Photodegradation Of Antibiotics Research Articles

Synthesis of BiOCl/Bi3NbO7 heterojunction by in-situ chemical etching with enhanced photocatalytic performance for the degradation of organic pollutants

The construction of heterojunction is an effective strategy for the design of novel photocatalysts. In this study, the heterojunction of BiOCl/Bi3NbO7 for the photodegradation of organic pollutants was successfully fabricated through the in-situ chemical etching. The obtained photocatalysts were characterized via various characterization techniques. The results showed that the size and morphology of the composite material could be adjusted by the reaction time. Besides, enlarging the specific surface area of the composites can effectively increase the adsorption of organic compounds. In-situ chemical etching can not only reduce the size of Bi3NbO7 particles and the photogenerated carrier transport distance but also make BiOCl/Bi3NbO7 have a tight linkage interface and strong interaction force, which can effectively separate electron-hole pairs. Compared with pure Bi3NbO7 or BiOCl, BiOCl/Bi3NbO7 heterostructures exhibited better photocatalytic performance for the photodegradation of typical antibiotics and dyes. B/BN-160 can almost completely degrade CIP in 120 min and 50 mg· L -1 of RhB in 50 min. This work provides a novel idea for the preparation of photocatalysts and promotes their applications in the industry.

Constructing nano-heterojunction of MOFs with crystal regrowth for efficient degradation of tetracycline under visible light

Antibiotic pollution, a kind of important plague to human society, has received increasing attention. The photocatalysis with high degradation efficiency, energy saving, and environmentally friendly, has been becoming one of the most promising wastewater treatment techniques. In this paper, using in-situ hydrothermal synthesis technology, a semiconductor material for photodegradation of antibiotics, SnS2 nanoparticles (SnSPs), was combined onto the surface of Zirconium-based metal organic frames (abbreviated to UiO-66), which afforded a nano-heterojunction of SnS2 nanoparticles@UiO-66 (SnSPs@UiO66), a novel photocatalytic material with regrowth of UiO-66 crystal during the hydrothermal reaction. After combining with metal organic frames (MOFs), the antibiotic degradation performance of SnSPs has been greatly improved because its specific surface areas could be enlarged, and provided more active sites for photocatalytic degradation. The obtained SnSPs@UiO66 was applied to photocatalytic degradation of antibiotics. It showed significant degradation of tetracycline (TC) under visible light irradiation, and the degradation rate got to 90.0% within 75 min, which was 4.3 times and 5.1 times higher than that of pure SnSPs and UiO-66, respectively. The possible photocatalytic mechanism of SnSPs@UiO66 nano-heterojunction was also investigated. In summary, a novel nano-heterojunction photocatalyst was prepared by a simple method, which had excellent application prospect for the treatment of medical wastewater.

Enhanced photodegradation of antibiotics based on anoxygenic photosynthetic bacteria and bacterial metabolites: A sustainably green strategy for the removal of high-risk organics from secondary effluent

Antibiotic residues in effluents discharged from wastewater treatment plants (WWTPs) have been considered high-risk organics due to biorefractory property and potential toxicity. Secondary pollution and unsustainability existed in advanced treatment of secondary effluent are currently in urgent need of improvement. In this study, a sustainably green strategy based on Rhodopseudomonas palustris (R.palustris) by regulating the structure of extracellular polymeric substances (EPS) was proposed for the first time to achieve efficiently removal of sulfadiazine (SDZ). Results showed that 0.2 V was the optimal external potential for R.palustris to efficiently remove SDZ, where the biodegradation rate constant obtained at this potential was 4.87-folds higher than that in open-circuit mode and a complete removal was achieved within 58 h in the presence of EPS extracted at this potential. Three-dimensional excitation-emission matrix (3D-EEM) spectra analysis suggested that tryptophan protein-like, tyrosine protein-like, humic acid-like and fulvic acid-like substances present in EPS were the main effective components which was responsible for the indirect photodegradation of SDZ. The quenching experiments showed that 3EPS* was the dominant reactive species which accounted for 90% of SDZ removal. This study provides new implications for the advanced treatment of secondary effluent organic matters by developing eco-friendly bioaugmentation technology and biomaterials.

