PT06 Organic, Metallic, Organometallic Pollutants
Exhibit Hall
8:00 AM - Tuesday
(PT093) Sorption and desorption of 2,4,6-trichlorophenol by and from clay minerals and humic acid-modified clay minerals.
Shan, Xiao-quan1, Wang, Xiao-ping2, Zhang, Shuzheng3, Wen, Bei4, 1 Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, Beijing, China2 Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, Beijing, China3 Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, Beijing, China4 Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, Beijing, China
ABSTRACT- Sorption and desorption of 2,4,6-trichlorophenol (2,4,6-TCP) by and from humic acid-modified K+- and Ca2+-montmorillonite and -illite were compared with unmodified ones using batch-equilibration methods. More 2,4,6-TCP was sorbed to K+- and Ca2+-illite than to K+- and Ca2+-montmorillonite with higher charged-density. K+-clays was more effective sorbent for 2,4,6-TCP than Ca2+-clays. In order to study the role of soil minerals and organic matter in sorbing 2,4,6-TCP these soil components were utilized individually or in combination as a sorbent. The humic acid-modified Ca2+- and K+-montmorillonite and Ca2+- and K+-illite caused increased sorption of 2,4,6-TCP. The sorption nonlinearity of 2,4,6-TCP on Ca2+- and K+-montmorillonite was also reduced by humic acid modification. However, less influence of humic acid modification on the sorption nonlinearity of 2,4,6-TCP were observed for Ca2+- and K+-illite. Moreover, humic acid-modified K+- and Ca2+-montmorillonite resulted in a pronounced desorption hysteresis of 2,4,6-TCP, desorption hysteresis was more remarkable with the increase in the proportion of humic acids in the modified K+- and Ca2+-montmorillonite. But it was not the main reason for desorption hysteresis of 2,4,6-TCP from humic acid-modified K+- or Ca2+-illite. Humic acids had minor influence on the desorption hysteresis of 2,4,6-TCP from humic acid-modified K+- and Ca2+-illites. The sorption nonlinearity and desorption hysteresis of 2,4,6-TCP were ascribed to the formation of more rigid (condensed) humic acid structures on the mineral surface, whereas the amosphrous humic acids play a minor role in both sorption nonlinearity and desorption hysteresis.
Key words: montmorillonite, Sorption and desorption , 2,4,6-trichlorophenol , illite