水产品中微囊藻毒素检测方法的研究进展

微囊藻毒素是蓝藻暴发中出现频率最高、产生量最大和造成危害最严重的藻毒素,具有多器官毒性、遗传毒性和致癌性。水产品中微囊藻毒素的残留会对人体产生危害,并对我国公众健康构成巨大威胁。因此,水产品中微囊藻毒素的检测和控制变得非常重要,迫切需要建立一种简便、快速、灵敏度较高的检测方法,以对水产品中的微囊藻毒素进行监控。为加强水产品中微囊藻毒素的痕量分析技术研究,对水产品中残留的微囊藻毒素开展监测,综述了国内外有关水产品中微囊藻毒素污染检测的提取、净化及分析技术进展。     

物化作用氧化降解PFOA/PFOS

全氟辛/磺酸（PFOX）具有环境持久、耐氧化、抗常规化学处理的特点。目前,针对PFOX的有效去除工艺研究已成为环境技术领域有机污染物降解方向的新热点。近年来,一些强氧化工艺被开发用于降解PFOX,主要通过各种物理作用增强化学氧化能力,实现PFOX的有效降解。本文综述了纯化学过程以及光、电、热、声、等离子体、微波、机械力等物理作用促进化学氧化降解PFOX的反应机理、降解途径和各因素的影响机制,以及去除效率和能耗等,介绍了该方向的最新研究进展,讨论分析了这些技术存在的问题,并提出了今后技术应用的重点研究方向。     

活性碳纤维阴极电芬顿反应降解微囊藻毒素研究

以具有高比表面积的活性碳纤维作为阴极,通过电芬顿反应降解水中微囊藻毒素(MCRR,MCLR)的电化学方法系统考察了电流密度、pH值和Fe2+浓度等因素对微囊藻毒素降解效果的影响.实验结果表明,在Fe2+浓度为1.0mmol/L和电流密度为6.6mA/cm2条件下,电化学处理60min,MCRR(8.81mg/L)去除率为75%,MCLR(6.36mg/L)去除率为94%.证明过氧化氢可以通过电化学还原在活性碳纤维阴极表面高效产生,微囊藻毒素可被高效降解去除.     

蓝藻水华衍生的微囊藻毒素污染及其对水生生物的生态毒理学研究

富营养化导致的蓝藻水华频发,引发各种衍生物污染,严重时造成重大生态灾害事件,甚至危及人类健康。其中微囊藻毒素以其毒性大、分布广和结构稳定的特点,成为水环境中常见的潜在危害物质,它主要由微囊藻产生,是一类具有多种异构体的环状七肽物质。本文根据微囊藻毒素污染现状及其水生生态毒理学研究的最新研究进展,介绍了微囊藻毒素的理化性质及其产生、迁移和转化,在我国天然水体、水库源水和饮用水中的污染现状以及部分水产品中的微囊藻毒素累积情况,较全面地评述了微囊藻毒素的分子致毒机理以及对水生生态系统的重要组成成分--常见水生植物和鱼类的生态毒理学效应,并提出了该领域未来研究的主要方向。     

微囊藻毒素在单波长紫外光照射下的光降解动态研究

研究了两种微囊藻毒素在两种紫外光照射下的光降解行为,研究结果表明:UV-C是降解微囊藻毒素较好的光源;光照强度是影响毒素降解重要的因素,其次是温度和酸度;在UV-C的照射下,水体腐殖质对光降解具有抑制作用;微囊藻毒素的光解反应符合准一级动力学模型.同时本工作还按实际环境水体中毒素的含量水平进行了模拟研究,发现紫外光UV-C对环境水体中低含量的微囊藻毒素具有很强的去除能力.为今后发展无毒、高效、经济实用的饮用水处理技术做了有益的探索.     

