Role of the surface chemistry of activated carbons in dye removal from aqueous solution

Hua-lei Zhou，Wen-juan Zhen，Qian Zhu，Xiao-bin Wu，Zhi-dong Chang，Wen-jun Li

Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, School of Chemistry and Biological Engineering, University of Science and Technology Beijing

摘 要：Commercial activated carbons were modified by a series of chemical or physical treatments using H2O2, NH3, and heating under N2 flow without notably changing their pore structures. The resultant carbons were characterized by N2 adsorption and Bohem titration and then used to remove Ponceau 4R, methyl orange and brilliant blue from aqueous solutions. Surface chemistry was found to play a significantly different role in removing these three compounds. The removal of anionic Ponceau 4R increases with increasing carbon surface basicity due to the predominant dispersive interaction mechanism. In contrast, surface chemistry has little effect on the removal of anionic methyl orange, which can be explained by two parallel mechanisms involving electrostatic and dispersive interactions due to the basic amine group in a dye molecule. The influence of surface chemistry on the removal of amphoteric brilliant blue dye can also be ignored due to a weak interaction between the carbons and dye molecules, which is resulted from strong cohesive energy from electrostatic forces inside amphoteric dye molecules.

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