| Environmental hormones, also was called environmental endocrine disruption chemicals, acted as estrogens in human and animal bodies. Most of them were discharged into the environment with the production and the life of the humanity. It had been found that environmental hormones existing in the environment having adverse effects on endocrine systems in human and animals. Of all EDCs, bisphenol A (BPA) was very important one. Due to a widespread use of these products in recent years, BPA has been found to be widely distributed in the environment. Therefore, the development of treatment techniques for the removal of BPA in water is urgently required. The previous studies showed that the various phenolic and azo compounds were degraded by HRP–H2O2 system. so it was an effective method to use HRP degrading waste water. Some correlative work was done:(1) The oxidation capability of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) coupled oxidation of bisphenol-A was investigated. The results showed that the optimal reaction time was 2 h; the optimum temperature was 25°C;the most suitable pH was 6.0; the best molar ratio between BPA and peroxide was 2:1; and the concentration of HRP was 0.5 U·mL-1. Under these conditions, the degradation of BPA reached the maximum level. Through the test, PEG-4000 was screened out to be the best additives, which can clearly enhanced BPA degradation. The kinetics of reaction was studied under the optimum conditions. The Michaelis constant of the enzyme reaction is 9.3×10-4 mol·L-1.(2) In this paper, Fe3O4 magnetic fluid were prepared by coprecipitation method, on this basis synthesised of magnetic microspheres by silk fibroin and 3.0G-PAMAM, then immobilizated horseradish peroxidase on magnetic microspheres. Magnetic microspheres were characterized by infrared spectra (FTIR) and SEM. The study on the degradation of bisphenol-A with magnetic immobilized horseradish peroxidase were provided. And made analysis on each influencing factor, such as time, pH, H2O2 concentration and HRP concentration. The result indicated that: the most suitable pH was about 3-9; temperature range to be widened. Reached the same degradation rate, the immobilized enzyme dosage was only half of native enzyme dosage. And even retains 60% relative activity after reused 5 times. The michaelis constant km of immobilized enzyme was 2.0×10-4 mol·L-1, is less than 9.3×10-4 mol·L-1 of native enzyme.(3) Bisphenol-A (BPA) was oxidized by using a membraneless electrochemical reactor with immobilized HRP. The optimum condition for the electrogeneration of H2O2 was investigated. During these experiments, when the catholyte was 30 mL of 0.1 mol·L-1 PBS (pH=5) saturated with oxygen at a flow rate of 30 mL·min-1, the optimum applied potential for the in situ electrogeneration of H2O2 was1.6 V. Below 1.6 V, the relative activity of HRP maintained at 0.95 compared to the initial activity. Under the optimum condition, the highest degradation efficiency of bisphenol-A was obtained at pH 5 and 25°C. Different methods for the degradation of BPA were examined. From the results, a higher degradation efficiency was obtained by using the electroenzymatic method, it can reach 79%.
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