Desalination of Sea Water by Akadama Soil and Akadama Soil-Inorganic Adsorbents Mixtures

Abstract

The purpose of this study is to investigate utilization of Akadama soil and evaluate its ion removal efficiency for seawater desalination. The chemical composition of the Akadama soil was Al_2O_3 0.334kg kg^<-1>, SiO_2 0.470kg kg^<-1>, Fe_2O_3 15.7kg kg^<-1> by weight. X-ray powder diffraction pattern, electron diffraction pattern and IR spectrum of Akadama soil showed that allophane was the main phase and low crystallinity kaolin was generated from the allophane. The column method was carried out to evaluate seawater desalination efficiency, the best mixture ratio of the Akadama soil (particle size was less than 250μm), aluminum silicate adsorbent, aluminium magnesium adsorbent, and magnesium oxide adsorbent was 3:1:1:1. Removal percentages of Na^+, Mg^<2+>, Ca^<2+>, K^+ and Cl^- from artificial seawater were 87.7, 84.4, 91.1, 97.3 and 90.7%, respectively. In the batch method, where the mixed adsorbent was used for removal of heavy metals from 20mg L^<-1> solution, the removal percentages of Cu^<2+>, Ni^<2+>, Mn^<2+>, Zn^<2+>, Cd^<2+> and Pb^<2+> were higher than 98%. The removal percentage of PO_4, from river water was 100%.