Laccase-Functionalized Hexagonal Boron Nitride-Coated Sponges for the Removal and Degradation of Anthracene

Abstract

Superhydrophobic porous materials, for instance, sponges, membranes, and meshes, have attracted great attention due to their ability for adsorption of organic solvents, hydrocarbons, and oils while repelling water. In this work, we report an organic-solvent-free, environmentally benign, and cost-effective preparation method of a bifunctional adsorbent using a melamine sponge coated with few-layer hexagonal boron nitride nanosheets (hBNNs) functionalized with laccase (LA). The hBNNs are used as a building block for immobilizing and stabilizing LA for the removal and degradation of anthracene, a polycyclic aromatic hydrocarbon in crude oil, and to convert them to lighter and less-toxic substances. The physiochemical properties and performance of the sponges for the removal and degradation of anthracene were investigated thoroughly. The highest hydrocarbon degradation of 89% was obtained at an LA concentration of 2.72 mg/mL and pH 7, after 72 h. The degradation increased to 91% after 7 days of functionalized sponge exposure to the medium. Moreover, the functionalized sponges’ reusability studies revealed that the anthracene degradation efficiency was still as high as 54% after the hBNN–polyethylene oxide–LA sponges were repeatedly used 5 times. The strategy proposed for the fabrication of these sponges is facile and easy to scale up, not requiring the use of a complicated process or expensive equipment. These nano-engineered sponges are promising candidates for the separation and degradation of oils and hydrocarbons in oil spill remediation applications.