| Effects of iron oxides on adsorption of Pb2+ by several loessial soils |
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| DOI：10.7606/j.issn.1000-7601.2017.01.10 |
| Key Words: loessial soil Fe oxides lead chemical selective stripping technique |
| Author Name | Affiliation | | LIANG Hua-xue | College of Resources and Environmental Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China | | WANG Yi-quan | College of Resources and Environmental Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China | | SHI Zong-lin | College of Resources and Environmental Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China | | SHI Hong-ping | College of Resources and Environmental Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China | | WANG Jia-xu | College of Resources and Environmental Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China |
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| Abstract: |
| Considering the ubiquity of iron oxide in soil and the important impact of iron oxide on soil physical and chemical properties, this paper studied the effects of different forms of iron oxide on the adsorption of heavy metals in soil. After removal of different forms of Fe oxide from Loessial soils by chemical selective stripping technique, the adsorption characteristics of Pb2+ on several loessial soils were studied by isothermal adsorption experiments and the Langmuir equation and Freundlich equation were used to analyze Pb2+ adsorption characteristics of soil before and after removal of different forms of iron oxide. The adsorption process of Pb2+ in three kinds of original soils increased gradually, the isotherm curve of Pb2+ adsorbed was more fitted by Freundlich equation and with no significant stage characteristics; after removal of different forms of Fe oxide, the isotherm curve of Pb2+ adsorbed was L-shaped, which was more fitted by Langmuir equation, and the phase characteristics was significant, while the bonding strength and the affinity of lead by soil multiplied; after removal complexing Fe oxides and amorphous Fe oxides in different soils could increase the amount of Pb2+ absorption,and after removal of amorphous Fe oxides, the adsorption amount of Pb2+ by paleosol increased by 14.71 mg·g-1; after removal free Fe oxides, the adsorption amount of Pb2+ by paleosol and eluvial cinnamon soil decreased by 5.95、3.10 mg·g-1 compared to their original soils, but increased by yellow cinnamon soil. In nature soil, the effect of iron oxide on the adsorption capacity of Pb2+ was not entirely depend on the content of iron oxide, but also affected by the state of iron oxide in the soil. Using chemical selective stripping technique to remove different forms of Fe oxide can obtain clay mineral materials with high adsorption capacity. |
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