Desalination of sea water by akadama soil and akadama soil-inorganic adsorbents mixtures

Abstract

(pp. 33–39)

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 Al₂₀₃ 0.334 kg kg⁻¹, SiO₂ 0.470 kg kg⁻¹, Fe₂₀₃ 0.157 kg 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 250 m), aluminum silicate adsorbent, aluminium magnesium adsorbent, and magnesium oxide adsorbent was 3:1:1:1. Removal percentages of Na⁺, Mg²⁺, Ca²⁺, 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 20 mg L⁻¹ solution, the removal percentages of Cu²⁺, Ni²⁺, Mn²⁺, Zn²⁺, Cd²⁺ and Pb²⁺ were higher than 98%. The removal percentage of PO₄ from river water was 100%.

Key words:

• Akadama soil
• allophane
• heavy metal removal
• kaolin
• seawater desalination