Adsorption of heavy metals on a modified activated carbon

Gryfskand's WD-extra activated C, de-ashed and oxidized 1 hr./400 degrees C in air, bulk d. 336 g/l.,was used to sorb Pb and Cd from aq. 2, 5, or 7 mmols/l. solns., or from (7.2, 1:1, and 2:7) 9-mmols/l. mixts., each passed at 125 mu m/s through a column (wet bed, 5 g., 8.5 cm high; liq. holdup 10 ml.). In either sorption, the Pb/Cd capacities corresponding to breakthrough ps. were 2:1. The Pb/Cd total sorption capacity ratio was 2:1 in each individual sorption. In mixts. it varied with the initial concn. of either metal. In 2, 4.5 and 7-mmol/l. mixt. solns., the sorption capacity ratios were 5:1, 3:1 and 2:1, resp. With the modified C, the sorption capacities were 7 and 3 times as high toward Pb and Cd as those with the non-modified C, resp.