Kraft lignin adsorption of alachlor and chloramben as a controlled-release function evaluation.
1994
Riggle B.D. | Penner D.
The experimental nonsulfonated kraft lignin, PC940C, had similar adsorption patterns for both [14C]alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] and [14C]chloramben (3-amino-2,5-dichlorobenzoic acid) as measured over a 60 min holding time. In the first 10 min, both compounds were rapidly adsorbed to the lignin, suggesting adsorption to readily available surface sites, while from 10 to 60 min, approximately one-third more [14C]chloramben, of the total available in solution, was adsorbed as compared to [14C]alachlor. On the basis of these results and in view of an earlier desorption study that found approximately 60% more of the total available [14C]-chloramben was desorbed from PC940C as compared to [14C]alachlor, the following is proposed. The chloramben aromatic amino group formed ionic bonds with the lignin's carboxylic and phenolic groups. This allowed for more adsorption of chloramben by the lignin and allowed for a more rapid desorption of chloramben through an ion-exchange mechanism. The adsorption/desorption characteristics for alachlor suggest hydrogen bonding to the lignin.
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