Iron-incorporated mesoporous silica for enhanced adsorption of tetracycline in aqueous solution

Fe-incorporated SBA15 (Fe-SBA15) with different contents of Fe(III) was synthesized in order to enhance the adsorption of antibiotic tetracycline (TC) from aqueous solution. The influence of the Fe(III) content on the structural, textural and morphological properties of the adsorbents and the adsorption process of TC were investigated. The results showed that the adsorbents exhibited mesoporous structural order after co-condensation with different ratios of Fe/Si. As the Fe/Si ratio increased from 0.02 to 0.1, the Fe(III) incorporated into the mesoporous silica framework offered abundant active sites for the adsorption of TC. The adsorption behavior was systematically studied and the results showed that Fe-SBA15 had higher adsorption capacity for TC than that of SBA15. The optimized solution pH for the adsorption was around 5.0 to 7.0, and the adsorption was endothermic and spontaneous. The adsorption mechanism mainly involved inner-sphere surface complexes formed between functional groups of TC and the Fe(III) on the adsorbent. The synthesized materials have excellent potential as adsorbents for environmental remediation.