| 梁韵,侯孟彬,张维,王星敏.胶体态及溶解态有机质对土壤镉吸附的影响[J].农业环境科学学报,2023,42(6):1285-1293. |
| 胶体态及溶解态有机质对土壤镉吸附的影响 |
| Effects of colloidal and dissolved organic matters on Cd adsorption in soil |
| 投稿时间：2022-12-01 修订日期：2023-02-07 |
| DOI：10.11654/jaes.2022-1238 |
| 中文关键词: 吸附 Cd 畜禽粪便 胶体 溶解性有机质 |
| 英文关键词: adsorption Cd livestock manure colloid dissolved organic matter |
| 基金项目:重庆市教委科学技术研究项目（KJQN202100807）；重庆市研究生科研创新项目（CYS21402）；重庆工商大学科研项目（2152023） |
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| 中文摘要: |
| 为研究外源细颗粒态有机质对土壤重金属吸附特征的影响，以紫色土坡耕地、冬水田和水旱轮作田土壤为对象，通过吸附动力学试验和等温吸附试验，探索猪粪源胶体态有机质（COM，10~0.45 μm）和溶解态有机质（DOM，<0.45 μm）及其不同初始浓度对土壤镉（Cd）吸附行为的影响。结果表明：准二级动力学方程能更好地描述3种利用方式土壤对Cd的动态吸附（R2>0.90），Langmuir模型能更好地拟合Cd的等温吸附（R2>0.95），供试土壤对Cd的吸附均为强烈的非线性（Freundlich模型非线性指数<0.42）化学吸附。3种利用方式土壤对Cd的吸附强度顺序为水旱轮作田>冬水田>坡耕地，Cd吸附强度与土壤pH、有机质和粉粒含量正相关。猪粪源DOM比COM更能抑制土壤Cd的吸附，且二者均对水旱轮作田土壤吸附Cd的影响最明显。猪粪源COM和DOM初始添加浓度（0~100 mg·L-1，以C计）对土壤Cd吸附量的影响呈现较快（<30 mg·L-1，以C计）降低和平稳非显著增加的特征。对于重金属污染的耕地土壤，在施用外源有机肥时，应同时注重外源DOM和COM对土壤中重金属的潜在活化效应，尤其是降雨径流中重金属的动态变化。 |
| 英文摘要: |
| Organic fertilizer-derived organic matter is an important exogenous factor affecting the fate of heavy metals in soil. In addition to the dissolved organic matter, the effect of colloidal organic matter on the sorption of heavy metals in soil has been rarely investigated. In this study, the sorption kinetics and sorption isotherms of cadmium（Cd）in three soil varieties obtained from sloping farmland, paddy field, and irrigation and non-irrigation rotation field, in the presence and absence of pig manure-derived colloidal organic matter（COM, 10-0.45 μm）and dissolved organic matter（DOM, <0.45 μm）, were investigated. The results showed that the quasi-secondary kinetic equation and Langmuir model were superior in the fitting of sorption dynamics（R2>0.90）and sorption isotherms（R2>0.95）of Cd, respectively. Each soil sample exhibited a strong nonlinear sorption of Cd as indicated by the low Freundlich nonlinearity index（n<0.42）. The sorption intensity of Cd by the three soil samples followed the trend of irrigation and non-irrigation rotation field>paddy field>sloping farmland, which was positively correlated to soil pH, soil organic matter, and silt content. Both COM and DOM exhibited mobilizing effects towards Cd sorption by the three soil samples, with DOM showing a greater impact. Particularly, Cd sorption in the soil from the irrigation and non-irrigation rotation field was affected by COM and DOM more extensively than that in the other two soil samples. Furthermore, a rapid decrease of Cd sorption was observed when COM or DOM were less than 30 mg·L-1（calculated by C）, followed by an insignificant increase thereafter. Therefore, the potential mobilization of heavy metals including but not limited to Cd, especially in the runoff, should be considered upon the application of animal manure to heavy metal contaminated fields. |
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