Phenolic wastewaters purification by thermal parametric pumping: modeling and pilot-scale experiments.

Thermal parametric pumping is a cyclic adsorptive process based on periodic changes in the bed temperature simultaneously with flow reversal. This is an innovative technology which may allow removing phenolic compounds from waste solutions to be recovered and recycled. The recovery and/or purification of liquid streams containing phenol and 4-nitrophenol by adsorptive parametric pumping was studied in this work. An automated parametric pumping pilot unit was operated in semi-continuous recuperative mode. The adsorbent used was the polymeric resin Sephabeads SP206 (Mitsubishi Kasei Corporation, Japan) and temperatures of the hot and the cold half-cycles were 333 and 293 K, respectively. Basic data were obtained from batch equilibrium experiments and fixed-bed adsorption. Different experimental conditions were run and two simplified models were used to simulate the results: an equilibrium model and a linear driving force (LDF) model. Experimental and simulated results using the LDF model were in quite good agreement. Purification levels below three orders of magnitude lower than the concentration of the feed solution were obtained for phenol and 4-nitrophenol.