Removal of phenylamine and catechol by adsorptive micellar flocculation

The surfactant/water partition ratios for phenylamine in the flocculates formed during adsorptive micellar flocculation (AMF) are found to be around four to five times higher than the ratios reported in the literature for micelle enhanced ultra filtration. Binding ratios phenylamine/surfactant may be as high a 0.25. This suggests that highly soluble organic compounds present in acidic form in aqueous solution are strong candidates for removal by adsorptive micellar flocculation. At concentrations of phenylamine 0.0128 M or higher, micelles may not aggregate into large easily filtered flocs if the concentration of Al3+ is less than 0.024 M, but into small colloidal aggregates in the size range of hundreds of nanometers. It is still possible to remove significant amounts of phenylamine and surfactant by a sequence of filtration of coarse solids and filtration through 200 nm pore membranes. The high efficiency of the smaller, less hydrophobic particles in capturing phenylamine, with binding ratios phenylamine/SDS of 0.35 and higher, strongly supports the view that hydrophobicity cannot be taken as the main reason why micellar flocculates capture contaminants. Catechol shows binding ratios up to 0.15, well above binding ratios up to 0.1 for phenol. That, being other properties similar, strong complexant catechol adsorbs much better than phenol, reinforces the view that superficial complexation with Al3+ is a key mechanism in adsorptive micellar flocculation.