| 赵玉婷,王耀晶,应博,杨丹,何娜,刘鸣达.硅对不同pH水田土壤镉吸附热力学特征的影响[J].农业环境科学学报,2017,36(10):2000-2006. |
| 硅对不同pH水田土壤镉吸附热力学特征的影响 |
| Effect of silicon additives on the adsorption thermodynamics of cadmium in paddy soil with different pH levels |
| 投稿时间：2017-02-28 |
| DOI：10.11654/jaes.2017-0245 |
| 中文关键词: 硅 镉 pH 水田土壤 吸附热力学 |
| 英文关键词: silicon cadmium pH paddy soil adsorption thermodynamics |
| 基金项目:国家自然科学基金项目（31040070，41371306） |
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| 摘要点击次数: 1965 |
| 全文下载次数: 2333 |
| 中文摘要: |
| 以硅酸钠为硅源，在中和其碱性和消除钠离子影响的基础上，进行不同温度条件下的吸附等温试验，探讨了加硅对土壤镉吸附热力学特征的影响。结果表明：不同硅水平下，Freundlich方程均可较好地描述三种温度下（25、35、45℃）两种土壤镉的吸附特征；在不同的温度下，加硅均降低了碱性土壤镉的吸附容量、增大了其吸附强度，增加了酸性土壤镉的吸附容量、降低了其吸附强度；两种土壤吸附镉的热力学参数均为△G <0、△H >0、△S >0，说明土壤对镉的吸附均是吸热、熵增的自发过程；加硅后，碱性土壤对镉吸附过程的△G变大、△H变小、△S变小，酸性土壤对镉吸附过程的△G变小、△H变大、△S变大，说明与对照相比，加硅使碱性土壤吸附镉的自发性降低，使酸性土壤吸附镉的自发性提高。 |
| 英文摘要: |
| In previous studies, most silicon additives for soil were alkaline compounds that increased soil pH and introduced potential interfering ions. In this study, the effect of silicon on the adsorption thermodynamics of Cd in paddy soil with different pH levels was investigated through adsorption isotherm experiments. HNO3 was used to neutralize the alkalinity of Na2SiO3, while different concentrations of NO3- and Na+ between treatments were balanced with NaNO3. The results showed that Freundlich adsorption models could fit well to simulate the Cd adsorption characteristics at three different temperatures(25℃, 35℃, 45℃) in two types of soils. Cd adsorption was restricted in alkaline soil but enhanced in acidic soil at different temperatures after the addition of silicon. Thermodynamic parameters showed that the adsorption processes were endothermic and spontaneous, and entropy increased. At increased levels of silicon, △G increased and △H and △S decreased in alkaline soil, whereas △G decreased, and △H and △S increased in acidic soil.This phenomenon indicates that the spontaneity of Cd adsorption decreased in alkaline soil, but increased in acidic soil, with the addition of silicon. |
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