| Abstract: | The molecular weight of humic substances influences their proton and metal binding, organic pollutant partitioning, adsorption onto minerals and activated carbon, and behavior during water treatment. We propose a lognormal model for the molecular weight distribution in aquatic fulvic acids to provide a conceptual framework for studying these size effects. The normal curve mean and standard deviation are readily calculated from measured M(n) and M(w) and vary from 2.7 to 3 for the means and from 0.28 to 0.37 for the standard deviations for typical aquatic fulvic acids. The model is consistent with several types of molecular weight data, including the shapes of high- pressure size-exclusion chromatography (HP-SEC) peaks. Applications of the model to electrostatic interactions, pollutant solubilization, and adsorption are explored in illustrative calculations.The molecular weight of humic substances influences their proton and metal binding, organic pollutant partitioning, adsorption onto minerals and activated carbon, and behavior during water treatment. We propose a log-normal model for the molecular weight distribution in aquatic fulvic acids to provide a conceptual framework for studying these size effects. The normal curve mean and standard deviation are readily calculated from measured Mn and Mw and vary from 2.7 to 3 for the means and from 0.28 to 0.37 for the standard deviations for typical aquatic fulvic acids. The model is consistent with several type‘s of molecular weight data, including the shapes of high-pressure size-exclusion chromatography (HP-SEC) peaks. Applications of the model to electrostatic interactions, pollutant solubilization, and adsorption are explored in illustrative calculations. |
| Genre: | Article |
| ProdID: | 70022864 |
| Citation Author: | Cabaniss, S. E.; Zhou, Q.; Maurice, P. A.; Chin, Y. -P.; Aiken, G. R. |
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| Citation End Page: | 1109 |
| Citation Issue: | 6 |
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| Citation Language: | English |
| Citation Larger Work Title: | Environmental Science and Technology |
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| Citation Number Of Pages: | 7 |
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| Citation Publisher: | ACS |
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| Citation Search Results Text: | A log-normal distribution model for the molecular weight of aquatic fulvic acids; 2000; Article; Journal; Environmental Science and Technology; Cabaniss, S. E.; Zhou, Q.; Maurice, P. A.; Chin, Y. -P.; Aiken, G. R. |
| Citation Start Page: | 1103 |
| Citation Volume: | 34 |
| Citation Year: | 2000 |
| Type: | citation/reference |
| Text: | A log-normal distribution model for the molecular weight of aquatic fulvic acids; 2000; Article; Journal; Environmental Science and Technology; Cabaniss, S. E.; Zhou, Q.; Maurice, P. A.; Chin, Y. -P.; Aiken, G. R. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1021/es990555y |
| Date Other: | Sat, 1 Jan 2000 00:00 -0600 |
| Publisher: | ACS |
