微生物对芘和苯并[a]芘污染土壤的修复

将枯草芽孢杆菌、白腐真菌和分离筛选菌群分别用于芘和苯并[a]芘污染土壤的修复,比较其修复性能,并对表面活性物剂Tween80和葡萄糖对修复效果的影响规律做了初步探讨.结果表明,60 d时,枯草芽孢杆菌和分离筛选菌修复芘污染的土壤,芘的残留率分别为7.58%±0.59%和8.69%±61.35%,空白残留率为48.18%...     

白腐菌锰过氧化物酶对2,2’,4,4’-四溴联苯醚的降解

多溴联苯醚(PBDEs)是一类在环境中普遍存在的全球性有机污染物,对这类污染物环境行为的研究虽然已有较多报道,但是微生物降解方面尤其是针对单一胞外酶降解的研究还比较少。文章以白腐菌模式菌种Phanerochaete chrysosporium为对象,研究其分泌的胞外酶锰过氧化物酶(MnP)对环境中最常检测到的2,2’,4,4’-四溴联苯醚(BDE47)的好氧降解,考察不同β-环糊精浓度对该酶降解BDE47的影响,并初步探讨了胞内细胞色素P450的作用。结果表明,MnP能有效降解BDE47,在培养15 d后,扣除空白损失,降解率达到70%左右。低浓度和高浓度的环糊精对MnP降解BDE47无显著性影响。胞内细胞色素P450对BDE47的降解没有明显贡献。     

吐温80降解菌的分离及其性能的初步研究

从生活污水污染的土壤中分离纯化得到一株高效降解非离子表面活性剂吐温80的菌株,经鉴定为假单胞菌(Pseudomonassp.),其降解吐温80的最适温度和pH值为30℃和6.5。该菌株在吐温80浓度高于5000mg/L情况下仍然可以旺盛生长。72h内可以将5000m g/L吐温80溶液降解98.6%,使其剩余浓度<70mg/L。     

Effects of microbial inoculations and surfactant levels on biologically- and chemically-assisted phytoremediation of lead-contaminated soil by maize (Zea Mays L.)

Assisted phytoremediation has been widely used for decontamination of potentially toxic elements contaminated soils. A greenhouse experiment was conducted to evaluate the effectiveness of different microbial inoculations and surfactant levels on the phytoremediation of a Pb-polluted calcareous soil by maize. The results showed that application of surfactant increased both root and shoot dry matter yields. Microbial inoculations, however, had no significant effect on the root or shoot dry matter yield. Mean Pb uptake in maize root or shoot increased only following the application of some surfactant levels. Inoculation with microorganisms significantly increased both mean Pb concentration and uptake in maize root but not in maize shoot. Application of 4?mmol surfactant kg?1 along with inoculation with Priformospora indica was effective in increasing Pb phytostabilisation potential. While the application of 2?mmol surfactant kg^?1 along with inoculation with Pseudomonas fluorescens was effective in increasing Pb phytoextraction potential. The fact that the values of translocation efficiencies were low in all treatments, demonstrated the low capability of maize for translocation of Pb from root to shoot. Inoculation with P. fluorescens was the most effective treatment in increasing metal micronutrient uptake. Microbial inoculation and surfactant levels enhanced Pb phytoremediation mostly through phytostabilisation of this metal by maize.     

地下水中Tween80对DNAPL运移和分布的影响

选用地下环境中普遍存在的四氯乙烯（PCE）为典型DNAPLs污染物,建立二维砂箱模型,研究一种人为引入表面活性剂Tween 80对粗砂介质中DNAPLs迁移和分布的影响.测定了含不同浓度Tween 80水溶液/石英砂/PCE三相体系下的液/液界面张力及PCE在石英介质表面的接触角,结果表明PCE在石英砂表面的接触角随着Tween 80浓度的增大而增大,PCE/水的界面张力随着Tween 80浓度的增大而减小,Tween 80浓度在CMC值附近时变化急剧.随后的二维砂箱实验定量描述地下水中表面活性剂Tween 80对PCE的迁移和最终形态的影响.由于Tween 80可以使石英砂介质由水相润湿转变为中间润湿或油相润湿态,相应地在20~30目的粗砂均质介质中Tween 80对DNAPLs迁移存在明显影响.背景溶液中表面活性剂的存在使得DNAPL的垂直运移速度减小,垂向迁移距离减小,最终使得被截留在运移路径上的残留PCE增加.和纯水流情况下相比,地下水中含有表面活性物剂Tween 80时,使得DNPAL污染羽向水流方向偏移减弱,污染羽展布面积与纯水情形下相比,在垂向上均明显减小,并且以较大饱和度残留的DNAPL量增加.     

