Abstract

FERNANDEZ-MAESTRE, Roberto  and  COLPAS-CASTILLO, Fredy. MERCURY AND CADMIUM ADSORPTION IN SUBBITUMINOUS XANTHATED, SULFONATED OR ACTIVATED CARBON AND COMMERCIAL SYNTHETIC RESIN. rev.udcaactual.divulg.cient. [online]. 2015, vol.18, n.1, pp.241-250. ISSN 0123-4226.

The combustion of low rank coal produces environmental impacts due to its low heat of combustion and high heteroatom content which has promoted its alternative uses as an adsorbent. A subbituminous coal (CS) was oxidized with air at 150°C on a fixed bed for 4 hours and xanthated with carbon disulfide in a basic solution, at 30°C. The resulting xanthated coal (CX) was evaluated for the adsorption of Hg²⁺ and Cd²⁺ from 0,100, 1,000, 12.48, 124.8 y 998.3mg/L aqueous solutions; metal concentrations were determined by atomic absorption spectrometry. CX was compared against CS, a sulfonated CS, activated CS (CAp), a commercial activated carbon (CAC), and a commercial synthetic resin (RC) in terms of Hg²⁺ and Cd²⁺ adsorption. RC showed the highest adsorption capacity (concentration factor 98%) followed by theCX (concentration factor 96%). The adsorption of cadmium on the sulfonated CS was 0.56meq/g, lower than that of CX, 1.85meq/g. In general, Hg²⁺ was less adsorbed than Cd²⁺; the adsorption capacities decreased in the order: RC, CX, sulfonated CS, activated CS, CS, and CAC. CX showed a better Cd²⁺ adsorption, 81% against 15%, than a non-oxidized 40-hours-xanthated coal, which shows that oxidation of coal increased the amount of oxygenated groups that enhanced xanthation.

Keywords : Adsorption; brown coal; activated carbon; subbituminous coal; xanthation; atomic absorption spectrometry.

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