title: Effects of humic substances on the decomposition of 2,4-dichlorophenol by ozone after extraction from water into acetic acid through activated carbon.
abstract: The objectives of this study are to clarify the behavior of humic substances throughout the processes of 2,4-dichlorophenol (2,4-DCP) adsorption on granular activated carbon (GAC) from water and extraction into acetic acid, and the influence of the extracted humic substances on the decomposition of 2,4-DCP by ozone in the acetic acid. The adsorption capacity of GAC for 2,4-DCP was not influenced by the humic substances preloaded to have equilibrium concentration of 24.9mg Cl(-1) (14.5mg Cg(-1)). The adsorption capacity of GAC for 2,4-DCP decreased to one tenth of new GAC after the first adsorption-extraction step because of only 16% desorption in the first step. However, 2,4-DCP adsorbed on GAC was completely extracted after the second step suggesting that GAC can be used as adsorbent to transfer 2,4-DCP from water to acetic acid. The concentration ratio of 2,4-DCP from water into acetic acid was around 2x10(5), whereas the concentration ratio of humic substances was about 3.5, indicating that 2,4-DCP was selectively adsorbed and extracted by this system. The first order degradation rate constant for 2,4-DCP by ozone in acetic acid increased with the addition of humic substances. The rate constant with 16mg Cl(-1) of humic substances was 2.6 times as high as that without humic substances. Humic substances behaved as a promoter for the degradation of 2,4-DCP by ozone.
authors.affiliation: Department of Material Science and Chemical System Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima City, Hiroshima 739-8527, Japan. okawa@fukuoka-u.ac.jp
authors.forename: Kiyokazu
authors.initials: K
authors.lastname: Okawa
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nakano
authors.forename: Wataru
authors.initials: W
authors.lastname: Nishijima
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Okada
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000327:Adsorption; D002606:Charcoal / Q000737:chemistry; D002733:Chlorophenols / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D006812:Humic Substances / Q000032:analysis*; D007700:Kinetics; D010126:Ozone / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D002733:Chlorophenols; D006812:Humic Substances; D014867:Water; D002606:Charcoal; D010126:Ozone; D019342:Acetic Acid; C004762:2,4-dichlorophenol