DNAPL在透镜体及表面活性剂作用下的运移研究

选择四氯乙烯(PCE)作为典型重非水相液体(DNAPLs)污染物,进行PCE在二维砂箱中的运移及修复实验,采用一种改进光透法探讨DNAPL在含不同透镜体非均质含水层中的运移和饱和度分布特性.在此基础上,考察非离子表面活性剂(吐温80)对DNAPL的原位冲洗修复效果.结果表明,在模拟天然地下水流条件下,当PCE运移到达各透镜体时,PCE均未进入透镜体而是在其上方聚集形成污染池,然后逐渐侧向扩散,即使在较粗透镜体(20/30目和40/60目石英砂按 1:1质量比例混合)上也无法进入.吐温80对PCE的修复效果显著,冲洗58h后,94.2%的PCE被去除.表面活性剂的引入能够减小PCE和水的界面张力,界面张力的减小量可达38.8dyn/cm,相应各透镜体上覆界面处的毛细压力水头值会有不同程度的减小,在较粗透镜体上的PCE可以穿透透镜体并继续向下运移.透镜体的毛细截留作用会限制修复后期的修复效率,修复75,3520min的修复效率分别为0.63,0.05g/g,其中较粗透镜体上截留的PCE相对其他较细透镜体容易移出.     

吐温80与氢氧化钠耦合污泥溶胞及生物水解酸化特性研究

采用吐温80与氢氧化钠耦合进行污泥溶胞,当污泥溶胞时间为15min时,污泥上清液中蛋白质与DNA浓度较初始上清液中分别提高了32.5倍和15.8倍,显示细胞壁已得到有效破解,胞内的蛋白质与DNA溶出进入水相。而且,溶胞后污泥的水解酸化过程中挥发性脂肪酸(VFAs)和氨氮产量随着吐温80浓度的增大和酸化时间的延长而增加,这表明吐温80的加入促进了水解酸化菌对蛋白质和碳水化合物的分解。酸化进行24h时,不同条件下系统的pH均达到7.4左右,此后系统进入稳定运行阶段。     

Tween80对黑麦草吸收土壤中2,2′,5,5′-四氯联苯影响

以黑麦草为供试植物,山地褐土为供试土壤,以黑麦草体内2,2',5,5'-四氯联苯含量、土壤中2,2',5,5'-四氯联苯含量为指标,研究了添加表面活性剂Tween80对黑麦草吸收土壤中2,2',5,5'-四氯联苯作用的影响。结果表明,黑麦草对土壤中2,2',5,5'-四氯联苯有较强的吸收。40 d实验后植物吸收到达高峰,此时,土壤中2,2',5,5'-四氯联苯浓度由1045.62 ng/g下降至340.61 ng/g。在添加量为0~20 mg/g范围内,Tween80对黑麦草的生长无明显胁迫或毒害作用,并可显著提高黑麦草对2,2',5,5'-四氯联苯的吸收。当Tween80添加量为1 mg/g时,供试40 d后,黑麦草体内2,2',5,5'-四氯联苯的积累量达到138.22μg/g,是无表面活性剂添加组积累量72.52μg/g的将近2倍。但同时,高Tween80添加量又会抑制黑麦草对2,2',5,5'-四氯联苯的吸收,当Tween80添加量分别为10 mg/g和20 mg/g时,供试40 d后,黑麦草中2,2',5,5'-四氯联苯的积累量比1 mg/g添加量组分别减少了12.80μg/g和17.12μg/g。     

非离子表面活性剂Tween20对菲生物降解的影响

以菲(PHE)为典型多环芳烃(PAHs),利用PAHs优势降解菌,研究了非离子表面活性剂Tween20(TW20)对PAHs类疏水性有机物生物降解过程的影响结果表明,TW20对PHE具有较好的增溶效果;TW20具有很好的生物降解性;不同浓度的TW20存在情况下,降解菌对PHE都有很好的去除效果.TW20可以用于PAHs污染的生物修复.     

Numerical simulation of PAHs sorption/desorption on soil with the influence of Tween80

In this paper, the influences of inionic surfactant Tween80 on polycyclic aromatic hydrocarbons （PAHs） sorption/desorption on artificially contaminated soil were studied, and γ model was applied to simulate the influences. Results showed that, with the use of Tween 80, the sorption behaviors of PAHs on soil altered significantly. Adsorbed Tween 80 increased the sorption amount of PAHs while the dissolved Tween80 increased the apparent solubility of PAHs. These two processes exert influences on the sorption coefficient of PAHs in soil-water system, which can be depicted by apparent sorption coefficient. The partition coefficients （the soil/water partition coefficient of PAHs and surfactants obtained fxom sorption experiments） and statistical parameters used in the amended γ model were obtained in independent experiments. With these parameters, the γ model could provide a satisfactory independent prediction of PAHs release from soil to aqueous phase at two surfactant concentrations.