Acta Montanistica Slovaca (Mar 2002)
Removal of Pb2+, Cd2+ and Co2+ ions by means of various magnetic sorbents
Abstract
The contribution presents the results of the cleaning of waters contaminated by heavy metal ions by means of magnetic sorbents that in special cases are also called magnetic carriers. The wastes from metallurgical industry and thermal power generation, such as the so called Albanian magnetite-containing leaching residuum (produced in the former Ni-hydrometallurgical plant in Sereï), a hematite-bearing red mud from Al2O3 production in iar n/Hronom and a magnetic fraction of ash from the coal-fired power plant EVO Vojany, were applied as magnetic sorbents.The sorbents coming out from Ni and Al2O3 production were subjected to the mechanical activation in a vibration mill before their using in cleaning tests, while the magnetic fraction of ash was applied without the activation. As to the sorbents properties, the grain size, the mineralogical and/or chemical composition as well as the magnetic susceptibility have been studied with the aim to assess and compare their possible sorption capacity.As contaminated waters the prepared water solutions containing ions of Pb2+, Cd2+, Co2+ were used. The magnetic sorbents after their mixing with contaminated waters have been filtered through a layer of spherical inductive bodies located in a magnetic field. The influence of the magnetic carrier concentration, time of agitation, and the pH value on the efficiency of water cleaning process was investigated.An efficacious sorption capacity was observed for all three applied sorbents. The most expressive reduction of Pb2+, Cd2+ and Co2+ content was achieved at the pH value of 9. During experiments on the Pb2+ content decrease, a reduction from 85 µg.ml-1 to <1 µg.ml-1 was observed for all three sorbents. Generally, regarding the Cd2+content decrease, it was showed, that a reduction from 105 µg.ml-1 to <0.1 µg.ml-1 can be attained. In the case of Co2+ content in water, the strongest reduction, i. e. from 99.2 µg.ml-1 to 0.06 µg.ml-1, was obtained by applying the sorbent prepared from ash.
