Comparison of hollow fiber membrane and solvent extraction techniques for extraction of cerium and preparation of ceria by stripping precipitation

Abstract

BACKGROUNDThe extraction of cerium by hollow fiber supported liquid membrane using tri-octyl methyl ammonium chloride (TOMAC) as mobile carrier was studied and the result was compared with solvent extraction data. The effect of different parameters such as pH, flow rates, extractant concentration, metal ion concentration and strip solution concentration on cerium extraction was investigated. RESULTSThese parameters were optimized for maximum cerium flux and were found to be: pH 1.0, 0.1 mol L-1 TOMAC, 290 mL min(-1) feed solution flow rate, 150 mL min(-1) strip solution flow rate and 0.9 mol L-1 H2SO4 as strip solution. The parameters were also optimized for solvent extraction study. The number of stages and Aqueous:Organic (A:O) ratio for extraction and stripping were determined from McCabe-Thiele diagrams. The extracted species was determined to be (R3NCH3)(2)Ce(SO4)(3). The selective separation of cerium in presence of various other metal ions such as iron, copper, zinc, cobalt, nickel and manganese using a hollow fiber supported liquid membrane (HFSLM) was carried out and the separation factor values were found to be in the order (Ce/Fe) <(Ce/Cu) < (Ce/Mn) < (Ce/Zn) < (Ce/Co) < (Ce/Ni). Finally highly pure (99.99%) CeO2 was prepared by stripping precipitation with oxalic acid and thermal decomposition at 900 degrees C for 1 h. CONCLUSIONThe efficiency of hollow fiber supported liquid membrane was greater than that of solvent extraction for the extraction of cerium for the present system. (c) 2014 Society of Chemical Industry