Sorption efficiency of kaolinte in removal Cd from aqueous solutions

Abstract

Because of the contaminants represented by heavy metals in the aquatic
environment have an adverse effects need to be addressed, therefore, a laboratory
simulation was conducted on Cd using kaolinite that collected from Ga’ara Formation
as considered as a natural sorbent material that can be used to remove heavy metals
from aqueous environments. Mineralogical study was conducted on kaolinite using
X-Ray diffraction (XRD), Scanning Electron Microscope (ESM) and Energy-
Dispersive X-ray Spectroscopy (EDS) for the purpose of investigating the microtexture.
It was found that kaolinite has pure phase of very fine grains with a very little
quantity of quartz and has a number of active sites for adsorption. Chemical analyzes
were performed using atomic absorption spectroscopy (AAS), Electron Probe Micro
analyzer (EPMA) and Energy-Dispersive X-ray Spectroscopy (EDS) techniques
confirmed a purity of kaolinite due to high alumina content, except a rare slica content
originated from quartz. Kaolinite sorption efficiency was investigated through a series
of laboratory experiments. The optimal reaction conditions were determined to be as:
pH 5 to 9, but the best is 9, and the eqilibrium reaction time is 40 minutes, and the
solid to liquid ration is 1.25 gm to 50 ml. The effect of the initial Cd concentration on
the sorption efficiency of kaolininte was also investigated and shows that the sorption
proportionally increases with high concentration. All the laboratory experiments
indicate that the reaction is an indothermic.