The effect of ammonia activation on the desalination potential of natural zeolite

Abstract

Despite the abundance of water bodies on Earth, there is a limited amount of potable water. Therefore, the desalination process is of great interest. Adsorption of the main contaminants of saline water (Na+, K+, Cl– ions) is an alternative process of desalination. In the present work, a sorbent based on natural zeolite (NZ) modified with ammonium chloride (NH4Cl) is obtained and the effect of modification on the removal of Na+ and K+ ions from saline water is studied. According to the Brunauer-Emmett-Teller (BET) analysis, the modification of zeolite with NH4Cl leads to an increase in its surface area (7.85 to 8.09 m2/g). According to the results of the cation exchange capacity (CEC) determination, the modification leads to a decrease in total CEC of zeolite (431.67±29.01 to 300.88±31.86 meq/100 g). According to the obtained results, ammonia modification enhances the adsorption ability of NZ to extract Na+ and K+ ions from saline water. The extraction degree (E) of Na+ ions by NH4-Z increases from 7.93±1.63 to 10.44±1.52%, while for K+ ions it increases about 2 times (27.69±2.45 to 56.46±3.71%). These results indicate that the ammonia-modified NZ can potentially be used as a desalination agent for the removal of Na+ and K+ ions from saline water.

Keywords

• natural zeolite
• ammonia activation
• desalination
• sodium adsorption
• potassium adsorption