Degradation Of Oxytetracycline Hydrochloride Research Articles

FeOOH coupling and nitrogen vacancies functionalized g-C3N4 heterojunction for efficient degradation of antibiotics: Performance evaluation, active species evolution and mechanism insight

In this study, the highly active g-C3N4-based photocatalysts were first constructed by assembling amorphous FeOOH nanoparticles on g-C3N4 nanosheets with nitrogen defects (FeOOH NPs/Nvac-CNNS). Such photocatalysts showed 92.83% and 73.86% degradation and mineralization efficiency of the oxytetracycline hydrochloride (OTC) within 90 min, respectively. Meanwhile, Response Surface Method (RSM) predicted that under optimal conditions (electricity 18.586 A, initial pH 6.371 and dosage 0.6 g/L), OTC degradation efficiency of 94.331% can be achieved. FeOOH NPs/Nvac-CNNS exhibited the excellent reutilization and practical application potential in OTC pollution purification of high and low concentration. The synergistic effect of N vacancies and FeOOH coupling endowed CNNS with advantages, such as the carrier’s fast separation, good visible-light adsorption, H2O2 fast decomposition and excellent molecular oxygen activation. Such advantages greatly contribute to OTC efficient removal in water. Based on the liquid chromatograph-mass spectrometer (LC-MS) analysis, the five possible degradation pathways of OTC were provided. Furthermore, through the quantitative structure-activity relationship (QSAR) analysis, biological toxicity prediction results of OTC and its intermediates indicated that the FeOOH NPs/Nvac-CNNS/vis system had great potential to achieve green and harmless treatment of OTC pollution.

Synthesis of a novel Z-scheme Ag/WO3/g-C3N4 nanophotocatalyst for degradation of oxytetracycline hydrochloride under visible light

In this work, Ag/WO3/g-C3N4 (AWC) nanocomposites were successfully prepared via a hydrothermal method. Oxytetracycline hydrochloride (OTC) was used to evaluate the photocatalytic activity of the photocatalysts under visible light. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra (Raman), scanning electron microscope (SEM), Ultraviolet–visible spectroscopy (UV–vis DRS), photocurrent density (I-t) and electrochemical impedance spectra (EIS). The results showed that WO3 and Ag nanoparticles were coupled with g-C3N4 successfully. Comparing with pure WO3 or g-C3N4, the visible light absorption region of AWC composites was effectively broadened. The photocatalytic performance experiment illustrated that AWC-2 composite had the highest photocatalytic activity, and 97.74% of OTC (10 mg/L) was degraded in 60 min with 0.4 g/L of AWC-2. The radical scavenging experiments indicated that the superoxide radical (•O2−) and hydroxyl radical (•OH) were the most important active species for OTC oxidation. The five cycle photocatalysis experiment further proved that AWC is a stable photocatalyst for degradation of OTC. Finally, the possible degradation mechanism of Z-scheme heterostructure photocatalysis was proposed according to the experimental results.

Synthesis of novel ternary Ag/BiVO4/GO photocatalyst for degradation of oxytetracycline hydrochloride under visible light

A ternary visible light responsive photocatalyst, Ag/BiVO 4 /graphene oxide (GO) composite was synthesized successfully using hydrothermal method. The prepared photocatalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis absorption spectroscopy, Raman spectra, photocurrent density and EIS analysis. The photocatalytic activity of Ag/BiVO 4 /GO (ABG) nanoparticles was tested on the removal efficiency of oxytetracycline hydrochloride (OTC) in aqueous phase. Compared with pure BiVO 4 and binary composites BiVO 4 /GO (BG), the fabricated ternary composite ABG exhibited the enhanced photocatalytic activity to degrade refractory organic pollutant. 90.43% OTC was removed with 0.4 g/L ABG composite after 70 min visible light irradiation. The enhanced photocatalytic ability was due to the addition of Ag and GO, which promoted the charge separation. The reusable performance for the degradation of OTC showed that 86.74% removal efficiency was maintained even after five recycles. Active species trapping experiments demonstrated that the photo-produced holes (h + ) and O 2 - played a crucial role in photocatalytic degradation of OTC. Finally, the photocatalytic mechanism was proposed. This work provided a simple preparation method for a ternary photocatalyst with greatly enhanced photocatalytic ability.