Effect of humic substances derived from pastoral areas in Zoige Plateau on photodegradation of sulfamethoxazole and ciprofloxacin

Sulfonamides and quinolones are widely used antibiotics. Some end up discharged into aqueous environments where they can seriously affect human health and safety. The photochemical degradation of sulfamethoxazole and ciprofloxacin with the various concentrations was analyzed in different pH natural waters. Meanwhile, the effect of natural humic and fulvic acids on the photodegradation was tracked. The photolysis curves were perfectly consistent with the first-order kinetics. High concentration of antibiotics was not conducive to photodegradation. Photodegradation of ciprofloxacin was generally occur in neutral and alkaline environments, while photodegradation of sulfamethoxazole was generally in lower acidic environments. Persistent free radicals including reactive oxygen species were found in the photolytic reactions. They were found to arise both from auto-decay of the antibiotics and from decay of the humic substances. According to EPR test,·OH and 1O2 both have a good promotion effect on the photodegradation of antibiotics, and the contribution rate of 1O2 (50.63%) is greater than that of •OH (25.56%), indicating that 1O2 is the main active species in the photodegradation of sulfamethoxazole and ciprofloxacin, and the contribution rate of 1O2 produced by humic acids to the photodegradation of antibiotics is greater than that of fulvic acids. Humic substances produced a strong single signal with good symmetry in darkness and light, indicating that the free radicals produced by humic substances were EPFRs with stability and persistence. However, the amount of EPFRs produced by humic acids were more than that of fulvic acids, indicating that the free radicals produced by humic acids were the carbon center free radicals containing oxygen functional groups. Results of this study will provide further comprehensive fundamental data for risk assessment and control of antibiotics in farmland ecosystems in pastoral areas of Zoige Plateau.

Bio-Inspired Znwo4-X Exhibiting Vacancy-Driven Uv-to-Nir Photodegradation of Antibiotics in Wastewater

Bio-Inspired Znwo4-X Exhibiting Vacancy-Driven Uv-to-Nir Photodegradation of Antibiotics in Wastewater

Algae mediated photodegradation of fluroquinolone antibiotic: Ofloxacin

Antibiotics are one of the most important pharmaceutical products and their excessive use generates significant adverse effectson the human environment. Their residues are harmful to the environment due to their potential hazard, toxicity and persistence. The indirect photodegradation of these residual antibiotics using algae as a potential photosensitizer provides a good low cost environmental solution. Herein, the photochemical behaviors of fluoroquinolone antibiotics, such as ofloxacin, were evaluated in the presence of an algal solution. The result of proposed research work clearly indicates that the algae play a crucial role in the photodegradation of ofloxacin and also accelerate the rate of photodegradation. The effect of concentration and pH of the algal solution on the photochemical behavior of the ofloxacin showed that as the concentration of algae was increased the rate of the photodegradation of drug became faster.

Green synthesis of CeO2 NPs using Manilkara zapota fruit peel extract for photocatalytic treatment of pollutants, antimicrobial, and antidiabetic activities

Here, we have synthesized CeO2 NPs using Sapodilla fruit (Manilkara zapota) peel (SFP) extract via a green approach. The synthesized SFP extract-CeO2 NPs were characterized by powder XRD, TEM, UV–vis DRS, PL, FTIR, and TGA techniques. CeO2 NPs and SFP extract-CeO2 NPs were confirmed by UV–vis spectra at the strong absorption peak at 400–435 nm and the calculated optical band gaps were well matched. The FT-IR spectra of CeO2 NPs reveal that the presence of carboxyl and amide groups in the SFP extract is confirmed and these are responsible for the bio-reduction of Ce ions into CeO2 NPs. From XRD, the average crystallite size of the SFP extract-CeO2 NPs is 10 ± 1.5 nm was observed, which is a good agreement with TEM analysis. The synthesized CeO2 NPs performed an excellent photodegradation of several dyes and antibiotics in aqueous solutions within 18 min of reaction under UV–visible irradiation. The synthesized SFP extract-CeO2 NPs show good antimicrobial activity against several pathogens (bacteria and fungi) using a paper disc method other than CeO2 NPs. In addition, the antidiabetic activity of SFP extract-CeO2 NPs is significantly inhibited by both α-amylase and α-glucosidase enzymes with IC50 values when compared with the standard (acarbose).

