Copper and molybdenum sorption onto selective ion exchangers

The sorption of Cu and Mo was carried out by dynamic experiments using glass vertical columns. Two types of sorbents were used for sorption (ion exchange). Tests proceeded under following conditions: sorbent volume – 15 mL, specific flow rate – 6 BV/h, inlet molybdenum and copper concentration – 10 mg/L, three pH scales – 3.5; 4 and 4.5. The first ion exchanger – protonized Purolite D4123 (styrene-divinylbenzene matrix and 1-deoxy-1-methyl-amino-D-glucitol functional group) was not effective for copper sorption at all studied pHs (3.5; 4; 4.5). However, due to the high sorption capacity of D4123 for molybdenum (0.82 mol/L, pH=3.5), mixed bed was made from ion exchangers. It was composed of Purolite D4123 and Lewatit TP 207 (in form of free acid) in volume ratio 1:1. Lewatit TP 207 ion exchanger contains iminodiacetate (IDA) functional group. In this case, sorption was successful at all three initial pHs. The best breakthrough capacities, reached at pH of 3.5, were 0.37 mol/L and 0.37 mol/L for copper and molybdenum, respectively. The concurrent sorption of Cu and Mo on TP207 at pH 4 showed molybdenum breakthrough capacity 0.013 mol/L. Therefore isolated sorption of Mo on TP207 was important to measure. In this case, molybdenum was probably in the form of molybdenyl cation.