Study on removal of oxytetracycline hydrochloride in marine aquaculture wastewater by Zn0.75Mn0.75Fe1.5O4/ZnFe2O4/ZnO photocatalyst

AbstractPhotocatalytic degradation of oxytetracycline hydrochloride (OTC‐HCl) in marine aquaculture wastewater and therefore the effects of factors on the effectiveness of photocatalysts are studied in this paper using Zn0.75Mn0.75Fe1.5O4/ZnFe2O4/ZnO under visible light and changing the molar ratio of Zn2+:Fe3+:Mn2+, calcination temperature of catalysts, hydrogen peroxide concentration, dose of catalysts, illumination time of photocatalytic and initial concentration of OTC‐HCl. The degradation of OTC‐HCl in marine aquaculture wastewater was optimized by orthogonal experiment. The best effect exists when the molar ratio of Zn2+:Fe3+:Mn2+ was 10:1:3, the calcination temperature of photocatalyst was 400°C, the concentration of hydrogen peroxide was 0.5 g/L, the dose of catalysts was 0.6 g/L, the illumination time was 2.5 h and the initial concentration of OTC‐HCl was 0.010 g/L. The degradation rate of OTC‐HCl can reach 80.18%. Zn0.75Mn0.75Fe1.5O4/ZnFe2O4/ZnO can effectively degrade the OTC‐HCl in marine aquaculture wastewater under visible light.

Silver iodide decorated ZnSn(OH)6 hollow cube: Room-temperature preparation and application for highly efficient photocatalytic oxytetracycline degradation

• AgI/ZSH hollow cubes are obtained by the self-templating and deposition-precipitation method at room temperature. • AgI/ZSH for photocatalytic degradation of oxytetracycline hydrochloride under visible light. • AgI/ZSH has a better degradation effect in the pH greater than 5. • Hollow structure forms a high surface area and fast charge separation. ZnSn(OH) 6 has been widely used in the photocatalytic field due to unique face-centered-cube structure and the full hydroxyl groups on the surface, but is still unsatisfied because of its wide band gap. Herein, a novel AgI/ZnSn(OH) 6 hollow cube nanocomposite (AgI/ZSH) with superior visible-light-driven photocatalytic activity was prepared by a simple and room temperature synthesis method for overcoming these defects. The experimental and density functional theory (DFT) theoretical calculations illustrated that AgI nanoparticles loaded ZSH hollow cube can significantly enhance light absorption and accelerate the transfer of charges because of the special hollow structure of ZSH as well as suitable band gap between AgI and ZSH. The AgI/ZSH photocatalyst presented superior degradation effect for oxytetracycline hydrochloride (OTC). The degradation rate of AgI/ZSH increased by 26.31% and 93.36% compared with AgI and ZnSn(OH) 6 , respectively. The influences of initial OTC concentrations, pH, coexistence ions, and water sources were discussed in detail. Results showed that the photocatalyst is adapted to different environments. The excellent photo-stability of the product was confirmed by the basically unchanged degradation rate after four cycles. ESR and radical trapping experiments were employed to certify superoxide radical ( O 2 − ) and holes (h + ) as the main active species. The degradation products and possible pathways of OTC were obtained through LC-MS/MS and the possible degradation mechanism was analyzed. This discovery provides an excellent approach for the synthesis of high-efficiency composite materials with non-spherical hollow structures under room temperature conditions for the degradation of antibiotics.

Polyacrylamide gel synthesis and photocatalytic performance of CuCo2O4 nanoparticles

The phase-pure and well-dispersed CuCo2O4 nanoparticles (NPs) were designed and fabricated for the first time using a simple and inexpensive polyacrylamide gel method. The crystal structure, morphology and optical property of the CuCo2O4 NPs were characterized by various instruments in detail. X-ray diffractometry (XRD) patterns show that the pure phase of CuCo2O4. The scanning electron microscopy (SEM) images reveal that the CuCo2O4 NPs have size distribution in the range of 50–200 nm. Photocatalytic degradation experiments show that the CuCo2O4 NPs possess superior photocatalytic activity and stability to degrade oxytetracycline hydrochloride (OTCH) under visible illumination. In addition, the active species trapping experiments confirm that the hydroxyl radicals (OH) and holes (h+) play the major role in the degradation of OTCH by CuCo2O4 NPs. Additionally, according to the analysis of the experimental results, a possible photocatalytic mechanism was discussed.

