Bentonite collected from Nowshera (Pakistan) was treated with NaCl, and the < 2-μm clay fractions were separated by sedimentation process. The textural changes in NaCl treated purified bentonite were compared with raw and physically purified sample. It was detected that the NaCl-treated purified bentonite and the sample purified by simple sedimentation, respectively, consist of sodium-montmorillonite and calcium-montmorillonite as a major clay mineral. The honeycombed-type morphology was observed for both the purified samples; however, the particles of NaCl treated purified bentonite were relatively in a compact form. The particle sizes of both the purified samples were found considerably smaller. The high volume percent of the fine particles was noticed in the NaCl-treated purified bentonite. This attributed that the sodium exchange has a valuable impact on the bentonite dispersion in aqueous media during particle size measurement. The relatively high mesopore area/volume and micropore area/volume and specific surface area (SSA) were detected in purified samples. The NaCl-treated purified sample showed relatively high mesopores area/volume than the sample obtained by simple sedimentation. These changes seem to be originated from either high montmorillonite contents and/or the smaller particle size, which might be produced after the layer re-arrangement during the interlayer cation replacement by Na + ions. The large SSA and high porosity of purified samples particularly the NaCl-treated bentonite suggest their potential use as adsorbents, catalysts, pharmaceuticals, and cosmetics.

中文翻译：

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NaCl处理前后物理净化引起Nowshera（巴基斯坦）Ca-膨润土质构变化的研究

从 Nowshera（巴基斯坦）收集的膨润土用 NaCl 处理，< 2-μm 粘土部分通过沉降过程分离。将 NaCl 处理的纯化膨润土的质地变化与原始和物理纯化样品进行比较。经NaCl处理的纯化膨润土和简单沉淀纯化的样品分别由钠蒙脱石和钙蒙脱石作为主要粘土矿物组成。两种纯化样品均观察到蜂窝状形态；然而，NaCl 处理的纯化膨润土颗粒相对紧密。发现两种纯化样品的粒径都小得多。在 NaCl 处理的纯化膨润土中观察到高体积百分比的细颗粒。这归因于在粒度测量期间，钠交换对水性介质中的膨润土分散具有重要影响。在纯化样品中检测到相对较高的中孔面积/体积和微孔面积/体积和比表面积 (SSA)。与通过简单沉淀获得的样品相比，NaCl 处理的纯化样品显示出相对较高的中孔面积/体积。这些变化似乎源于高蒙脱石含量和/或较小的粒径，这可能是在层间阳离子被 Na + 离子置换期间层重新排列后产生的。纯化样品的大 SSA 和高孔隙率，特别是 NaCl 处理的膨润土，表明它们具有作为吸附剂、催化剂、药物和化妆品的潜在用途。