Study of facilitated bulk liquid membrane transport of lithium ion from seawater and use of carbon nanotube as additive in membrane

In this century, lithium and its compounds as most important trace element find many applications such in making ceramics, lubricants, atomic energy, aerospace, pharmaceuticals, and lithium battery [1]. But we must find other potential sources of lithium to compensate for the increasing demand and in the meantime, seawater with estimating amount of 231.2 billion tons of lithium has attracted as suitable alternative source of this element [2,3].Here, Transport of lithium ion as a valuable and useful metal in major industries was done through a facilitated bulk liquid membrane using 12 crown 4 as carrier. Procedure affecting parameters such pH of the feed and receiving, type of membrane solvent, concentration of carrier, stripping solution conditions, time, temperature were investigated. On the other hand, effect of carbon nanotube as additive of liquid membrane was studied which shown a noticeable increase in the lithium transport process. In the optimum work conditions and after 2 hr, %12 (±0.06) of Li+ from feed phase (containing Li+ = 0.0057 M, NaCl = 0.1 M, pH = 6.2) across a dicholoromethane membrane (12C4 = 0.005 M) was transported into the receiving phase (containing (NH4)2SO4 0.001 M and pH = 6.1). The selectivity of method was evaluated by performing the competitive transport experiments on the seawater simulated mixtures containing Na+, K+, Ca2+and Mg2+ ions with their conservative concentration in seawater