Coupling extraction-flotation with surfactant and electrochemical degradation for the treatment of PAH contaminated hazardous wastes.
The performance of a two-stage process combining extraction of polycyclic aromatic hydrocarbons (PAHs) with an amphoteric surfactant (CAS) followed by electro-oxidation of PAH-foam concentrate was studied for the decontamination of aluminum industry wastes (AIW) and polluted soils. The PAH suspensions extracted from AIW and soils were treated in a 2L-parallelepipedic electrolytic cell containing Ti/RuO2 anodes and stainless steel cathodes. Current densities varying from 4.6 to 18.5 mA cm(-2) have been tested with and without addition of a supporting electrolyte (6.25 to 50 kg Na2SO4 t(-1) of dry waste). The best performance for PAH degradation was obtained while the electrolytic cell was operated during 90 min at a current density of 9.2 mA cm(-2), with a total solids concentration of 2.0%, and in presence 12.5 kg Na(2)SO(4)t(-1). The application of the process on AIW (initial PAH content: 3424 mg kg(-1)) allowed extracting 42% of PAH, whereas 50% of PAH was electrochemically degraded in the resulting foam suspensions. By comparison, 44% to 60% of PAH was extracted from polluted soils (initial PAH content: 1758 to 4160 mg kg(-1)) and 21% to 55% of PAH was oxidized in the foam suspensions. The electrochemical treatment cost (including only electrolyte and energy consumption) recorded in the best experimental conditions varied from 99 to 188 USD $ t(-1) of soils or AIW treated.
Tran
Lan-Huong
LH
Institut National de la Recherche Scientifique (INRS-Eau Terre et Environnement), Université du Québec, 490 Rue de la Couronne, Québec, QC G1K9A9, Canada.
Drogui
Patrick
P
Mercier
Guy
G
Blais
Jean-François
JF
D000535:Aluminum; D004563:Electrochemistry; D004573:Electrolytes; D006256:Hazardous Waste / Q000032:analysis* / Q000191:economics; D007220:Industrial Waste; D008669:Metallurgy; D010084:Oxidation-Reduction; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D012037:Refuse Disposal / Q000191:economics; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis; D013501:Surface-Active Agents / Q000737:chemistry*
D004573:Electrolytes; D006256:Hazardous Waste; D007220:Industrial Waste; D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; D013501:Surface-Active Agents; D000535:Aluminum