Investigating the Effect of Using Iranian Zeolite and Bentonite in Desalination

Global water demand is constantly increasing, while freshwater resources are limited due to increased demand and the effects of climate change, especially in arid and semi-arid regions such as Iran. The cost of water production is one of the most important factors in choosing a desalination method. In the adsorption method using natural materials, the cost of desalination can be reduced. In this study, Iranian zeolite and bentonite were used to reduce salinity by batch test. The adsorbents were identified by EDx, XRD, and BET. Clays were also modified with 1 M hydrochloric acid. The results showed that Iranian zeolite and bentonite used in this study as mineral adsorbents do not have the efficiency to reduce salinity and increase the electrical conductivity and sodium content of water. The highest increase in sodium concentration in samples was related to natural bentonite (102.5 mg/g) at the highest salinity concentration (64000 mg/L) and the lowest increase in sodium concentration was related to natural zeolite at 0.066 mg/g in the lowest salinity concentration (640 mg/L). Also, the highest increase in electrical conductivity was related to natural bentonite with an increase of 4.3 dS/m. It is noteworthy that after acid correction, the amount of electrical conductivity increased significantly in both clays. Therefore, due to the differences between the clays, it is better to first examine them in terms of construction and then use them in the field of desalination.