负载型纳米Bi2WO6/AC的制备及在可见光下降解邻硝基苯酚

采用水热法在160℃条件下以活性炭(AC)为载体合成了光催化剂Bi2WO6/AC,用X射线衍射仪(XRD)、电子扫描电镜(SEM)对催化剂进行了表征.同时,以邻硝基苯酚为目标污染物,在可见光照射下,讨论了催化剂用量、溶液的pH、污染物初始浓度等因素对催化剂光催化活性的影响.结果表明,当[Bi2WO6/AC]=5 g·L-1、pH=5[邻硝基苯酚]0=100 mg·L-1时,催化剂可见光降解活性最好,60 min后邻硝基苯酚的降解率可达到99.81%.     

利用太阳光与固定床型光反应器处理有机废水的研究

自制了一种模拟工业处理废水的光催化反应器。该反应器将TiO2固定在玻璃板上，以太阳光为光源，以邻氯苯酚为处理对象，研究了邻氯苯酚水溶液光降解的可行性。结果表明，在实验条件下，该系统能对邻氯苯酚水溶液进行有效的光解。光照60分钟后．其降解率可达87％。此外还探讨了流速、邻氯苯酚溶液初始浓度和初始pH值对光解反应的影响。     

酶催化氧化处理含酚废水的研究

考察了不同反应条件对酶催化氧化效率的影响。结果表明,对于苯酚、邻氯苯酚和邻氨基酚三种单一含酚废水的处理,当pH接近中性时,酚的去除率最高,分别为75％、95％和62％。在低温(4℃)和高温(40℃)下,苯酚废水和苯酚-邻氯苯酚-邻氨基酚混合废水的酚去除率下降约10％。在处理中不同的酚类物间存在明显的协同效应。     

高铁氧化去除饮用水中邻氯苯酚的研究

采用自制的固体高铁酸钾作为氧化剂，研究高铁对水中微量邻氯苯酚的去除效果及主要影响因素。结果表明，当水中邻氯苯酚的含量为4mg/L时，加入60mg/L的K2FeO4氧化处理10min，对邻氯苯酚的去除率可达99．3％。取得高铁酸钾对邻氯苯酚的最佳氧化去除效果的pH范围为9－10，高铁氧化邻氯苯酚近似的二级动力学反应。     

静电纺丝制备TiO2／PAN纳米纤维毡及其性能研究

采用超声波水解技术水解TiCl4制备纳米TiO2粒子,与聚丙烯腈（PAN）的N,N-二甲基甲酰胺（DMF）溶液共混后,通过静电纺丝制得具有光催化活性的TiO2／PAN纳米纤维毡,并用其对模拟废水中苯酚进行光催化降解实验。X射线衍射（XRD）表征结果显示制备的TiO2为锐钛矿。用场发射扫描电镜（FE—sEM）观察纤维毡的形态,显示纤维的直径随纺丝液浓度增大而增大。对苯酚进行光催化降解结果表明：纺丝液浓度质量分数为5％TiO2／PAN纤维毡对苯酚的降解率最高,对100mg／L,50mg／L和20mg／L苯酚的降解率分别为51．1％,87．5％和99．6％。纤维毡循环使用5次后对于20mg／L苯酚的降解率为87．4％。     

对硫磷分子印迹膜传感器的制备及识别特性

用电聚合的方法在金电极上制备了以对硫磷为模板分子的自组装邻氨基硫酚分子印迹膜传感器.在含有5 mmol/L对硫磷模板分子、5mmol/L四丁基高氯酸铵支持电解质和30 mmol/L邻氨基硫酚的二氯甲烷的聚合液中于-0.3～1.4 V范围内循环伏安扫描30圈即得到邻氨基硫酚印迹聚合膜.结合在印迹膜上的对硫磷模板分子用0.5 mol/L HCl溶液超声20 min洗脱.循环伏安法用于电化学检测.当富集时间为10 min,磷酸盐缓冲溶液的pH=6.8时,在1.0×10-4～5.0×10-7mol/L浓度范围内与对硫磷还原峰电流成良好的线性关系,检测下限为2.0×10～mol/L.用分子印迹膜传感器对实际样品进行分析,回收率为98.0%～104%.印迹膜传感器和非印迹膜传感器对一系列与对硫磷相近似的化合物如甲基对硫磷、对氧磷、辛硫磷、氧乐果、硝基苯及邻、间、对硝基苯酚进行检测,该传感器对对硫磷具有良好的选择性和灵敏度.     

