Conductive and hydrophobically modified sodium alginate hydrogels for enhanced gaseous para-xylene removal by functional bacteria

Abstract

Hydrogel adsorption for volatile organic compound (VOC) removal shows great potential for application, but the hydrophilic nature of hydrogels, low removal efficiency, and reusability limit the use of hydrogels for VOC removal. Herein, a new conductive bacteria–hydrogel system is reported for the rapid and complete removal of para-xylene (PX). This new system was constructed by combining hydrophobically modified sodium alginate (SA) with bacteria and electron shuttles. In comparison with conventional single hydrogels, this system provides allows hydrogel to adsorb VOCs through the action of hydrophobicity and solves the problem of subsequent treatment after adsorption. Furthermore, the system was designed to be electrically conductive to enhance the removal of PX by bacteria, and it exhibits excellent PX removal without the fear of secondary contamination. Under the synergistic effect of hydrogel adsorption, electrical tension, and electronic mediators, the degrading bacteria that can self-produce surfactants can completely remove 25,830 mg/m3 of PX within 3 h, resulting in a 75% time saving. In addition, the bacteria–hydrogel system is reusable and can maintain the same PX removal effect after three cycles. This work provides a new idea for the treatment of VOCs and the development of amphiphilic hydrogels.