Achieving high-efficient photocatalytic persulfate-activated degradation of tetracycline via carbon dots modified MIL-101(Fe)octahedrons

The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)degradation.The electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of CDs.Finally,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry technique.This research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.

Development of a Simple Extraction Method for Tetracycline Analogues from Bovine Milk

Tetracycline and analogues are among the most used antibiotics in the dairy industry. Besides the therapeutic uses, tetracyclines are often incorporated into livestock feed as growth promoters. A considerable amount of antibiotics is released unaltered through milk from dairy animals. The presence of antibiotic residues in milk and their subsequent consumption can lead to potential health impacts, including cancer, hypersensitivity reactions, and the development of antibiotic resistance. Thus, it is important to monitor residual levels of tetracyclines in milk. The purpose of this study is to develop a quick and simple method for simultaneously extracting five tetracycline analogues from bovine milk. Specifically, five tetracycline analogues: Chlortetracycline (CTC), demeclocycline (DEM), doxycycline (DC), minocycline (MC), and tetracycline (TC) were simultaneously extracted from milk using trifluoroacetic acid. Subsequently, the extracted analogues were separated by reverse-phase high-performance liquid chromatography (RP-HPLC) and detected at 355 nm using UV/Vis. Calibration curves for all five tetracycline analogues show excellent linearity (r2 value > 0.99). Percent recovery for MC, TC, DEM, CTC, and DC were: 31.88%, 96.91%, 151.29, 99.20%, and 85.58% respectively. The developed extraction method has good precision (RSD < 9.9% for 4 of the 5 analogues). The developed method with minimal sample preparation and pretreatment has the potential to serve as an initial screening test.

Mesoporous amorphous FeOOH-encapsulated BiO_(2–x) photocatalyst with harnessing broad spectrum toward activation of persulfate for tetracycline degradation

With the growing concern about the water environment,the advanced oxidation process of persulfate activation assisted by photocatalysis has attracted considerable attention to decompose dissolved organic micropollutants.In this work,to overcome the drawbacks of the photocatalytic activity reduction caused by the photo-corrosion of non-stoichiometric BiO_(2–x),a novel material with amorphous FeOOH in situ grown on layered BiO_(2–x) to form a core-shell structure similar to popcorn chicken-like morphology was produced in two simple and environmentally beneficial steps.Through a series of degradation activity tests of hybrid materials under different conditions,the as-prepared materials exhibited remarkable degradation activity and stability toward tetracycline in the FeOOH@BiO_(2–x)/Vis/PS system due to the synergism of photocatalysis and persulfate activation.The results of XRD,SEM,TEM,XPS,FTIR,and BET show that the loading of FeOOH increases the specific surface area and active sites appreciably;the heterogeneous structure formed by FeOOH and BiO_(2–x) is more favorable to the effective separation of photogenerated carriers.The optimal degradation conditions were at a catalyst addition of 0.7 g·L^(–1),a persulfate concentration of 1.0 g·L^(–1),and an initial pH of 4.5,at which the degradation rate could reach 94.7%after 90 min.The influence of typical inorganic anions on degradation was also examined.ESR studies and radical quenching experiments revealed that·OH,SO_(4)^(-)·,and·O_(2)^(-)were the principal active species generated during the degradation of tetracycline.The results of the 1,10-phenanthroline approach proved that the effect of dissolved iron ions on the tetracycline degradation was limited,and the interfacial reaction that occurs on the active sites on the material's surface was a critical factor.This work provides a novel method for producing efficient broad-spectrum Bismuth-based composite photocatalysts and photocatalytic-activated persulfate synergistic degradation of tetracycline.

Selective adsorption of tetracycline by β-CD-immobilized sodium alginate aerogel coupled with ultrafiltration for reclaimed water

In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycline antibiotics from reclaimed wastewater.A series of characterizations were utilized to confirm the successful synthesis of the adsorbent and this β-CD/NaAlg presented a three-dimensional network at the nanoscale or microscale.Under optimal conditions(pH=4,t=8 h,β-CD:NaAlg=9,adsorbent dosage = 1.5 g·L-1),the maximum removal rate of β-CD/NaAlg to tetracycline was 70%.The adsorption behavior of tetracycline on β-CD/NaAlg conformed to the Freundlich isotherm model(R2=0.9977) and the pseudo-second-order kinetic model(R^(2)=0.9993).Moreover,the adsorbent still removed 55.3% of tetracycline after five cycles.Specially,the adsorbent was integrated with ultrafiltration to adsorb tetracycline antibiotics from simulated reclaimed wastewater,and the removal rate of tetracycline reached 78.9% within 2 h.The existence of Cr(Ⅵ) had a negligible impact on tetracycline removal,while the presence of humic acid exhibited a promoting effect.The possible adsorption mechanisms were also elucidated through X-ray photoelectron spectroscopy and density functional theory analysis.In summary,β-CD/NaAlg represents an environmentally friendly,efficient,and sustainable adsorbent for removing tetracycline antibiotics from reclaimed water.

