Removal of Mercury in Aqueous Solutions Using Tri n-Butyl Phosphate-Based Polymer Inclusion Membrane

Abstract

Polymer inclusion membranes (PIM) have gained global attention in the removal of heavy metals from aqueous samples. Mercury is a toxic metal that can cause serious health effects to humans even if present in traces. Hence, its removal from water bodies and wastewaters is a necessary action. The present work, thus, aims at studying the removal of Hg2+ ions by using PIM with a new and unexplored neutral carrier, namely, Tri n-butyl phosphate and Dioctyl phthalate as a plasticizer. One hundred percent removal was attained for feed phase mercury concentrations from 0.01 to 2 mg/L and about 96% for 10 mg/L under optimum conditions (thickness of the membrane: 30 μm, feed phase acid: 0.3 M, strip phase alkali: 0.4 M, carrier: 3% and stirring speed: 400 rpm). The PIM system has been successfully demonstrated to remove trace concentrations of mercury in spiked seawater, thermal powerplant wastewater discharge, and contaminated lake water samples. The PIM was highly stable (60 h) and selective for Hg2+ ions. Also, the most significant factor in the transport of mercury through the PIM was determined as the feed phase mercury concentration using the Taguchi method. Thus, the proposed PIM system could be used for the selective removal of mercury ions from water and wastewater samples.