Adsorption of dyes using shale oil ash

The adsorption of reactive dyes on shale oil ash has been investigated duri ng a series of batch adsorption experiments. The adsorption isotherm data w ere fitted to Langmuir isotherm. The two-resistance mass transfer model has been developed based on the film resistance and homogeneous solid phase di ffusion. A computer program has been developed to estimate the theoretical concentra tion-lime dependent curves and to compare them with the experimental curves by means of the best-fit approach. The model predicts that the external ma ss transfer coefficient K was not affected by varying the initial dye conce ntration, but it increases when the agitation speed and temperature was rai sed. The diffusion coefficient D was Found to increase when the initial dye concentration, and temperature was raised. (C) 2000 Elsevier Science Ltd. Ail rights reserved.