Investigation of the Effect of Different Parameters on the Separation of Lead, Arsenic, and Cadmium Ions from Wastewater using Aqueous Two-Phase Systems

In this study, dextran-based Aqueous Two-Phase Systems (ATPS) were used as the environmentally-friendly systems for extraction of metal ions. To this end, sodium citrate or sodium phosphate was used to create the two-phase region. The temperature, pH, metal ion concentration in wastewater, and amount of extractant were among the factors affecting the extraction efficiency in aqueous two-phase systems that were investigated in this study. For this purpose, the effect of pH on the extraction of lead, arsenic, and cadmium ions was investigated at the pH levels of 7-10, and the experiments were repeated at the temperatures ranging from 5 to 45 degrees Celsius. The laboratory results showed that cadmium and lead ions could be removed up to 100 % in the dextran/sodium phosphate system while the maximum separation of the lead ions was 60 % in the dextran/sodium citrate system. The maximum separation of arsenic ions was found to be 88 %. The UNIQUAC model was used to investigate the thermodynamic equilibrium in the aqueous two-phase systems. According to the obtained results, the proposed model could accurately predict the distribution coefficient of the metal ions in the ATPS. The error rate of the model was approximately 1 %. The proposed model can also be used to predict the distribution coefficient of the metal ions in the ATPS.