Enhanced photocatalytic activities of visible light-responsive Ag3PO4-GO photocatalysts for oxytetracycline hydrochloride degradation

A series of Ag3PO4-GO-X (X = 1, 2 and 3) photocatalysts, with different graphene oxide (GO) content, were successfully prepared by chemical precipitation. Oxytetracycline hydrochloride (OTC) was selected as target compound to assess the photocatalytic efficiency of the Ag3PO4-GO -X composites. The characteristics of the photocatalysts were studied by SEM, TEM, XRD, XPS, UV–vis DRS, Raman spectroscopy and photoelectrochemical measurements. The enhanced photocatalytic mechanism of Ag3PO4-GO composite was proposed. Results indicated that Ag3PO4 was successfully integrated with GO. The visible light absorption range of Ag3PO4-GO composites effectively was expanded more than pure Ag3PO4. The adsorption capacity of the catalyst for OTC was also greatly enhanced. 99.24 % of OTC was removed in 60 min visible light irradiation, as the content of GO was 6% in the composite. After being reused five times, the photocatalytic degradation efficiency still reached 94.77 %. Reactive species of h+ were the main participants in oxidizing OTC, meanwhile •O2− and OH• contributed to the degradation process. This work provided a simple and effective approach to prepare Ag3PO4-GO composites. The results suggested that the addition of GO increased the electron-hole pairs separation efficiency of Ag3PO4 and improved the photocatalytic degradation activity of Ag3PO4 The as-prepared Ag3PO4-GO composites displayed promising effects in the photocatalytic removal of refractory organic pollutants as a visible light-responsive photocatalyst.

1D porous tubular g-C3N4 capture black phosphorus quantum dots as 1D/0D metal-free photocatalysts for oxytetracycline hydrochloride degradation and hexavalent chromium reduction

As an "up-and-coming" two-dimensional (2D) material, black phosphorus (BP) has attracted much attention due to its abundant metal-free properties and broad application prospects in photocatalysis. This study introduces a promising sunlight-driven metal-free photocatalyst for oxytetracycline hydrochloride degradation and hexavalent chromium reduction in water and wastewater. The roles of BP quantum dots (BPQDs) in the distribution of electrons and photocatalytic performances were well identified by experimental and density functional theory (DFT) calculations. As expected, the specially designed 0D/1D structure shows unusual photocatalytic efficiency toward the degradation of oxytetracycline hydrochloride (0.0276 min−1) and reduction of hexavalent chromium (0.0404 min−1). Reactive species, namely, O2− and h+ comprised the primary photocatalytic mechanisms for oxytetracycline hydrochloride degradation. This work highlights that the combination of tubular g-C3N4 (TCN) with BPQDs facilitates the charge spatial separation in the photocatalytic process, and provides alternative strategy for design of highly active and metal-free nanomaterials toward environmental remediation and sustainable solar-to-chemical energy conversion.

Application of response surface methodology for optimization of oxytetracycline hydrochloride degradation using hydrogen peroxide/polystyrene-supported iron phthalocyanine oxidation process.

Inspired by metalloporphyrin-based enzymes, a biomimetic catalyst, R-N-Fe, was prepared by grafting iron phthalocyanine (FePc) covalently onto a macroporous chloromethylated polystyrene-divinylbenzene resin (R), which was pre-functionalized using 4-aminopyridine (4-ampy) as an axial ligand. The novel catalyst was used for the degradation of oxytetracycline hydrochloride (OTCH). The response surface methodology was employed to optimize the independent operating parameters, including temperature, catalyst amount, H2O2 dosage, and initial pH value. The results displayed that the initial pH and temperature had the most significant effect on the removal efficiency. Under optimum conditions, the OTCH removal efficiency was 93.98%. Additionally, the classical quenching experiment and electron paramagnetic resonance (EPR) test indicated that R-N-Fe could generate hydroxyl radicals by decomposing H2O2, which was the main active species for eliminating OTCH. Furthermore, R-N-Fe can be easily recycled and can maintain high stability in the reusability test, rendering it a good potential for practical application.

Architecting a Double Charge-Transfer Dynamics In2S3/BiVO4 n-n Isotype Heterojunction for Superior Photocatalytic Oxytetracycline Hydrochloride Degradation and Water Oxidation Reaction: Unveiling the Association of Physicochemical, Electrochemical, and Photocatalytic Properties.

