Adsorption and removal of Cr(VI) from aqueous solution with amine-functionalized porous boron nitride

Abstract

Heavy metals in water environment do great harm to the life and health of the public and the stability of the ecological environment. Therefore, it is necessary to find an efficient solution to deal with the increasingly serious problem of heavy metal pollution. In this paper, N, N'-methylene bisacrylamide was loaded on porous boron nitride (pBN) surface with a simple synthesis method using 3-aminopropyltriethoxysilane as a coupling agent for the adsorption of Cr(VI). The prepared adsorbents were characterized with XRD, SEM, TEM, FTIR, XPS, BET, and other analytical methods. We discovered that the capacity of pBN-AS@MBA reached 83.78 ​mg/g, which was significantly higher than that of pBN, with an initial concentration of 20 ​mg/L of Cr(VI). Besides, the chemosorption of exothermic spontaneity predominated the entire process, determined from pseudo-second-order kinetics, intra-particle diffusion model, thermodynamics, and Langmuir isotherm. Not only Cr(VI) chemically react with amine groups on the sorbent, but also elicited electrostatic attractions. The reusability of sorbent was proved with a reduction rate of lower than 20%, after a few cycles of running.