Characterization and application of kaolinite clay as solid phase extractor for removal of copper ions from environmental water samples

Reactions of copper with kaolinite clays are important in determining copper fate in the environment. Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), thermal gravimetric analysis (TGA), energy dispersive x-ray (EDX) and particle size distribution (PSD) techniques investigated for characterization of kaolin sorbents (kaolin, metakaolin and dealuminated kaolin). Furthermore, the scan electron microscope (SEM) used for their surface morphology. Thus, the present study includes the removal of Cu(II) from aqueous solutions on kaolin sorbents through the process of adsorption under various conditions (pH, equilibrium time, amount of sorbent and concentration of copper ion) using batch technique. Increasing pH favors the removal of copper ions till they are precipitated as the insoluble hydroxides. The interaction of Cu(II) with natural kaolin sorbent is rapid within 60 min equilibrium time with maximum extraction percentage (100%) and high distribution coefficient (8.406 x 104) at pH 6.5 compared with the other two sorbents. In addition, the adsorption kinetics data were best fitted with the pseudo-second-order (r2= 0.994). Also, the results of adsorption isotherm indicated that these data can be better ?tted with the Langmuir model with r2= 0.986. Finally, kaolin sorbent was be applicable for removing copper ions from environmental water samples and it was found that these ions were highly recovered (90.0-100.0% with RSD%=0.001-0.017%) using batch experiments.