Removal of phenol by adsorptive micellar flocculation: Multi-stage separation and integration of wastes for pollution minimisation

Adsorptive micellar flocculation (AMF) is a method for the removal of pollutants from water involving the attraction of cationic species to the surface of anionic surfactant micelles, and the flocculation of said micelles as their mutual electrostatic repulsion is neutralised. The process of flocculation creates an aggregate that can be filtered with ease, allowing the removal of small molecules like phenol, benzoic acid or 2,4-D, and ions like Zn and Cu by filtration instead of membrane separations. Such flocculate forms as micelles throughout the solution aggregate, taking with them some amount of water. This paper discusses the use of AMF to remove phenol. The results show that the capacity of the micellar flocculates to hold phenol is similar to the capacity of micelles in micelle-enhanced ultra filtration (MEUF). AMF leaves both surfactant and a flocculant cation (Al3+) in the stream, and the use of marble dust as an adsorbent to limit the concentration of these chemicals in the effluent is proposed as a refinement of the separation process. This combination is interesting because marble dust is produced in vast amounts (about 6 million tonnes per year only in Europe) as a waste in quarries. Thus, a waste becomes an auxiliary reagent in water treatment. (c) 2005 Elsevier B.V. All rights reserved.