Adsorption of Natural Organic Polyelectrolytes by Activated Carbon:  A Size-Exclusion Chromatography Study

Abstract

The adsorption of several different organic polyelectrolytes from aqueous solution by activated carbon was characterized. Polyelectrolytes included humic acids extracted from peat and soil, polymaleic acid, a synthetic polymer identified as a fulvic acid surrogate, and natural organic matter in Huron River (Ann Arbor, MI) water. Isotherms of individual ultrafiltration size fractions confirmed that smaller molecular size components adsorb to a greater extent on an adsorbent mass basis. The molecular weight distributions of organic polyelectrolytes remaining in solution after equilibration with various amounts of activated carbon were measured with high-performance size-exclusion chromatography (HPSEC). A comparison of molecular weight distributions demonstrated conclusively that small molecular size components are adsorbed preferentially; i.e., adsorptive fractionation on the basis of molecular size occurs. This behavior was observed for each of the wide variety of samples studied, suggesting that it may be a rather general feature of the adsorption of polyelectrolyte mixtures from solution by activated carbon.

Effects of Sodium and Calcium in Lignite on the Performance of Activated Carbon Products

“…The improved linearity of the plot show that the data fit this normalized model approach much better than the conventional Freundlich model. The resulting slope ( n = 0.27) for the high-sodium carbon is, in fact, not too much different from that obtained in the literature for Calgon F400 activated carbon adsorbent with a humate substrate (Kilduff et al, 1996). A different humate was used, so the results cannot be compared exactly.…”

“…To adjust for this complex behavior, the equilibrium concentrations in each experiment were normalized by dividing the unadsorbed humate amount (in mg) by the amount of sorbent (in g) added (Kilduff et al, 1996). The logs of these normalized concentrations (c/m) were then plotted versus the logs of the x/m values for each experiment.…”

Sorption of atrazine onto humic acids (HAs) coated nanoparticles

“…Aquatic humic substances are a category of the most widely distributed organic matters that constitute 30-50% of dissolved organic matter (DOM) in natural aquatic systems [7,8]. HAs has a wide range of molecular size, which ranges from 1 to 50 nm in size [9].…”

“…They could not only cause color, odor and chlorination, but also foul membranes used for water treatment. Many interfacial processes may happen between HAs and particles and adsorption is one of the most important processes that have been reported for their removal [8,10]. Humic acids can adsorb readily onto silicate clay and kaolinite [11][12][13][14].…”

Characteristics of NOM released from soil under different pH conditions: physicochemical properties and activated carbon adsorbability

“…Polydispersity, a parameter calculated by the ratio of computed Mw to Mn (Polydispersity = Mw/Mn) was adopted for evaluating the differences in the heterogeneity of NOM released from soil under different pH conditions and the changes after activated carbon adsorption 3,11) . Like most previous studies 3,4,11,12) , in this study, UV detector was used in the HPSEC system. It is thus important to emphasize that the results obtained were not complete and could only reflect the apparent MW characteristics that could be achieved with the detector since, as well-known that, of the total constituting components of NOM, only those possessing UV absorbing features could be detected with the detector and, even for the detected ones, their molar absorbance might be different.…”