四环素类抗生素在土壤环境中的残留及环境行为研究进展

四环素类抗生素因具有预防疾病与促生长作用而被广泛应用于临床与养殖业中,进而会通过各种途径(有机肥施用、污水灌溉)进入土壤,并在土壤环境中长时间累积。在介绍此类抗生素基本性质及结构的基础上,针对此类抗生素在土壤中的残留状况及各种环境行为(吸附和解吸、降解、迁移)进行了论述,并简要概括了其对土壤微生物、动物、植物的危害,重点介绍了四环素类抗生素在土壤中的吸附、降解和淋溶行为及影响因素,以期为这类抗生素带来的生态风险评估及控制提供参考依据。     

四环素类抗生素的去除技术研究进展与展望

四环素类抗生素作为广谱类抗生素广泛用于临床医疗和畜禽水产养殖业,然而抗生素的大量使用、滥用和处理不当,致使环境水体和土壤中被频繁检出,对环境生态系统安全和人类健康构成潜在威胁,因此去除源头和环境中的四环素类抗生素尤为重要。本文介绍了近年来的四环素类抗生素去除技术,包括以吸附为代表的物理法、基于羟基自由基和硫酸盐自由基的高级氧化技术和以生物膜为核心的微生物电化学系统,并分析了影响抗生素去除的关键因素及相关去除机理,最后对四环素类抗生素去除技术进行了展望,旨在为后期的抗生素去除技术研发提供参考。     

SPE-HPLC法测定牛奶中残留的四环素类抗生素

建立了一种简单、高效的同时检测牛奶中四环素(tetracycline,TC),金霉素(chlortetracycline,CTC),强力霉素(doxytetracycline,DC),三种四环素类抗生素(TCs)残留量的方法。首先对牛奶中四环素类药物进行提取,再经多壁碳纳米管做吸附剂的固相萃取柱净化,然后进行高效液相色谱(HPLC)测定。采用Agilent TC-C18柱(250mm×4.6mmi.d,5μm),以甲醇:乙腈(1:3,V/V)混合溶液和0.01mol/L的草酸溶液(4:6,V/V)作为流动相,流速0.7mL/min,检测波长355nm,在十分钟内分离检测三种四环素类抗生素。在线性范围内,相关系数大于0.998;三种四环素类抗生素的平均回收率为88%到95%,相对标准偏差小于5%。     

四环素类抗生素在我国水环境污染现状及其对水生生物的毒性研究进展

综述了近年来我国水环境中四环素类抗生素的污染现状及其对水生生物的毒性效应的研究进展。总体而言,四环素类抗生素在我国的生产和使用量较大且缺乏相应的排放标准,导致四环素类抗生素在我国水环境污染情况严峻;高浓度的四环素类抗生素急性暴露对水生生物具有一定的致死和亚致死效应,在环境浓度长期暴露下会影响水生生物的正常生长。目前对四环素类抗生素生态毒性的研究还有一些不足之处,例如,对四环素类抗生素与其它污染物的联合暴露及其降解产物的毒性的了解有限,尚需更多研究以全面地评价四环素类抗生素在环境中的风险。     

蒙脱石对水中Ni2＋的吸附动力学研究

吸附法是一种常用于去除废水中重金属离子的方法。近年来,对新型吸附剂的探索已成为研究的热点。蒙脱石是一种2：1型的粘土矿物,具有较高的比表面积和较强的吸附能力。本文采用拟实验方法,研究了蒙脱石在常温（293 K）对水溶液中Ni2＋的吸附特性。结果表明,在293 K时,最大饱和吸附容量为153.85 mg/g,蒙脱石对Ni2＋的吸附类型是物理吸附。而二级动力学数据拟合表示（相关系数平方R2=0.999）蒙脱石是一种比较理想的去除Ni2＋的环境矿物材料。     

蒙脱石对水中Ni2+的吸附动力学研究

吸附法是一种常用于去除废水中重金属离子的方法。近年来,对新型吸附剂的探索已成为研究的热点。蒙脱石是一种2:1型的粘土矿物,具有较高的比表面积和较强的吸附能力。本文采用拟实验方法,研究了蒙脱石在常温(293 K)对水溶液中Ni2+的吸附特性。结果表明,在293 K时,最大饱和吸附容量为153.85 mg/g,蒙脱石对Ni2+的吸附类型是物理吸附。而二级动力学数据拟合表示(相关系数平方R2=0.999)蒙脱石是一种比较理想的去除Ni2+的环境矿物材料。     

伊利石对四环素的吸附动力学及热力学研究

对伊利石原矿和采用擦洗分散-离心分选方法选矿提纯后的精矿吸附溶液中四环素的饱和吸附量、吸附动力学和热力学进行了研究,并考察了pH值对四环素在伊利石上吸附效果的影响.结果表明,伊利石原矿与选矿提纯后的伊利石精矿在常温条件下(T=25℃)的饱和吸附量分别为28.11 mg/g与45.37 mg/g;pH值为4～6时伊利石有较好的吸附效果;准二级动力学方程对伊利石吸附四环素分子的过程描述更为准确;伊利石对四环素的等温吸附过程符合Langmuir等温吸附模型,是一个不可逆的自发吸热过程,吸附热力学参数吉布斯自由能(△G0)＜0,焓变(△H0)＞0,熵变(△S0)＞0.     

