The effects of GAC adsorption on DOM structure and size distribution changes with time

Abstract

The primary objectives of this study were to investigate the effects of granular activated carbon (GAC) adsorption on dissolved organic matter (DOM) and changes in structure and size distribution with time to establish the interrelationships between its breakthrough and size distribution through pilot-scale and rapid small-scale column testing (RSSCT). Results indicate that most hydrophobic DOM (HPO) was removed at the beginning of testing, and the removal efficiency decreased with time. In addition, hydrophilic DOM concentration was unchanged. Therefore, it was determined that HPO and transphilic DOM (THP) was affected by GAC adsorption. Moreover, organic matter of the 1-3 K size range was affected the most by GAC adsorption. As GAC breakthrough progressed, number average molecular weight (Mn) increased slowly. The rho index, which represents the weight average molecular weight:Mn ratio and is used to determine polydispersivity, peaked at the beginning of RSSCT. As bed volumes increased with the progress of adsorption, rho decreased.