Thiol functionalization of short channel SBA-15 through a safe, mild and facile method and application for the removal of mercury (II)

Abstract

To avoid the dangerous operational conditions, shorten the preparation time and improve the adsorption performance of common mesoporous SBA-15, a highly ordered short channel SBA-15 was successfully functionalized with thiol group (SH) by a safe, mild and facile hydrothermal method without the addition of any acetone or toluene. The as-prepared thiol functionalized SBA-15-SH material was characterized by various means and applied for the removal of heavy metal of mercury (Hg(II)) from aqueous solution. The results indicated that the preparation process of thiol functionalization of SBA-15 was greatly shortened from 24–48 h to about 15 h. The adsorption of heavy metal Hg(II) with prepared SBA-15-SH material presented a high adsorption capacity of 195.6 mg/g at pH of 8 and had a good correlation with the pseudo-second-order and Freundlich models. Moreover, the removal process of Hg(II) was endothermic and spontaneous. The characterization of SBA-15-SH material before and after adsorption showed that the chemical combination of thiol and Hg(II) ions through covalent bond and electrostatic attraction were the main removal way of Hg(II). The good reusability, economy and hydrothermal stability further displayed that the resultant SBA-15-SH material can be a promising adsorbent for the removal of heavy metals from aqueous solution in practical application.