Tunable hollow mesoporous organosilica for efficient adsorption of heavy metal ions from water

Abstract

A new multi-shelled hollow mesoporous organosilica (M-HPMO) bearing thiol moieties on dual surfaces of the pore has been prepared. M-HPMO exhibits simultaneous removal of Hg(II), Cr(VI), and Pb(II) from water with fast adsorption kinetics (C₀ = 320 mg L⁻¹, equilibrium within 5 min) and ultrahigh adsorption capacities of 990.19, 877.19, and 826.45 mg g⁻¹, respectively. Variation of pore parameters and the composition in M-HPMO reveals that the well-defined pore structure makes abundant thiol sites on multiple shells available for coordination with metals, contributing to highly efficient adsorption. Furthermore, the stability of the framework structure enables M-HPMO to resist wear and tear and maintain ideal adsorption capacity even after multiple cycles. Coupled with excellent adsorption selectivity and in-depth treatment of trace ions, M-HPMO will surely play an important role in practical water treatment in future.