Abstract

C. Dulcy Evangelin¹ , Sai Venkat Naren² and M. Dharmendirakumar¹*

Comparison between three activated carbons having the silk cotton hull origin was done by characterizing them using various methods to find out the changes occur during the modification process. One sample was modified by H₂SO₄ (AC), the second was modified by the mixture of H₂SO₄ and H₂O₂ (AC1) and the third was modified by the mixture of H₂SO₄ and NH4S₂O₈ (AC2). Structural properties of carbons and their oxidized counterparts were determined using sorption of nitrogen. Surface acidity was evaluated using Boehm titration and FTIR spectral analyses. It was demonstrated that, despite the same origin, the carbons significantly differ in their pore structure and surface chemistry. The carbon obtained using H²SO⁴ and H₂O₂ modification is microporous with high surface area 107.23 m².g^-1 (BET). On the other hand, the carbon modified by H₂SO₄and NH4S₂O₈ contains a high surface acidic oxygenated groups and its surface area is significantly lower. We have used these adsorbents for heavy metal ion removal and got the result more than 90%. In this paper, surface features of these activated carbons were compared.

SCH; oxidation; surface area; surface acidity

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