固定化辣根过氧化物酶催化去除五氯酚

Removal of Pentachlorophenol (PCP) by Immobilized Horseradish Peroxidase (HRP)

采用辣根过氧化物酶催化去除模拟废水中的五氯酚,使其形成沉淀;并探讨了影响反应的因素如溶液酸度、酶浓度、五氯酚起始浓度、过氧化氢起始浓度以及温度等.结果表明辣根过氧化物酶去除五氯酚的最佳pH为5～6;去除率随酶浓度增加而增加,在所采用的最高酶浓度0.05u/mL,五氯酚初始浓度为12.6mg/L的情况下,去除率可达70%左右;五氯酚起始浓度对去除率也有一定影响,起始浓度为13.0mg/L时,去除率可达73.7%,而当起始浓度为0.7mg/L时,去除率只有35.7%;过氧化氢与五氯酚反应的摩尔数之比为1:2.此外还采用化学键合法将辣根过氧化物酶固定在聚丙烯酰胺载体上,发现酶活性可保持较长时间,并可反复用于催化去除五氯酚.固定酶去除五氯酚最适pH值与自由酶类似,并且在pH＝5.15条件下,1h内将五氯酚从13.4mg/L去除到4.9mg/L并达到平衡;将固定酶装入反应柱制成酶柱,可多次反复催化五氯酚的反应.

Researches on the removal of PCP by free HRP with the existence of H2 02 were conducted, PCP was measured by safranine-T spectrophotometric method （GB 9803-88）. Results indicated that HRP could effectively oxidate PCP in aqueous solution. Factors, such as acidity, temperature, enzyme activity, and initial concentration of PCP and H2O2, which could influence the oxidation, were studied. Results showed that the optimum pH value for free enzyme was 5-6; relative higher temperature could accelerate the reaction greatly; removal rate increased with the increase of enzyme concentration, and removal rate could reach nearly 70% under the highest enzyme concentration （about 0.05 u/mL） adopted in the experiment; removal rate increased slightly with the increase of initial concentration of PCP; the molar ratio of the reaction between PCP and H2O2 is about 1 ：2. Based on above results, researches on the oxidation of PCP by immobilized HRP were conducted, Firstly, through chemical bonding method, free HRP was immobilized on pelyacrylamide gel prepared by γ ray radiation method; then immobilized HRP was filled into a column, and PCP was successfully oxidated by immobilized HRP column, Finally, results were analyzed and compared with results using free HRP.