Variation of cationic dye absorption capacity with the sintering temperature of natural montmorillonite clay

Abstract

Development of montmorillonite clay as inexpensive natural absorbent to remove organic anionic dyes from waste water was investigated as the main objective of this study. It was a part of a major project concerning development of local minerals and related materials for low-cost and efficient water purification. The work carried out on investigation of the effect of sintering temperature of the montmorillonite clay on methylene blue adsorption is reported in this paper. It was carried out by sintering the selected clay at different temperatures of 100 -900 0C, followed by an dye adsorption study performed using methylene blue dye. The XRD phase analysis confirmed the existence of appropriate montmorillonite phase in the selected clay. The pore size decreases with the increase of sintering temperature as expected. The endothermic peak was observed at 400 0C due to loss of hydroxyl groups resulting reduction of adsorption above 400 0C. That may result in reduction of reactive sites in clay surface also by minimizing adsorption capacity. Hence this suggests 450 0C as the optimum sintering temperature of this clay, with an adsorption capacity of 12.8 mgg-1 at room temperature, to be used for water filtration application