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.

In Vitro Dissolution Kinetics of α-TCP Cement Containing Tetracycline Hydrochloride

In vitro dissolution kinetics of a-tricalcium phosphate （α-TCP） cement and α-TCP cement containing tetracycline Hydrochloride（TTCH） were studied in the present paper. It shows that dissolution process of α-TCP cement and TTCH-loaded α-TCP cement accords with Avrami dissolution kinetics model： x=1-exp（-kt^n）, and Avrami constant n is 0.5 and 0.4 respectively, which means dissolution process is diffusion control. Apparent dissolution activation energy of α-TCP cement and TTCH-loaded α-TCP cement is about 9.87 kJ/moland 7.17 kJ/mol respectively. Comparing with α-TCP cement, activation energy and Avrami constant of TTCH-loaded α-TCP cement decrease slightly, but its [Ca^2＋] solubility decreases from 40 ppm to 11.5 ppm, which could result from the change of interracial property and morphology of hydrated apatite crystal caused by absorption of TTCH on the apatite.

蒙脱土吸附去除盐酸四环素(TCH)实验研究

盐酸四环素(TCH)被广泛应用于医疗、畜牧养殖和农业等行业中,但由于在使用过程中不能被人和动物完全吸收,而是随粪便与尿液排泄进入环境水体,而TCH会破坏生态环境、危害人体健康、催生耐药毒菌,对环境和人体健康造成威胁,因此找到一种经济高效的去除方法对于水质安全非常重要。目前,水中TCH的去除方法主要包括化学法、生物法和物理法,相对于化学与生物处理法,物理法中的吸附法去除污染水体中的TCH具有成本低、环境友好、高效稳定、操作简单的特点,其中在吸附材料的选择上,炭基材料和矿物材料往往呈现粉末状,不易回收,对环境有二次污染的隐患,与之相比,凝胶材料适宜于对有机污染物的去除,因此,寻求一种价格低廉,吸附效果好的吸附剂是目前吸附法的研究热点。蒙脱土(MMT)作为一种土状矿物,表面带有大量永久性负电荷,晶体结构稳定,机械强度高,由于其价格低廉,易于获得,吸附性能优越的特点,在污水处理中,常用于吸附去除重金属离子、染料、酚类化合物,多环芳烃等,去除效果较好,但目前还没单独使用MMT进行TCH吸附方面的研究,鉴于此背景,旨在研究MMT吸附TCH的吸附性能和效果。通过研究,发现Freundlich等温吸附模型和准二级动力学模型对MMT吸附TCH具有较好的拟合效果,表明其吸附为多层吸附,且在60 min内即可达到总吸附量的87%,Langmuir饱和吸附量可达到118.6 mg/g。Gibbs自由能ΔG0皆为负值,表明MMT对TCH的吸附是自发过程,容易进行。计算所得焓变和熵变均大于零,说明吸附进程为吸热过程,吸附随机发生在固液表面,提高温度对吸附有促进作用,与温度影响实验所得结论一致,再次说明吸附过程为吸热反应,提高温度有利于吸附进行。溶液pH对吸附性能影响显著,pH从3增加到10,吸附量先增大后减小,最佳pH值为6~8。这是由于在强酸性条件下,H+与TCH形成竞争吸附,所以MMT对TCH的吸附量较低。当pH值提高,H+浓度降低,与TCH的竞争吸附减弱,因此MMT对TCH的静电吸附量提高。但随着pH值继续升高,TCH逐渐变为H2TC-及HTC2-形态,与带负电荷的MMT之间产生静电斥力,造成吸附量降低。根据上述实验结果和表征分析,分析机理可得,MMT对TCH的吸附过程包括同时包括物理吸附与化学作用,其中化学作用在其中占主导。MMT中的Al-O-H基团能与TCH分子上的三羰基酰胺基团以及羟基基团形成氢键作用,且在pH<5时存在一定的静电引力。综上所述,由于MMT成本低廉,对TCH的吸附速率快,吸附量大,在吸附TCH性能上有其独特优势,因此在实际含TCH废水处理中具有较好的应用前景。

