Desalination of Saline Irrigation Water Using Hydrophobic, Metal–Polymer Hydrogels

Abstract

Saline irrigation water accounts for 15% to 30% of global, anthropogenic, water usage, and around 10% to 15% of global arable food production. Decreasing the salinity of this irrigation water has the potential to substantially increase the yields associated with these crops. In this paper, 87 sol–gel hydrophobic and supra-hydrophobic, hollow, metal, hydroxyoxide and polymer formulations (constructed using inexpensive, agricultural chemicals) were demonstrated to remove Na+ ions and Cl− ions from saline water. The process operates without producing a waste brine or requiring an external energy source and is designed to desalinate water within existing tanks and impoundments. The desalination results of the polymer were combined with the salinity reduction profiles of 70 crops suitable for cultivation, including arable, orchard, horticultural, and livestock forage crops. The analysis established that use of the desalinated water may result in both substantial increases in crop yield, and an increase in the variety of crops that can be grown. Analysis of the ion removal process established a novel methodology for assessing the salinity of the product water. This methodology allows the salinity of the product water to be determined from a combination of EC (electrical conductivity) and pH measurements.