Optimization of palm oil bleaching with Anfoega kaolin clay: a local solution

Abstract The bleaching properties of locally acid-activated Anfoega kaolin clays have been studied to investigate their applicability as a substitute for the expensive imported acid-activated bleaching clays used in vegetable oil refinery industries in Ghana. The clay was characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrophotometer, and scanning electron microscopy (SEM). The bleaching properties of the clay were investigated by varying the clay dosage, acid concentration, and bleaching temperature. Activation of the Anfoega kaolin clay at 100 °C and 2.5 h with constant stirring was found to be optimum conditions of temperature and contact time, respectively. The clay/acid ratio was found not to significantly affect the clay properties. Palm oil was used to investigate the bleaching performance of the activated clay samples. When the oil was bleached at 90 °C for 30 min using 10% wt/vol of oil, clay activated with 2 mol/L H 2 SO 4 , the bleaching performance obtained was up to 94.54%. Response surface plot methodology revealed that the optimal bleaching conditions were achieved with a clay dosage of 10 g, a temperature range of 70 to 120 °C, and a bleaching duration of 60 min resulting in a bleaching efficiency of 81%.