Complexation of Ni(II) by Dimethylglyoxime for Rapid Removal and Monitoring of Ni(II) in Water

The complexation of Ni(II) with dimethylglyoxime (DMG) entrapped within a Nafion membrane and a DMG-sol-gel matrix was studied and compared for different solutions. First and pseudo-second order kinetic models, Elovich, intra-particle, and liquid film diffusion models were applied to evaluate sorption kinetics. Complexation of Ni(II) by DMG entrapped in the polymeric materials followed a pseudo-second order kinetic model; moreover, DMG in Nafion also allowed diffusion-controlled uptake. The pseudo-second order rate constant was significantly higher for the free ligand in solution than for Ni(II) accumulation in the surface-attached DMG-Nafion. The DMG-sol-gel removal ability of Ni(II) was tested using actual mine water. The presence of interferences only insignificantly decreased the removal percentage of Ni(II), thus confirming the high selectivity of DMG towards Ni(II). Also, an electrochemical sensor modified with DMG in Nafion was investigated further for direct electrochemical determination of Ni(II) in untreated mine water. Determination errors and interference effects were low. Thus, this approach represents an effective potential solution for selective Ni(II) removal from mine water as well as a rapid and cheap sensor for on-site monitoring of Ni(II) in mine and environmental waters.