[Characteristics of adsorption and desorption isotherm of cresol isomers on activated carbon].

Simulated wastewater containing o-, m- and p-cresol was used respectively to study the effects of substituted position on adsorption and desorption and the feasibility of activated carbon adsorption-bioregeneration treatment. According to the isotherm, the adsorbability sequences in the order of p-cresol > o-cresol > m-cresol, which is positively correlated to pK(a) and negatively correlated to solubility and critical oxidation potential (COP); and the desorbability sequences in the order of o-cresol > m-cresol > p-cresol, which is negatively correlated to boiling point and viscosity. According to comparative analysis, irreversible adsorption is found to be the main reason for differences between adsorption and desorption isotherms. A mathematical statistics method was applied to estimate the amount of irreversible adsorption. The irreversible adsorption amounts of o, m, p-cresol are 27.9 mg/g, 28.5 mg/g and 33.4 mg/g, respectively.