Significant role of carbonate radicals in tetracycline hydrochloride degradation based on solar light-driven TiO2-seashell composites:Removal and transformation pathways

TiO2-seashell composites prepared via a sol-gel method were used to generate carbonate radicals(·CO3–) under solar light irradiation. ·CO3–, a selective radical, was employed to degrade the target tetracycline hydrochloride contaminant. A series of characterizations was carried out to study the structure and composition of the synthesized TiO2-seashell composite. This material exhibits excellent solar light-driven photochemical activity in the decomposition of tetracycline hydrochloride. The possible pathway and mechanism for the photodegradation process were proposed on the basis of high-resolution electrospray ionization time-of-flight mass spectrometry experiments. Finally, we investigated the reusability of the TiO2-seashell composite. This study is expected to provide a new facile pathway for the application of ·CO3– radicals to degrade special organic pollutants in water.

Use of tetracycline hydrochloride and alizarin complexone for immersion marking black rockfish Sebastes schlegelii

We tested the utility of chemical marking techniques in the juvenile black rockfish Sebastes schlegelii. Juveniles （30-40 mm total length） were immersed in a range of tetracycline hydrochloride （TC） solutions at concentrations ranging from 300 to 500 mg/L, and alizarin complexone （ALC） solutions at concentrations ranging from 200 to 400 mg/L in filtered sea water （salinity of 30） for 24 h, respectively. Otoliths （sagittae, asteriscus）, scales, fin rays （dorsal, pectoral, ventral, anal, and caudal fin rays）, and fin spines （dorsal, ventral, and anal fin spines） were sampled and used to detect fluorescent marks after a 60-day growth experiment. With the exception of 300 mg/L TC, acceptable marks were produced in the otoliths and fin spines by all concentrations of TC and ALC. In particular, we observed clearly visible marks in the sagittae, asteriscus, and fin spines under normal light at concentrations of200~00 mg/L, 250-400 mg/L, and 250-400 mg/L ALC, respectively. Scales and fin rays had acceptable marks at much higher concentrations （_〉350 mg/L TC, 〉250 mg/L ALC for scales and _〉350 mg/L TC, 〉300 mg/L ALC for fin rays）. The best mark quality （i.e., acceptable marks were observed in all sampled structures after immersion marking） were obtained following immersion in TC at between 350-500 rag/L, and ALC between 300-400 mg/L. In addition, there was no significant difference in survival and growth of TC and ALC marked fish compared to their controls up to 60 days post-marking （P〉0.05）.

Unique electronic structure of Mg/O co-decorated amorphous carbon nitride enhances the photocatalytic tetracycline hydrochloride degradation

g-C3N4 is a hot visible light photocatalyst. However, the fast recombination of photogenerated electron- hole pairs leads to unsatisfactory photocatalytic efficiencies. In this study, Mg/O co-decorated amorphous carbon nitride (labeled as MgO-CN) with a unique electronic structure was designed and prepared via a combined experimental and theoretical approach. The results showed that the MgO-CN exhibited an increased light absorption ability and promoted charge separation efficiency. The Mg and O co-decoration created a unique structure that could generate localized electrons around O atoms and enhance the reactant activation capacities via the C→O←Mg route. This could dramatically promote the O2 molecule activation on the catalyst surface to generate reactive species (?O2 –/?OH). The optimized MgO-CN exhibited a high photocatalytic activity for the degradation of tetracycline hydrochloride in water, which was five times higher than that of pristine g-C3N4. The present work could provide a new strategy for modifying the electronic structure of g-C3N4 and enhancing its performance for environmental applications.

