Removal of Low Concentrations of Cadmium from Water Using Improved Rice Husk

Abstract

This paper studies the effect of different molarities of sodium bicarbonate on enhanced absorption capacity of rice husk to remove cadmium in low concentrations. Maximum absorption efficiency was achieved at a pH of 6 and absorption equilibrium time was 1.5 hours. Results of chemical experiments and photography by electronic microscope from improved rice husk revealed a good relationship to exist between number and average diameter of absorber pores, on the one hand, and absorption efficiency, on the other. Meanwhile maximum absorption efficiency of rice husk in cadmium removal was 99.1 percent which shows improvement due to 0.3 molar sodium bicarbonate. In this study, kinetic absorption models were also studied. Both Lagergrn (1898) and Ho et al. (1996) models satisfactorily described data with a confidence level of 95 percent; however, the latter model was found superior in this respect. Comparison of the coefficients calculated here with those reported in other models showed a faster cadmium absorption rate by improved rice husk due to 0.3 molar sodium bicarbonate.

Keywords

• Rice husk
• cadmium
• Absorption
• Sodium Bicarbonate Solution
• Porosity