Selection of design parameters and optimization of operating parameters of soybean oil-based bulk liquid membrane for Cu(II) removal and recovery from aqueous solutions

The objectives of this work were to select suitable design parameters and optimize the operating parameters of a soybean oil-based bulk liquid membrane (BLM) for Cu(II) removal and recovery from aqueous solutions. The soybean oil-based BLM consists of an aqueous feed phase (Cu(II) source), an organic membrane phase (soybean oil (diluent), di-2-ethylhexylphosphoric acid (D2EHPA) (carrier) and tributylphosphate (phase modifier)) and an aqueous stripping phase (sulfuric acid solution (H2SO4)). Effects of design parameters (stirring condition and stripping/membrane to feed/membrane interface area ratio) of soybean oil-based BLM on the Cu(II) removal and recovery from aqueous solutions were investigated and the suitable parameters were selected for further studies. Optimization of the operating parameters (D2EHPA concentration, H2SO4 concentration, stirring speed, temperature and operating time) of soybean oil-based BLM for maximum percentage (%) recovery of Cu(II) was then conducted using Response Surface Methodology and the optimum parameters were determined. A regression model for % recovery was developed and its adequacy was evaluated. The experimental % recovery obtained under the optimum operating conditions was compared with the predicted one and they were found to agree satisfactorily with each other.