Faculty Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, Hubei, China.
School of Environment Studies, China University of Geoscience, Wuhan 430074, Hubei, China.
Chemosphere. 2017 Nov;186:733-742. doi: 10.1016/j.chemosphere.2017.08.039. Epub 2017 Aug 13.
In this work, magnetic FeO was utilized to immobilize horseradish peroxidase (IM-HRP) in order to improve its stability and reusability by crosslinking method process with glutaraldehyde. The physicochemical properties of NHFeO@SiO and IM-HRP were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermo-gravimetric Analysis (TGA) and Transmission electron microscopy (TEM). The thermal stability of immobilized-HRP was considerably improved in comparison with free counterpart. The catalytic performance of IM-HRP for estrogens removal from aqueous solution was evaluated, it was found that the presence of natural organic matters (NOM) have no significant effects on E2 removal and the E2 enzyme-degradation reached around 80% when pH = 7.0 with 0.552 × 10 ratio of IM-HRP/HO In addition, the active radicals responsible for estrogens degradation were identified with electro-spin resonance spectra (ESR). It was found that immobilization process on FeO showed no adverse effects on catalytic performance on HRP, estrogens degradation could be fitted well with pseudo-second kinetic equation. Estrogens degradation efficiency was reduced in the presence of humic substances. Both O and OH were detected in IM-HRP catalyzed HO system and radicals quenching test indicated O played a more important role in estrogens removal. IM-HRP exhibited excellent stability and E2 removal efficiency could reach 45.41% after use seven times. Therefore, HRP enzymes immobilized on NHFeO@SiO by cross-linking method in glutaraldehyde solutions was an effective way to improve stability and reusability of HRP, and which could avoid potential secondary pollution in water environment caused by free HRP after treatment.
在这项工作中，利用磁性 FeO 通过交联法与戊二醛结合固定辣根过氧化物酶（IM-HRP），以提高其稳定性和可重复使用性。通过粉末 X 射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）、热重分析（TGA）和透射电子显微镜（TEM）对 NHFeO@SiO 和 IM-HRP 的物理化学性质进行了表征。与游离 HRP 相比，固定化-HRP 的热稳定性得到了显著提高。评估了 IM-HRP 从水溶液中去除雌激素的催化性能，发现天然有机物（NOM）的存在对 E2 的去除没有显著影响，当 pH=7.0 时，E2 的酶降解率约为 80%，IM-HRP/HO 的比例为 0.552×10。此外，利用电子顺磁共振谱（ESR）鉴定了负责雌激素降解的活性自由基。结果表明，FeO 的固定化过程对 HRP 的催化性能没有不利影响，雌激素的降解可以很好地符合拟二级动力学方程。腐殖质的存在降低了雌激素的降解效率。在 IM-HRP 催化 HO 体系中检测到 O 和 OH，自由基猝灭试验表明 O 在雌激素去除中起更重要的作用。IM-HRP 表现出良好的稳定性，使用七次后 E2 的去除效率可达 45.41%。因此，在戊二醛溶液中通过交联法将 HRP 固定在 NHFeO@SiO 上是提高 HRP 稳定性和可重复使用性的有效方法，并且可以避免处理后游离 HRP 可能在水环境中造成的潜在二次污染。
