Potential of waste glass to adsorb graphene oxide from aqueous solutions: Mechanisms and behavior

Abstract

Graphene oxide (GO) is commonly used in wastewater treatment owing to its high adsorption efficiency; however, the separation of GO from treated water presents a considerable challenge, causes secondary pollution and poses an enormous threat to organisms and the environment. In this study, waste glass (WG) is employed in the aquatic environment to adsorb GO, and the adsorption mechanism is examined by SEM, TEM, BET, XRD, AFM, FTIR, Raman spectroscopy, XPS and Zeta potential testing methods. The effect of the pH, mass of WG, initial GO concentration, temperature, and adsorption time on the adsorption of GO by WG is examined. The adsorption mechanism included electrostatic interactions, hydrogen bonding and surface complexation. The optimal WG adsorption effect on GO was achieved at a pH, WG mas, GO initial concentration, and temperature of = 3, 40 mg, 80 mg/L, and 313 K, respectively; the corresponding adsorption rate was 95.5 %. An increase in temperature favoured the adsorption reaction. The Freundlich isotherm model more accurately represents the adsorption behavior. The adsorption of GO by WG proceeds via a spontaneous, endothermic multilayer adsorption process. Adsorption equilibrium was attained after 750 min, which was more consistent with the pseudo-second-order kinetic model. WG is highly reusable and stable. This study demonstrates that solid-waste WG can be employed as an inexpensive and highly-efficient adsorbent for the effective and efficient removal of GO from aqueous solutions, providing a reference for water pollution treatment in the environment.