Carbon-doped CuFe_(2)O_(4) with C-O-M channels for enhanced Fenton-like degradation of tetracycline hydrochloride: From construction to mechanism

Carbon-doped copper ferrite(C–CuFe_(2)O_(4))was synthesized by a simple two-step hydrothermal method,which showed enhanced tetracycline hydrochloride(TCH)removal efficiency as compared to the pure CuFe_(2)O_(4) in Fenton-like reaction.A removal efficiency of 94%was achieved with 0.2 g L^(-1) catalyst and 20 mmol L^(-1) H_(2)O_(2) within 90 min.We demonstrated that 5%C–CuFe_(2)O_(4) catalyst in the presence of H_(2)O_(2) was significantly efficient for TCH degradation under the near-neutral pH(5–9)without buffer.Multiple techniques,including SEM,TEM,XRD,FTIR,Raman,XPS M€ossbauer and so on,were conducted to investigate the structures,morphologies and electronic properties of as-prepared samples.The introduction of carbon can effectively accelerate electron transfer by cooperating with Cu and Fe to activate H_(2)O_(2) to generate·OH and·O_(2)^(-).Particularly,theoretical calculations display that the p,p,d orbital hybridization of C,O,Cu and Fe can form C–O–Cu and C–O–Fe bonds,and the electrons on carbon can transfer to metal Cu and Fe along the C–O–Fe and C–O–Cu channels,thus forming electron-rich reactive centers around Fe and Cu.This work provides lightful reference for the modification of spinel ferrites in Fenton-like application.

Determination of fluoroquinolones, sulfonamides, and tetracyclines multiresidues simultaneously in porcine tissue by MSPD and HPLC-DAD

An efficient method is provided to detect simultaneously some important veterinary drugs from different classes in highly complex animal tissue matrix. This method using matrix solid-phase dispersion (MSPD) and high performance liquid chromatography (HPLC) with diode array detection (DAD) is developed to effectively determine two fiuoroquinolones (enoxacin and lomefioxacin), two sulfonamides (sulfanilamide and sulfamethoxazole) and one tetracycline (tetracycline) simultaneously in porcine tissues. In the process, MSPD methodology was used to treat samples, washed by n-hexane to remove lipid, eluted the analytes with acetonitrile–dichloromethane (1:1, v/v). Solvent acetonitrile and solvent acetic acid (0.1%) were combined in a gradient. HPLC–DAD analysis of the tissue samples was performed within 15 min at a fiow rate of 1.0 mL/min. The results showed that a recovery at 0.1, 0.5 and 1.0 mg/g fortification levels ranged from 80.6% to 99.2% with satisfactory relative standard deviations (RSDs) (below 6.1%, nfi3) and the limits of quantitation (LOQ) ranged from 7 mg/kg to 34 mg/kg in porcine tissues. Utilization of the method in successfully simultaneous analysis of porcine tissue incurred with veterinary drug multiresidues is described.

Determination of Tetracyclines and Their Epimers in Agricultural Soil Fertilized with Swine Manure by Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry

A rapid, sensitive and specific ultra-high-performance liquid chromatography tandem mass spectrometry （UPLC-MS） method was developed for the analysis of tetracycline antibiotics, including tetracycline （TC）, oxytetracycline （OTC）, chlortetracycline （CTC） and their 4-epimers （4-epiTCs） in agricultural soil fertilized with swine manure. Soil samples were extracted and cleaned-up with 10 mL EDTA-McIlvaine buffer solution （pH 4.0）, then cleaned-up and pre-concentrated using the Oasis MAX cartridge and then eluted with 1 mL solution by mixing formic acid, methanol and water at a ratio of 2：15：83 （v/v/v）. The purified samples were separated by an ACQUITY UPLC BEH C18 column using acetonitrile and water containing 0.1% formic acid mobile phase and detected by a single quadrupole MS. The limits of detection for the soil extraction method （LODsoil） ranged from 0.6-2.5 lag kg-~ with recoveries from 23.3-159.2%. Finally, the method was applied to an agricultural field in an area with intensive pig-fattening farming. Tetracyclines were detected in soil from 2.8 to 42.4 μg kg-1 soil. These results demonstrate that soil from swine farms can become severely contaminated with tetracycline antibiotics and their metabolites.

