Potential of Carbon Adsorbents Derived from Cotton Stalks in the Decolorization of Sugar Liqour

摘要

Cotton stalks, an abundant feild residue, were investigated as a potential carbon precursor, and the derived products were tested in column decolorization of cane sugar liqour. Chars obtained by carbonization, at 400-970℃. exhibit low color removal capacity that decays with lime, except the 400℃ - char which shows moderate performance with good stability. Raw material impregnated with low concentration of different acids (acetic, sulphuric, and phosphoric) or basic substances (sodium or magnesium carbonate) proved the superior effect of H_3PO_4. Pyrolysis of H_3PO_4 - impregnated stalks at 400-850℃ which resulted in activated carbons (AC_s) of identical decolorizing performance, and that capacity drops by heating at 970℃. The high temperature AC exhibits, however, a recommending property as it keeps the effluent pH within the neutral range. Soaking of cotton stalks with 10% H_3PO_4, and heated at 970℃, resulted in an AC with satisfactory performance which is similar to AC_s derived from other local wood trees, treated under the same conditions.