Chen, H.-F.; Lin, Y.-J.; Chen, B.-H.; Yoshiyuki, I.; Liou, S. .-H.; Huang, R.-T. A Further Investigation of NH4+ Removal Mechanisms by Using Natural and Synthetic Zeolites in Different Concentrations and Temperatures. Minerals2018, 8, 499.
Chen, H.-F.; Lin, Y.-J.; Chen, B.-H.; Yoshiyuki, I.; Liou, S. .-H.; Huang, R.-T. A Further Investigation of NH4+ Removal Mechanisms by Using Natural and Synthetic Zeolites in Different Concentrations and Temperatures. Minerals 2018, 8, 499.
Chen, H.-F.; Lin, Y.-J.; Chen, B.-H.; Yoshiyuki, I.; Liou, S. .-H.; Huang, R.-T. A Further Investigation of NH4+ Removal Mechanisms by Using Natural and Synthetic Zeolites in Different Concentrations and Temperatures. Minerals2018, 8, 499.
Chen, H.-F.; Lin, Y.-J.; Chen, B.-H.; Yoshiyuki, I.; Liou, S. .-H.; Huang, R.-T. A Further Investigation of NH4+ Removal Mechanisms by Using Natural and Synthetic Zeolites in Different Concentrations and Temperatures. Minerals 2018, 8, 499.
Abstract
We investigate the ammonium removal abilities of natural and synthetic zeolites, which have distinct Si/Al ratios and various surface areas, to study how adsorption and ion-exchange processes in zeolites perform under different ammonium concentrations and different temperatures. Five zeolites including natural mordenite, chabazite, erionite, clinoptilolite and synthetic merlinoite were immersed in 20 mg/kg, 50 mg/kg and 100 mg/kg ammonium solutions. The results demonstrate that zeolites under high ammonium concentrations (100 mg/kg) possess higher physical adsorption capacity (0.398–0.468 meq/g), whereas those under lower ammonium concentrations (20 mg/kg) possess greater ion-exchange property (64–99%). The ion-exchange ability of zeolites are extremely dependent on the cation content of the zeolites, and the cation content is affected by the Si/Al ratio. The surface area of zeolites also has a partial influence on its physical adsorption ability. When the surface area is less than 100 m2/g, the adsorption ability of zeolite increases obviously with surface area; however, adsorption ability is saturated as the surface area becomes larger than this critical value of 100 m2/g. When we carried out the zeolites in 50 mg/kg ammonium concentration at different temperatures (5~50 ℃), we found that zeolites exhibit the highest ammonium removal ability at 30°C and the potassium release was enhanced at 30~40 ℃.
Keywords
zeolite; ion-exchange; adsorption; ammonium; Si/Al; temperature
Subject
Environmental and Earth Sciences, Geochemistry and Petrology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