Fast photodegradation of antibiotics and dyes by an anionic surfactant-aided CdS/ZnO nanodispersion

Raspberry shaped nanostructures synthesized by a one-pot precipitation method for the photocatalytic degradation of tetracycline and dyes.

A Supercritical Carbonization Method to Prepare Nickel Single Atom Catalysts for Efficient Photodegradation of Antibiotics

A Supercritical Carbonization Method to Prepare Nickel Single Atom Catalysts for Efficient Photodegradation of Antibiotics

Self-assembly synthesis of S-scheme g-C3N4/Bi8(CrO4)O11 for photocatalytic degradation of norfloxacin and bisphenol A

To realize the high-efficiency photodegradation of antibiotics, a novel S-scheme heterojunction photocatalyst g-C3N4/Bi8(CrO4)O11 was proposed and successfully prepared in this work. The 10% g-C3N4/Bi8(CrO4)O11 heterojunction exhibits the highest degradation rate of norfloxacin (NOR) and bisphenol A (BPA). The degradation rate of NOR on 10% g-C3N4/Bi8(CrO4)O11 is about 1.38 and 2.33 times higher than that of pure Bi8(CrO4)O11 and g-C3N4, respectively. Further, the degradation rate of BPA over 10% g-C3N4/Bi8(CrO4)O11 heterojunction is bout 1.35 and 9.11 times higher than that of pure Bi8(CrO4)O11 and g-C3N4, respectively. The formation of S-scheme heterojunction facilitates the separation of photogenerated electron-hole pairs and reduces the recombination of charge carriers, which was confirmed by photocurrent, electrochemical impedance spectroscopy, steady-state and time-resolved transient photoluminescence spectrum, etc. The in-situ X-ray photoelectron spectroscopy, radical trapping experiments and electron paramagnetic resonance results demonstrate that the charge transfer is in accord with S-scheme mechanism.

Efficient photodegradation of cefixime catalyzed by a direct Z-scheme CQDs-BiOBr/CN composite: Performance, toxicity evaluation and photocatalytic mechanism

Development of low-cost, nontoxic, highly efficient performance photocatalyst for water pollution control engineering is critical for environmental remediation. In this contribution, a direct Z-scheme heterojunction based on C quantum dot (CQDs), bismuth oxybromide (BiOBr) and bulk graphitic carbon nitride (g-C3N4, CN) (CQDs-BiOBr/CN composite) with outstanding photocatalytic activity and good reusability is successfully fabricated though a hydrothermal procedure for cefixime antibiotic photodegradation. In particular, the CQDs-BiOBr/CN composite possess the best cefixime degradation effect, the degradation rate is about 92.82% within 120 min. The enhancement photocatalytic activity of CQDs-BiOBr/CN can be ascribed to the improved light-harvest ability, the excellent adsorption performance, the efficient charge transportation and separation capability. A possible degradation pathway of cefixime is proposed base on HPLC-MS. Toxicity experiments demonstrate that the antibiotic activity of cefixime is effectively deactivated after degradation process, and which is no toxic effect for Rye seeds in deionized water. The CQDs-BiOBr/CN also displays the excellent photoactivation activity towards Escherichia coli (E. coli). Reactive-species-trapping experiments show that hydroxyl radical (⋅OH) and superoxide radical (⋅O2−) are the active reactive species in the photodegradation process. The CQDs-BiOBr/CN composite demonstrate an effective potential practical application in antibiotic pollutants degradation from wastewater.

