Regina O. Ajemba
The Physico-chemical properties of Udi clay mineral were modified in this work to increase its adsorptive performance. The Udi clay was mined from Eke town, separated from dirt, washed, sun-dried, and grinded to a particle size of 0.045mm. The modification of the sized samples were done by two physico-chemical methods; thermal activation at different temperature range of 100 to 500 0C and acid activation at different concentrations of sulphuric acid ranging from 2 to 10M. The physicochemically modified samples were characterized using X-ray fluorescence, Fourier transform infrared (FTIR) spectroscopy, and Brunner-Emmet-Teller (BET) method for surface area. The modified samples were used to bleach palm oil to investigate their adsorptive performance. The equilibrium data were analyzed using Langmuir and Freundlich adsorption isotherms. Results of the characterization showed that the modified samples had more surface area and adsorptive capacity than the raw samples. The surface area was increased to more than three times and four times that of the raw sample for the thermal and acid activated samples, respectively. The bleaching efficiency increased from 29.67% to 75.3% and 92.74%, for thermally and acid activated samples, respectively. Results of the equilibrium analysis showed that the adsorption of colour pigment onto the thermally and acid modified samples occurred in multi-layer in agreement with Freundlich isotherm model. This study has shown that local clay from Udi can be thermally and chemically activated to modify the physico-chemical properties which increase its adsorptive capacity.