新型功能材料在藻毒素萃取中的应用进展

藻毒素为有害藻类所产生的次级代谢产物,具有毒性强、种类多和生物蓄积性等特点,对人类健康、水产养殖业以及水生生态系统都会造成严重的威胁,已成为当前全球范围的研究热点。由于藻毒素在样品中的含量很低、样品基质复杂等因素,在仪器分析前进行有效的样品前处理不可或缺。高效的样品前处理技术不但能够减小或去除样品基质对分析的干扰,而且可以实现目标物的富集,增加分析方法的灵敏度与准确性。近年来,固相萃取(SPE)、固相微萃取(SPME)、磁性固相萃取(MSPE)、分散固相萃取(DSPE)、吸管尖端固相萃取(PT-SPE)等样品前处理技术已在藻毒素分离分析领域广受关注。这些前处理技术性能的好坏主要取决于萃取材料的特性。由于藻毒素的理化特性各不相同,在分子尺寸、亲疏水性、电荷等性质上差异较大,合理设计并制备适合藻毒素萃取的材料十分必要。最佳的萃取材料必须实现对藻毒素的可逆吸附,并且最好具有多孔结构和高的比表面积,从而能够提供高的回收率和与藻毒素良好的界面接触。此外,萃取材料还应该在样品溶液、洗脱溶剂、工作pH范围内具有良好的化学稳定性,否则萃取材料可能会溶解或丢失其官能团。本文综述了近十几年来国内外关于藻毒...     

超高效液相色谱-四极杆-飞行时间质谱法快速测定水产品中微囊藻毒素和节球藻毒素

通过超声提取、固相萃取纯化、超高效液相色谱-四极杆-飞行时间质谱(UPLC-Q-TOF-MS)联用技术快速测定水产品中的微囊藻毒素-RR、-YR、-LR和节球藻毒素.分别采用选择离子监测质荷比(m/z)为519.84、1045.66、995.67、825.54分子离子峰进行定量分析.该法检出限为5.0～10.0μg/kg,在浓度0.02～5mg/kg的范围内,峰面积与样品浓度呈良好线性关系;4种藻毒素的回收率为76.2％～93.7％,相对标准偏差为2.0％～7.1％.采用上述方法对45个太湖水产品样品进行测定,发现有少量水产品中存在藻毒素污染,其中微囊藻毒素-RR最高含量为15.2μg/kg,微囊藻毒素-LR最高含量为0.84μg/kg,MC-YR、节球藻毒素均未检出.此方法可作为监测水产品体内蓄积藻毒素的分析方法.     

藻类去除水体中重金属的机理及应用

重金属污染水体的修复,以及含重金属工业废水的处理关乎地球上生物的健康发展。利用低耗能、高修复效率、环境友好、适用范围广泛的藻类去除水体中的重金属,已越来越受到研究者的关注。本文综述了国内外藻类去除水体中重金属的研究进展。分析了藻类去除重金属的生化结构;重点阐述了藻类吸附及富集重金属的机理;讨论了活藻体和死亡藻体用于水体中重金属去除的应用及影响因素,并比较了两者的适用范围及筛选标准;最后指出此领域尚存在的问题,展望了藻类去除重金属的未来发展方向。     

还原-氧化协同降解全/多卤代有机污染物

全/多卤代有机污染物大多具有生态毒性、生物蓄积性、环境持久性及长距离迁移性,不仅危害环境与生态安全,而且可经食物链传递威胁人类健康。由于卤原子是吸电子基团且取代数目多,这类物质的最高占据分子轨道能较低,难于被氧化降解,相反较易被还原法脱卤降解。随卤原子取代数减少,脱卤产物难被进一步还原,而其毒性甚至高于母体污染物。注意到低卤代有机物更容易发生氧化降解,一些研究构建了还原-氧化接力降解体系,即先利用还原法将全/多卤代有机污染物还原为低卤代产物,再利用氧化法降解这些中间产物,从而实现深度/完全脱卤和矿化。本文根据催化反应类型对还原-氧化联用法进行了归纳,分类介绍了基于传统化学催化、光催化、电化学、光电化学及机械化学等构建还原-氧化协同降解体系的原理及应用,以期为开发高效的处置技术提供思路和建议。     