Green synthesis of ZnO: Effect of plant concentration on the morphology, optical properties and photodegradation of dyes and antibiotics in wastewater

Commelina beghalensis (C. benghalensis)-mediated zinc oxide nanoparticles (NPs) were successfully synthesised. The effect of C. benghalensis plant extract concentration on the morphology, optical and photodegradation efficiency was investigated. These materials were characterised using SEM, XRD, UV–vis, FTIR, TGA, BET, EPR, PL and VSM. XRD and UV–vis confirmed the formation of these materials. According to XRD measurements, the green-synthesised nanoparticles have a hexagonal wurtzite structure. SEM displayed various morphologies from platelets-flaky to spherical spheres. Ferromagnetism features were concentration-dependent since the material synthesised using 30 g of the extract was highly magnetic. This behaviour was also supported by the EPR and PL analyses which confirmed the formation of a higher concentration of oxygen vacancies. Furthermore, the lowest bandgap energy of 3.4 eV and the smallest particle sizes (28 nm) were also achieved using the most concentrated extract. The photocatalytic properties of the prepared materials were tested against methylene blue dye (MB) and sulfisoxazole (SSX). The highest degradation was achieved at 81% for MB using the highest concentrated material. Trapping studies showed that hydroxyl radicals were the major species responsible for the degradation of MB. From this analysis, it can be noted that the effect of plant concentration did play a role on the morphology and degradation of various pollutants. Lastly, these environmentally safe materials can be used for the degradation of various pollutants.

Photodegradation of Aquaculture Antibiotics Using Carbon Dots-TiO2 Nanocomposites.

In this work, carbon dots (CD) were synthesized and coupled to titanium dioxide (TiO2) to improve the photodegradation of antibiotics in aquaculture effluents under solar irradiation. Oxolinic acid (OXA) and sulfadiazine (SDZ), which are widely used in aquaculture, were used as target antibiotics. To prepare nanocomposites of CD containing TiO2, two modes were used: in-situ (CD@TiO2) and ex-situ (CD/TiO2). For CD synthesis, citric acid and glycerol were used, while for TiO2 synthesis, titanium butoxide was the precursor. In ultrapure water (UW), CD@TiO2 and CD/TiO2 showed the largest photocatalytic effect for SDZ and OXA, respectively. Compared with their absence, the presence of CD@TiO2 increased the photodegradation of SDZ from 23 to 97% (after 4 h irradiation), whereas CD/TiO2 increased the OXA photodegradation from 22 to 59% (after 1 h irradiation). Meanwhile, in synthetic sea salts (SSS, 30‰, simulating marine aquaculture effluents), CD@TiO2 allowed for the reduction of SDZ’s half-life time (t1/2) from 14.5 ± 0.7 h (in absence of photocatalyst) to 0.38 ± 0.04 h. Concerning OXA in SSS, the t1/2 remained the same either in the absence of a photocatalyst or in the presence of CD/TiO2 (3.5 ± 0.3 h and 3.9 ± 0.4 h, respectively). Overall, this study provided novel perspectives on the use of eco-friendly CD-TiO2 nanocomposites for the removal of antibiotics from aquaculture effluents using solar radiation.

Construction of mechanically robust and recyclable photocatalytic hydrogel based on nanocellulose-supported CdS/MoS2/Montmorillonite hybrid for antibiotic degradation

A novel photocatalytic hydrogel was prepared by the direct coagulation casting of CdS/MoS2/Montmorillonite (CMMt) and TEMPO-oxidized cellulose nanofiber (TOCN)-mediated polyacrylamide (PAM). The extremely high specific surface area of CdS/MoS2/Mt and the three-dimensional network-structured PAM-TOCN matrix contributed to the adsorption of tetracycline (TC) in wastewater treatment. The effect of the initial pH on the degradation of TC by PAM-TOCN-CMMt was analyzed, and its degradation rate reached 90.03% in 120 min at pH 7.5. In addition to being a visible-light-driven catalyst, CdS/MoS2/Mt acts as a reinforcing agent, and the tensile stress of PAM-TOCN-CMMt increased by 41% compared with that of PAM-TOCN. The compressive strength of TOCN-PAM-CMMt at an 80% strain level was 65% higher than that of PAM-TOCN. Thus, PAM-TOCN-CMMt, with high mechanical strength, offers multiple separations and recycling, and the TC removal rate is still more than 70.5% after five cycles. Moreover, the mechanism of TC degradation was proposed based on the photoelectric performance. The strong interaction between the CdS/MoS2 heterojunction and the electronegative Mt is conducive to the effective separation and transportation of photogenerated electrons. The prepared nanocomposite hydrogels with a desirable catalytic degradation rate, mechanical strength, environmental friendliness, and recyclability are promising for the photodegradation of antibiotics.

