Assessment of the surface areas of silica and clay in acid-leached clay materials using concepts of adsorption on heterogeneous surfaces

Ethylene Adsorption on Acid-Treated Clay Minerals

“…Similarly, acid activation of the kaolinite and bentonite samples resulted in increased specific surface areas (see Table 1). Similar results have also been observed by other workers when sepiolites, bentonites and kaolinites were treated with acid solutions (Vermeiren et al 1999;Önal et al 2002;Grim 1962;Srasra et al 1989;Myriam et al 1998). The increase in the specific surface area brought about by acid treatment is due to the dissolution of impurities, the replacement of the exchangeable cations with hydrogen ions and also the disaggregation of particles (Vermeiren et al 1999;Srasra et al 1989;Novak and Cicel 1978;Nguetnkam et al 2005).…”

“…During acid treatment, cations are leached from the octahedral and tetrahedral sheets, impurities such as calcite and dolomite are dissolved and exchangeable cations are replaced by hydrogen ions. All these changes give rise to an increase in the specific surface area of the clays (Christidis et al 1997;Lazarevic et al 2007;Panda et al 2010). There are many reports regarding the structural and textural properties of clays after acid treatment (Christidis et al 1997;Volzone and Ortiga 2006;Önal et al 2002;Grim 1962;Srasra et al 1989;Myriam et al 1998;Balcı 1999).…”

“…All these changes give rise to an increase in the specific surface area of the clays (Christidis et al 1997;Lazarevic et al 2007;Panda et al 2010). There are many reports regarding the structural and textural properties of clays after acid treatment (Christidis et al 1997;Volzone and Ortiga 2006;Önal et al 2002;Grim 1962;Srasra et al 1989;Myriam et al 1998;Balcı 1999). Nevertheless, only a limited number of studies have been carried out on the adsorption of ethylene by clay-based samples and other natural adsorbent materials.…”

Controlled fluorination of clays

“…More compacted aggregates are also observed. This is consistent with the reported SEM micrographs for bentonite [34,35]. However, smaller platlet sizes for the fluorinated samples compared to the untreated samples are clearly seen in the micrograph for treated sample.…”

The Degradation Mechanisms Study of the Organoclay by Using the Nitrogen Absorption/Desorption and X-ray Diffraction

“…Thus, organoclay degradation becomes an issue that must be considered when forming polymer nanocomposites by melt processing. Although there are loads of the reports about the organoclay degradations during the melt process [8][9][10][11][12][13][14][15][16][17][18][19][20][21], the details about the mechanic of degradation are still unclear which is of prime importance to the understanding of organoclay degradation.…”