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The objective of this research was to determine the efficacy of using impregnated activated carbons for the removal of various heavy metals from aqueous solutions. Two impregnates (iron oxide and a ceramic cationic ion-exchanger) were impregnated onto two different commercial activated carbons and the resultant products were called FeAC and HD4000-ATC, respectively. In the first phase of research, acid-base behaviors of the non-impregnated and impregnated carbons were characterized at several ionic strengths by acidimetric-alkalimetric titrations and the pHzpc of the carbons was determined. The impregnated carbons required more acid/base to alter the pH, indicating that there were more surface sites available for metal removal in comparison with non-impregnated carbons. In the second phase, pH-adsorption edges (% metal removed versus pH) were developed for the impregnated and non-impregnated carbons using 1 mg/L solutions of either As(III), As(V), Hg(II), and Pb(I1). For all carbons studied, adsorption of all metals was a function of pH. The impregnated activated carbons removed significantly more metals (excluding Hg) than their non-impregnated counterparts at all pH values. Freundlich and Langmuir isotherm relationships were developed as a function of pH. Adsorption of heavy metals onto impregnated activated carbons was successful and warrants further investigation using continuous flow processes. Includes 18 references, figures.

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Edition: Vol. - No. Published: 06/01/2001 Number of Pages: 15File Size: 1 file , 1000 KB