Photodegradation of norfloxacin in ice: Role of the fluorine substituent

Ice is an important medium in cold regions, because it regulates the environmental behaviors and the fate of pollutants. The photodegradation of fluoroquinolone (FQ) antibiotics as emerging contaminants of concern in ice remains poorly understood. Here, the photodegradation of fluorine-containing norfloxacin (NOR) as one model of FQs in ice formed from freezing solutions was investigated. Pipemidic acid (PPA) as a structural analogue of NOR was selected to compare the effect of molecular structure on the antibiotic photodegradation in the ice. Results suggested that the photodegradation rate constant of NOR in ice relative to pure water increased by 40.0%. Both the absorbance in the absorption spectra and quantum yields of NOR in ice over water increased by 1.4 times. Direct photodegradation mainly caused the defluorination of NOR, which was more important than cleavage and oxidation of the piperazine ring by self-sensitized photooxidation in ice. The defluorination rate of NOR in the ice relative to water increased by about 12.7%. The fluorine substituent played a more important role in the NOR photodegradation in the ice, resulting in a 1.6-fold increase in the photodegradation rate constant of NOR relative to PPA. This work provides a new insight into the role of fluorine substituents in the photodegradation of fluorinated pharmaceuticals in cold regions.

Interaction of levofloxacin with reverse micelle sol-gel synthesized TiO2 nanoparticles: Revealing ligand-to-metal charge transfer (LMCT) mechanism enhances photodegradation of antibiotics under visible light

Synthesis of TiO2 through reverse micelle sol–gel (RMS) route showed 18 nm mean diameter with homogeneous particle size distribution (PDI = 0.11). TiO2 nanomaterial with a bandgap of 3.15 eV exhibited degradation efficiency of 83% towards levofloxacin (LFX) aqueous pollutant of 50 mg/L under 6H of the visible LED light. Visible light photoactivity ascribed to ligand to metal charge transfer (LMCT) process between the targeted antibiotic pollutant and titania photocatalyst. At neutral pH, photocatalytic degradation performance of TiO2 was observed higher due to adsorption of LFX through N of piperazinyl ring causing LMCT. The basic pH encouraged adsorption of LFX through the carboxylate group, which showed comparatively lesser activity. In acidic pH conditions, the lowest photoactivity resulted from the synergetic effect of lower adsorption and participation of the ketone-carboxyl adsorption site of LFX with TiO2.

Bifunctional BiOCl/TiO2 decorated membrane for antibiotic photodegradation and oil-water emulsion separation

Membrane separation is a simple and efficient technology for waste water treatment. However, organic pollutants such as antibiotics in complex water environment are hard to remove by the physical separation process. The coupling of photocatalysis and membrane separation can effectively remove the oil pollutants, meanwhile degrade the antibiotics. In this work, a composite membrane (BiOCl/TiO2@PAN) was prepared by the electrospinning technology and hydrothermal process. The membrane showed an excellent superhydrophilicity in air and an underwater superoleophobicity, thus it could separate a series of oil in water emulsions with a high permeability (231–613 L m-2h−1) without extra energy supply. Moreover, owing to the photoresponse ability of BiOCl and TiO2, the membrane could effectively degrade a variety of antibiotics including the typical antibiotic tetracycline, chlortetracycline, oxytetracycline and demeclocycline within 30 min under full-spectrum and visible light irradiation. Eight-cycle repeating experiments showed that composite membrane had an excellent stability and an efficiency in photocatalytic degradation and oil–water emulsion separation. Photo-responsive composite membrane prepared in this work showed a broad application prospect in treatment of complex sewage where oily waste and antibiotics simultaneously exist.

