Corncob-supported Ag NPs@ ZIF-8 nanohybrids as multifunction biosorbents for wastewater remediation: Robust adsorption, catalysis and antibacterial activity

Comprehensive utilization of bio-based polymers, such as cellulosic materials, for water purification has drawn intensive attention in recent years. Herein, we demonstrate using cellulose-rich corncob residues as scaffolds for in-situ anchoring Ag NPs decorated ZIF-8 nanohybrids, to fabricate multifunction biosorbents with robust adsorption-catalytic performance and antibacterial activity for the above purpose via a simple 'tea bag' strategy. Results show that upon delignification and TEMPO oxidation, the porous corncob particles have high contents of cellulose fraction and carboxyl groups, with rough surfaces, thus facilitating the anchoring and dispersion of the nanosized ZIF-8s via enhanced coordination. The corncob-supported porous ZIF-8s, loaded with well-dispersed Ag NPs in their matrix, can lead to corncob-based adsorbents (Ag NPs@ ZIF-8s/P-OCBs) with excellent adsorption, catalysis and antibacterial activities. The Ag NPs@ ZIF-8s/P-OCBs biosorbents have very high adsorption capacity, and the catalytic reduction for RhB and MB dyes reach 100% within 10 min, with excellent recyclability. Furthermore, the Ag NPs@ ZIF-8s/P-OCBs exhibit robust inhibition against E. coli and S. aureus (100% of GIB). The green and sustainable strategy developed can broaden the utilization of cellulose-rich agro-wastes for complex wastewater remedies.