EFFECT OF THE ACID TYPE ON THE NATURAL ZEOLITE STRUCTURE

Abstract

In this study, Clinoptilolite-rich zeolitic tuff was treated with acids such as HCl, HNO₃, H₂SO₄, and H₃PO₄. The effect of periods of time (3 hours and 6 hours), concentration (1 M, 2 M, 3 M, 5 M, and 10 M) and acid type  were taken as parameters. In the characterization of the zeolites, XRD, ICP-AES, FTIR, and SEM techniques were used. As the acid concentration and the treatment time were increased, the aluminum and cation removal from the structure was increased.

HCl and HNO₃ were more effective acids for the dealumination than H₂SO₄ and H₃PO₄. It was found out that considerable change in the texture of the zeolitic tuff didn’t take place during the H₃PO₄ treatment. On the other hands, acid treatment resulted in an increase in the micropore surface area and volume of the zeolite. Specific surface area of the zeolitic tuff (19 m²/g) was increased up to 213 m²/g, 236 m²/g, 202 m²/g, 118 m²/g with HCl, HNO₃, H₂SO_4, and H₃PO₄ treatments, respectively. In the cases of HCl and HNO₃, an increase in their concentration furthermore than 5 M caused to the collapse of the structure.

Keywords

• Acid treatment,characterization

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