To surmount incompatibility provoked efficiency suppression of an anisotype heterojunction and to pursue an improved intrinsic photocatalytic activity by manipulating oriented transfer of photoinduced charge carriers, an In2S3/BiVO4 (1:1) n–n isotype heterojunction was fabricated successfully through a simple two-step calcination method, followed by a wet-chemical deposition method. The formation of an n–n isotype heterojunction was confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV–visible diffuse reflectance spectroscopy. The photocatalytic efficiency of the In2S3/BiVO4 catalyst was examined over degradation of oxytetracycline hydrochloride (O-TCH) and oxygen (O2) evolution reaction. Consequently, an n–n In2S3/BiVO4 isotype heterojunction exhibits a superior O-TCH degradation efficiency (94.6%, 120 min) and O2 evolution (695.76 μmol, 120 min) of multiple folds as compared to the pure BiVO4 and In2S3 solely. This is attributed to the proper band alignment and intimate interfacial interaction promoted charge carrier separation over the n–n isotype heterojunction. The intimate interfacial contact was confirmed by transmission electron microscopy (TEM), high-resolution TEM, and field emission scanning electron microscopy analysis. The proper band alignment was confirmed by Mott–Schottky analysis. The photoelectrochemical linear sweep voltammetric study shows a superior photocurrent density (269 μA/cm2) for In2S3/BiVO4 as compared to those for pristine BiVO4 and In2S3, which is in good agreement with the photocatalytic results. Furthermore, the superior charge antirecombination efficiency of the n–n isotype heterojunction was established by photoluminescence, electrochemical impedance spectroscopy, Bode analysis, transient photocurrent, and carrier density analysis. The improved photostability of the heterojunction was confirmed by chronoamperometry analysis. An orderly corelationship among physicochemical, electrochemical, and photocatalytic properties was established, and a possible mechanistic pathway was presented to better understand the outcome of the n–n isotype heterojunction. This study presents an effective way to develop new n–n isotype heterojunction-based efficient photocatalysts and could enrich wide applications in other areas.

UV/Vis Light Induced Degradation of Oxytetracycline Hydrochloride Mediated byCo-TiO2 Nanoparticles.

Pharmaceuticals, especially antibiotics, constitute an important group of aquatic contaminants given their environmental impact. Specifically, tetracycline antibiotics (TCs) are produced in great amounts for the treatment of bacterial infections in both human and veterinary medicine. Several studies have shown that, among all antibiotics, oxytetracycline hydrochloride (OTC HCl) is one of the most frequently detected TCs in soil and surface water. The results of the photocatalytic degradation of OTC HCL in aqueous suspensions (30 mg·L−1) of 0.5 wt.% cobalt-doped TiO2 catalysts are reported in this study. The heterogeneous Co-TiO2 photocatalysts were synthesized by two different solvothermal methods. Evonik Degussa Aevoxide P25 and self-prepared TiO2 modified by the same methods were used for comparison. The synthesized photocatalysts were characterized by X-ray powder diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), UV/vis diffuse reflectance spectroscopy (DRS), and N2 adsorption (BET) for specific surface area determination. The XRD and Raman results suggest that Ti4+ was substituted by Co2+ in the TiO2 crystal structure. Uv/visible spectroscopy of Co-TiO2-R showed a substantial redshift in comparison with bare TiO2-R. The photocatalytic performance of the prepared photocatalysts in OTC HCL degradation was investigated employing Uv/vis spectroscopy and high-performance liquid chromatography (HPLC). The observed initial reaction rate over Co-TiO2-R was higher compared with that of Co-TiO2-HT, self-prepared TiO2, and the commercial P25. The enhanced photocatalytic activity was attributed to the high surface area (153 m2·g−1) along with the impurity levels within the band gap (2.93 eV), promoting the charge separation and improving the charge transfer ability. From these experimental results, it can be concluded that Co-doping under reflux demonstrates better photocatalytic performances than with the hydrothermal treatment.

Photocatalytic degradation of oxytetracycline hydrochloride pollutants in marine aquaculture wastewater under visible light

A CuO/ZnO nanocomposite for use as photocatalyst was successfully prepared by co-precipitation method. Its chemical and physical properties were evaluated by X-ray diffractometry, scanning electron microscopy, EDS, UV–vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The average particle size of CuO/ZnO composite was found to be around 80 nm. The degradation of oxytetracycline hydrochloride pollutants in marine aquaculture wastewater using ZnO and CuO/ZnO was compared. CuO/ZnO nanocomposite was found to be more efficient than ZnO. The effects of external factors on the photocatalytic efficiency of the nanocomposite were investigated under visible light. Moreover, conditions for the degradation of oxytetracycline hydrochloride using CuO/ZnO nanocomposite were optimized. Based on both, the ability and efficiency of degradation, 10:1 molar ratio of Zn2+/Cu2+ and 0.4 g L–1 nanocomposite, were found to be optimal, using which the average photocatalytic degradation rate of oxytetracycline hydrochloride reached 90%.

