The Influence of Molecular Weights of Polyethylene Glycols on Activated Carbon Adsorption in Aqueous Solution

Abstract

The adsorption characteristics of polyethylene glycols (PEG) with various molecular weights on two kinds of commercial activated carbons were investigated.
The experimental data for adsorption equilibria of P EG were expressed by Langmuir-type adsorption isotherm within the range of equilibrium concentration from sev e r al to several hundreds of mg/i. The adsorption capacity q_∞(g/g-C) tended to increase with incr e asing molecular weights of PEG. However, _∞* ( mmol/g-C) had the maximum value at m olecular weights of 150 or 300. The adsorption of PEG with higher molecular weights was c o nsidered to be affected by the pore size of the activated carbons.
The effective intraparticle diffusion coefficients D₁'(cm²/sec) were calculated from the estimated values of adsorption rates in an agitated tank, and those values showed a tendency to decrease with increasing molecular weights. The breakthrough times by down flow column ad s o rption exhibited complicating features with molecular weights, because of the competing e ffects of adsorption equilibria and adsorption rates on molecular weights.