Study on Adsorption Effects of Heavy Metal Ions by Reformed Soils with Fixed Ratios of Sodiummodified Bentonite to Soil at Different pH Conditions

The adsorption effects of heavy metals by reformed soils with fixed ratios of 1∶10 and 1∶20 of sodiummodified bentonite (SB) to local soil (LS) at different pH conditions were studied. Heavy metals in the soils were extracted using AB-DTPA method. The results showed that the adsorption effect for heavy metals by reformed soil with ratio of 1∶20 (SB/LS) was better than the reformed soil with 1∶10 (SB/LS). And the reformed soil with ratio of 1∶20 (SB/LS) and at pH=9.14 exhibited the best adsorption effect for heavy metals. The results also showed that in the actual soil remediation, the ratios of remediation materials to local soils and soil pH conditions should be flexible and adjustable for different heavy metal polluted soils.