Applications of HRP-immobilized catalytic beads to the removal of 2,4-dichlorophenol from wastewater

Abstract

2,4-Dichlorophenol, as a highly toxic pollutant, widely exists in wastewater discharged from several industries. In this work, the use of immobilized horseradish peroxidase for 2,4-dichlorophenol removal from wastewater was investigated. Sodium hydroxide and hydrochloric acid treated PAN-based beads were modified with ethanediamine and chitosan, and then were activated with glutaraldehyde. The enzyme was immobilized onto the activated beads by covalent crosslinking. The surface of the immobilized bead was observed using EDX (SEM) and FTIR. The removal of 2,4-dichlorophenol has been studied using immobilized beads in beakers equipped with magnetic stirrer. Optimum pH of the free and immobilized enzyme were determined as 6.0 and 7.0 respectively, and the optimum ratio of hydrogen peroxide to 2,4-dichlorophenol is 1. The experimental results showed that about 90% of the 2,4-dichlorophenol was removed by the enzyme-immobilized capsules, and the immobilized enzyme had a lower efficiency in the removal of 2,4-dichlorophenol in comparison with the free enzyme. However, the immobilized beads have shown good operational stability.