Removal of pyrene by colloidal gas aphrons of a biodegradable surfactant

Two commercial biodegradable and non-toxic surfactants (BioSolve and BioNonex) were studied for efficiency of pyrene removal from soil. Pumice was used as a model of natural soil with free of organic material. Pumice and natural soil were pretreated by soaking in pyrene solution to obtain the pyrene loading at various concentrations. In preliminary study, at the same concentration, BioNonex solution could remove pyrene from pumice better than BioSolve solution. The removal of pyrene by colloidal gas aphron (CGA) of BioNonex was conducted in a packed column of pumice operated in continuous up-flow mode. It was demonstrated that BioNonex CGA could remove pyrene (78% removal) more efficiently than BioNonex solution (68% removal) and water (11% removal) particularly based on the aqueous volume. The initial rate of removal was high and retarded after 2 h. 7% BioNonex CGA provided the maximum rate of pyrene removal which decreased from 120 to 40 mg/h within 2 h.