Optimum Bleaching Efficiency of Activated Ntezi Bentonite using Response Surface Methodology

Abstract

The optimization of the bleaching efficiency of acid-activated Ntezi bentonite was studied by reacting raw bentonite with different concentrations of hydrochloric acid solution for varying periods to activate it. The raw and activated samples were characterized using X-ray fluorescence. The activated samples were used to bleach palm oil and the effects of bleaching process variables were investigated using the Response Surface Methodology (RSM). Results of the analysis showed that the structure of the bentonite was altered by the acid activation and this increased the adsorptive capacity of the activated samples. The statistical analysis indicated that the main and quadratic effects of the bleaching process parameters were significant at the 95% confidence level. The optimum conditions were determined to be: reaction temperature 156.66°C; reaction time, 2.74 hours; adsorbent dosage, 5.93 g; adsorbent/oil ratio, 0.04 g/ml; and stirring speed, 411.62 rpm. Under these conditions, the optimum bleaching efficiency was determined to be 85.48%, which agreed with the experimental value of 86.07%. This study showed that Ntezi bentonite can be used as an effective adsorbent under optimized process conditions.