Efficient cellulose aerogel biosorbents functionalized by nanosized zero-valent iron: Isotherms, kinetics, thermodynamics and mechanism of tellurium adsorption

Abstract

Fabrication of eco-friendly and efficient biosorbents played a crucial role in adsorbing tellurium from wastewater, yet which was confronted with large obstacles to achieve a high adsorption capacity and biocompatibility simultaneously. Herein, a simple and economical strategy for adsorbing tellurium by nanosized zero-valent iron/ cellulose fiber hybrid aerogel (nZVI/CFA) is proposed. Cellulose fiber aerogel (CFA) was firstly fabricated by freeze-drying the cellulose fibers that were extracted from agricultural waste maize bracts. Then, the nZVI was uniformly anchored on the porous network skeleton structure of CFA by liquid-phase reduction. The nZVI/CFA exhibited mesoporous structure with a large specific surface area (399.85 m2/g), uniform pore size (3.92 nm) and pore volume (0.47 cm3/g). According to the kinetics and isothermal model, the tellurium adsorption by nZVI/CFA was uniform and endothermic-chemical on the monolayer surface. Due to the highly exposed specific surface area, more active sites and the synergistic effect of electrostatic attraction, reduction and substitution, nZVI/CFA has a high adsorption capacity (119.32 mg/g). As a low-cost and efficient biosorbent, nZVI/CFA provided a new idea for the treatment with other abandoned photovoltaic materials and agricultural waste.