纳米TiO_2胶体分离富集水样中痕量镍研究

利用纳米二氧化钛胶体比表面积大,吸附能力强以及吸附离子沉积后又很容易转化为胶体的特点,提出用纳米二氧化钛胶体富集水样中痕量镍。系统研究了胶体纳米二氧化钛对N(iII)的吸附行为,考察了吸附时间、酸度以及共存离子对吸附行为的影响。研究结果表明:在优化条件下,纳米二氧化钛胶体对N(iII)的吸附率可达99%以上。建立了纳米二氧化钛胶体分离富集与火焰原子吸收光谱联用测定水样中痕量镍的方法。该法检出限(3σ)为4.17μg/L,相对标准偏差(RSD)为2.8%;并且由于纳米二氧化钛胶体吸附镍后不需要脱附,分析过程简便、快速;用于实际水样中痕量镍的测定,结果满意。     

Cu暴露条件下翡翠贻贝（Perna viridis）消化腺内金属和类金属硫蛋白的变化

通过室内急性暴露实验研究了翡翠贻贝（Perna viridis）消化腺富集Cu及其MTLP （metallothionein like protein）水平随时间的变化规律.结果表明,2种Cu浓度暴露条件下（12.7 μg/L和63.5 μg/L）,贻贝消化腺内Cu的平均吸收速率分别为2.045和7.028 μg·（g·d）^-1,富集系数分别为2 074和1 619.实验测定了所有样本的溶解态Cu与总Cu含量,2个暴露组二者的比值随时间呈现出不同的变化趋势,低浓度组先降低随后上升到与对照样本几乎相同的水平,而高浓度组一直呈下降趋势,表明不同污染程度生物体内金属消化机制进程存在差异.利用Brdicka极谱法测定了贻贝消化腺内MTLP的含量,对照组贻贝消化腺的MTLP平均含量为（0.551±0.037）mg/g;12.7 μg/L Cu暴露组MTLP含量随时间的变化范围是0.407～0.699 mg/g,而63.5 μg/L Cu暴露组在暴露初始MTLP水平就显著增加（p<0.001）,变化范围由初始0.942 mg/g降至0.826 mg/g.分析结果表明贻贝消化腺内的MTLP水平随着水体及生物体内的金属含量升高而增加,并与体内Cu浓度成明显的负指数增长关系（p<0.000 1）.     

东洞庭湖网箱养殖鲤鱼生长期内重金属的富集特征

于2012年2—7月对东洞庭湖网箱养殖鲤鱼(Cyprinus carpio)按生长期进行样品采集,采用原子吸收分光光度法测定水样和饲料以及鲤鱼鳃、肝脏和肌肉中的重金属含量. 结果表明:鲤鱼生长环境中的水质属于GB 3838—2002《地表水环境质量标准》中Ⅰ类水平,但饲料中重金属质量分数相对较高,成为鲤鱼富集重金属的主要来源. 在鲤鱼生长期内,鱼体内的w(Pb)和w(Cu)均随着鲤鱼的生长而增加. 鲤鱼鳃中Pb未检出,w(Cu)为0.143～0.703mg/kg;肝脏中w(Pb)和w(Cu)分别为0.006～0.181和0.625～6.177mg/kg;肌肉中w(Pb)和w(Cu)分别为nd～0.034和nd～0.161mg/kg. w(Zn)和w(Cd)均随着鲤鱼的生长先增加后下降,在1～4月龄的鲤鱼体内w(Zn)在鳃、肝脏和肌肉中分别从40.121、21.302和2.032mg/kg增至258.964、146.155和18.011mg/kg,w(Cd)则分别从0.015、0.031和0.003mg/kg增至0.078、0.151和0.021mg/kg;4月龄后,w(Zn)在鳃、肝脏和肌肉中逐渐降至173.182、104.219和5.490mg/kg,w(Cd)也降至0.037、0.111和0.018mg/kg. 在鲤鱼生长过程中,肝脏是Pb、Cd和Cu的主要富集部位,鳃是Zn的主要富集部位,肌肉是重金属富集的最弱部位,并且这3个部位间重金属富集的相关性较强.      

