化工学报2015，Vol.66Issue(9)：3705-3711,7.DOI:10.11949/j.issn.0438-1157.20150871
多巴胺包埋磁性 SiO2 固定化漆酶催化去除 4-氯酚
Immobilization of laccase on magnetic SiO2 through dopamine self-polymerization for 4-CP removal
摘要
Abstract
In recent years, laccase has been reported to be successfully immobilized on many different supports. Among them, potential applications of magnetic silica microspheres have been widely investigated for enzyme immobilization and the enzymatic stabilities can improve obviously. However, to the best of our knowledge, there is no report for the laccase immobilization on silica coated nanoparticles via one-step dopamine (DA) self-polymerization method, and nor any reports concerned with the degradation performance of paraphlorophenol (4-CP) by this immobilized laccase. In this work, the immobilized laccase on silica-coated magnetic nanoparticles were prepared through dopamine (DA) in situ entrapment, and then the immobilized laccase was applied for 4-chlorophenol (4-CP) removal. Briefly, the silica-coated magnetic nanoparticles were prepared through a sol-gel method, then the mixture of Fe3O4@SiO2 nanoparticles and DA was added to PBS (pH 6.0) containing laccase, the reaction was performed for 18 h at 25℃ with vigorous stirring, and was separated by an external magnetic field. After being washed 4 times, the product (Fe3O4@SiO2-PDA-Lac) was obtained. The scanning electron microscope images and size distribution analysis indicated that Fe3O4@SiO2 had a spherical and uniform size distribution with the average diameter of about 134 nm. The high saturation magnetization of Fe3O4@SiO2 made it easily to be separated from the reaction system. The results of X-ray diffraction (XRD) revealed that the prepared samples were Fe3O4 nanoparticles and Fe3O4@SiO2 nanoparticles. The preparing conditions of the Fe3O4@SiO2-PDA-Lac were optimized by orthogonal experiment. In the best level, the total activity recovery of the Fe3O4@SiO2-PDA-Lac can reach to 43.28%. In the degradation process, the effects of laccase concentration, solution pH and ABTS mediator on the removal efficiency of 4-CP were investigated. The results showed that when solution pH was 6 and laccase concentration was 1.2 U·ml?1, 95% percentage of 4-CP was removed within 8 h enzymatic catalysis. When 50 μmol·L?1 of ABTS was added in the reaction system, the removal efficiency of 4-CP kept about 99% within 10 min enzymatic catalysis, which certified that the ABTS as a mediator could enhance the enzymatic reaction rate of the immobilized laccase. After degraded 10 times by the immobilized laccase, the removal efficiency of 4-CP still remained 67%, which exhibited an excellent reusability and operational stability.关键词
磁性纳米颗粒/漆酶/固定化/催化/降解/氯酚/废水Key words
magnetic nanoparticle/laccase/immobilization/catalysis/degradation/chlorophenol/wastewater分类
资源环境引用本文复制引用
张笛,邓满凤,赵赫,曹宏斌,张松平..多巴胺包埋磁性 SiO2 固定化漆酶催化去除 4-氯酚[J].化工学报,2015,66(9):3705-3711,7.基金项目
国家自然科学基金项目(51378487,51108441).supported by the National Natural Science Foundation of China (51378487, 51108441). （51378487,51108441）
