过氧化氢(H2O2)和连二亚硫酸钠-柠檬酸钠-碳酸氢钠(DCB)作为土壤沉积物前处理的经典方法, 对土壤沉积物中黏土矿物的富集有着举足轻重的作用, 但关于二者对黏土矿物的影响研究较少。 运用X射线衍射作为检测技术, 对比研究H2O2和DCB两种前处理方法对红土中黏土矿物的影响。 结果表明, H2O2或DCB处理均可促进土壤矿物颗粒的充分分散, 有效地将石英等杂质分离, 进而提取到很纯的黏土矿物。 同时发现, DCB处理由于其Na+与黏土矿物层间阳离子交换导致数据失真, 而H2O2处理可以保证数据的真实性。 结果表明: 采用H2O2进行前处理能获取较为准确的黏土矿物学信息。

As classical procedures for pretreatment of soil sediments, hydrogen peroxide (H2O2) and sodium dithionite-citrate-bicarbonate (DCB) treatment methods are very important in removing the organic matter and iron oxides acting as cementing agents in the soils. However, both of these methods have less been focused on the effect on the clay minerals when separating. Here, we report the comparable methods between H2O2 and DCB to reveal their effect on clay minerals in red earth sediments using X-ray diffraction (XRD). The XRD results suggested that mineral particles can be totally decentralized by either H2O2 or DCB method in the soils and high purity clay minerals can be obtained by separating quartz and other impurities from clay minerals effectively. However, the XRD data were distorted by the DCB treatment owning to the cation exchange between Na+ and interlayer cation. On the contrary, the authentic data can be obtained by H2O2 treatment. Therefore, the H2O2 treatment seems to be a more appropriate method to obtain authentic information of clay mineralogy when separating of clay minerals from red earth sediments.