Rapid and efficient removal of microcystins by ordered mesoporous silica

To alleviate the environmental and health threats from water resources polluted by large-sized microcystins (MCs), we demonstrate for the first time that ordered mesoporous silica materials with large pore sizes of 2-12 nm can be used as adsorbents for rapid and efficient removal of MCs. The obvious correlations between adsorption performance of MCs and physicochemical properties of adsorbents including pore mesostructure, texture and size, and surface chemistry have been well established. Accordingly, an excellent candidate, mesoporous silica SBA-15 templated from Pluronic P123 has been sorted out, exhibiting extremely rapid rate (one minute) as well as high capacities of 5.99 and 13 mg g(-1) for removing high-concentration MC-LR and MC-RR, respectively, which are much higher than that of other silica-based adsorbents reported previously. The adsorption performance can be further improved from 50 to 95% at around pH 4 by grafting positively charged and/or hydrophobic groups onto pore surface of SBA-15. Furthermore, thermodynamic and kinetic evaluations provide additional valuable information for a better understanding of the adsorption process. Given the excellent adsorption performance, it is expected that mesoporous silica materials with unique characteristics are attractive for actual applications in removal of MCs from wastewater.