Utilization of Calcined Sandstone and Calcined Laterite as an Adsorbent for the Removal of Arsenic from Water

Abstract

Calcined sandstone and calcined laterite were tested as adsorbent at a low cost for the removal of arsenic (As) from the drinking water. The natural materials were collected in Côte d'Ivoire, washed and then dried at a temperature of 60 ° C and finally calcined in an oven at the atmospheric air in several temperatures 300 ° C, 400 ° C, 500 ° C, 600 ° C and 700 ° C. The study of adsorption of the arsenic was realized for the various adsorbates. It showed that the biggest efficiency of the elimination was attributed to the calcined sandstone to 300°C and 400°C for laterite during 2h with a percentage that reached 99.4 %. At this calcination temperature, amount of arsenic in treated water, satisfying the World Health Organization (WHO) standard for drinking water at initial arsenic concentrations greater than 5 mg/L. The chemical composition of the obtained adsorbs was analyzed by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) and thermal analysis (TGA-DSC). Adsorption has been described by the pseudo-second-order model. Calcination of sandstone and laterite increases the adsorption of arsenic on the materials.

Keywords: Arsenic, calcined sandstone, calcined laterite, adsorption, temperature.