A functionalized porous clay heterostructure for heavy metal ion (Hg 2+) trapping

Abstract

A heavy metal ion adsorbent that binds Hg 2+ ions from solution to a capacity of 0.74 mmol/g has been prepared by grafting 3-mercaptopropyltrimethoxysilane to the intragallery framework walls of a porous fluorohectorite clay heterostructure (PCH). Up to 67% of the immobilized thiol groups are accessible for Hg 2+ trapping. This represents a significant improvement over previously reported clay-based ion adsorbents in which pore blockage limits the access of metal ions to fewer than 10% of the complexing sites. The uniform open-framework mesoporosity of PCH materials greatly facilitates access to most of the reactive sites attached to the pore walls. The possible use of PCH materials in future environmental remediation efforts is briefly discussed.