JOURNAL OF ENVIRONMENTAL ENGINEERING, cilt.137, sa.11, ss.1012-1025, 2011 (SCI-Expanded)
The effects of increasing sonication time (60-150 min), calcium chloride (CaCl2; 1-10 g/L), ferrous oxide (FeO; 2-10 mg/L), aluminium oxide (Al2O3; 2-10 mg/L), and Na2CO3 (2-12 mg/L) on the destruction of six polycyclic aromatic hydrocarbons (PAHs) and acute toxicity in a petrochemical industry wastewater in Izmir (Turkey) were investigated at a sonication intensity and a frequency of 51.48 W/cm(2) and 35 kHz, respectively. The contribution of 4-6 mg/L CaCl2 to the yields in more hydrophobic PAHs [(benz[a]pyrene (BaP) and indeno[1,2,3-cd]pyrene (IcdP)] was low (6-8%), whereas it was high (21-26%) in less hydrophobic PAHs [acenaphthene (ACT), fluoranthene (FL), benz[a]anthracene (BaA), benz[k]fluoranthene (BkF)] at 30 degrees C after 150 min sonication. 8 g/L Na2CO3 suppressed the removal of less hydrophobic PAHs (90-96%) although it did not contribute to the yields of more hydrophobic PAHs at 30 degrees C after 150 min sonication. 6 g/L Al2O3 and 8 g/L FeO increased both less (E = 93-95%) and more (E = 90-94%) hydrophobic PAH yields. The reason for the decrease in BkF and BaA yields at long sonication time (150 min) was the reformation of these PAHs from their by-products namely, p-hydroxybenzoic acid, benzoic acid, Fluoranthene (FL), and Anthracene (ANT). Hydroxylation is the major process for complete sono-degradation of less hydrophobic ACT, FL, BaA, and BkF, whereas the pyrolytic process is the major path for complete degradation of BaP and IcdP. The maximum acute toxicity removal (98%) was provided by 4 g/L CaCl2, 4 mg/L Na2CO3, 4 mg/L FeO, and 8 mg/LAl2O3 after 150 min of sonication time at 30 degrees C. DOI: 10.1061/(ASCE)EE.1943-7870.0000428. (C) 2011 American Society of Civil Engineers.