Study of the adsorption kinetics of trichlorethylene from aqueous solutions
The kinetics of adsorption deals with the questions of determining the rate of adsorption and the adsorption capacity of adsorbent granules and the issues of adsorptive diffusion in single granules. Therefore, the study of kinetics is one of the most important issues in the study of adsorption. The research of kinetics of trichloroethylene adsorption from water solution on active carbon (A.C.) of grades CKD-515, PFC, CoAC, Puerolate - Standard was made. The primary information on the adsorption rate obtained during the experiment, i. e. the rate of granule saturation by adsorbate is represented by kinetic curves, which characterize the change in the value of adsorption with time. The mechanism of mass transfer during trichloroethylene adsorption on A.C. of explored grades was studied, and kinetic curves describing change in value of adsorption in time were built. The kinetic curves were analyzed in coordinates γ vs τ. Dependence data allow finding out the model of active carbon granules structure. One of the objectives of this study is to find a controlling type of mass transfer, which can be solved using the method developed by R.М. Marutovsky. For this purpose dimensionless kinetic parameters T were calculated and graphs of T (calculated theoretically) versus τ (experimental process time) were plotted for the same γ values. It was determined that for the system “active carbon - water solution of trichloroethylene” the limiting stage of adsorption process in interval 7-40 minutes depending of active carbon characteristic is external diffusion. Coefficients of external mass transfer for explored carbon are calculated, their magnitudes are close and have fairly high values, which indicates high speed of sorption process limiting by external mass transfer. Data for engineering calculation of adsorption column parameters are found.