Survey of Tetracyclines, Sulfonamides, Sulfamethazine, and Quinolones in UHT Milk in China Market

This study surveyed 180 samples of ultra high temperature （UHT） milk of four top Chinese dairy brands collected in the 25 cities in China in June 2011, and assessed their contamination with antibiotics, using the ELISA method. The percentages of tetracyclines, sulfonamides, sulfamethazine, and quinolones detected in the samples were 0, 16.7, 40.6, and 100%, respectively. The maximum concentrations of the tetracyclines, sulfonamides, sulfamethazine and quinolones in UHT milk samples were 〈1.5, 26.2, 22.6, and 58.8 μg kg-1, respectively. None of the samples exceeded the maximum residue levels （MRLs） for these four veterinary drugs, according to the regulations set by China, the European Union （EU） and the Codex Alimentarius Commission （CAC）.

Study on Rapid Detection of Tetracyclines,Fluoroquinolones and Sulfonamides in Milk

Aiming at the market demand for rapid detection of tetracyclines,fluoroquinolones and sulfonamides in milk,a golloidal gold immunochromatography test strip for simultaneous detection of tetracyclines,fluoroquinolones and sulfonamides in milk was prepared based on the principle of competitive inhibition immunochromatography. The performance indicators of the test strip were verified. The results showed that the test strip can simultaneously detect 4 tetracyclines,13 fluoroquinolones and 13 sulfonamides,and the detection limits all can meet the national residue limits; the tests strip exhibited false positive rate≤5% and false negative rate = 0; and no cross-reaction with other drugs was commonly found in milk,indicating good specificity. The method is simple,rapid,and has low cost and easy popularization. It provides a means for realizing on-site rapid detection and is of important practical significance to guarantee of safety of milk and dairy products in China.

Green remediation of tetracyclines in soil-water systems

The presence of tetracyclines in soil and surface water is an emerging concern. The present study was undertaken to investigate remediation of tetracylines (tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC)) from aqueous solution using vetiver grass, water lettuce, and sunflower and root exudates of water lettuce, sunflower and from soil by tomato, Indian mustard and carrot plant. The data of this study denote that vetiver grass, water lettuce, sunflower remedy tetracyclines from water. The remediation % after 63 days of treatment was 87-61 for TC;88-68 for OTC and 87-68 for CTC. The remediation of tetracyclines at lower concentration of antibiotics in presence of root exudates of water lettuce and sunflower was more than 99% and remediation was faster than water lettuce or sunflower. The remediation of tetracyclines from aqueous solution may be due to oxidation of-OH group(s) of tetracycline through a process that is thought to involve reactive oxygen intermediates and/or role of peroxidase enzyme. The plant crops viz., tomato, Indian mustard and carrot can remedy 41%-72% of amended tetracyclines. The maximum bioaccumulation of TC and CTC was in Indian mustard and OTC was maximally bioaccumulated in tomato.

Indirect Flow Injection Chemiluminescence Method for the Determination of Tetracyclines Using Cu(Ⅱ) as a Probe Ion

This paper reported an indirect flow injection chemiluminescence （FI-CL） method for the determination of the drugs tetracycline （TC）, chlortetracycline （CTC） and oxytetracycline（OTC） using Cu（ Ⅱ ） as a probe ion. The CL reaction was induced on-line and after injection of the sample the negative peaks appeared as a result of complexation. The method was applied to the determination of TCs in pharmaceuticals and human urine with recoveries in the range95-105%.

Colloidal Gold Immunochromatographic Assay for Rapid On-Site Detection of Tetracycline in Seawater

