Mining Ag+ ions from wastewater with Bio-MOF-1: From adsorption to high value-added application

Abstract

In this work, Bio-MOF-1 was adopted to remove and recover the Ag+ ions in the corresponding wastewater, which exhibited excellent Ag+ ions adsorption ability with adsorption capacity up to 655.3 mg/g. The adsorption kinetics, isotherm and thermodynamic parameters confirmed the adsorption process was dominated by multilayer chemisorption. The Ag+ ions adsorption behavior over Bio-MOF-1 was spontaneous, exothermic and orderly. In addition, Bio-MOF-1 displayed efficiently selective sorption toward Ag+ with the presence of the co-existence ions (including Cu2+, Ni2+, Co2+, Zn2+, Pd2+, Cd2+, Pt2+ and Au3+), in which the selective sorption efficiency could reach > 99.9% toward Ag+ with the distribution coefficients up to 1.4 × 107 mL/g. The possible adsorption mechanism of Bio-MOF-1 towards Ag+ mainly involved ion exchange, electrostatic and coordinative interactions, which was further analyzed by both experimental determination and Density Functional Theory (DFT) calculations. In particular, the Bio-MOF-1 adsorptively saturated with Ag+ could be used as the antimicrobial agent for long time (40.0 h) inhibition of the Escherichia coli (E. coli) growth. This work proposed and affirmed the possibility that mining resource was recovered from wastewater to produce the highly valued products.