Novel sulfhydryl functionalized covalent organic frameworks for ultra-trace Hg2+ removal from aqueous solution

Two kinds of novel sulfhydryl functionalized covalent organic frameworks were fabricated as adsorbents for the removal of ultra-trace concentrations of Hg(2+)from water. The two kinds of sulfhydryl functionalized covalent organic frameworks were obtained via a thiol-ene click reaction between the thiol groups of trithiocyanuric acid (TTC) or bismuththiol (BMT) and vinyl groups on the surface of covalent organic frameworks. The material structure was characterized by XRD, SEM, EDS, FT-IR, BET, and TG analysis. Due to their rich sulfur content, both adsorbents (COF-SH-1 and COF-SH-2) exhibited a high level of selective Hg2+ removal from aqueous solution with maximum adsorption capacities of 763.4 mg g(-1) and 526.3 mg g(1,) respectively. Furthermore, in the presence of ultra-low concentrations of Hg2+ both materials exhibited excellent performance, achieving rapid Hg2+ removal at concentrations from 10 mu g L-1 to less than 0.02 ng L-1. Analysis of the adsorption mechanism indicates that the sulfur containing chelating groups exhibit a strong binding capacity for Hg2 +. Results show that the structure determines the performance, with the amount of adsorption sites being related to the adsorption capacity. Therefore, as sulfhydryl functionalized covalent organic frameworks contain an abundance of adsorption sites, these materials can effectively achieve the removal of ultra-low trace Hg2+ concentrations and have promising future application potential for the environmental detection of heavy metals. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.

Automated summary

Two novel sulfhydryl functionalized covalent organic frameworks, COF-SH-1 and COF-SH-2, were successfully fabricated for the efficient removal of Hg(2+) from water, showing excellent performance even at ultra-trace concentrations. The high sulfur content in the material structure is crucial for the selective binding of Hg(2+), indicating promising potential for environmental detection of heavy metals.