Specific adsorption of molybdenum(VI) on activated carbon and oxine-impregnated activated carbon

The specific adsorption of molybdenum(VI) on activated carbon (Merck Co. Ltd.) and oxine-impregnated activated carbon {AC(HOx)} was studied by using a column method. The amount of molybdenum(VI) adsorbed on activated carbon and AC(HOx) were remarkably dependent on the value of pH. The optimum pH for the adsorption of molybdenum(VI) from 5.00 × 10-3 M molybdenum(VI) solution was 2.0 for activated carbon and AC(HOx) at the flow rate of 1.0 ml/min. The amount of molybdenum(VI) adsorbed on 5 g of the adsorbents was 1.15 g for activated carbon and 0.56 g for activated carbon impregnated with 0.5 g of oxine. The amounts of other metal ions such as copper(II), which were adsorbed on activated carbon and AC(HOx) at pH 2.0, were very small compared with that of molybdenum(VI). From 1.0 M HNO3 solution, 30 mg and 60 mg of molybdenum(VI) could be specifically adsorbed on 5.0 g of activated carbon and 5.0 g of AC(HOx) respectively, but copper(II), zinc(II), nickel(II), lead(II), manganese(II), cobalt(II), chromium(II), iron(III), and cadmium(II) were not adsorbed. The adsorbed quantity of molybdenum(VI) on activated carbon and AC(HOx) in 1.0 M acids increased in the order HNO3