Preparation of BiOCl0.9I0.1/β-Bi2O3 composite for degradation of tetracycline hydrochloride under simulated sunlight

A novel and effective BiOCl0.9I0.1/x%β-Bi2O3 composite catalyst was synthesized through a precipitation method. The structure, morphology, and optical properties of the samples were certified by X-ray diffraction, UV-Vis diffuse reflectance, scanning electron microscopy, and X-ray photoelectron spectroscopic characterizations. Photocatalytic experiments demonstrated that the synthesized BiOCl0.9I0.1/x%β-Bi2O3 composite catalyst exhibited excellent photocatalytic performance toward the degradation of tetracycline hydrochloride(TCH) under simulated sunlight. Furthermore, the TCH degradation rate of BiOCl0.9I0.1/15%β-Bi2O3 increased by 27.6% and 61.4% compared with those of the pure BiOCl0.9I0.1 and pure β-Bi2O3, respectively. Due to the multiple vacancies and valence states possessed by BiOCl0.9I0.1/x%β-Bi2O3, namely Bi5+, Bi(3-x)+, Bi5+–O, Bi3+–O, I- and I3-, the charge separation in photocatalysis reactions can be effectively promoted. The Mott-Schottky measurements indicate that the conduction band(CB) level of BiOCl0.9I0.1/15%β-Bi2O3 becomes more negative relative to that of BiOCl0.9I0.1, guaranteeing an advantageous effect on the redox ability of the photocatalyst. This study provides a new bright spot for the construction of high-performance photocatalysts.

Application and Mechanism of ZnSb2O4 and ZnSb2O6 in the Photocatalytic Degradation of Tetracycline Hydrochloride

The photocatalytic performances in the photocatalytic degradation of tetracycline hydrochloride(TC) of ZnSb2O4 and ZnSb2O6 synthesized by hydrothermal method were explored.The effects of synthesis conditions including reaction temperature, reaction time, precursor solution pH, and the amount of hydrazine hydrate on the photocatalytic activity were discussed.The ZnSb2O4 and ZnSb2O6 photocatalysts prepared under optimal conditions exhibited similar photocatalytic activities for the degradation of TC. However, the areal photoctalytic activity of ZnSb2O4 was 12 times higher than that of ZnSb2O6 because of their different electronic and geometric structures. The photocatalytic degradation mechanisms of TC over ZnSb2O4 and ZnSb2O6 were proposed. Our work will facilitate the development of composite oxides consisting of p-block metal ions as new semiconductor photocatalysts.

Synthesis plasmonic Bi/Bi VO4 photocatalysts with enhanced photocatalytic activity for degradation of tetracycline(TC)

In recent years,the excessive use of antibiotics has become a serious problem for human health.BiV04 regarded as one of the most promising visible-light-driven photocatalysts was used to degrade the antibiotics.In this paper,we fabricated Bi/BiV04 plasmonic photocatalysts which enhanced the photocatalytic activity of BiV04 for degradation of tetracycline(TC)antibiotic.The Bi/BiV04 photocatalysts were characterized by X-ray diffraction,X-ray photoelectron spectroscopy,scanning electron microscopy,transmission electron microscopy and high-resolution transmission electron microscopy.In addition,the photocatalytic experiment results show that the 0.04-Bi/BiVO4 sample has the best photocatalytic activity for 2 times than the pure BiV04 photocatalyst.The cycle experiments,after four repetitions of the experiments,showed the sample still maintained a high photocatalytic activity.Finally,the photocatalytic reaction mechanism was also studied by free radical capture experiments and electron paramagnetic resonance spectroscopy.

Plasma-catalytic degradation of tetracycline hydrochloride over Mn/γ-Al2O3 catalysts in a dielectric barrier discharge reactor

A coaxial dielectric barrier discharge (DBD) reactor was used for plasma-catalytic degradation of tetracycline hydrochloride over a series of Mn/γ-Al2O3 catalysts prepared by the incipient wetness impregnation method.The combination of plasma and the Mn/γ-Al2O3 catalysts significantly enhanced the degradation efficiency of tetracycline hydrochloride compared to the plasma process alone,with the 10% Mn/γ-Al2O3 catalyst exhibiting the best tetracycline hydrochloride degradation efficiency.A maximum degradation efficiency of 99.3% can be achieved after 5 min oxidation and a discharge power of 1.3 W,with only 69.7% by a single plasma process.The highest energy yield of the plasma-catalytic process is 91.7 g kWh-1.Probable reaction mechanisms of the plasma-catalytic removal of tetracycline hydrochloride were also proposed.

