Adsorption of Cu(II) and Cr(III) ions on SBA-15 mesoporous silica functionalized by branched amine

SBA-15 mesoporous silica-bearing branched amine was explored as the adsorbent for the efficient removal of Cu(II) and Cr(III) ions from aqueous solutions. The nanoabsorbent was prepared by the Michael addition of amino-modified SBA-15 with methyl acrylate and subsequent amidation with diethylenetriamine (DETA). Batch tests were performed and the optimal adsorption pH was determined to be 5.0 for Cu(II) and 3.0 for Cr(III). The experimental data showed the adsorption process was well represented by both pseudo-second-order kinetic model and Langmuir isotherm model. According to the Langmuir equation, maximum Cu(II) and Cr(III) adsorption capacities of SBA-15-DETA were 57.5 and 48.3 mg g(-1), respectively, which were much higher than the values of amino-functionalized silica precursor. Furthermore, the adsorbent showed excellent stability and could be readily regenerated by acid treatment without an obvious reduction in adsorption efficiency. Thus, SBA-15-DETA prepared here shows great application prospects for the adsorption and recovery of aqueous heavy metal ions.