School of Chemical Engineering and Technology, Tianjin University, Tianjin, PR China.
Chemosphere. 2011 Mar;83(2):124-30. doi: 10.1016/j.chemosphere.2011.01.014.
A novel horseradish peroxidase (HRP)-catalyzed H₂O₂ process in the presence of reduced nicotinamide adenine dinucleotide (NADH) was applied to remove aqueous pentachlorophenol (PCP). Parameters (pH, H₂O₂ concentration, HRP activity and NADH dosage) on PCP removal were investigated. It was found that initial 0.05mM PCP was removed by 98% in HRP-NADH-H₂O₂ system at pH 5.0 and 30°C for 1h. Addition of O₂ in HRP-NADH-H₂O₂ system enhanced the removal rate of PCP due to promoting hydroxyl radicals (.OH) and superoxide anion radical (.O₂⁻) generation, which were confirmed by electron paramagnetic resonance (EPR)-spin trapping method. PCP removal efficiency decreased when .O₂⁻ and H₂O₂ were scavenged by superoxide dismutase and catalase in HRP-NADH-O₂ system, indicating that .OH/.O₂⁻ played a great role in the degradation of PCP. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that octachlorinated dibenzodioxin (OCDD) in residual solution was reduced after treated by the HRP-NADH-O₂ process, resulting in lower toxicity of treated solution than conventional enzymatic process. Two enzymatic-catalysis pathways were proposed for PCP removal in HRP-NADH-H₂O₂/O₂ system: (i) OH/.O₂⁻ free radical oxidation (ii) conventional phenoxy polymerization.
一种新型辣根过氧化物酶（HRP）-催化的 H₂O₂ 体系在还原型烟酰胺腺嘌呤二核苷酸（NADH）存在下被应用于去除水中的五氯苯酚（PCP）。研究了参数（pH、H₂O₂ 浓度、HRP 活性和 NADH 用量）对 PCP 去除的影响。结果表明，在 pH 值为 5.0 和 30°C 的条件下，HRP-NADH-H₂O₂ 体系中初始浓度为 0.05mM 的 PCP 在 1h 内去除率达到 98%。在 HRP-NADH-H₂O₂ 体系中添加 O₂ 由于促进了羟基自由基（.OH）和超氧阴离子自由基（.O₂⁻）的生成，从而提高了 PCP 的去除率，这通过电子顺磁共振（EPR）-自旋捕获法得到了证实。在 HRP-NADH-O₂ 体系中，O₂⁻和 H₂O₂ 被超氧化物歧化酶和过氧化氢酶清除后，PCP 的去除效率降低，表明.OH/.O₂⁻在 PCP 的降解中起了重要作用。气相色谱-质谱（GC-MS）分析表明，经 HRP-NADH-O₂ 工艺处理后，残留溶液中的八氯二苯并对二恶英（OCDD）减少，处理后溶液的毒性低于传统酶法。提出了 HRP-NADH-H₂O₂/O₂ 体系中 PCP 去除的两种酶催化途径：（i）OH/.O₂⁻自由基氧化（ii）传统的苯氧基聚合。
