FACILITATED TRANSPORT OF Ni(II) THROUGH SUPPORTED LIQUID MEMBRANES CONTAINING DITHIOPHOSPHONATES AS ION CARRIER.

Facilitated transport of Ni(ll) ions across a supported liquid membrane (SLM) by dithiophosphonates dissolved in methanol as carrier has been investigated. In this work, the SLMs were composed of ionic ligands ammonium-O-ethyl (4-methoxyphenyl) dithiophosphonate (LI), ammonium-O-propyl (4-methoxyphenyl) dithiophosphonate (L2), ammonium-O-isopropyl (4-methoxyphenyl) dithiophosphonate (L3), and ammonium-O-butyl (4-methoxyphenyl) dithiophosphonate (L4) as the carriers. Polyvinylidene fluoride (PVDF) hydrophobic microporous membrane was used as support. The experiments were carried out at various operating conditions such as feed phase pH, receiver phase concentration, carrier concentration in the membrane phase, different valence metal ion, and SLM stability. The morphology of SLMs was characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), andfourier transform infrared spectroscopy (FTIR). The SEM, AFM, ami FTIR images, comparing the PVDF membrane support to SLMs, indicate that the surface morphologies of the membranes are different. The flux values (J) and recovery factors (RF) of Ni(II) ions were obtained at optimum pH 2. Similar flux results were obtained for all SLMs at optimum condition and in a period of 8 h. Increase in carrier concentration inside the membrane enhances Ni(II) concentration with its maximum value at 4.0 x 10-1 mol/L carrier. [ABSTRACT FROM AUTHOR]