Evaluation of Quantitative Determination of Dissolved Organic Matter Adsorption Processes Using Charcoals and Activated Carbon

Abstract

In this study the processes of dissolved organic matter (DOM) adsorption by charcoals and activated carbon were quantitatively evaluated by the adsorption rate model. Five types of charcoal and a commercial granular activated carbon (GAC) were used to remove DOM eluted from rice-straw in an adsorption test. The adsorption rate model was considered as the adsorption process in the early steps which showed significant adsorption changes. The results of the adsorption test indicated that the DOM adsorption rate and volume treated by charcoals carbonized at high temperature (group-2) showed significantly higher levels than those of charcoals carbonized at low temperature (group-1). Although group-2 adsorbed less DOM than GAC after 6 hours, the adsorption rate and adsorbed volume of group2 were greater than those of GAC under 6 hours. The results of the evaluation by the adsorption rate model showed that the calculated value agreed well with the measurements obtained from the adsorption test. It was suggested that DOM could move to the adsorption surface of group-2 more rapidly than that of the GAC in the early adsorption process. In the latter process the volume of DOM adsorption from sample water treated by group-2 was exceeded by that of the GAC which has a large specific surface area. The DOM adsorption processes depended on the specific surface area of charcoals/GAC as well as the DOM transfer rate and desorption.