Uptake capacity of zeolitic tuff from Gunungkidul, Indonesia for environmental and agriculture application

Abstract

Zeolitic tuff samples from Gunungkidul Yogyakarta, Indonesia was investigated for mineralogical and chemical composition and its uptake capacity. Five zeolitic tuff samples were obtained from the field and measured for the mineralogical, chemical composition, and uptake capacity by XRD analysis, ICP AES, and BaCl2 method, respectively. The result of mineralogical composition showed that the mordenite type-zeolite was found as significant zeolite mineral, with percentages varying from 24.1% to 38.1% and with an average amount of 34,3%. Chemical analysis revealed that the mordenite contents influenced amounts of SiO2 ranging between 60.06% to 66.06% and Al2O3 from 12.12% to 13.57%, and this Si/Al ratio obtained. The measured uptake capacity or cation exchange capacity (CEC) value varies from 67 meq/100 g to 98 meq/100 g with an average value of 82,4 meq/100 g. The vary of these values most probably was influenced by the differences in the percentage of zeolite minerals and other mineral impurities. Mordenite type of zeolite is thought the most affected of the uptake capacity, while clay minerals contribute to a relatively small influence. The uptake capacity of the five zeolitic tuff studied showed positive correlations with the content of mordenite-type zeolite as well as with the total content of microporous minerals and Si/Al ratio. These materials could be an excellent material candidate in a wide range and scale of agricultural, and environmental applications.