酚类化合物在活性炭纤维上的竞争吸附

文章探讨邻甲苯酚，对甲苯酚以及2．4-二甲基苯酚在活性炭纤维上的吸附行为．并应甩理想吸附溶液理论(IAST)分别对其双组份体系和多组份体系的竞争吸附规律进行描述。结果表明．Freundlish公式能较好地描述酚类化合物在活性炭纤维上的吸附行为：当有机物的物理和化学性质相差不大时．其分子结构是影响其吸附行为的重要因素；IAST能较好地预测酚类化合物在活性炭纤维上的竞争吸附行为，但对于有氧条件下聚合作用较强的化合物如邻甲苯酚等．LAST的预测值和实测值之间存在着一定的偏差。     

2-烯丙基苯酚在液相中的光化学降解研究

以太阳光和紫外灯为光源研究了 2 烯丙基苯酚在溶液相中的光化学降解 .太阳光下 ,2 烯丙基苯酚在甲醇、正己烷、重蒸水以及不同pH的缓冲溶液中的光稳定性很强 ,但在丙酮中可以光解 ,10 4mg·L-1 的 2 烯丙基苯酚在丙酮中的光解半衰期为 36 4h .核黄素、过氧化氢、三氯化铁能加快 2 烯丙基苯酚在水溶液中的光解速率 ,其中核黄素的敏化效果最显著 .在紫外光照下 ,2 烯丙基苯酚在各种溶剂中光解迅速 ,速率遵循一级动力学方程 ;水中溶解物质对其光解有一定的抑制作用 ;在pH=9的缓冲溶液中的光解速率 >pH =7的缓冲溶液中的光解速率 >pH =4的缓冲溶液中的光解速度 ;紫外光照 2h ,2 烯丙基苯酚在甲醇中的主要光降解产物经GC MS和LC MS鉴定为 :2 ,4 ,5 三羟基苯甲醛、邻羟基苯乙酸甲酯、对烯丙基苯酚、2 甲基苯并二氢呋喃     

分散絮凝法去除废水中邻氯苯酚的试验研究

采用表面活性剂(吐温-20和0.5%的十二烷基苯磺酸钠溶液)作分散剂、三氯化铁作絮凝剂,对废水中邻氯苯酚的去除进行了试验研究,探讨了絮凝pH值、分散剂用量及絮凝剂用量等因素对处理效果的影响.试验结果表明:在最佳条件下,处理质量分数为1.0%的邻氯苯酚废水去除率可达88.6%;加入分散剂,可有效提高三氯化铁絮凝剂对邻氯苯酚的去除率.     

单歧藻富集和降解烷基酚类化合物的动力学过程

选择单歧藻(Tolypothrix)研究其对苯酚、邻甲酚、间甲酚和4-辛基酚的生物富集过程及生物降解动力学。5d内单歧藻的生长经历了停滞期、对数期、静止期3个阶段;苯酚、邻甲酚、间甲酚、4-辛基酚的生物富集因子(BCF)平均值为4 59,3 87,5 82,292 48,与KOW值线性相关;单歧藻平均每天降解苯酚、邻甲酚、间甲酚、4-辛基酚分别为2 54,3 17,1 84,0 16mg L;用新近提出的二级反应动力学方程拟合其降解过程,得到它们的生物降解二次动力学常数K分别为0 386,0 500,0 254,0 023,K值由污染物的初始浓度决定并与分子量(M)线性相关,K=-0 003M+0 69,R=0 87,N=4。      

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.