固定化辣根过氧化物酶催化去除五氯酚

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。

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

Researches on the removal of PCP by free HRP with the existence of H₂O₂ 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 0.05u/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 polyacrylamide 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.