材料期刊网

本文将聚乙烯醇（ PVA）分别与添加剂碳酸钙（ CaCO3）、活性炭（ AC）、二氧化硅（ SiO2）以及海藻酸钠（SA）掺杂，并对大肠杆菌（E． coli）进行包埋，形成4种PVA包埋细菌复合胶体颗粒．同时，采用以铁氰化钾为探针的电化学方法监测被包埋菌体的活性变化，进而对各复合颗粒中的添加剂含量进行择优筛选．在最优条件下，研究各复合颗粒的储藏时间和方式对菌体的活性影响及各种包埋材料的机械稳定性．将筛选出的最优活性下各包埋细菌复合胶体颗粒应用于3，5二氯苯酚（DCP）的毒性检测，其对DCP的灵敏度排序依次为SA＞AC＞CaCO3＞SiO2．因此，以PVA?SA固定微生物的复合胶体颗粒与PVA固定微生物胶体颗粒分别应用于1—5 mg·L－1的乙嘧酚水样的毒性检测，得其抑制率范围分别为6．38％—21．44％和3．21％—16．98％．由此表明，加入添加剂后的PVA固定法对毒物毒性的灵敏度有显著提高，在固定化微生物水质毒性检测领域具有一定的实际应用价值．

In this paper, polyvinyl alcohol (PVA) was doped with calcium carbonate (CaCO3), activated carbon (AC), silica (SiO2) and sodium alginate (SA), respectively. And then these entrapped PVAs were used to embed Escherichia coli ( E. coli) and produce four type of entrapped PVA?bacteria agents. Potassium ferricyanide was used as a probe to monitor the changes of bacterial activities, and the optimum contents of additives were selected based on the results of the above activity tests. Thus the effects of storage, mechanical stability of various composites on the bacterial activities were further studied under the optimum contents of additives. Based on the optimum conditions, embedded bacteria in all 4 types of composites were employed to detect the toxicity of 3, 5 dichlorophenol ( DCP ) . The experimental results showed that the sensitivity of embedded bacteria in different composites to DCP was SA >AC >CaCO3>SiO2 . Therefore, the embedded bacteria in PVA?SA composite and PVA were used seperatiely to detect the toxicities of ethirimol water samples in 1—5 mg·L-1.The obtained ranges of inhibition rate were 6.38%—21.44% for PVA?SA composite embedding bacteria and 3.21%—16.98% for PVA embedding bacteria. These results indicated that the doped additives effectively improved the sensitivity of PVA immobilizing method and provided an alternative for the technique of bacterial immobilization in the field of toxicity test.