碳纳米管负载TiO_2及去除复合重金属废水性能研究

以酸氧化的碳纳米管为载体,通过水热方法合成碳纳米管负载纳米二氧化钛复合物。纳米复合物采用X-射线衍射(XRD)、扫描电镜(SEM)、和比表面积(BET)测定。结果显示,负载在碳纳米管上二氧化钛为锐钛矿型,颗粒粒径在30~60 nm之间。合成样品比表面积为139.5 m~2/g。采用模拟的铅废水以及铅与丁基黄药复合废水为处理对象,对其吸附性能进行研究。当起始铅浓度为50 mg/L,溶液的pH值为5.5,吸附剂投加量为0.5 g/L,吸附时间为30 min的条件下,铅的去除效率为92.2%,饱和吸附量为92.2 mg/g。当起始铅和丁基黄药的浓度分别为50 mg/L和10 mg/L,溶液的pH值为5.5,铅和丁基黄药的去除效率分别为93.2%和99.3%。饱和吸附量为113.0mg/g。     

酵母菌-活性污泥法吸附处理含铬电镀废水的性能

研究了解脂假丝酵母(Candida lipolytica 1977)、产朊假丝酵母(Candida utilis 1225)和活性污泥处理含铬电镀废水的吸附与还原性能.结果表明,解脂假丝酵母对废水的pH适应范围广.当pH=3.2～6.0时,25g/L菌体对电镀废水中30.2 mg/L总铬的去除率达85.0%;对27.7mg/L Cr⁶⁺的还原率高达100%.2株酵母协同处理电镀废水,可以有效的提高铬的生物吸附效率,对30.2 mg/L 总铬的去除率达91.1%.曝气生物吸附法研究结果表明,该法是本研究中处理含铬电镀废水最有效的方法.10g/L酵母菌,5g/L活性污泥处理50.3mg/L 总铬、46.2mg/L Cr⁶⁺水样8h后,去除率达93.8%;而当污泥浓度为10g/L时,去除率高达99.5%.     

不同晶型纳米TiO_2在斑马鱼体内的富集与清除

为探讨纳米材料的慢性生物效应以及材料结构对生物富集的影响,开展了A-TiO2(锐钛型纳米TiO2)和R-TiO2(金红石型纳米TiO2)在斑马鱼(Danio rerio)体内的长期富集和清除试验.采用半静态暴露试验,试验周期为46 d(暴露阶段28 d,清除阶段18 d),每种晶型设置2个处理组(ρ分别为4.0和10.0 mg/L),测定各时间点斑马鱼体内不同晶型纳米TiO2含量(以w计);以暴露阶段的BAF(生物富集系数)以及清除阶段的排出速率常数、总量清除率为终点,比较斑马鱼对2种晶型纳米TiO2的富集、清除的异同.结果表明:在暴露阶段,A-TiO2在斑马鱼体内的富集量显著高于R-TiO2,10.0 mg/L处理组斑马鱼体内富集量均显著高于4.0 mg/L处理组;4.0和10.0 mg/L的A-TiO2处理组的BAF分别为76.7和105.4 L/kg,略高于R-TiO2(41.6和36.1 L/kg),二者在斑马鱼体内均不具有生物蓄积性.在清除阶段,斑马鱼体内的2种晶型的纳米TiO2均可被排出,清除阶段的清除率为88.0%~100%;斑马鱼体内2种晶型纳米TiO2富集量的下降均符合一阶指数衰减方程,排出速率常数在0.26~1.01 d-1之间.     

气态原子化原子吸收分光光度法联用测地面水中铅

本文阐述了氢化发生-原子吸收光谱法测定地面水样中铅的方法研究，该方法线性好（浓度在0.00～20.00μg/L,0.00～40.00μg/L,0.00～80.00μg/L各级范围内直线回归相关系数分别为0.9993,0.9995,0.9997，精密度好（变异系数为1.68～3.16%)，准确度高（回收率为95.0～103.6%）特征浓度为0.53μg/L/1%,本法能快速,简便,灵敏,准确测定地面水样中的铅.     

