Effects of adsorption characteristics of different amendments on heavy metals (Pb, Zn, and Cd)

Abstract

Different amendments have diverse adsorption capacity for heavy metals. The objectives of this study were to evaluate adsorption efficiency of different kinds of amendments for heavy metals and to provide theoretical guidance for alleviation of heavy metals. The indoor oscillating experiments were carried out to investigate the adsorption efficiency of five amendments (i.e., lime, illite ilerite, ground phosphate rock, chitin, and corn straw charcoal) for adsorption capacity of heavy metals (i.e., Zn, Pb, and Cd). The adsorption efficiency of lime for Zn and Cd was 99.64% and 99.99% followed by chitin with adsorption efficiency of 74.94% and 81.63% respectively. The adsorption efficiency of amendments for Pb, Zn, and Cd was increased gradually with adsorption time. The adsorption efficiency has gradually reached a stable stage after certain time. In addition to adsorption of Pb by corn straw charcoal, the other four materials (i.e., lime, illite ilerite, ground phosphate rock, and chitin) have reached equilibrium when pH value was 3. The adsorption efficiency of lime (1%) for Zn was highest (99.98%). The adsorption efficiency of other materials for Pb was enhanced with increase in dosage except for chitin; however, the unit adsorption capacity was not decreased. It is concluded that adsorption efficiency of lime and chitin for heavy metals such as Zn, Pb, and Cd was more than illite ilerite, ground phosphate rock, and corn straw charcoal, which can be considered as an active sorption materials.