Recently increasing concerns from the scientists and public have been paid for seawater pollution due to tetracycline(TC)overuse in maricultural area.However,there are few methods or instruments that can be used for specific and rapid detection of this antibiotic in seawater.In this study,the colloidal gold immunochromatographic assay(CG-ICA)was used to achieve this goal.A commercialized monoclonal antibody against TC(anti-TC mAb)was selected because of its higher sensitivity(half-maximal inhibitory concentration of 2.38μgL^(-1)).The prepared CG particles(average diameter of 20 nm)were used to label anti-TC mAb at pH 8.0.The conjugate pad was formed by spraying the CG-labeled anti-TC mAb on a glass fibre membrane followed by proper dryness.The test pad was made by immobilizing artificial antigen and anti-mouse mAb in the test line and the control line,respectively,in a nitrocellulose membrane.The test strip,assembled with sample pad,conjugate pad,test pad and absorbent pad,could be used to detect TC during seawater sample flowing through these components in turn.The results could be observed by the naked eye in 10min.The visible limit of detection(vLOD)was 20μgL^(-1) for TC in seawater.The CG-ICA test results were in good agreement with those of liquid chromatography-tandem mass spectrometry(LC-MS/MS).The assay also showed that,oxytetracycline(OTC)and chlortetracycline(CTC),as the structural analogues of TC,did not interfere with TC determination.Furthermore,the TC concentration given by test strip could not be affected by the fluctuation of temperature(10℃–30℃),pH(7–9)and salinity(0–40)of seawater.Therefore,CG-ICA is a suitable tool for rapid,on-site,and semi-quantitative detection of TC in seawater.

Synthesis of porous carbon nanomaterials and their application in tetracycline removal from aqueous solutions

The low-cost and efficient elimination of tetracycline from wastewater and to decrease the concentration in soils,sediments,rivers,underground water,or lakes are crucial to human health.Herein,threedimensional porous carbon nanomaterials were synthesized using glucose and NH_(4)Cl by sugarblowing process at 900℃ and then oxidized under air atmosphere for surface functional group modification.The prepared 3D porous carbon nanomaterials were applied for the removal of tetracycline from aqueous solutions.The sorption isotherms were well simulated by the Langmuir model,with the calculated sorption capacity of 2378 mg·g^(-1) for C-450 at pH=6.5,which was the highest value of today's reported materials.The porous carbon nanomaterials showed high stability at acidic conditions and selectivity in high salt concentrations.The good recycle ability and high removal efficiency of tetracycline from natural groundwater indicated the potential application of the porous carbon nanomaterials in natural environmental antibiotic pollution cleanup.The outstanding sorption properties were attributed to the structures,surface areas and functional groups,strong interactions such as H-bonding,π-π interaction,electrostatic attraction,etc.This paper highlighted the synthesis of porous carbon nanomaterials with high specific surfaces,high sorption capacities,stability,and reusability in organic chemicals'pollution treatment.

Facile one-pot synthesis of a BiOBr/Bi_(2)WO_(6) heterojunction with enhanced visible-light photocatalytic activity for tetracycline degradation

Photocatalytic removal of tetracycline(TC)from the wastewater is of great value in the chemical and environmental engineering field.Here,we introduced a facile one-step method for the synthesis of BiOBr/Bi2WO6 heterojunctions by using cheap CTAB as the Br source.We showed the possibility of our method to fine-tune the content of BiOBr in the produced BiOBr/Bi2WO6 by simply changing the dosage of cetyltrimethylammonium bromide(CTAB),providing a platform for the delicate tuning of the visiblelight absorbance ability of the composites.With a suitable heterojunction structure of BiOBr/Bi2WO6-0.2,it exhibited an ultrarapid photocatalytic activity towards TC(20 mg
L^(-1)),with a competitive removal efficiency of 88.1%within 60 min and an ultrahigh removal rate of 0.0349 min^(-1).It could also be robustly recycled for at least 5 cycles with slight removal efficiency loss.We demonstrated that this exciting photocatalytic performance was due to the highly decreased recombination of photoinduced electrons and holes on our composites by constructing this heterojunction structure,and the resulting
OH and
O^(-)_(2)contributed to the effective degradation of TC to CO_(2).

Efficacy and safety of modified tetracycline dosing in a quadruple therapy for Helicobacter pylori:A retrospective single center study

