Cation Xanthated Exchangers from Colombian Sub-Bituminous Coals Effectively Removed Cadmium and Lead from Aqueous Solutions

Resumen

In Colombia, low rank coals are almost totally used for power and metallurgical aims, which are activities that produce contamination. In this investigation, as an altemative to the traditional use of low rank coals, we prepared cationic xanthated exchangers from a subbituminous coal (67.6% C, 4.6% H, 22.4% O, 0.6% S, 3.2% ashes and 46.2% volatile matter) of Montelibano-Córdoba; this exchanger showed better exchange capacities for cadmium and lead (1.8 meq/g) than traditional sulphonated exchangers (0.56 and 1.11 meq/g for cadmium and lead respectively). Xanthation was verified at 30 ºC and at 5-10 ºC with NaOH and CS₂. Toe best performance of xanthation, determined by Infrared spectrometry and ion exchange experiments, occurred at low temperatures maybe due to CS₂ volatility. By diminishing the particle size of coal the exchange capacity increased. The exchange capacity was evaluated by flame atomic absorption spectrometry.