Simultaneous removal and recovery of heavy metal by emulsion liquid membrane (ELM): kinetic study

The presence of heavy metal in industrial effluents has become one of the major factors leading to environmental pollution and human health deficiencies. Owing to this issue, the emulsion liquid membrane (ELM) has been discovered as an advanced and effective technique for heavy metal removal from aqueous solution. This study is aimed to conduct component selection and kinetic study for ELM in favor of Cd(II) and Cu(II) ions removal from synthetic wastewater. On top of that, the selectivity of extraction process in ELM system was identified. Two different types of facilitated carrier; di-(2- ethyhlhexyl) phosphoric acid (D2EHPA) and trioctylamine (TOA) were studied and compared. Membrane phase was incorporated of 0.05 wt% of carrier and 0.95 wt% of kerosene. HC1 and NaOH are as the stripping agent accompanied by the carrier were kept constant at 1M concentration while the feed phase was maintained at pH 4. The results revealed that D2EHPA is more preferred as carrier compared to TOA due to higher extraction efficiency (>98%) achieved. Furthermore, it was analyzed that both carriers are being more selective toward Cu(II) removal. The system's ability to remove Cu(II) ions from the feed phase was identified through the use of dimensional reduced concentration, Rf It was identified that the reaction rate constants for extraction and stripping on Cd(II) removal were found to be 7.66 h-1 and 22.95 h-1 for D2EHPA system and 0.11 h-1 and 2.49 h-1 for TOA system. Meanwhile, as for Cu(II) extraction, reaction rate constants for extraction and stripping obtained for D2EHPA system were 3.66 h-1 and 2.87 h-1, whereas 0.17 h-1 and 3.20 h-1 for TOA system.