Porous g-C3N4 with enhanced adsorption and visible-light photocatalytic performance for removing aqueous dyes and tetracycline hydrochloride

Porous g-C3N4samples were obtained by simply calcining bulk g-C3N4in static air in a muffle oven.The photocatalytic performance of these samples was evaluated through the removal of aqueous organic dyes（methylene blue and methyl orange）and tetracycline hydrochloride under visible-light irradiation（λ〉420 nm）.Compared to bulk g-C3N4,porous g-C3N4exhibited much better capability for removing these contaminants,especially under visible-light irradiation,due to the enlarged specific surface area and more efficient separation of photogenerated charge carries.In particular,porous g-C3N4obtained by calcining bulk g-C3N4in air at 525℃ showed the highest visible-light-driven catalytic activity among these samples.Superoxide radical anions（·O2^-）were found to be the primary active species responsible for photodegradation.

Preparation and Characterization of Sulfated Cellulose Nanocrystalline and its Composite Membrane for Removal of Tetracycline Hydrochloride in Water

The removal of antibiotic pollutants remaining in the environmental media has been a big challenge nowadays.Herein,we report a facile and green approach to fabricate an eco-friendly composite membrane without addition of any toxic polymers or chemical cross-linking agents to effectively remove the tetracycline hydrochloride in Water.Firstly,the sulfated cellulose nanocrystalline(CNC) was obtained via hydrolysis of sulfuric acid by using microcrystalline cellulose(MCC) as raw material under ultrasonic condition.The as-prepared CNC has a nanowhisker dimension with 200.2 ± 110.2 nm in length,15.7 ± 9.3 nm in width,and 7.2 ± 3.1 nm in height.The obtained CNC is cellulose type I as determined by X-ray diffraction(XRD),while its crystallinity index(Crl) can reach 82.3%.Then,the composite membrane derived from the obtained CNC and commercial mixed cellulose ester(MCE)membrane was facilely prepared through vacuum dewatering process,which is applied to remove tetracycline hydrochloride(Th) in solution.The results showed that the removal efficiency of Th through the neat MCE was only28 ± 4%,while it could be improved to 58 ± 5% and 89 11%,respectively,by filtering through composite membranes with different contents of CNC deposition.Such effect is derived from the combine factors based on both steric hindrance(sieving) and electrostatic interaction(Donnan) effect of the composite membranes.The development of related CNC materials and composite fabrication processes is in favor of cost-effective and "green"polymer composites for the remediation of increasing antibiotic pollution and the purification of contaminated water nowadays.

Using Goethite as a Heterogeneous Fenton Catalyst for The Removal of Tetracycline Hydrochloride: Effects of Its Adsorptive and Reductive Activities