High photocatalytic degradation efficiency of oxytetracycline hydrochloride over Ag/AgCl/BiVO4 plasmonic photocatalyst

A series of ternary Ag/AgCl/BiVO4 photocatalysts with different UV light reduction time were synthesized. All the samples were investigated and characterized by XRD, XPS, SEM, PL and so on. The results of UV–Vis DRS and PL demonstrated that the ternary photocatalysts exhibited higher absorption in visible light region. And from the XRD patterns, it could be inferred that with the increase of illumination time, the content of metallic Ag on the surface of ternary photocatalysts increased. In the ternary photocatalyst system, Ag nanoparticles acted as the electron mediator and induced the surface plasmon resonance to facilite the photocatalytic activity of as-obtained ternary photocatalysts. During the photocatalytic degradation of oxytetracycline hydrochloride, the 1 h-Ag/AgCl/BiVO4 photocatalyst showed the best degradation activity, and the main active species participating in the reaction were holes and superoxide radicals. According to the experimental results, the 1 h-Ag/AgCl/BiVO4 photocatalyst exhibited excellent stability and effectively degraded OTC under a wide pH range condition or co-existing ions. The experimental results provided a scientific basis for the practical application of the 1 h-Ag/AgCl/BiVO4 photocatalyst, especially for the treatment of antibiotics in the water.

Enhanced Escherichia coli inactivation and oxytetracycline hydrochloride degradation by a Z-scheme silver iodide decorated bismuth vanadate nanocomposite under visible light irradiation

Novel Z-scheme AgI/BiVO4 photocatalysts were fabricated by a chemical deposition-precipitation approach. The photocatalytic activities of the obtained catalysts were evaluated by disinfection of Escherichia coli (E. coli) and degradation of oxytetracycline hydrochloride (OTC-HCl) under visible-light irradiation. The BA3 (contained 9.09% of AgI) exhibited the highest photocatalytic activity and maintained good stability. It could completely inactivate 7.0×107 CFU/mL of E. coli in 50 min and degrade 80% of OTC-HCl in 60 min. The enhanced photocatalytic activity of AgI/BiVO4 composites could be ascribed to the lower recombination rate of electron-hole pairs. Meanwhile, radical trapping experiments revealed that the superoxide radical (O2−) and holes (h+) were the dominant reactive species in photo-disinfection process. Furthermore, the effects of bacterial initial concentration and inorganic anions were also investigated to optimize the photocatalyst for practical application. This study will give a new insight to construct the effective Z-scheme system for bacterial inactivation and organic pollutants degradation.

Hydrothermal synthesis of the cauliflower-like CdS microspheres to enhance solar photocatalytic degradation of Oxytetracycline hydrochloride

The Cadmium sulfide (CdS) microsphere photocatalysts with the cauliflower-like morphology have been synthesized by hydrothermal method. The as-prepared photocatalysts have been characterized by powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, UV–vis absorption (UV–vis), and the thermo-gravimetric analysis. The UV–vis measurements show that the CdS microsphere prepared with 2 h have a band gap about 2.13 eV, which is smaller than the reported 2.42 eV, thus the as-prepared photocatalysts can be easily photoexcited and exhibit better photocatalytic performance. The photo-degradation experiments have been performed with CdS photocatalysts prepared with various synthesis conditions. Particularly, the CdS microsphere photocatalysts show the highest degradation ratio (72.78%) of Oxytetracycline hydrochloride under the visible light irradiation.

Kinetics of the acid and alkaline degradation of oxytetracycline hydrochloride

The kinetics of the acid degradation of oxytetracycline hydrochloride in absence and in presence of Fe(III) and/or Cu was followed spectrophotometrically at 245 nm. The reaction was found to be first order in oxytetracycline, in hydrogen ions and is inhibited by the presence of cations. Values of 96 and 54 kJ mol −1 were obtained for the overall energy of activation, and the corresponding values for the entropy of activation are −4.2 and −117 JK −1. The products of the reaction were identified by TLC as α- and β-apoterramycin. The alkaline degradation was traced at 380 nm. The reaction followed first order kinetics in both reactants and was unaffected by the presence of cations. Values of 65 kJ −1 mol −1 and −96 JK −1 were obtained for the activation parameters.