Influence of physico-chemical properties of soil clay fractions on the retention of dissolved organic carbon
Influence of physico-chemical properties of soil clay fractions on the retention of dissolved organic carbon
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DOI：
10.1007/s10653-017-9939-0
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发表时间：
2017-03
影响因子：
4.2
通讯作者：
Mandeep Singh;B. Sarkar;S. Hussain;Y. Ok;N. Bolan;G. Churchman
中科院分区：
文献类型：
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作者：
Mandeep Singh;B. Sarkar;S. Hussain;Y. Ok;N. Bolan;G. Churchman
研究了高岭石-伊利石、蒙皂石和水铝英石3种粘粒组分（SCFs）表面官能团、阳离子交换量（CEC）、表面电荷、倍半氧化物和比表面积（SSA）对土壤溶解性有机碳（DOC）持留的影响。去除天然碳和/或倍半氧化物之前和之后的SCFs的物理化学性质进行了表征，DOC吸附-解吸试验通过一个批次的方法进行。天然有机碳（OC）/倍半氧化物去除处理导致高岭土伊利石的CEC值的变化不大，但在蒙脱石和水铝英石的显着变化。净负表面电荷增加，在所有样品中的pH值的增加，表明其可变的电荷特性。去除原生OC导致土壤粘土表面的净正电荷略有增加，而倍半氧化物去除增加了负电荷。SCF表面官能团的变化导致CEC和zeta电位值的变化。Langmuir最大DOC吸附量（Qmax）与SSA之间存在较强的相关性（R2= 0.93，p < 0.05）。Qmax值与zeta电位（pH 7）呈中等程度的正相关（R2= 0.55，p < 0.05），与CEC和天然OC含量的相关性较差。因此，沿着SSA，SCFs的表面电荷和官能团在决定DOC在土壤中的吸附亲和性和保持性方面起着关键作用。
This study investigated the effects of surface functional groups, cation exchange capacity (CEC), surface charge, sesquioxides and specific surface area (SSA) of three soil clay fractions (SCFs) (kaolinite–illite, smectite and allophane) on the retention of dissolved organic carbon (DOC) in soils. Physico-chemical properties of the SCFs before and after removing native carbon and/or sesquioxides were characterised, and the DOC adsorption–desorption tests were conducted by a batch method. Native organic carbon (OC)/sesquioxide removal treatments led to a small change in the CEC values of kaolinite–illite, but significant changes in those of smectite and allophane. The net negative surface charge increased in all samples with an increase in pH indicating their variable charge characteristics. The removal of native OC resulted in a slight increase in the net positive charge on soil clay surfaces, while sesquioxide removal increased the negative charge. Changes in the functional groups on the SCF surfaces contributed to the changes in CEC and zeta potential values. There was a strong relationship (R2= 0.93,p< 0.05) between the Langmuir maximum DOC adsorption capacity (Qmax) and SSA. TheQmaxvalue also showed a moderately strong relationship (R2= 0.55,p< 0.05) with zeta potential (at pH 7).Qmaxwas only poorly correlated with CEC and native OC content. Therefore, along with SSA, the surface charge and functional groups of SCFs played the key role in determining the adsorption affinity and hence retention of DOC in soils.