| Abstract: | Abstract Cloud point extraction (CPE) has been successfully scaled up to continuously remove aromatic contaminants from wastewater in a multi-stage rotating disc contactor (RDC) using t-octylphenolpolyethoxylate. The extraction performances for the removal of organic solutes with different structures and degrees of hydrophobicity were compared here for both batch and continuous CPE. Included are the volatile aromatics benzene, toluene, and ethylbenzene; volatile chlorinated compounds dichloroethane, trichloroethylene, and tetrachloroethylene; and non-volatile phenolics phenol, o-cresol, and catechol. The higher the Kow (octanol-water partition coefficient) or hydrophobicity of the solutes, the better the extraction due to the greater affinity of solutes to solubilize into micelles. The empirical linear correlations between log Kow, log (solute partition ratio), and log (height of transfer unit or HTU) were developed. Toluene is used as a model solute for the study of effect of initial solute concentrations in the continuous RDC. The extraction ability decreases as the concentration of toluene in the wastewater increases mainly due to coacervate entrainment into the overhead effluent. |