壬基酚在鱼体组织中的累积及对鱼类性腺的影响

采用HPLC法测定了在一定条件下暴露后鲤鱼和草鱼体内壬基酚的含量和分布,分析了鱼类性腺重量的变化.结果表明,在试验浓度下,20～25d后鲤鱼和草鱼体内的壬基酚可达到累积和释放的动态平衡,其最大累积系数分别为84.3和78.8,累积规律为鲤鱼>草鱼,肝脏>肌肉.受试雌鱼的性腺重量有明显的提高,相当于100ng/L17β-雌二醇(E₂)作用下鱼类性腺重量的34%～41%,表明壬基酚对鱼类具有一定的雌激素活性,且壬基酚的生物累积性和雌激素活性在产生时间和活性数值方面均是同步的和成正相关的.     

微回流分光光度法测定水中化学需氧量的研究

采用美国哈希公司生产的COD测定仪和加热器,用微回流管封闭回流消解水样,对水中化学需氧量的测定方法进行研究.实验结果显示,该方法的准确度和精密度较高,测定结果的相对标准偏差在0.33％～ 2.20％之间,变异系数在0.49％～2.54％之间;检出限较低,采用质量浓度测定范围为3～ 150mg/L的试剂测定水样,检出限为3mg/L;对标准样品及具有代表性的水样测定,结果与国标回流法的测定结果相比没有显著性差异,且结果的相对偏差均在质控要求范围内.     

Cu暴露条件下翡翠贻贝(Perna viridis)消化腺内金属和类金属硫蛋白的变化

通过室内急性暴露实验研究了翡翠贻贝(Perna viridis)消化腺富集Cu及其MTLP(metallothionein like protein)水平随时间的变化规律.结果表明,2种Cu浓度暴露条件下(12.7μg/L和63.5 μg/L),贻贝消化腺内Cu的平均吸收速率分别为2.045和7.028μg/·(g·d)-1,富集系数分别为2 074和1 619.实验测定了所有样本的溶解态Cu与总Cu含量,2个暴露组二者的比值随时间呈现出不同的变化趋势,低浓度组先降低随后上升到与对照样本几乎相同的水平,而高浓度组一直呈下降趋势,表明不同污染程度生物体内金属消化机制进程存在差异.利用Brdicka极谱法测定了贻贝消化腺内MTLP的含量,对照组贻贝消化腺的MTLP平均含量为(0.551±0.037)mg/g;12.7 μg/L Cu暴露组MTLP含量随时间的变化范围是0.407～0.699 mg/g,而63.5 μg/L Cu暴露组在暴露初始MTLP水平就显著增加(p＜0.001),变化范围由初始0.942 mg/g降至0.826 mg/g.分析结果表明贻贝消化腺内的MTLP水平随着水体及生物体内的金属含量升高而增加,并与体内Cu浓度成明显的负指数增长关系(p＜0.0001).     

Effect of sub-acute exposure to TiO2 nanoparticles on oxidative stress and histopathological changes in Juvenile Carp (Cyprinus carpio)

Increasing application of nanotechnology highlights the need to clarify and understand nanotoxicity. Mammalian and in vitro studies have raised concerns about the toxicity of titanium dioxide nanoparticles (TiO2-NPs), but there are limited data on ecotoxicity to aquatic organisms. In this work, the sub-acute toxicity of TiO2-NPs to carp (Cyprinus carpio) was assessed. Superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities and lipid peroxidation (LPO) levels in liver, gill and brain tissues of carps varied with concentration of TiO2-NPs suspensions and exposure time (up to 8 d). As a result, 100 and 200 mg/L TiO2-NPs caused statistically significant decrease in SOD, CAT and POD activities and significant increase in LPO levels in tissues (P < 0.05), suggesting that the fish exposed to these two concentrations of TiO2-NPs su ered from the oxidative stress. The extent of depletion of antioxidant enzymes activities and the elevation of LPO in the liver was the greatest, indicating that the liver might be the most susceptible organ to TiO2-NPs exposure. In addition, carps had gill pathologies including edema and thickening of gill lamellae as well as gill filaments, and liver pathologies including necrotic and apoptosis hepatocytes after exposed to 100 and 200 mg/L TiO2-NPs for 20 d. These results indicated a potential risk from TiO2-NPs released into the aqueous environment.     

