Batch Adsorption Kinetics in Sewage—Activated Carbon

Batch adsorption experiments using a well-mixed system of secondary effluent domestic waste water and granular activated carbon were performed, and the rate of decay of organic contaminants associated with bacterial action was determined. These results were used to establish that a Freundlich type adsorption isotherm characterized the system and that the decay of organic solutes by bacteria could be represented by a modified first order rate expression. Comparison of the experimental concentration histories, expressed in terms of the total organic carbon content of the liquid phase, with theoretical results for two assumed mass transfer models (internal diffusion and pore diffusion) permitted evaluation of diffusion coefficients for the system. For internal diffusion the coefficients ranged between 1.6 x 10-9 sq cm per sec and 2.6 x 10-8 sq cm per sec, while for pore diffusion the range was from 3.4 x 10-9 sq cm per sec to 1.6 x 10-7 sq cm per sec.