Method to estimate the size of an adsorber using the breaskthrough curve for unknown multi-component wastewater

Abstract

A simple practical method first proposed by Okazaki et.al. (1989) to predict the breakthrough curve of unknown multi-component wastewater in a fixed bed adsorption column is adopted in the present work. Using only the information for simple jar tests, Okazaki et. al. assumed instantaneous adsorption equilibrium between the unknown solutes and the activated carbon adsorbent. In this work, activated carbon fibers (ACFs) are used as adsorbent. The total concentration of pollutants in the wastewater is given in terms of a comprehensive concentration index, namely, Total Organic Carbon (TOC) concentration index. Synthetic wastewater systems (1- ,2- and 3- component) , tapwater, natural humic substance and domestic factory wastewater are investigated. Based on experimental column test results, the suitability of the present method is examined by comparison between the predicted and observed breakthrough curves as well as the breakthrough times. It is found that the agreement is quite good for the single-solute systems and not so bad for the binary and tertiary systems. In the case of unknown natural humic substance and industrial wastewater, however, the agreement is not good because the assumption of instantaneous adsorption is not valid when the solute molecules are too bulky to enter quickly the micropores of ACF. Nevertheless, the method is still a handy tool to predict the breakthrough time and to size a packed adsorber.