Mercury Adsorption on Thiol-Modified Porous Boron Nitride: A Combined Experimental and Theoretical Investigation

Abstract

Heavy metal pollutants from industrial wastewater pose a great threat to public health and ecosystem safety. In this paper, a thiol-modified porous boron nitride (pBN–SH) adsorbent synthesized by a facile acid-etching method was studied for the highly selective adsorption of Hg­(II) in a complex environment. pBN–SH was characterized by X-ray diffraction, thermogravimetric, elemental analysis, Brunauer–Emmett–Teller analysis, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy. The effect of adsorption dosage, pH, contact time, and temperature on Hg­(II) adsorption was comprehensively investigated. Characterized results show that thiol groups are loaded on the surface of pBN through oxygen-containing groups and π–π bond. Due to the abundant structural defects and surface modification of functional groups, pBN–SH can effectively capture Hg­(II) from water. Compared with the pristine pBN, the adsorption capacity of pBN–SH increases significantly by nearly 2.1 times, which suggests broad application prospects of pBN–SH in removing the Hg­(II) aspect. Experimental results corresponding to the pseudo-second-order kinetic, the intra-particle diffusion model, and the Langmuir isotherm demonstrate that pBN–SH holds a high potential in environmental remediation. In addition, the recovered pBN–SH loaded with Hg­(II) waste can be available for a valid catalyst for the conversion of phenylacetylene to acetophenone, providing a new way for the reuse of Hg­(II)-adsorbed materials. Density functional theory calculations revealed that multitudinous defects and thiol functional groups on the pBN–SH surface, electrostatic attraction, and ligand exchange are responsible for the excellent Hg­(II)-selective adsorption capability discovered in the experiment.

Rational design of selective functionalized silica adsorbents for Hg(ii) removal from FGD wastewater. A combined experimental and theoretical study

“…The ab initio calculations were performed using density functional theory (DFT) following the approach described in the literature using the DMol 3 module as part of Dassault Syste `mes Biovia's Material Studio. [48][49][50][51][52][53] The monodentate and bidentate complexes, Hg 2+ (L) and Hg 2+ (L) 2 , where L represents an MPTMS functional group were taken as initial geometries. The functionalized silica surface was represented by a functional group bound to a single cluster of Si(OCH 3 ) 3 to reduce the computational demand required for the DFT calculations.…”