Synergistic separation of Co (ii) and Ni (ii) from aqueous solutions by D2EHPA and TBP dissolved in waste vegetable oil / Farhan Shah Mohamad Johari

The objective of the present work was to determine the effect of pH on the extraction of Co (II) and Ni (II) and to determine the effect of different ratio of concentration of D2EHPA and TBP on Co (II) and Ni (II) on the extraction. A solvent extraction process with the D2EHPA and TBP have been developed to extract cobalt and nickel in waste cooking oil as diluent. The process is environmentally friendly than traditional solvent extraction processes since no volatile and flammable diluent have to be used. The scope of the work were conducted in solvent extraction process method at varying pH (2.0-5.5) for the first parameter and ratio of concentration of D2EHPA to TBP (1:2, 2:1 and 3:1) for second parameter. Both parameters were constant the initial concentration of nitrate solution. The results of sample were be analyzed by determine the metal content in aqueous phase of cobalt and nickel by hydroxide precipitation method. It was found from the experiment that the optimum pH for the extraction of cobalt and nickel from aqueous nitrate solutions was a pH of 4.5 with the ratio concentration of D2EHPA to TBP 3:1 to give the highest degree of extraction with percentage extraction of cobalt (80%) and nickel (76.9%).