The measurement of surface areas of some silicates by solution adsorption

In this study, the adsorption from solution technique was used for the dete rmination of surface areas of some silicate samples (bentonite, sepiolite, zeolitic tuff and kaolin). Methylene blue (MB), orthophenanthroline (OP) an d p-nitrophenol (PNP) were selected as solutes. The adsorption data was found to conform with the Langmuir equation within the concentration range studied, and Langmuir constants were determined for each of the samples. The surface area values obtained were compared with those determined by nit rogen adsorption. Also the results were discussed with respect to the catio n exchange capacities of the samples. The specific surface area values of the samples were found to decrease in t he following order: Bentonite > Sepiolite > Zeolite > Kaolin (for MB and OP adsorption) Sepiolite > Bentonite > Zeolite > Kaolin (for PNP and N-2 adsorption).