粉煤灰对水中铜镍的吸附平衡、动力学及机理研究

对粉煤灰样品进行表征,探索了其与铜、镍吸附相关的形态和物化特性,并进行了水中铜、镍的静态吸附实验,用Langmuir、Freundlich和Tenkin方程对吸附等温线进行建模,分析了铜、镍的吸附平衡性质,还进行了吸附动力学研究以描述吸附过程,研究了潜在的吸附速率控制步骤和吸附机理。结果表明,该粉煤灰为规整的球形颗粒和不定形颗粒的混合物,含少量未燃炭颗粒,样品的矿物质组分主要为石英、莫来石、钙长石、赤铁矿、石灰等物相。粉煤灰表面含有的M-O(M为Si或Al或Fe或Ca)官能团对铜、镍的吸附起着主要作用,未燃炭颗粒对吸附也有一定作用。Langmuir等温线方程拟合结果最佳,说明粉煤灰表面结构均匀,对水中铜、镍的吸附属于单分子层吸附。在25℃条件下,粉煤灰对水中铜、镍的最大吸附量分别为34.48 mg/g和15.36 mg/g。准二级动力学模型能很好地描述铜、镍在粉煤灰上的吸附过程,说明化学吸附是吸附速率的控制步骤。     

蒙脱石有机改性对邻苯二甲酸二丁酯吸附的影响

以钠蒙脱石和十六烷基三甲基溴化铵(CTAB)有机改性蒙脱石为吸附剂对水溶液中的邻苯二甲酸二丁酯(DBP)进行了静态吸附对比。考察吸附时间、溶液初始p H等因素对吸附效果的影响,研究了DBP在蒙脱石有机改性前后的两种吸附剂上的吸附机制。结果表明,有机改性后的蒙脱石吸附效果更好,吸附的主要机制是表面吸附,有机改性蒙脱石还存在分配吸附作用。     

氯霉素在活性炭上的吸附平衡与动力学

为去除水体中残留的氯霉素,采用生物相容性佳的活性炭作吸附剂,测定了25,30,35℃下氯霉素在自制活性炭上的吸附平衡与动力学,并与商用竹炭作对比。结果表明高比表面积活性炭是去除水体中残留氯霉素的高效吸附剂,活性炭的吸附容量随着吸附剂比表面积和孔容的增大而增大,但随温度从25,30到35℃升高而减小,自制高比表面积活性炭的吸附容量达到3种市售活性炭样品吸附容量的10倍以上;Freundlich吸附等温线方程可较好地描述氯霉素在活性炭上的吸附平衡,准二级方程是用来描述氯霉素在活性炭上吸附的合适动力学模型,并通过拟合得到了其动力学参数。随着温度的升高吸附容量逐渐减小。本研究为活性炭对水体中残留氯霉素的吸附处理提供了科学依据。     

Adsorption Equilibrium and Kinetics of Toxic Dye-Erythrosine B Adsorption onto Montmorillonite

Erythrosine B is extensively used in the textile and food industry. It is reported to be a neurotoxicant and is carcinogenic in nature. It can induce DNA damage in the gastrointestinal organs even at low doses. In this study, adsorption efficiency of montmorillonite (MMT) has been investigated for the removal of erythrosine B (EB) from aqueous solution. The batch adsorption model was developed to predict the equilibrium adsorption capacity with respect to the pH of the dye solution, contact time, initial dye concentration, and adsorbent dosage. A maximum monolayer adsorption capacity of 578.03 mg/g was obtained at the original pH (7.5) of the aqueous dye solution within 5 minutes of contact time. It was found that the Langmuir adsorption isotherm yielded the most favorable representation of the adsorption behavior of EB. The dye was found to be chemisorbed on the adsorbent as confirmed by the FTIR spectral analysis. Although anionic in nature, the dye was found to be intercalated into the clay interlayers as suggested by the X-ray diffraction studies.     

片状纳米氢氧化镁吸附铅离子吸附平衡与动力学

采用共沉淀法制备片状纳米氢氧化镁,通过XRD、TEM、SEM和BET进行表征.片状纳米氢氧化镁直径大约在100 nm左右.在此基础上,研究片状纳米氢氧化镁对水溶液中铅离子的吸附特性.研究结果表明,片状纳米氢氧化镁对Pb2+的等温吸附符合Langmuir吸附等温式.吸附机理以化学吸附为主,吸附过程是自发的;片状纳米氢氧化镁对Pb2+的吸附动力学符合Lagergren二级吸附动力学模型,吸附过程由膜扩散和颗粒内扩散联合控制.     

