Journal of Hazardous Materials, Vol.217, 224-230, 2012
Effect of heavy metals on the stabilization of mercury(II) by DTCR in desulfurization solutions
Several heavy metals, including Cu2+, Ni2+, Pb2+, and Zn2+, were investigated in simulated desulfurization solutions to evaluate their interferences with Hg2+ during the reaction with dithiocarbamate type chelating resin (DTCR). Appropriate DTCR dosage and the effect of pH were also explored with respect to restoration of high Hg2+ precipitation efficiency and reduction of mercury concentrations. The experimental results suggested that increasing heavy metal concentration inhibited Hg2+ precipitation efficiency to a considerable extent and the inhibition order of the four heavy metals was Cu2+ > Ni2+ > Pb2+ > Zn2+. However, the coordination ability was closely related to the configuration and the orbital hybridization of each metal. In the cases of Cu2+ and Pb2+, increased DTCR dosage was beneficial to Hg2+ precipitation, which could lay the foundation of practical applications of DTCR dosage for industrial wastewater treatment. The enhanced Hg2+ precipitation performance seen for increasing pH might have come from the deprotonation of sulfur atoms on the DTCR functional groups and the formation of metal hydroxides (M(OH)(2), M = Cu, Pb, Hg). (C) 2012 Elsevier B.V. All rights reserved.