Removal of pyrene in pumice by biodegradable surfactant in the forms of colloidal gas aphron and aqueous solution

Abstract

Two commercial types of non-toxic and readily biodegradable surfactants, i.e., BioSolve and BioNonex, were compared in their efficiencies of removing Polycyclic Aromatic Hydrocarbons (PAHs) from pumice. Pumice was used instead of natural soil in order to avoid interference of organic matters in the soil. Pumice was loaded with pyrene, a 4 benzene-rings PAHs, In the preliminary study, pumice soaked with pyrene was extracted by 5 vol% solution of BioNonex and BioSolve. After 24 hours, pyrene removals were 76% and 25% by BioNonex and BioSolve, respectively. BioNonex was therefore used in subsequent experiments. Comparison of extraction of pyrene by BioNonex in the forms of colloidal gas aphron (CGA) and conventional solution was conducted in a packed column with continuous up-flow condition. It was demonstrated that BioNonex in CGA form could extract pyrene more efficiently than that in solution form. Pyrene removal increased with increasing surfactant concentration ranging from 1 to 7 vol%. However, increasing surfactant concentration from 7% to 10% did not affect pyrene removal significantly. The results of this study confirmed that CGA generated by non-toxic and biodegradable surfactant, BioNonex, enhanced the rate of removal of pyrene in pumice.