Adsorption of Cr(VI) by lanthanum oxide-loaded porous mullite–corundum ceramics

Abstract

In this study, a novel lanthanum oxide-loaded porous mullite–corundum ceramic was prepared and adopted to remove Cr(VI) from aqueous solution. The lanthanum oxide-loaded porous mullite–corundum ceramic was characterized by XRD, SEM-EDS, and XPS, and batch adsorption experiments were employed to investigate the effect of main interfering factors on Cr(VI) adsorption. The results showed that the adsorption capacity of lanthanum oxide-loaded porous mullite–corundum ceramic was significantly improved, and the dynamic adsorption equilibrium could be reached at 720 min; the adsorption capacity almost did not decrease after five adsorption cycles. Cr(VI) adsorption process abided by pseudo-second-order kinetic model and Freundlich model, indicating that Cr(VI) adsorption onto lanthanum oxide-loaded porous mullite–corundum ceramic was multi-molecular layer chemical adsorption. Therefore, lanthanum oxide- loaded porous ceramics are an efficient and highly reusable adsorbent, which is expected to be used for the treatment of Cr(VI) in wastewater.