对氯苯酚在石墨上的吸附行为及其机理研究

Adsorption characteristics and mechanisms of p-chlorophenol by graphite

通过静态吸附实验探讨了对氯苯酚在石墨表面的吸附行为及其机理.结果表明,在pH值<3的条件下,对氯苯酚可与溶液中的H+发生H+–π作用,导致其吸附量有所降低;在pH值>7的条件下,随着pH值上升,对氯苯酚的水溶性增加且与石墨表面的静电斥力增强,对氯苯酚在石墨表面的吸附量显著下降.离子强度对该吸附行为无明显影响.对氯苯酚与石墨表面芳环结构之间的π–π作用是占主导地位的吸附驱动力,而疏水力和静电力作用在该吸附过程中不占主导地位.

Adsorption of p-chlorophenol by graphite and mechanisms was investigated by batch adsorption experiments. And the adsorption was decreased both below pH 3 and above pH 7. H^＋-π interaction between p-chlorophenol molecules and protons was the primary reason for the slight decrease in p-chlorophenol adsorption by graphite below pH 3. Dramatic decrease in p-chlorophenol adsorption above pH 7 was probably caused by its increased solubility in water and elevated electrostatic repulsion experienced by adsorbate molecules on graphite surfaces. Ionic strength did not have significant impact on the adsorption. The major driving force for adsorption of p-chlorophenol on graphite was suggested to stem from the π-π interaction between the aromatic rings of graphite and p-chlorophenol molecules.