BACKGROUND Although highly effective as a component of Helicobacter pylori(H.pylori)treatment regimen,tetracycline is associated with a high incidence of medicationrelated adverse events.Modified dosing of tetracycline as part of quadruple therapy may improve safety while providing comparable eradication rates.AIM To evaluate the efficacy and safety of modified dosing of tetracycline in patients receiving tetracycline and furazolidone-containing quadruple therapy in patients with H.pylori infection.METHODS Consecutive patients(10/2020-12/2021)who received tetracycline and furazolidone quadruple therapy for H.pylori infection at Sir Run Run Shaw Hospital were identified.All patients received tetracycline,furazolidone,proton pump inhibitor,and bismuth for 14 d as primary or rescue therapy.Modified tetracycline dose group received tetracycline 500 mg twice daily while standard group received 750 mg twice daily or 500 mg three times daily.RESULTS Three hundred and ninety-four patients[mean age=46.3±13.9,male=137(34.8%),and 309(78.4%)primary therapy]completed tetracycline and furazolidone quadruple therapy for H.pylori infection including those who received modified tetracycline dose in 157 and standard doses in 118(750 mg twice daily)and 119(500 mg three times daily).Eradication rates in the modified tetracycline dose group were 92.40%and in the standard groups,eradication rates were 93.20%for 750 mg twice daily group and 92.43%for 500 mg three times daily group,respectively,without statistical difference(P=0.959).The incidence of adverse events was lower in the modified tetracycline dose(15.3%vs 32.3%and 29.4%;P=0.002)compared to the standard dose group.CONCLUSION In a real-world experience,modified tetracycline dosing as part of tetracycline and furazolidone quadruple therapy for 14 d demonstrated high efficacy,comparable to standard tetracycline dose regimens,with a favorable safety profile.

Preliminary Study on the Treatment Efficiency of Pasteurized Lime Thermal Alkaline Hydrolysis for Excess Activated Sludge and Reduction of Tetracycline Resistance Genes

Thermal alkaline hydrolysis is a common pretreatment method for the utilization of excess activated sludge(EAS).Owing to strict environment laws and need for better energy utilization,new methods were developed in this study to improve the efficiency of pretreatment method.Direct thermal hydrolysis(TH),pasteurized thermal hydrolysis(PTH),and alkaline pasteurized thermal hydrolysis(PTH+CaO and PTH+NaOH)methods were used to treat EAS.Each method was compared and analyzed in terms of dissolution in ammonium nitrogen(NH_(4)^(+)-N)and soluble COD(SCOD)in EAS.Furthermore,the removal of tetracycline resistance genes(TRGs)and class 1 transposon gene intI1 from EAS was investigated.The NH_(4)^(+)-N and SCOD concentrations in EAS treated by PTH were 1.24 and 2.58 times higher than those of TH.However,the removal efficiency of total TRGs and intI1 between the groups was comparable.The SCOD concentration of the PTH+NaOH group was 4.37 times higher than that of the PTH group,and the removal efficiency of total TRGs was increased by 9.52%compared with that by PTH.The NH_(4)^(+)-N and SCOD concentrations of the PTH+CaO group could reach 85.04%and 92.14%of the PTH+NaOH group,but the removal efficiency of total TRGs by PTH+CaO was 19.78%lower than that by PTH+NaOH.Thus,to reduce the financial cost in actual operation,lime(CaO)can be used instead of a strong alkali(NaOH),and pasteurized steam at 70℃ instead of conventional high-temperature heating to treat EAS.This study provides a reference for the development of alkaline hydrolysis under moderate temperatures along with the removal of TRGs in EAS.

基于适配体-杂交链式反应比色检测生鲜牛乳中四环素类抗生素

)以特异性识别四环素类抗生素(TCs)的广谱型适配体为识别元件,结合杂交链式反应(HCR)信号放大策略,提出了一种TCs多残留比色检测方法,并优化了检测条件和进行了方法学考察。取40 nmol·L^(-1)生物素化检测探针(bio-DP)溶液加入到包被有亲和素的酶标板中,室温孵育后加入牛血清白蛋白(BSA)溶液,封闭反应1 h。加入生鲜牛乳样品稀释液,室温孵育20 min,如果样品中含有TCs,TCs与bio-DP的适配体序列结合,其发夹结构被打开。加入200 nmol·L^(-1)生物素化发夹DNA1(bio-H1)溶液和200 nmol·L^(-1)生物素化发夹DNA2(bio-H2)溶液,室温下进行HCR 40 min,从而形成具有多个重复单元的双链DNA(dsDNA)纳米线。加入辣根过氧化物酶(HRP)标记链霉亲和素(SA-HRP),室温孵育标记dsDNA。加入显色剂[含3,3′,5,5′-四甲基联苯胺(TMB)],HRP催化TMB生成蓝色物质,显色5~8 min后终止反应,在酶标仪中于450 nm测量上述体系的吸光度。结果显示,bio-DP对四环素、土霉素、金霉素和多西环素具有高特异性,和卡那霉素、庆大霉素、氨苄青霉素、泰乐菌素、磺胺嘧啶和恩诺沙星等抗生素无交叉反应。四环素、土霉素、金霉素和多西环素的质量浓度总和在0.8~100μg·L^(-1)内与对应的吸光度总和呈线性关系,检出限(3s/k)为0.18μg·L^(-1)。对生鲜牛乳样品进行加标回收试验,TCs回收率为86.4%~106%,测定值的相对标准偏差(n=3)为2.5%~7.1%。方法应用于生鲜牛乳样品的分析,检测结果与国家标准方法GB 31658.6-2021差异不显著(P>0.05),检出的TCs总量也均未超标(GB 31650-2019)。与文献报道的其他方法相比,上述方法兼具简单、快速、检出限低、准确度高等优点,适用于食品中四环素类抗生素多残留的快速检测。

