Determining Heavy Metal (loid) Stabilization Materials and Optimum Mixing Ratio: Aqueous Batch test

초록

Acid mine drainage sludge (AMDS) has been classified as mine waste and generally deposited in land. For thisreason, studies have been conducted to examine the possibility of recycling AMDS as an amendment forheavy metal stabilization in soil. The main objective of this study was to evaluate heavy metal stabilizationefficiency of AMDS comparing with the widely used lime stone. Also, optimum mixing ratio was evaluatedfor enhancing heavy metal stabilization. AMDS and limestone were mixed at the ratio of 0:100, 25:75, 50:50,75:25, and 100:0 with five different heavy metal solutions (100 mg L-1 of NaAsO2, CdCl2, CuCl2, Pb(NO3)2,and ZnSO4·7H2O). The amendments were added at a rate of 3% (w/v). In order to determine the stabilizationkinetics, samples were collected at different reaction time of 0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024minutes. The heavy metal stabilization by AMDS was faster and higher than those of limestone for allexamined heavy metals. While limestone showed only 20% of arsenic (As) stabilization after 1,024 minutes,96% of As was stabilized within 1 minute by AMDS. The highest effect on the stabilization of heavy metal(loid) was observed, when the two amendments were mixed at a ratio of 1:1. These results indicated thatAMDS can be effectively used for heavy metal stabilization in soil, especially for As, and the optimum mixingratio of AMDS and lime was 1:1 at a rate of 3% (w/v).

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