Sustainable separation of Cu(II) and Cd(II) from aqueous solution by using solvent extraction technique with di-2-ethylhexylphosphoric acid (D2EHPA) as carrier: optimization study

Abstract

Abstract In wastewater treatment field, physicochemical techniques containing conservative substance such as metal or substance that are non-biodegradable are typically employed. However, these techniques have their own drawbacks and none of them is universal in treating all kinds of metal present in the wastewater. Separation procedure is known to be very suitable for the separation and recovery of metal ions. The solvent extraction or liquid–liquid extraction, LLE, was opted in this study to identify the influencing factors on the extraction of cadmium(II) and copper(II) ions from aqueous solution by using soybean-based oil as organic solvent. The experiment was approached using fractional factorial design to determine the significance of six factors which are concentration of di-2-ethylhexylphosphoric acid (D2EHPA), concentration of tributyl phosphate (TBP), shaking time, the concentration of Na2SO4, O/A phase ratio and aqueous pH. The results have shown that %E shows that Cu(II) was obtained in the range from 35.77 to 91.81%, while the result obtained from the factorial plot of screening experiment shows that the interaction effect AB (shaking time × [D2EHPA]), CE ([TBP] × O/A) and DF ([Na2SO4] × pH) influences significantly the Cu(II) %E. Meanwhile, %E for a sample containing Cd(II) ion was obtained in a range from 54.77 to 87.35%.

Keywords

• di-2-ethylhexyphosphoric acid (D2EHPA)
• Cu(II)
• Cd(II)
• liquid-liquid extraction (LLE)
• separation
• sustainable