氧化石墨烯纳米颗粒对抗生素类污染物吸附特征及影响因素

本文通过吸附动力学和吸附等温线探究了氧化石墨烯(GO)纳米颗粒对3种典型的四环素类抗生素(即四环素(TC)、土霉素(OTC)和金霉素(CTC))吸附特征.结果表明,伪二级动力学模型可以很好的拟合吸附动力学的结果,吸附速率可能受化学吸附控制.吸附等温线的结果显示GO对3种抗生素均有较高的吸附能力,且吸附能力依次为:CTC>OTC>TC.这主要是由于四环素类抗生素可以通过π-π作用、阳离子-π键、疏水作用以及静电作用等机制与GO产生结合.此外,四环素类抗生素在GO上的吸附行为与背景溶液的水化学条件(如pH、离子强度和二价金属离子)密切相关.总体来讲,由于静电斥力的增强,抗生素在GO上的吸附量随着背景溶液pH值的升高或离子强度(NaCl)的增加而降低,这主要是由于静电引力和吸附点位的减少所致;二价阳离子(Cu^(2+))可以通过表面桥连作用,显著促进抗生素在GO上的吸附.本研究结果清楚地表明抗生素本身的化学性质和背景溶液的水化学条件在GO去除抗生素的过程起着重要作用.

高效降解盐酸四环素的CdS/BiOCl复合光催化剂的制备及性能

采用水热法制备了BiOCl超薄纳米片,并将CdS纳米晶体沉积于BiOCl表面制备CdS/BiOCl复合光催化剂。XRD测试结果证明CdS的沉积不会改变BiOCl的晶体结构。XPS测试结果表明CdS/BiOCl复合材料已被成功合成。SEM及HRTEM测试结果证明,CdS纳米晶体均匀沉积在BiOCl的表面。荧光光谱分析数据表明CdS/BiOCl复合材料的电子-空穴分离效果得到有效提高,均优于纯BiOCl材料,且随着Cd(Ac)_(2)·2H_(2)O添加量的增加,复合材料的荧光光谱强度呈现先减弱后增强的现象。根据紫外可见漫反射光谱及XPS价带谱测试结果,计算出复合材料的价带与导带电位。以盐酸四环素作为模拟污染物评价光催化剂的活性,结果表明,CdS/BiOCl复合材料光催化活性更高,仅需经过5 min的可见光照射后,优选的CdS/BiOCl(CB-8)复合材料对盐酸四环素的去除率可达70.6%,为纯BiOCl的16.2倍。最终,根据XPS价带谱和活性物种捕获实验结果推测了CdS/BiOCl复合光催化剂的光催化反应机理。

N-CDs@Nb_(2)O_(5)-AMMC纳米材料的制备及其可见光催化性能研究

通过工艺简单的水热法成功制备出N-CDs和不同含量N-CDs修饰的N-CDs-X@Nb_(2)O_(5)-AMMC纳米材料。对N-CDs-X@Nb_(2)O_(5)-AMMC进行XRD、SEM、TEM、FT-IR、XPS和UV-vis DRS等表征分析。结果表明,经过N-CDs改性之后Nb_(2)O_(5)-AMMC的带隙变窄,样品的吸收边红移和光吸收范围变宽,从而有利于提高光催化性能。另外,N-CDs减少了电子传输的阻力,有利于光生电子向N-CDs结构的转移,同时光生载流子的迁移及分离效率提高,有利于光催化反应的进行。与纯Nb_(2)O_(5)-AMMC相比,N-CDs-X@Nb_(2)O_(5)-AMMC在可见光下光催化降解TC-HCl的性能均有提高,其中样品N-CDs-1@Nb_(2)O_(5)-AMMC的降解效率最高,1 h内对TC-HCl的降解率能达到63.2%,是纯Nb_(2)O_(5)-AMMC的1.59倍。