p-n型异质结催化剂Ag2O-BiVO4对微囊藻毒素(MC-RR)的光化学氧化机理研究

微囊藻毒素(MC-RR)是一种具有两个精氨酸结构的微囊藻毒素,它是由蓝藻细菌产生的一种能普遍被检测到的细胞毒素,近来由于其潜在的肝毒性受关注.在可见光(λ≥420 nm)照射条件下,以MC-RR为光催化降解污染物,对BiVO4,Ag-BiVO4,Ag2O-BiVO4和Ag/Ag2O-BiVO4光催化降解性能进行了比较研究.通过HPLC-MS测定了其中间产物,并分析了其可能的降解途径.结果表明,Ag的存在通过构筑p-n异质结光催化剂而提高了Ag/Ag2O-BiVO4的光催化效率.此外,Ag0的存在极大地促进了MC-RR在光催化剂表面上的吸附作用.小鼠的毒理学实验表明,MC-RR经过光催化降解后毒性显着降低.由于水体富营养化形成的蓝绿藻促进微囊藻毒素的形成,这已成为全球关注的问题.被微囊藻毒素污染的饮用水除了会毒害野生动物,家畜和家禽外,还会损害人类肝脏,这也是肝癌的发病率高的原因.毒理学研究发现,微囊藻毒素通过结合到1A(PP1)和2A(PP2)上强烈地抑制蛋白磷酸酶的活性,从而导致肝细胞的损伤,引发原发性肿瘤.目前对光催化降解MC-RR的研究主要集中在紫外光催化氧化领域.采用太阳光中的紫外区或者近紫外区,利用传统的TiO2光催化剂对MC-LR的光催化氧化研究;太阳光中只有极少部分(约4%)的紫外光,大部分(约43%)是可见光,因此,如何将光催化剂的吸收光谱拓宽至可见光区域,提高催化剂对可见光的利用率,进一步提高光催化降解MC-RR的能力,具有一定的理论和实际意义.钒酸铋是一类新型的p型可见光光催化剂,将其与n型半导体Ag2O材料选择性的复合制备出p-n型异质结复合光催化剂能够显著地提高其光催化性能.本文将这种复合光催化剂的应用扩展到广泛检测到的毒素MC-RR的降解中,以实现可见光降解.发现Ag/Ag2O-BiVO4可以在可见光照射下有效光催化降解MC-RR.跟踪其降解中间产物,研究了其可能降解途径,并提出了在异质结催化剂表面上的光催化降解机理.催化剂表征结果表明,Ag2O和BiVO4形成有效的异质结界面,在降解中发挥重要作用.在该异质结结构中,Ag和Ag2O作为电子受体以增强电荷载流子寿命并提高光催化活性.依据MC-RR氧化产物的结构、化学性质和降解体系中所检测到的产物,推测其可能的机理:Ag-Ag2O-BiVO4可见光光催化降解MC-RR是一个涉及到羟基自由基和超氧自由基的共同氧化作用,同时根据液相质谱对中间产物的鉴定,得到MC-RR两条主要的可能降解途径,其中主要涉及到Adda中不饱和碳碳双键和Mdha中烯键的氧化,以及各氨基酸之间肽键的水解.小鼠急性毒理实验表明,经光催化反应后MC-RR的毒性明显减小.     

高级氧化降解饮用水中嗅味物质土臭素和2-甲基异莰醇的研究进展

土嗅素(GSM)和2-甲基异莰醇(2-MIB)是受藻类污染的饮用水源中普遍存在的嗅味物质。常规工艺对GSM和2-MIB的去除能力十分有限,因嗅味问题引发的公众投诉时有发生,嗅味物质的有效去除已成为亟需解决的饮用水处理技术难题。本文梳理了水源中GSM和2-MIB的来源及存在形态,综述了高级氧化法降解GSM和2-MIB的研究进展,旨在为GSM和2-MIB的高效去除提供理论指导和技术支撑。     

Microcystin-LR and chemically degraded microcystin-LR electrochemical oxidation

Microcystins (MCs) are cyclic hepatotoxic heptapeptides produced by certain strains of freshwater cyanobacteria toxic for humans and animals. The electrochemical behaviour of microcystin-LR (MC-LR) at a glassy carbon electrode (GCE) was investigated using cyclic voltammetry (CV), square wave voltammetry (SWV) and differential pulse voltammetry (DPV). The oxidation of MC-LR is a diffusion-controlled irreversible and pH-independent process that occurs with the transfer of only one electron and does not involve the formation of any electroactive oxidation product. Upon incubation in different pH electrolytes, homogeneous degradation of MC-LR in solution was electrochemically detected by the appearance of a new oxidation peak at a lower potential. The electrochemical behaviour of chemically degraded MC-LR is an irreversible, pH-dependent process, and involves the formation of two redox products that undergo reversible oxidation. The formation of degradation products of MC-LR was confirmed by HPLC with UV detection at room temperature. Experiments were also carried out in solutions containing constituent MC-LR amino acids, which enabled the understanding of the MC-LR electron transfer reaction and degradation. An oxidation mechanism for MC-LR is proposed.     