Rapid photodegradation of linezolid antibiotic and methylene blue dye over Pt nanoparticles/polypyrrole-carbon black/ZnO novel visible light photocatalyst

Exhaustive efforts are urgently anticipated in photocatalysis to tackle the present grave environmental problems especially water pollution. The proposed work aims to provide decidedly active visible light inclined ternary photocatalyst consists of ZnO nanostructure having admirable photocatalytic activity merely doped with polypyrrole-carbon black (PPy-C) and Pt nanoparticles for environmental concerns. Pt and PPy-C doped ZnO ternary framework was created via a reformed sol-gel route and a facile ultrasonication methodology. The XRD examination revealed that ZnO possesses a hexagonal wurtzite structure, while FTIR and XPS investigations established the efficacious formation of ternary framework among Pt, PPy-C and ZnO nanostructures. The TEM exploration displayed that Pt nanoparticles (3–8 nm) were successfully disseminated on ZnO nanostructures (~20–120 nm) associated with spongy dumbbell shape PPy-C, recommending the ternary photocatalyst development. The UV–vis spectroscopic analysis showed a lowering in band-gap energies upon Pt and PPy-C incorporation. This newly synthesized Pt@PPy-C/ZnO photocatalyst has been successfully employed to photo-catalytically treat linezolid (an antibiotic drug) and methylene blue (MB) dye using visible-light. This Pt@PPy-C/ZnO photocatalyst showed amazing activity with 94.0% elimination of linezolid drug in just 40 min with ultrafast removal rate that is approximately 1.67 fold than undoped ZnO. Moreover, this Pt@PPy-C/ZnO ternary framework has proven to be very influential in removing MB using visible light irradiation.

Amino-functionalized NH2-MIL-125(Ti)-decorated hierarchical flowerlike Znln2S4 for boosted visible-light photocatalytic degradation

Developing novel heterojunction photocatalysts with visible-light response and remarkable photocatalytic activity have been verified to applying for the photodegradation of antibiotics in water environment. Herein, NH2-MIL-125(Ti) was integrated with flowerlike ZnIn2S4 to construct NH2-MIL-125(Ti)@ZnIn2S4 heterostructure using a one-pot solvothermal method. The photocatalytic performance was evaluated by the degradation of tetracycline (TC) under visible light illumination. The optimized NM(2%)@ZIS possesses a photodegradation rate (92.8%) and TOC removal efficiency (58.5%) superior to pristine components, which can be principally attributed to the positive cooperative effects of well-matched energy level positions, strong visible-light-harvesting capacity, and abundant coupling interfaces between the two. Moreover, the probable TC degradation mechanism was also clarified using the active species trapping experiments. This study inspires further design and construction of NH2-MIL-125(Ti) and ZnIn2S4 based photocatalysts for effective removal of antibiotics in water environment.

A dramatic enhancement of antibiotic photodegradation catalyzed by red mud-derived Bi5FeTi3O15

• Red mud-derived Bi 5 FeTi 3 O 15 was successfully synthesized via a molten-salt growth path. • The superior light absorption and charge separation of RM-BFTO-M are obtained. • RM-BFTO-M shows an enhanced photocatalytic activity for degradation of antibiotic. • A photocatalytic degradation mechanism over RM-BFTO-M is elucidated. The current scale of aluminum production and the accompanying waste disposal problems provide a largely untapped opportunity for chemical upcycling. Herein, red mud was recovered in the process of alumina extraction from bauxite and reutilized as a precursor to obtain layered ferroelectric perovskite Bi 5 FeTi 3 O 15 (RM-BFTO-M) via a molten-salt growth path. The as-prepared samples were characterized systematically by various techniques. The EDS and XPS results indicate that in addition to Fe element, several elements (Co, Ca, Al) in red mud are also introduced in RM-BFTO-M, while the photocurrent analysis and EIS date reveal the enhanced light absorption and charge separation of RM-BFTO-M relative to comparative Bi 5 FeTi 3 O 15 sample (BFTO-M). RM-BFTO-M shows superior photocatalytic performance for degradation of tetracycline hydrochloride with the rate of 211.8 times higher than that of comparative BFTO-M. The active species h + and OH play a crucial role during this degradation process. In order to reveal the enhancement mechanism, Co, Ca and Al elements were artificially doped into Bi 5 FeTi 3 O 15 , respectively. As expected, the enhanced photocatalytic activity is observed in the doping samples. Finally, a potential visible-light driven catalytic mechanism over RM-BFTO-M was put forward. Our work provides new thought for resource utilization of red mud.