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| Effect of added silicon on adsorption-desorption characteristics of cadmium on paddy soil with different pH |
| Received:December 03, 2016 |
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| KeyWord:silicon;cadmium;paddy soil;adsorption;desorption |
| Author Name | Affiliation | E-mail | | LIU Ming-da | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | LI Cai | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | ZHAO Yu-ting | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | YING Bo | Liaoning Environmental Monitoring and Experiment Center, Shenyang 110161, China | | | YANG Dan | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | HE Na | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | WANG Yao-jing | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China
College of Science, Shenyang Agricultural University, Shenyang 110866, China | wyjsau@163.com |
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| Abstract: |
| Adsorption-desorption isotherm experiments were conducted to investigate the effects of silicon on adsorption-desorption characteristics of cadmium on paddy soil with different pH.HNO3 was used to neutralize the alkalinity of Na2SiO3. NaNO3 was added to keep constant electrolyte concentrations in all the treatments. The effects of silicon addition on soil pH and the influence caused by the attendant ion were eliminated. The results showed that the Freundlich model was optimal to simulate the adsorption-desorption process among the three isothermal absorption-desorption models(Langmuir, Freundlich and Temkin). Compare with the control treatment, the alkaline soil showed higher adsorption constant(k value increases and n value decreases), while the acid soil showed lower adsorption constant(k value decreases and n value increases) with increasing silicon addition. Furthermore, the desorption amount and rate of silicon decreased with increasing silicon addition in two soils, and the hysteresis was enhanced. When adding the same amount silicon, the effects of adsorption-desorption of cadmium on the two soils were different:the adsorption and desorption capacity of cadmium in alkaline soil was decreased, and the adsorption capacity of cadmium in acid soil increased and desorption capacity decreased. Both of the two soils demonstrated that the desorption amount was decreased with increasing silicon addition, while the increasing lag coefficients stimulated hysteresis effects of adsorption-desorption. |
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