Degradation of iodinated X-ray contrast media by advanced oxidation processes:A literature review with a focus on degradation pathways

Available online Iodinated X-ray contrast media (ICMs) are clinical drugs used to enhance the imaging effect.Triiodobenzene ring structures of ICMs lead to its extremely high chemical stability,biological inertness,which makes it difficult to be completely removed by traditional water treatment processes.Hence,considerable concentration of ICMs can be frequently detected in aquatic environment.Relying on the strong oxidation capacity of HO·or SO4·–,various advanced oxidation processes (AOPs) hav...     

Fundamentals of 2, 4 Dichlorophenoxyacetic Acid Removal from Aqueous Solutions

Herbicides are widely used in farmlands worldwide. However, after their application on farmlands, they accumulate in high amounts in continental and marine waters. Herbicides are endocrine disruptors, and are known to cause toxicity, carcinogenicity and mutagenicity. Besides, they also spoil the taste and odor of water bodies. To prevent these effects, it is necessary to perform an in-depth study on various herbicide removal methods. This review discusses the various methods of herbicide removal from aqueous body, using a commonly used herbicide (2,4-dichlorophenoxyacetic acid) as a representative chemical. This paper includes a systematic tabulated review of all reported removal methods with important parameters and their mechanism. Adsorption, biological degradation, electrochemical treatment, Fenton degradation, oxidation, ozonation and photocatalytic degradation are investigated and compared for removal of 2,4-D. The advantages and disadvantages and the factors influencing selection of the aforementioned processes are discussed.     

钯基氧还原反应电极的构筑及其在水处理领域的研究进展

发展氧气还原反应(ORR)的二电子高效电催化剂一直是燃料电池领域的研究热点,但针对具有二电子还原特征且可应用于水处理领域电极材料的研究还处在起步阶段。本综述介绍了近年来二电子还原特征的贵金属电极材料及其在电催化处理水中污染物的研究进展。在Fe~(2+)存在下,Pd基电极材料催化氧气还原合成H_2O_2,间接催化氧化水中有机污染物,实现有机物的矿化降解和水质的净化;Pd基电极催化还原水中有机污染物、无机盐等,将其转化为低毒性、易处理产物并彻底去除;Pd基催化电极的高效电子传导性能增强了水中重金属离子的氧化/还原转化,实现重金属去除。本综述展望了纳米电极材料在水处理应用的机遇与发展方向。     

应用于水溶液介质中喹啉氧化的电芬顿工艺实验设计方法(英文)

采用碳毡阴极和铂阳极的电芬顿工艺研究了喹啉模型分子8-羟基喹啉硫酸盐（8-HQS）在水溶液介质中的降解行为. 由于电化学诱导芬顿药剂（H2O2,Fe2+）产生大量的羟基活性基（OH）,成为与有机物发生反应直到有机物完全矿化的强有力氧化剂,因此,电芬顿工艺具有很强的氧化能力. 采用正交实验设计确定了水溶液介质中8-HQS降解的操作参数. 结果表明,电流密度和8-HQS的初始浓度是影响降解速度的主要因素. 8-HQS浓度随着电解时间而减少,说明8-HQS的氧化遵循准一级反应动力学. 通过竞争动力学方法确定的由OH引起8-HQS氧化的绝对反应速度常数为1.62×109 mol^-1·L·s^-1. 通过Doehlert 矩阵研究了8-HQS矿化的最佳实验参数,由此确定最佳条件下电芬顿工艺能导致8-HQS在水溶液中的准完全矿化（总有机成分去除率95%）. 对8-HQS水溶液的处理,使得8-HQS矿化前的最终产物为短链羧酸. 同时研究了电芬顿处理中短链羧酸的演变行为. 溶液毒性演变的跟踪研究发现,中间产物的毒性比8-HQS强,但溶液的毒性在中间产物矿化后可以完全消除.     

