Fundamental Study on Simple Desalination Treatment of Natural Zeolite for the Production of Irrigation Water from Seawater

Abstract

We attempted to make irrigation water from seawater with a simple treatment of natural zeolite. Cations contents in artificial seawater can be adjusted by the treatment of natural zeolite, and Na⁺ can be reduced, but high contents of Cl^- and SO₄^2-remains in the solution after treatment. With a simple two-step process using calcined hydrotalcite and natural zeolite, Cl^- and SO₄^2- in artificial seawater can be reduced by calcined hydrotalcite, and Na⁺ can be reduced by ion exchange with natural zeolite. The obtained solution was neutral, and includes the nutrients, K⁺, Mg²⁺, and Ca²⁺, and low levels of Na⁺ and Cl^-. Although Radish sprouts did not grow in artificial seawater, the solution treated with natural zeolite and the solution treated with calcined hydrotalcite, they could be grown in the solution treated with two-step process. These results suggest that it is possible to make a solution for irrigation water from seawater.