Nonwoven Polyethylene Terephthalate Paper Loaded with Enzyme Coupled Multiwall Carbon Nanotubes for Superior Photocatalytic Activity for Water Remediation

Abstract

A highly photocatalytic, carbon coated nonwoven polyethylene terephthalate paper (CCPETP) is developed by using the wet-laid method for photodegradation of dye effluents from the textile wastewater treatment. The designed nonwoven PET paper is coated with Multiwall walled carbon nanotubes (MWCNT) catalyst coupled with cationised enzyme agent. Three different types of enzymatic coupling agents were used i.e. Lipase, Glucose oxidase, and Laccase, respectively. Enzymes are generally globular proteins, packed with amino complex N-terminals, oxygenated amines and hydroxyl atoms. The sequence of the amino acids specifies the structure which in turn determines the catalytic activity of the enzyme. The cationization of the enzyme under acidic condition (∼pH 3), detach the amino/oxygen complex structure from their core structure and encapsulate over MWCNT surface. The coupled enzyme dissipates functional oxygenated amines, pyrrolic, pyridinic, graphitic and quaternary type of nitrogen contents. The attachment of functionalized surface groups without forming any defect-rich vacancy promotes efficient charge generation and photocatalytic degradation of methylene blue dye (MB) particulates. Besides, the suggested low-cost porous PET nonwoven paper helps to absorb a large number of dye molecules for efficient dye degradation. The excellent photocatalytic activity of the proposed thin CCPETP photocatalyst is mainly attributed to its specific coupled enzyme, high adsorbing capacity of PET paper, and low recombination of the photogenerated electrons and holes. The optimal loading content of enzyme coupled MWCNT over nonwoven PET paper decolorized ∼99.0% methylene blue (MB) dye in 100 min. The excellent dye degradation efficiency of this low-cost material is attributed its surface characteristics and high absorbing properties. The synergistic effect of cluster active sites and the functional amine/oxygen surface groups promoting the generation of OH ions for MB degradation. The fabricated nonwoven paper is expected for large industrial applications and will provide a generic route towards the fabrication of textile structured photocatalyst.