Competitive sorption behavior of copper(II) and herbicide propisochlor on humic acids

• Published in: Journal of colloid and interface science 2005-07, Vol.287 (2), p.422-427
• Main Authors: Xu, Zhonghou, Huang, Manxiang, Gu, Qingbao, Wang, Yu, Cao, Yunzhe, Du, Xiaoming, Xu, Duanping, Huang, Qing, Li, Fasheng
• Format: Article
• Language: English
• Subjects: Acetamides - chemistry; Adsorption; Binding, Competitive; Chemistry; Competitive sorption; Copper - chemistry; Cu 2; Exact sciences and technology; General and physical chemistry; Herbicide; Humic acids; Humic Substances; Models, Chemical; Molecular Structure; Propisochlor; Surface physical chemistry
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2005.02.006

The competitive sorption behavior of Cu 2+ and propisochlor on humic acids (HA) was investigated using a batch method. The sorption equilibrium time of propisochlor on HA was 12 h when its initial concentration was 4 or 10 mg L −1. The results showed that the Langmuir model can best describe the sorption behavior of propisochlor on HA. The added Cu 2+ reduced the solid-phase concentration of propisochlor on HA, and the Langmuir model can also describe the sorption behavior of propisochlor on HA when the Cu 2+ concentration is 100 and 200 mg L −1. The sorption of propisochlor on HA did not remarkably affect the sorption of Cu 2+ on HA when the concentration of propisochlor was below 20 mg L −1. Cu 2+ may compete with propisochlor for the sorption sites of HA, such as carboxylic and phenolic groups. It can be concluded that Cu 2+ fast adsorbed to the HA matrix, altered its physical and chemical properties, and thus decreased the solid-phase concentrations of propisochlor on HA. In natural water, Cu 2+ may promote the release of propisochlor from HA, and thus affect its transport, transformation, and fate in the environment.