfully fabricated. The morphology and facets of anatase TiO2 nanoparticles covered on the top of NTA layer could be controlled by adjusting precalcination temperature and heating rate as the pure NTA was clamped with glasses. Appropriate recalcination can timely remove surface F from {001} facets, and the photocatalytic activity of the resultant photoanode was subsequently activated. NSC/NTA photoanode fabricated under 500 °C precalcination with 20 °C min(-1) followed by 550 °C recalcination possessed highest photoelectrocatalytic efficiency to simultaneously remove bacteria and antibiotics. Results suggest that two-step calcination is necessary for fabrication of high photocatalytic activity NSC/NTA photoanode. The capability of simultaneous eradication of bacteria and antibiotics shows great potential for development of a versatile approach to effectively purify various wastewaters contaminated with complex pollutants.