Accumulation and elimination of iron oxide nanomaterials in zebrafish (Danio rerio) upon chronic aqueous exposure

A 52-day continuous semi-static waterborne exposure (test media renewed daily) regimen was employed to investigate the accumulation and elimination profiles of two iron oxide nanomaterials (nano-Fe₂O₃ and nano-Fe₃O₄) in zebrafish (Danio rerio). Adult zebrafish were exposed to nanomaterial suspensions with initial concentrations of 4.0 and 10.0 mg/L for 28 days and then were moved to clean water for 24 days to perform the elimination experiment. Fe content was measured in fish body and feces to provide data on accumulation and elimination of the two iron oxide nanomaterials in zebrafish. The experiment revealed that: (1) high accumulation of nano-Fe₂O₃ and nano-Fe₃O₄ were found in zebrafish, with maximum Fe contents, respectively, of 1.32 and 1.25 mg/g for 4.0 mg/L treatment groups and 1.15 and 0.90 mg/g for 10.0 mg/L treatment groups; (2) accumulated nanoparticles in zebrafish can be eliminated efficiently (the decrease of body burden of Fe conforms to a first-order decay equation) when fish were moved to nanoparticle-free water, and the elimination rates ranged from 86% to 100% by 24 days post-exposure; and (3) according to analysis of Fe content in fish excrement in the elimination phase, iron oxide nanomaterials may be adsorbed via the gastrointestinal tract, and stored for more than 12 days.     

孤东水库水体富营养化评价及其生态控制研究

对孤东水库水生物状况进行系统调查和水体富营养状态进行评价,在此基础上,提出了生态修复技术,通过理论计算与试验确定草食性和滤食性鱼类的投放量,并进行了围格试验.结果表明,孤东水库菹草优势度达80%,浮游植物量为22,32mg/L,单位面积上的总磷浓度是0.310 g/(m<'2>·a),水体处于富营养化状态,通过保持孤东水库鲢、鳙鱼的水体生物量在19-25 g/m<'3>左右,在9月藻类繁殖高峰期,生物量由14.6 mg/L降为3 mg/L.总磷、总氮和高锰酸盐指数年均值分别由生态控制前的0.06 mg/L、3.06 mg/L和4.42 mg/L降为0.03 mg/L、1.58 mg/L和3.73 mg/L,水库水质改善效果明显,同时下游水厂的单方水药耗也由生态控制前的42g/rn3降至25g/m<'3>.试验证明,通过采用合理投放草食性和滤食性鱼类的生态修复技术,可以有效控制水库富营养化状态,并取得显著的社会、经济效益.     

鲢鱅鲴混养对水环境及氮素迁移转化的影响

利用¹⁵N稳定同位素技术研究混养细鳞斜颌鲴对鲢鱅鱼水环境及氮素迁移转化的影响.结果显示：实验期间,鲴鲢鱅组各营养盐浓度经过短暂升高后迅速降低,实验结束时,TN,TP,NO₃^--N,NO₂^--N,PO₄^3--P浓度分别达到2.67,0.13,0.93,0.026,0.0035mg/L,鲢鱅组各营养盐浓度总体保持增长趋势并于第10d后显著大于鲴鲢鱅组相应值（P<0.05）,到实验结束分别为鲴鲢鱅组的1.80,1.69,1.73,1.72,1.83倍.与对照组相比,有鱼组的叶绿素浓度Chla和藻细胞密度明显下降,到实验结束,鲢鱅组的Chla和藻细胞密度分别为34.69mg/m³,1.96×10⁶cells/L,鲴鲢鱅组分别为25.32mg/m³,1.9×10⁶cells/L,均显著低于对照组（P<0.05）.同位素分析结果显示：标记物¹⁵N微囊藻进入系统后,部分被鲢鱅鱼摄食同化为机体组成部分,再通过鱼类分泌,排泄等方式进入水体,水体中含氮营养盐被藻类生长吸收,此外,一部分微囊藻沉淀和鱼类排泄物作为沉积腐质被鲴鱼摄食同化为其机体组成部分.     

