Removal of Hg2+ ions using tri n-butyl phosphate based supported liquid membrane from aqueous samples

Abstract

Mercury is a poisonous heavy metal that causes deleterious effects on public health and the ecosystem, even with a trace level of contamination. Selective separation of mercury ions in an aqueous environment is a challenging task, while supported liquid membrane poses to be a promising tool. In this research work, the removal of mercury ions using a porous PTFE membrane with TBP as a carrier has been studied. Batch experiments were carried out in an SLM reactor with feed phase and strip phase solution on either side of the membrane. Maximum removal of 97% of Hg2+ ions occurred under optimum conditions, namely, 0.5 M of HCl (feed), 0.4 M NaOH (strip), 90% of TBP, stirring speed at 300 rpm and 3 h of reaction time. SEM analysis of the membrane confirmed the formation of a complex between TBP and Hg2+ ions. SLM was found to be stable for 18 h. The high selectivity of the SLM towards Hg2+ ions was unaltered in the presence of Cd2+, Ni2+ and Zn2+ ions. The proposed SLM was used for the treatment of spiked seawater samples, wastewater from a thermal power plant, and contaminated lake water samples. The results indicated that the SLM system was highly efficient in removing Hg2+ ions from real contaminated samples.