REMOVAL OF LEAD IN A FIXED-BED COLUMN PACKED WITH ACTIVATED CARBON AND CRAB SHELL

Crab shell particles (Protunus trituberculatus) and activated carbon ( Norit 0,8 SUPRA) were used as packing materials in a fixed-bed column. When 1 g crab shell was added in a column packed with 10 g activated carbon, breakthrough occurred at 1500 bed volumes as compared to 380 b ed volumes for 10 g activated carbon only. The addition of crab shell particles into an activated carbon column resulted in an increased upt ake of lead. The dramatic improvement might be attributed to an increa se in CO32- and OH- available for binding lead. From the results of SE M, XRD, and FT-IR analyses, the major mechanism of lead removal was ba sed on dissolution of CaCO3 in the crab shell followed by precipitatio n of Pb-3(CO3)(2)(OH)(2(s)) on the surface of activated carbon. The le ad uptake increased twofold when the influent lead concentration was i ncreased from 10 to 50 mg/L.