Kinetic Study of Cd(II) Ions Extraction Using Trioctylamine as Carrier in Bulk Liquid Membrane (BLM)


Simultaneous extraction and stripping of Cd(II) ions from aqueous solution by using bulk liquid membrane (BLM) was explored. This study was aimed to identify the conditions to achieve maximum Cd(II) ions removal and the reaction kinetics was thoroughly analysed. The membrane phase was made by using trioctylamine (TOA) and kerosene, as carrier and diluent, respectively. Meanwhile, the feed phase contained the targeted solute (CdCl2) dissolved in a pH adjusted solution while ammonia was used as the stripping agent. To achieve maximum Cd(II) ions removal, the effect of carrier concentration, stirring speed as well as extraction time were studied. Experimental data obtained shows that 0.1 wt% TOA in kerosene, 400 rpm stirring speed and 4 h of extraction time resulted in highest removal of Cd(II) ions. Furthermore, it was identified that the extraction process across BLM prefers acidic condition (pH of 1). The capability of the system to extract Cd(II) ions from the feed phase was known by using dimensionless reduced concentration, Rf where the maximum removal of Cd(II) ions achieved was 0.0193 at the mentioned conditions. The reaction kinetics were investigated to identify the reaction rate constants for extraction reaction (k1) and stripping reaction (k2). The value of k1 and k2 were found to be 0.94 h–1 and 2.45 h–1, respectively.