Immobilization of laccase on chitosan functionalized halloysite nanotubes for degradation of Bisphenol A in aqueous solution: degradation mechanism and mineralization pathway

Autor: Zhaobo Wang, Dajun Ren, Yaohui Cheng, Xiaoqing Zhang, Shuqin Zhang, Wangsheng Chen
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Heliyon, Vol 8, Iss 7, Pp e09919- (2022)
Druh dokumentu: article
ISSN: 2405-8440
DOI: 10.1016/j.heliyon.2022.e09919
Popis: As a hazardous organic chemical raw material, Bisphenol A (BPA) has attracted a great deal of scientific and public attention. In this study, the chitosan functionalized halloysite nanotubes immobilized laccase (lac@CS-HNTs) was prepared by simultaneous adsorption-covalent binding method to remove BPA for the first time. We optimized the preparation of lac@CS-NHTs by controlling one-factor variable method and response surface methodology (RSM). The cubic polynomial regression model via Design-Expert 12 was developed to describe the optimal preparation conditions of immobilized laccase. Under the optimal conditions, lac@CS-NHTs obtained the maximum enzyme activity, and the enzyme loading was as high as 60.10 mg/g. The results of batch removal experiment of BPA showed that under the optimum treatment condition, the BPA removal rate of lac@CS-NHTs, FL and heat-inactivated lac@CS-NHTs was 87.31 %, 60.89 % and 24.54 %, respectively, which indicated that the contribution of biodegradation was greater than adsorption. In addition, the relative activity of lac@CS-NHTs dropped to about 44.24 % after 8 cycles of BPA removal, which demonstrated that lac@CS-NHTs have the potential to reduce costs in practical applications. Finally, the possible degradation mechanism and mineralization pathway of BPA were given via High-performance liquid chromatography (HPLC) analysis and gas chromatography-mass spectrometry (GC-MS) analysis.
Databáze: Directory of Open Access Journals