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

Abstract

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.

Immobilization of horseradish peroxidase on modified PAN‐based membranes for the removal of phenol from buffer solutions

“…From the figure, the immobilized horseradish peroxidase was capable of removing phenol maximally at pH 6.0 (pH 5.0 for free enzyme), and the immobilized enzyme could remove a higher percentage of phenol over a wide range of buffers of varying pH, compared to free enzyme. The reason for this difference may be that many amino acid groups and/or the active centres were bared because of the changes in the structures of the immobilized enzyme . In addition, the removal efficiency of phenol decreased inordinately at other pH levels.…”

“…In light of the serious effects on health and environment, removing phenols from high‐strength phenolic wastewater is of great importance. Horseradish peroxidase, a widely researched enzyme, has been successfully used to remove phenolic compounds (such as phenol, p‐chlorophenol, 2,4‐dichlorophenol) from different solutions . HRP possesses a heme cofactor with a distal and proximal histidine on either side, and it catalyzes the oxidatives of phenolic compounds to their corresponding oligomers and insoluble polymers when activated by H 2 O 2 .…”

Hemin-bound cysteinyl bolaamphiphile self-assembly as a horseradish peroxidase-mimetic catalyst

“…10 Thus, the maximum catalytic activity at pH 7.0 suggests that the optimal performance was not due to an enhanced substrate activity or hemin activation, but is indicative of the HRP-like character of the prepared catalyst, which is consistent with the optimal pH of HRP (6.0-7.2). [24][25][26] The pH-dependent activity of the HRP-mimetic catalyst suggests the anionic cysteinate coordination to Fe(III) of hemin, which is common for many metalloproteins. 21 Under acidic conditions, the cysteinate is protonated to form neutral cysteine that weakly binds Fe(III).…”

Applications of Biocatalysts for Sustainable Oxidation of Phenolic Pollutants: A Review

“…Hence, a combination of chemical and enzymatic wastewater remediation methods was also shown to be effective in further increasing the efficiency of individual treatment approaches, and completely detoxifying and removing different recalcitrant pollutants from the various effluents. Some studies suggested that homogenous enzymes are more efficient than heterogeneous reaction systems [150], while other investigations reported an opposite observation [126]. These differences in the obtained results might be according to various operating conditions (i.e., enzyme concentration, treatment time and source of enzyme) used in these two studies.…”