Ethanedithiol-modified silica nanoparticles for selective removal of Hg2+ ions from aqueous wastewater

Abstract

A mesoporous silica nanoparticle was synthesized by incorporating (3-glycidoxypropyl trimethoxysilane (GPTS)) via sol-gel co-condensation method using Pluronic P123 as structure directing agent and further reacted with ethanedithiol (ED) by post-surface modification process. To produce ethanedithiol-modified silica nanoparticles, approximately 20 wt% of GPTS was incorporated into the mesoporous silica pore walls by reacting tetraethyl orthosilicate and GPTS mixture (80:20 wt/wt%). Next, the ethanedithiol groups were introduced onto the silica surface by reacting with the epoxy part of GPTS and thiol groups of ED to produce the ED-modified-mesoporous silica adsorbent (MS-ED NPs) material. The synthesized MS-ED NPs show a high surface area, pore size, and mesopore volume of approximately 556 m2/g, 2.7 nm, and 0.052 cm3/g, respectively. The MS-ED NPs showed selective removal of mercury ions (Hg2+) ions from the aqueous solution in the presence of other competitive metal ions with an adsorption amount of ∼168 mg/g with a removal capacity of approximately >90 % from the initial metal ion solutions (100 mg/L). The produced MS-ED NPs can be reusable up to 5 times by treating the metal-adsorbed MS-ED NPs in an acidic (0.1 M HCl) aqueous solution. Hence, the MS-ED NPs could be utilized to selectively remove Hg2+ ions from aqueous wastewater.