湿式氧化用于染料废水脱色:过去20年回顾（英文）简

Wet air oxidation (WAO), a liquid phase reaction between organic materials in water and oxygen, is one of the most economical and technologically viable advanced oxidation processes for wastewater treatment, particularly toxic and high organic content wastewater. WAO is the liquid phase oxidation of organics or oxidizable inorganic components at elevated temperatures (125-320℃) and pressures (0.5-20 MPa) using gaseous oxygen (or air) as oxidant. In the past two decades, the WAO process was widely studied and applied in the treatment of dye wastewater. Compared to conventional WAO, catalytic WAO processes have higher efficiency and use moderate reaction conditions. The catalysts included homogenous and heterogeneous types. The key points that need to be solved are recycling of homogenous catalysts and better stability of heterogeneous catalysts. In the present review, the technological processes are first introduced, then some research history and hotspots of WAO research are presented, and finally, its application in the treatment of dye wastewater in the past two decades is summarized to reveal the impressive changes in modes, trends, and conditions used. The application includes model pollutant studies and wastewater tests.     

Inhibition of the toxic byproduct during photocatalytic NO oxidation via La doping in ZnO

It is of a great challenge to develop semiconductor photocatalysts with potential possibilities to simultaneously enhance photocatalytic efficiency and inhibit generation of toxic intermediates.In this study,we developed a facile method to induce the La doping and cationic vacancie(V(Zn))on ZnO for the highly efficient complete NO oxidation.The photocatalytic NO removal efficiency increases from 36.2%to 53,6%.Most importantly,a significant suppressed NO2 production also has been realized.According to the DFT calculations,ESR spectra and in situ FTIR spectra,the introduction of La^3+induce the redistribution of charge carriers in La-ZnO,which promote the production of·O2^- and lead to the formation of V(Zn)for the formation of·OH,contributing to the complete oxidation of NO to nitrate.Besides,the conversion pathway of photocatalytic NO oxidation has been elaborated,This work paves a new way to simultaneously realize the photocatalytic pollutants removal and the inhibition of toxic intermediates generation for efficient and safe air purification.     

The removal of chlorinated organic herbicide in water by gamma-irradiation

In this study, the radiation-induced degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide in aqueous solution was studied under various conditions as a function of irradiation dose in the absence and presence of hydrogen peroxide. The obtained data confirmed that largest yield of radiolytic degradation is obtained in oxidation processes/ionizing radiation, where oxidation is carried out with hydroxyl radicals. For complete degradation of 50?ppm 2,4-D, a required dose was lower in the presence of hydrogen peroxide. The formed major toxic phenolic intermediates were 2,4-dichlorophenol (2,4-DCP) and 4-chlorophenol (4-CP). The chemical analysis of the 2,4-D and the intermediates resulted from the radiolytic degradation were performed using a gas chromatography associated to mass spectrometry (GC?CMS) with ion trap dedector (ITD) and ion chromatography (IC). The formation of chlorophenols in addition to chloride, formaldehyde and carboxylic acids was studied as a function of absorbed dose.     

微生物电化学污水处理技术的优势与挑战

微生物电化学技术（Microbial Electrochemical Technology, MET）最为一种新型水处理工艺,因其具有污染物同步去除和能源化的特点受到广泛重视. 近年来微生物电化学系统（Microbial Electrochemical System, MES）的研究者在其电子传递机理、功能菌群分析、系统功能拓展、低成本材料开发和大型系统构建等方面取得大量进展. 然而该技术作为污水处理工艺的可行性却始终存在争议. 本文从应用角度将MET工艺与现有厌氧、好氧工艺进行对比,分析各工艺在有机物降解和能量回收方面的特点,有助于找到MET工艺在水处理领域中的适宜定位. 相对厌氧与好氧工艺,MET工艺具有低污泥产率,运行过程能量自给以及电流加速污染物去除等优势特征,但在推进MET工艺的实用化进程中仍需进一步简化其系统结构、降低构筑成本、提高运行稳定性,并应基于MET的运行特征确定其适宜的应用范围以发挥MET工艺的技术优势.