Comparison of Adsorption of U(VI) by Magnetic MCM-41, MCM-48 and SBA-15 Mesoporous Silicas

Three types of magnetic mesoporous silicas (MMSs), namely, MMCM-41, MMCM-48 and MSBA-15 were prepared by a hydrothermal method using CTAB and P123 as templates. The structure and physicochemical properties of MMSs were characterized by small angle XRD, VSM, ζ potential analyzer, contact angle measurer, and XPS, etc. The potential applications of MMSs in U(VI) recovery were thoroughly investigated. The adsorptive kinetics, thermodynamics, and selectivity of MMCM-41, MMCM-48 and MSBA-15 were compared. The results show that MSBA-15 revealed a high capacity for U(VI) (341.94 mg·g −1 ) and a superior selectivity than MMCM-41 and MMCM-48. The adsorption mechanism was explored by using the relevant adsorption models and XPS. The results indicated that MSBA-15 could be considered a strong candidate for the adsorption and recovery of U(VI) from radioactive wastewater.