Effects of Background Dissolved Organic Matter on TCE Adsorption by GAC

Abstract

The effects of dissolved organic matter, reactor configuration, and granular activated carbon (GAC) particle size on equilibrium adsorption of trichloroethylene (TCE) were examined under simultaneous loading and early preloading conditions. Differences in isotherm capacities obtained using batch‐reactor and column‐reactor estimation methods were observed when natural background organic matter and TCE were adsorbed simultaneously onto nonpreloaded GAC. Differences in isotherms derived from the two methods were diminished, however, when the carbon was first preloaded with the background organic matter in a river water in the absence of TCE. Significant increases in isotherm slope were observed with increasing preloading time for GAC of two different particle sizes. Isotherms determined using powdered activated carbon sieved from crushed preloaded GAC had essentially parallel slopes, however, with capacities greater than the parent preloaded GAC over the concentration range of interest. The observed effects were analyzed in the context of a proposed dualistic model for interpretation of interactions among background organic matter, target solutes, and microporous adsorbents.

Removal of nitroimidazole antibiotics from aqueous solution by adsorption/bioadsorption on activated carbon

“…The effectiveness of treatment would be reduced by the competition between dissolved organic matter and TNZ molecules for active sites on the activated carbon, as previously reported [43,44]. Similar values for the fractional capacity of the mass transference zone (˚) were observed in all water samples studied ( Table 9).…”

Humic acid degradation in aqueous solution by the photo-Fenton process

“…Humic materials may be specifically targeted for removal from potable water supplies because they can adversely affect appearance and taste, and they can react with chlorine to form potentially carcinogenic chlorinated organic compounds. Further, the presence of macromolecular dissolved organic matter may reduce the effectiveness of water treatment processes that employ membranes or microporous adsorbents [3][4][5]. Even when not specifically * Corresponding author.…”

“…targeted for removal, macromolecular dissolved organic matter has been shown to compete with low molecular weight synthetic organic chemicals, reducing their adsorption rates and equilibrium capacities [3][4][5]. The removal of (or the reduction in concentration of) such organic matter is therefore an important factor in water treatment.…”

Changes of the porous structure of activated carbons applied in a filter bed pilot operation

“…Pore blockage and direct site competition are generally regarded as the mechanisms most likely to affect activated carbon adsorption of organic micropollutants in the presence of NOM [6,[82][83][84][85][86]. However, the biological processes are not taken account in this study.…”