Affiliation:
1. Jordan University of Science and Technology, Civil Engineering Department
Abstract
Wastewater treatment and desalination are considered important solutions to meet the water scarcity in Jordan. The irrigation with reclaimed wastewater, that usually has elevated salinity levels, may adversely change soil structure, stability, and hydraulic properties. Water traditional desalination techniques require huge energy and capital investments. Zeolites in normal and nano scales enhance the desalination process performance and reduce its economic and energy requirements. In this study, batch experiments were conducted to investigate the salinity removal of reclaimed wastewater by using natural zeolite (Clinoptilolite), acid-treated zeolite as well as zeolites nanoparticles. The effect of salt�s initial concentrations, adsorbents mass, and pH on the adsorption process was determined. The results showed that potassium concentration was reduced by 75%, 76%, 81%, and 86% by using 5 g of natural zeolite, nano zeolite, acid-treated zeolite, and acid-treated nano zeolite, respectively. Also, water salinity was reduced by 17%, 12%, 18%, and 23% by using natural zeolite, nano zeolite, acid-treated zeolite, and acid-treated nano zeolite, respectively. It was observed that the nano zeolite performance was worse compared to the other zeolite types, but the acid treatment significantly enhanced the nano zeolite performance. Also, the highest removal efficiencies of potassium ions were achieved at neutral to slightly acidic pH (5-7). On the other hand, the nature of the adsorption process of salts onto zeolites surfaces was favorable and referred to a physical process. The kinetic adsorption was rapid and achieved within 5-10 minutes. It was found that the Langmuir, Freundlich, and Temkin isotherms and pseudo second order kinetic model were well fitted to the experimental data. It was concluded that the zeolite and its modified form in normal and nano scales can be widely used for salinity removal of reclaimed wastewater as effective adsorbents.