ABSTRACT
A biocatalytic membrane offers an ideal alternative to the conventional treatment process for the removal of toxic pentachlorophenol (PCP). The limelight of the study is to utilize superparamagnetic iron oxide nanoparticles (SPIONs) incorporated (poly (methyl vinyl ether-alt-maleic acid) (PMVEAMA) and poly (ether - ether) sulfone (PEES)) membrane for immobilization of laccase and its application towards the removal of PCP. In regard to immobilization of Tramates versicolor laccase onto membranes, 5 mM glutaraldehyde with 10 h cross-linking time was employed, yielding 76.92% and 77.96% activity recovery for PEES/PMVEAMA/La and PEES/PMVEAMA/SPIONs/Lac, respectively. In the context of kinetics and stability studies, the immobilized laccase on PEES/PMVEAMA/Lac membrane outperforms the free and PEES/PMVEAMA laccases. At pH 7.0, the free enzyme loses half of its activity, while the immobilized laccases maintained more than 87% of their initial activity even after 480 min. With regard to PCP removal, the removal efficiency of immobilized laccase on the membrane was more than free enzyme. With 100 ppm of PCP, immobilized laccase on PEES/PMVEAMA/SPIONs membrane at pH 4.0 and 50 °C had a removal efficacy of 61.65% in 24 h. Furthermore, to perk up the removal of PCP, the laccase-aided system with mediators was investigated. Amongst, veratryl alcohol displayed 71.04% of PCP removal using immobilized laccase. The reusability of the laccase heightened after immobilization on PEES/PMVEAMA/SPIONs portraying 62.44% of the residual activity with 39.4% of PCP removal even after five cycles. The current investigation reveals the efficacy of the mediator-aided PEES/PMVEAMA/lac membrane system towards removing PCP from the aqueous solution, which can also be proposed for a membrane bioreactor.