The removal of the antibiotic compound tetracycline hydrochloride (TC) was investigated by using goethite/H2O2 as a heterogeneous Fenton reagent. Five principle operational parameters, especially solution pH value, were taken into account to investigate how the heterogeneous Fenton process factors mediated the TC removal. This process was effective but seriously impacted by the pH value and temperature, as well as the dosages of α-FeOOH, TC and H2O2. Very interestingly, the acidic and alkaline aqueous medium conditions were both very favorable due to the occurrence of transformation of Fe(III) to Fe(II) on goethite surfaces reduced by TC at pH 3.0~4.0 even though with a low adsorption capacity of TC because its maximum adsorption of negatively charged form occurred at pH around 8.0[1], thereby greatly promoting the TC Fenton oxidative elimination. However, a rapid initial TC decay was observed at the first 5 min, followed by a much slower retardation stage, which was likely because the reductive transformation of Fe(III) to Fe(II) by TC in the solution was inhibited as the Fenton reaction proceeded. Moreover, the hydroxyl radical scavenger t-butanol addition can decrease the removal rate of TC in the goethite/H2O2 system to a certain extent. This further indicated that the main reactive species in this process were hydroxyl radicals[2]. All the goethite-catalysed heterogeneous Fenton reactions are responsible for the TC removal following the Langmuir-Hinshelwood model, were well fitted to pseudo-first order kinetics (R2】0.99), and their apparent activation energy (E) for this Fenton-like reaction was 31.86 kJ mol 1, a low value that is highly consistent with the ease of TC decay greatly enhanced by the temperature rise, indicated that the interfacial controlling interactions such as a proton induced solubilization and a reductive dissolution of goethite can clearly improve its Fenton catalytic activity[3], and these dissolution processes may not be effective in some cases, while the TC adsorption process may always play an important role to control the TC removal rate during the Fenton reaction.

Photocatalytic Performance of α- and β-Ga_2O_3 for the Degradation of Tetracycline Hydrochloride in Water

α- and β-Ga2O3 were prepared via a precipitation method. The as-prepared α- and β-Ga2O3 were characterized by X-ray diffraction （XRD）, N2-sorption BET surface area, UV-vis diffuse reflectance spectra （DRS）, photoluminescence spectroscopy （PL） and electron spin resonancespectroscopy （ESR）. The photocatalytic activities of Ga2O3 were evaluated by the photocatalytic degradation of tetracycline sydrochloride solution. The results showed that the photocatalytic activity of β-Ga2O3 was higher than that of α-Ga2O3 and β-Ga2O3 obtained at the calcination temperature of 900℃, which showed the best photocatalytic activity. The reasons for the differences in photocatalytic activity of Ga2O3 are discussed in terms of crystallinity, surface area, crystals and electronic structures.

Low Molecular Weight Poly(Lactide-<i>co</i>-Caprolactone) for Tissue Adhesion and Tetracycline Hydrochloride Controlled Release in Wound Management

The use of biopolymers as bioadhesives for human tissue is becoming a preferred alternative to suturing due to their superior adhesive, biocompatible, and biodegradable properties. In this work, low molecular weight poly(L-lactide-co-ε-caprolactone) (P(LA-co-CL) was synthesized to achieve the glass transition temperature (Tg) of the copolymer at ambient temperature so that during application on the skin, the copolymer when combined with chitosan (CHI) into the CHI/P(LA-co-CL) film could provide the strong support at the injury site. Using alcohols with different numbers of hydroxyl groups as the co-initiator in polymerization provided the distinctive characteristics of copolymers. Among all copolymers synthesized, P(LA-co-CL) copolymer using pentaerythritol as the co-initiator when combined with CHI at the ratio of copolymer/CHI at 70/30 yielded the good film properties in tissue adhesion and tetracycline hydrochloride release.

乳液静电纺制备PCL/TCH图案化纳米纤维膜

为解决药物突释问题,实现药物的有效包埋和长效释放,设计了具有稳定皮芯结构的图案化微纳米纤维膜,用于药物控释领域。采用乳液静电纺丝技术,将盐酸四环素(TCH)作为模型药物,以聚己内酯(PCL)/六氟异丙醇(HFIP)作为油相、TCH/水溶液作为水相进行纺丝并优化工艺参数,使盐酸四环素(TCH)在纺丝过程中保持性能稳定并能够持续释放。同时,探究图案化对纳米纤维膜的力学性能、载药能力和TCH在体外释放性能的影响。结果表明:当药物质量分数为2%时,纺丝乳液的液滴均匀性较好,液滴的平均直径为0.65μm,制备的纤维形貌均匀连续,平均直径为200 nm,药物累计释放率达到了52.15%;图案化纤维膜具有良好的柔韧性和延展性,断裂伸长率从78.65%提高到98.96%,载药能力和TCH在体外释放性能均有所提升,药物累计释放率从52.15%提高到65.60%。该研究表明,通过乳液静电纺丝技术,可以将模型药物TCH包裹在PCL的内部,有效改善PCL/TCH纤维膜的药物释放性能,同时图案化可进一步提高机械性能。因此,通过乳液静电纺制备的PCL/TCH图案化纳米纤维膜在医疗敷料方面具备一定的应用前景。