Trophic transfer of mercury and methylmercury in an aquatic ecosystem impacted by municipal sewage effluents in Beijing,China

Gaobeidian Lake, located in Beijing, China, serves as a recipient lake for efluents from a large municipal sewage treatment plant (MSTP). In order to evaluate the effects of discharging MSTP efluent on the mercury contamination of the local aquatic ecosystem, sediment cores, water, plankton, fish, and turtle samples were collected from Gaobeidian Lake for mercury speciation analysis. High concentrations of total mercury (T-Hg) were detected in sediment cores (5.24–17.0 μg/g dry weight (dw), average: 10.1 μg/g). The ratio of methylmercury (MeHg) to T-Hg was less than 0.3% in sediments and ranged from 35% to 76% in biota samples. The highest level of T-Hg and MeHg were found in aquatic bryophyte and crucian carp (3673 and 437 ng/g dw, respectively). The relative contents of MeHg were significantly correlated with trophic levels (R2 = 0.5506, p 0.001), which confirmed that MeHg can be bio-transferred and biomagnified via food chain in this aquatic ecosystem.     

Trophic transfer of mercury and methylmercury in an aquatic ecosystem impacted by municipal sewage e uents in Beijing, China

Gaobeidian Lake, located in Beijing, China, serves as a recipient lake for e uents from a large municipal sewage treatment plant (MSTP). In order to evaluate the e ects of discharging MSTP e uent on the mercury contamination of the local aquatic ecosystem, sediment cores, water, plankton, fish, and turtle samples were collected from Gaobeidian Lake for mercury speciation analysis. High concentrations of total mercury (T-Hg) were detected in sediment cores (5.24–17.0 g/g dry weight (dw), average: 10.1 g/g). The ratio of methylmercury (MeHg) to T-Hg was less than 0.3% in sediments and ranged from 35% to 76% in biota samples. The highest level of T-Hg and MeHg were found in aquatic bryophyte and crucian carp (3673 and 437 ng/g dw, respectively). The relative contents of MeHg were significantly correlated with trophic levels (R2 = 0.5506, p < 0.001), which confirmed that MeHg can be bio-transferred and biomagnified via food chain in this aquatic ecosystem.     

3,5-二硝基水杨酸表面修饰纳米Ti2吸附对硝基苯酚

化学吸附法合成3,5-二硝基水杨酸表面修饰的TiO₂纳米粒子,TiO₂表面修饰后呈浅黄色,TiO₂表面羟基与3,5-二硝基水杨酸发生类似于醇和酸间的酯化反应.表层链接有苯环,极性减弱,非极性增强,在水、苯、乙醇中均分散性良好,与芳香族污染物的亲合力增强,有利于吸附去除芳香族污染物.表面修饰的TiO₂纳米粒子20mg,在最佳吸附pH值3、吸附时间10min,对100mL对硝基苯酚(3～10 mg/L)的吸附率可由改性前的43%增至99.9%.该法吸附效率高,可直接达到一级排放标准,提供了深度处理对硝基苯酚废水的新方法.     

广东电子垃圾污染区水体底层鱼类对PCBs的富集效应

采用GC/MS分析方法测试了广东电子垃圾回收地水体沉积物中多氯联苯(PCBs)含量,并利用以前测定的底栖性鱼类(鲮鱼、鲫鱼和乌鳢)PCBs含量数据,计算了生物/沉积物富集因子(BSAF)和生物放大因子(BMF),研究底栖性鱼类对PCBs的富集能力及其影响因素.研究表明,沉积物中总PCBs含量达到24.5~38.6μg/g干重,证实当地环境已受到PCBs严重污染.鲮鱼、鲫鱼和乌鳢的BSAF范围分别为0.05~2.52、0.01~1.20和0.01~5.03.根据乌鳢/鲮鱼和乌鳢/鲫鱼食物关系计算的BMF范围分别为0.14~2.23和0.14~4.93, 其中大部分PCB同系物的BMF>1,表明乌鳢对PCBs具有生物放大作用.BSAF及BMF均与PCBs的KOW和氯原子取代数具有显著相关性,说明化合物的理化性质是控制其生物富集的主要因素.     

纳米二氧化钛光催化降解造纸废水的试验研究

以廉价的无机盐四氯化钛为原料,采用溶胶-凝胶法制备出纳米TiO2粉末作为光催化剂,在高压汞灯的光源照射下对河北省某造纸厂废水进行了光催化降解.考察了TiO2光催化剂的热处理温度、用量、pH值、反应时间等因素对废水COD降解率的影响.研究表明:经460℃热处理1 h的Ti02光催化效果较好,在COD浓度300 mg/L,...