Adsorption Equilibrium and Adsorption Kinetics: A Unified Approach

Conventional methods for the characterization of adsorption systems (determination of equilibrium and kinetic parameters) have been discussed. It is shown that the kinetic parameters determined by conventional methods are completely inconsistent with the equilibrium parameters. This inconsistency is due to the application of completely different models for equilibrium and kinetic study. In the present study adsorption is viewed as a Langmuir type physico‐chemical reversible process and a three‐parameter model is proposed which describes an adsorption system from both equilibrium and kinetic viewpoints. The model satisfactorily describes the kinetic and the equilibrium data reported by previous authors.     

Adsorption of Lead by Geomaterial Matrix: Adsorption Equilibrium and Kinetics

Industrial activity generates huge amounts of waste, whose storage can lead to serious problems of groundwater pollution by infiltration of landfill leachates. Geomaterials used as water barriers may be a solution to this problem. This work is devoted to the elaboration of new geomaterials based on Algerian clay, activated carbon, cement, and polymer for containment of stored waste and the study of their performances towards inorganic pollutants. Thus we elaborated a set of three geomaterials GM1, GM2, and GM3 with various clay and activated carbon contents and whose polymer and cement compositions are maintained constant. The higher clay content (80%) was used in preparing GM1.

The retention properties towards lead were assessed by the adsorption isotherms of geomaterials and their minerals constituents. The study of lead adsorption isotherms on geomaterials showed mainly that GM1, with the highest clay and lowest activated carbon contents and with the highest specific surface area, is very effective for trapping lead. Moreover, its adsorption capacity is pH-dependant; the highest Pb²⁺ amount adsorbed is obtained for pH12. On the other hand, it has been shown that the retention of lead is a result of the components contribution: clay, activated carbonm and cement.     

四环素类抗生素微观分子特性的理论研究

采用密度泛函理论(DFT),选用B3LYP/6-311G (d,p)计算水平,对四环素、金霉素、地霉素、多西环素以及土霉素等四环素类抗生素进行理论模拟与计算,并对其结构参数、以及构型全优化后的震动频率、前线分子轨道能级、电荷分布等分子特性进行模拟预测与分析。预期为四环素类抗生素的亲核反应位点研究提供重要的理论依据,为今后对四环素类抗生素分子构型及其微观特性提供重要的理论依据,同时为抗菌谱广、抗菌活性强并具备较好耐药菌抗生素的寻找提供了理论基础。     

Equilibrium,Kinetics, and Thermodynamics of Bovine Serum Albumin Adsorption on Single-Walled Carbon Nanotubes

We investigated the equilibrium, kinetics, and thermodynamics of bovine serum albumin (BSA) adsorption on single-walled carbon nanotubes (SWNTs) from aqueous solutions with different pH and temperatures. We analyzed the experimental adsorption equilibrium and kinetic data to evaluate the adsorption characteristics of SWNTs for BSA. The results show that the effects of pH and temperature were important. Moreover, the adsorption isotherm data of BSA on SWNTs are consistent with the Langmuir and Freundlich models, while the kinetics can be expressed by the pseudo-first-order and the intraparticle diffusion rate models. The maximum protein adsorption capacity of SWNTs, which have a surface area of 191.2 m²/g, was found to be 609.8 mg g^?1 at pH 4 and 40°C, and this was the highest value obtained among our previous studies examined with various metal oxides. In addition, the zeta potential measurements were examined to understand the effects of charge density of the surface and the protein on the adsorption process. Thermodynamic analysis results indicate that the nature of adsorption changes with pH. SWNTs were found to be effective for BSA adsorption.     

四氢呋喃水溶液在3Å分子筛上的吸附平衡与动力学研究

研究了四氢呋喃水溶液在间歇搅拌槽内3 A分子筛上的吸附平衡和动力学,用Langmuir方程拟合了吸附等温线,并用粒内表面扩散模型和Langmuir方程对吸附动力学曲线进行拟合.求取了表面扩散系数Ds,并研究了温度、初始浓度和粒径的变化对Ds的影响.Ds在25℃下C0为6.5%、dp为1 46～1.97mm时为7.83×10-7(cm2·s-1),并随着温度的升高及随着浓度的加大而增加,但不受粒径变化的影响.此外还求取了表面扩散指前因子Dso为1.85×10-5(cm2·s-1)和不同浓度下的活化能E.     

蒙脱石对胰岛素吸附行为的研究

以胰岛素为模型药物、钠基蒙脱石为载体材料,在一定条件下制备出胰岛素/蒙脱石(INS/MMT)复合物,并通过X射线衍射(XRD)、红外光谱(FT-IR)和热重(TGA)等分析表征手段对该复合物进行表征.结果表明,胰岛素确实插层进入了钠基蒙脱石的片层,但由于分子体积太小,胰岛素对钠基蒙脱石层间距的影响并不显著.