Effect of basicity and hydrophobicity of amines on their adsorption onto charcoal

Abstract

AbstractAmines are toxic and precursors for highly toxic nitrosamines and chloramines. Two groups of aliphatic highly soluble amines (methylamine MA, glucosamine GA) and aromatic amines (benzylamine BA, aniline AN, diphenylamine DPA) with varying degree of basicity and hydrophobicity were investigated for their adsorption onto charcoal. The adsorption experiments were carried out at 25 and 80°C close to the temperature used in water treatment and decolorization processes, respectively, in order to understand the efficiency of charcoal in removal of amine pollutants in these processes. The adsorption order at 25°C was: BA (0.9) > MA (0.72) > AN (0.63) > DPA (0.48) > GA (0.30 mmol/g), and the order at 80°C was BA > AN > GA ~ MA ~ DPA. Both the orders reflected the importance of basicity over hydrophobicity of amines in the adsorption onto charcoal. The charcoal was characterized using FTIR, SEM, elemental analysis, Boehm titration, pH titration, and pH drift methods. The charcoal was found to have significa...