Chemical and Thermal Characterization of a Clayey Material Found Near Gaborone Dam

Mineralogical studies were carried out on clayey material found near the water dam in Gaborone city, in Botswana, in order to deduce its chemical composition. Samples of the material were subjected to chemical elemental, thermal and cation exchange capacity analyses. Traces of Kaolinite were found together with quartz and microcline. The chemical formula was found to be FeSiAl6O10(OH)6

A STUDY OF THE ADSORPTION OF DYES FROM THEIR AQUEOUS SOLUTIONS BY MORUPULE COAL 1

The adsorption of methyl orange (MO) from its solution by steam activated coal from Morupule colliery was investigated spectrophotometrically using the batch technique, through kinetics and thermodynamics’ study, and found to be reversible at all temperatures used. This was to check whether the coal could be used to purify dye-polluted water from dying and printing textile industry. The effects of varying methyl orange concentration, solution pH and temperature were investigated. The adsorption rate and the adsorption capacity increased with increasing initial concentration, with decreasing solution pH and with increasing temperature. The adsorption capacity was generally low probably due to the low coal surface area (10 m2g-1). The increase in rate and capacity with increasing temperature is believed to be increased surface area due to the swelling of coal which accompanies its heating.  The adsorption kinetics fitted the Lagergren pseudo second order model best indicating overall third order or dual simultaneous pseudo first order processes. Results from the thermodynamic study fitted  Freundlich model best indicating heterogeneity of the surface of the coal sample.Â

<b>Characterisation of silica surfaces III: Characterisation of aerosil samples through ethanol adsorption and contact angle studies</b>

Aerosil samples, heat treated and then silylated with various silanes at various temperatures have been characterised by adsorption of ethanol at 293 K. Adsorption isotherms were plotted and the BET specific surface areas were determined. Contact angles were measured by the captive bubble method at the three phase contact line in ethanol, on glass slides similarly modified. Silylation was found to alter the ethanol adsorptive properties on aerosil and increase the contact angles on the glass slides to extents that depend on the silane used as well as the concentration of residual silanols and that of surface silyl groups

Chemical and Thermal Characterization of a Clayey Material Found Near Gaborone Dam

Mineralogical studies were carried out on clayey material found near the water dam in Gaborone city, in Botswana, in order to deduce its chemical composition. Samples of the material were subjected to chemical elemental, thermal and cation exchange capacity analyses. Traces of Kaolinite were found together with quartz and microcline. The chemical formula was found to be FeSiAl6O10(OH)6