Granulation of gibbsite with inorganic binder and its ability to adsorb Mo(VI) from aqueous solution

摘要

In this study, we prepared a new adsorbent and evaluated its ability to adsorb Mo(VI). Gibbsite was granulated with colloidal alumina or colloidal silica. The amount of Mo(VI) adsorbed onto granular gibbsite with a binder, effect of contact time and pH on the adsorption of Mo(VI), and column experiments were investigated. The amount of Mo(VI) adsorbed was greater in the order of ST12 (colloidal silica, 12%) < AS10 (colloidal alumina, 10%) < GB400 (calcined gibbsite at 400°C). Adsorption isotherms data were fitted to the Freundlich equation (correlation coefficient: 0.941-0.978), suggesting monomolecular adsorption on a heterogeneous surface. The amount of Mo(VI) adsorbed onto granular gibbsite with a binder was correlated with the amount of hydroxyl groups rather than the specific surface area. The adsorption rate data of Mo(VI) were fitted to the pseudo-second-order equation, which indicated that the rate limiting step may be chemisorption. Recovery of Mo(VI) using AS10 packed in a column was 95.6%. After five adsorption and desorption steps, adsorption and desorption ability of Mo(VI) using AS10 was unchanged. These results suggest that AS10 packed in a column could be useful for the recovery of Mo(VI).