Drinking water polluted with trace heavy metals cause serious problems in water supply system in many parts of the world. The heavy metals, nickel (II) and cobalt (II) mixtures are among the important contaminants in drinking water, the removal of which can be achieved by Electrocoagulation (EC). Electrocoagulation (with aluminum as electrode) to remove nickel and cobalt from aqueous medium was studied in the present study. Different concentration of nickel (Ni) and cobalt (Co) solution in tap water was considered for the experiment. During EC process, various amorphous aluminum hydroxides complexes with high sorption capacity were formed. It was observed that the removal of Ni (II) and Co (II) increases with current densities. Inter electrode distance was varied from 0.005 to 0.025 m and was found that least inter-electrode distance is suitable in order to achieve higher mixture removal. Other parameters such as conductivity, pH and salt concentration were kept constant as per tap water quality. Satisfactory mixture removal of around 99% was obtained at the end of 35 min of operation from initial concentration of 25 mg L-1 of Ni (II) and Co (II). Mixture of nickel and cobalt concentration in the solution was determined using Atomic absorption Spectrophotometer. The values of resistances, equivalent conductance and viscosity at under current density 0.04 A m-2 using AC of 50 Hz and 50 volt were calculated. The results from the kinetic studies showed, that the kinetic data fit the second-order kinetic model. The standards for drinking water are met for a very large relative volume of treated water.
Saber E. Mansour and Ibrahim H. Hasieb, 2012. Removal of Ni (II) and Co (II) Mixtures from Synthetic Drinking Water by Electrocoagulation Technique Using Alternating Current. International Journal of Chemical Technology, 4: 31-44.