Highly Stable Biocatalyst Based On Encapsulating Method For High Performance Azo Dye Removal In Water

Dye has been closely related to human production and life since ancient times.Azo dyes are known as the largest category of synthetic dyes,the chemical structure of azo dye is usually very complex,with anti-microbial,acid,alkali resistance and other characteristics.It is difficult to be natural degradation of the environment,if not properly handled,may be retained in the environment for a long time,posing a great threat to the ecological environment.Therefore,how to safely and efficiently remove dyes from water has become an urgent problem to be solved.In recent years,biological decolorization has been considered as an environmentally friendly method of dye degradation with the diversified development of wastewater treatment process.As a kind of polycopper oxidase,laccase has attracted extensive attention because of its wide range of substrates and high catalytic activity.In this paper,different carriers were used to immobilize laccase in the form of encapsulating.The removal mechanism of methyl orange and methylene blue by the composite material was investigated.The main research contents and results are as follows:(1)In this work,a highly stable biocatalyst was prepared by using laccase and magnetic biochar co-encapsulated in particles(Lac-m BC-PEG).The Lac-m BC-PEG,prepared by the UV assisted emulsion polymerization.The immobilized laccase showed superior p H stability,thermal stability and storage stability than the free laccase。Lac-m BC-PEG can be rapidly separated by magnets in aqueous solution within 3seconds,which have a higher removal capacity for methyl orange than Lac/PEG,due to the addition of m BC.The methyl orange in the water can be absorbed and removed by the Lac-m BC-PEG in a short time(5 min),so that the methyl orange is in full contact with lac enzyme,which then degrades the methyl orange in the Lac-m BC-PEG.The process of the Lac-m BC-PEG discoloration,the degradation of methyl orange by laccase,can be observed with the naked eye.The removal rate of methyl orange remained at a high level after 8 repeated use.Due to the economical,stability and maneuverability,the Lac-m BC-PEG has a great prospect in the removal of methyl orange of environmental waste water.(2)In order to remove methylene blue dye from wastewater,the laccase and biochar encapsulated copper alginate(Lac-BCA)were prepared.Copper alginate is a carrier with good biocompatibility.The experimental results showed that the Lac-BCA could remove 100.0% methylene blue(15 mg/m L)after 8 h,and 94.4% methylene blue could still be removed after five times of reuse.Compared with the free laccase,the Lac-BCA have a wider operating range of p H(3～7)and temperature(10～80 ℃)The relative activity of Lac-BCA could still be 79.4% when stored at 4 ℃ for 15 d.Moreover,due to the addition of highly adsorbent biochar,the removal effect of Lac-BCA on pollutants was further enhanced.This study provides the idea and application prospect for the actual dye wastewater remediation.