One-pot synthesis of mercapto functionalized Zr-MOFs for the enhanced removal of Hg²⁺ ions from water

Abstract

Mercapto functionalized Zr-MOFs have been developed via a one-pot synthesis for the selective adsorption of Hg2+ ions. Mercaptoacetic acid (MAA) or alpha lipoic acid (ALA) was used as the modulators and functionalized molecules to synthesize mercapto functionalized Zr-MOFs (Zr-MOFs-SH(O)). In comparison with the mercapto functionalized Zr-MOFs via the traditional postsynthetic modification (Zr-MOFs-SH(P)), Zr-MOFs-SH(O) had a much higher content of -SH groups, thus leading to a much higher adsorption capacity for Hg2+ ions. In particular, PCN-224-MAA(O) had an adsorption capacity for Hg2+ ions up to 843.6 mg g-1, which is much higher than that of PCN-224-MAA(P) (138.5 mg g-1). Additionally, PCN-224-MAA(O) can be used to reduce Hg2+ ion concentrations (5-20 μg L-1) in water to the limit acceptable (1 μg L-1) for drinking water. Moreover, PCN-224-MAA(O) also exhibited good selectivity, recyclability, and chemical stability.