Swell Behavior of Organo Clay and Organo Clay-Bentonite Mixtures: Fid-Bau Portal

Swell Behavior of Organo Clay and Organo Clay-Bentonite Mixtures

Sreedharan, Vandana / Sivapullaiah, P. V.

A conventional mineral lining system with a minimal hydraulic conductivity is usually found to exhibit no appreciable sorption capacity against most of the organic contaminants. The widespread occurrence of organic contaminants demands the use of an innovative barrier system to address this problem. Organic modification of clay minerals by ion exchange process can render the clay surface to be organophilic and hence organo clays are often suggested as amendments in barrier systems. As the swelling of clays plays a role in controlling the performance of liners, a detailed study on the effect of organic modification on the swell behavior of clays is vital. Further the role of polarity of the pore fluid on the swelling of organo clays also needs to be investigated as most of the organic contaminants contained are of lower polarity. Therefore an experimental study was conducted using conventional oedometer to assess the swell behavior of organically modified and unmodified clays and mixture of organo clay and unmodified clay in pore fluids of different polarity. The organic modification reduced the swell potential of clays in water, and the organically modified clays and their mixtures showed highest swell in low polar fluids. The mechanism of swell in the case of organically moified clays was governed more by the chemical interactions rather than by the dielectric constant of the pore fluid and the role of such interactions are confirmed by the Fourier tranform infrared (FTIR) studies.