含盐酸四环素α-TCP骨水泥的理化性能

对含有盐酸四环素的α TCP骨水泥的理化性能进行了研究。盐酸四环素吸附和同钙离子螯合而结合到磷酸钙晶体表面,从而对磷酸钙骨水泥的水化过程产生影响。研究结果表明,盐酸四环素的加入一定程度上延长了骨水泥的凝结时间,但XRD分析显示并不影响α TCP的最终的转化;同时改变了骨水泥固化体的晶体形貌和微结构,使形成的羟基磷灰石晶体由原来发散的针状晶转变为相互交织的条状和层状晶,这种晶体形貌的改变在一定盐酸四环素含量的条件下明显提高了骨水泥的抗压强度。

盐酸四环素/α-TCP骨水泥载药体系的体外释放研究

对盐酸四环素 /磷酸钙骨水泥药物释放体系进行了体外释放研究。 XRD分析结果表明 ,一定含量的盐酸四环素的存在不会影响 α- TCP的水化。在体外释放实验中 ,各种药物含量的载药体系均表现出了良好的缓释性能 ,持续释放时间超过 12 0 0 h;由于盐酸四环素同磷酸钙的吸附与结合 ,当药物在体系中的含量发生改变时 ,释放控制机理发生改变。当抗生素在固相中含量较大时 ,药物释放速率以扩散控制为主 ,药物释放量满足时间平方根关系 ;当药物含量较低时 ,在释放前期 ,药物释放速率仍然以扩散控制为主 ;释放后期 。

降脂颗粒对四环素致脂肪肝小鼠血清ALT、AST及肝组织TG、TC水平的影响

目的:观察降脂颗粒对四环素致脂肪肝小鼠模型血清ALT、AST及肝组织TG、TC水平的影响。方法:将80只昆明种小鼠随机分为7组。各用药组给予相应药物,日1次,连续11d,从第8天起,除空白组外,各组小鼠均腹腔注射0.25mmol/kg四环素,共4d。末次给药后1h,处死小鼠,行生化和病理学检测。结果:①降脂颗粒能明显降低四环素致脂肪肝小鼠的肝脏指数,以降脂颗粒高剂量组为最好;②除模型组外,各用药组均可改善肝功能,以降脂颗粒高剂量组为最佳;③模型组小鼠肝脏TG、TC明显增高,各用药组均能降低肝组织TG、TC水平,以降脂颗粒高剂量组为最好。结论:降脂颗粒能明显降低由四环素所引起的小鼠血清ALT、AST及肝组织TG、TC水平的升高,改善脂肪变性,降低肝脏炎症反应,对四环素致脂肪肝小鼠的肝脏及炎症有较好的治疗作用。

Cu-Mn-EFBC的制备及其对水中TCH的吸附机理研究

为实现农业废弃物废菌棒(EF)资源化利用,使用CuCl_(2)·2H_(2)O和KMnO4对低温制备的EF生物炭(EFBC)进行改性,制备出铜锰改性EFBC(Cu-Mn-EFBC),对其进行了SEM、BET、XRD、FTIR、Zeta电位和EA表征分析,并研究了制备条件和反应条件对Cu-Mn-EFBC吸附水中盐酸四环素(TCH)的影响及机理。结果表明:Cu-Mn-EFBC对水中TCH的去除率为90.03%,远高于EFBC对TCH的去除率(21.44%);生物炭的投加量和离子强度对吸附影响较小,溶液pH值影响较大;拟二级动力学方程和Freundlich方程可更好地拟合吸附过程。吸附机理主要为阳离子-π作用、π-π相互作用、氢键作用和络合反应。