Adsorption Removal of Ni(II) from Aqueous Solution by Raw and Acid-Activated Kaolinite

Abstract

X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen physical adsorption, potentiometric titrations and batch adsorption experiments were employed to characterize the crystal structure, micromorphologies and surface properties of raw kaolinite (RKao) and acid-activated kaolinite (AAKao). Compared to RKao, the particle size of AAKao became smaller, but the specific surface area (SSA), cation exchange capacity (CEC) and surface negative charge at pH 5.5 increased. The adsorption capacity (qmax) for Ni (II) of RKao and AAKao was 3.25 mg/g and 5.09 mg/g, respectively. The adsorption data for Ni (II) by RKao and AAKao could be fitted by Langmuir model (R2 =0.991 and 0.989, respectively).