Aqueous and Gaseous Adsorption from Montmorillonite−Carbon Composites and from Derived Carbons

Abstract

Clay-carbon composites and the carbons derived from demineralization of the clay template were examined for their aqueous adsorption properties (2,4,6-trichlorophenol and methylene blue) and for their gas adsorption/separation abilities regarding CO(2), CH(4), and N(2) gases. The sorption results are discussed in relation with their structural properties (surface area, pore width and volume, and surface chemistry). It was found that the properties of the adsorbents depend highly on the synthetic route, for instance, on the use of clay or H(2)SO(4) as structure mediating and activating agents, respectively. Particularly, the simultaneous use of clay and H(2)SO(4) leads to a synergistic action, which imparts to the final solids the highest sorption capacity and the best potential for separation of CO(2) from gaseous mixtures of CH(4) and N(2).

From used montmorillonite to carbon monolayer–montmorillonite nanocomposites

“…Previous studies have shown that this type of nanocomposites has quite wide applications. For example, they can be directly used as adsorbents for organic compounds (Bakandritsos et al, 2005;Putyera et al, 1994), and they have also been used as precursor for synthesizing derivative nanomaterials (Bandosz et al, , 1996Leboda et al, 2005;Zhang et al, 2012). One of the interesting nanomaterials is the graphene-like material, which can be obtained by removing Mt layers from the nanocomposites (Bandosz et al, , 1996Leboda et al, 2005).…”

“…One example is the insitu synthesis of 2D carbon nanomaterials within Mt interlayer spaces. Thanks to its layered structure, expandable interlayers, and chemically inert siloxane surface, Mt has been considered as ideal template for insitu transforming pre-intercalated carbon-rich organic compounds into 2D carbon nanomaterials (Bakandritsos et al, 2004(Bakandritsos et al, , 2005BarataRodrigues et al, 2003;Sakintuna and Yurum, 2005;Xu et al, 2013;Zhang et al, 2012). Polymers have most often been used as precursor in previous studies.…”

“…After calcining at high temperature (e.g., 400-900°C) under the protection of N 2 , the intercalated polymer can be transformed into carbon monolayer within the interlayer spaces of Mt (Bakandritsos et al, 2004(Bakandritsos et al, , 2005Bandosz et al, 1994Bandosz et al, , 1996Xu et al, 2013;Zhang et al, 2012). The resulting carbon monolayer-Mt nanocomposites themselves show special physicochemical properties and applications (Anadão et al, 2011;Bakandritsos et al, 2004Bakandritsos et al, , 2005Zhang et al, 2012), and can be used for synthesizing derivative nanomaterials as well (Xu et al, 2013;Zhang et al, 2012). For example, 2D graphene-like nanomaterials can be obtained by removing Mt layers (Xu et al, 2013).…”

High-pressure adsorption of methane on montmorillonite, kaolinite and illite

“…CH 4 and N 2 have often been used as probe molecules to evaluate the gas adsorption capacity and porosity of Mt and its derivatives (Bakandritsos et al, 2005;Barrer and Reay, 1957;Maes et al, 1997;Volzone and Ortiga, 2004). The estimation parameters of Mt based on N 2 and CH 4 adsorption are comparable (Volzone and Ortiga, 2004) because i) both CH 4 and N 2 are nonpolar molecules and are physically adsorbed on Mt, and ii) the kinetic diameter of CH 4 (0.38 nm) is similar to that of N 2 (0.35 nm).…”

Influence of interlayer species on the thermal characteristics of montmorillonite

“…The former band indicated the incomplete dehydroxylation at 700°C, which was also reported by previous studies (Kloprogge et al, 1999); the later may result from water molecules readsorbed (during the sample preparation process for FTIR characterization) by the abundant micropore and strong hydrophilicity of Al 13 -Mt-700 as discussed above. On the other hand, the absorption band at 1588 cm −1 for MB-Mt-700 arose from the C_C stretching vibration (Bakandritsos et al, 2005;Szabó et al, 2005), implying the formation of graphene-like (sp 2 -hybridized) carbon within the interlayer space.…”