Kim J H, Shin W S, Kim Y H, Choi S J, Jeon Y W, Song D I
Dept. Environ. Eng., Kyungpook National University, Taegu 702-701, Korea.
Water Sci Technol. 2003;47(9):59-64.
Effect of pH on the sorption and desorption of the chlorinated phenols (2-chlorophenol and 2,4-dichlorophenol) in HDTMA-montmorillonite organoclays was investigated using sequential batch experiments. 2,4-dichlorophenol exhibited higher affinity in both sorption and desorption than 2-chlorophenol at pH 4.85 and 9.15. For both chlorophenols, the protonated speciation (at pH 4.85) exhibited a higher affinity in both sorption and desorption than the predominant deprotonated speciation (about 80% and 95% of 2-chlorophenate and 2,4-dichlophenate anions at pH 9.15, respectively). Desorption of chlorinated phenols was strongly dependent on the current pH regardless of their speciation during the previous sorption stage. No appreciable desorption resistance of the chlorinated phenols was observed in organoclays after sequential desorptions. Affinity of both chlorophenols in bisolute competitive sorption and desorption was reduced compared to that in a single-solute system due to the competition between solutes. The ideal adsorbed solution theory coupled with the single-solute Freundlich model successfully predicted the bisolute competitive sorption and desorption equilibria.
采用连续批次实验研究了pH值对HDTMA-蒙脱石有机粘土中氯酚（2-氯酚和2,4-二氯酚）吸附和解吸的影响。在pH 4.85和9.15条件下，2,4-二氯酚在吸附和解吸方面均表现出比2-氯酚更高的亲和力。对于两种氯酚，质子化形态（在pH 4.85时）在吸附和解吸方面均表现出比主要的去质子化形态更高的亲和力（在pH 9.15时，2-氯酚盐和2,4-二氯酚盐阴离子分别约占80%和95%）。氯酚的解吸强烈依赖于当前的pH值，而与它们在前一个吸附阶段的形态无关。在连续解吸后，未观察到有机粘土中氯酚有明显的解吸阻力。由于溶质之间的竞争，与单溶质体系相比，两种氯酚在双溶质竞争吸附和解吸中的亲和力降低。理想吸附溶液理论与单溶质Freundlich模型成功预测了双溶质竞争吸附和解吸平衡。
