Fixation Effect of Modified Bamboo Charcoal on Typical Heavy Metals in Sediment

Abstract

In this study, we studied the influence of the dosage of modified bamboo charcoal (KAM-500-400-3) on the fixation effect of single Cu(II)-contaminated and mixed Cu(II)–Cd(II)-contaminated sediment. The results showed that it could effectively fix the heavy metals in both sediment types. In the single Cu(II)-contaminated sediment, when the amount of added KAM500-400-3 was greater than or equal to 5%, the Cu(II) content in the overlying and pore water was substantially reduced, and the form of heavy metal Cu(II) in the sediment changed from the acid-extractable state to a relatively stable, reducible, oxidizable, and residual state, its bioavailability markedly reduced, and the toxic leaching amount of heavy metal TCLP in the sediment also gradually reduced. In the sediment polluted by Cu(II)–Cd(II), the Cu(II) and Cd(II) could not be detected in the overlying or pore water when the addition amount was greater than or equal to 2.5%. The contents of Cu(II) and Cd(II) in the acid-extractable state considerably decreased and they transformed into other forms with low bioavailability, in which the content of Cd(II) in the oxidizable state was so low that it was lower than the detection limit. The TCLP toxicity of the leached amount of Cd(II) also gradually decreased. This showed that adding KAM500-400-3 to sediment helps with inhibiting the release of heavy metals from contaminated sediment into water bodies, so KAM500-400-3 is a material that can effectively adsorb and fix heavy metals Cu(II) and Cd(II) in sediment.