Removal of polycyclic aromatic hydrocarbons (PAHs) from industrial sludges in the ambient air conditions: Automotive Industry

Abstract

Removal of polycyclic aromatic hydrocarbons (PAHs) existed in automotive industry treatment sludge was examined by considering the effects of temperature, UV, titanium dioxide (TiO₂) and diethyl amine (DEA) in different dosages (i.e., 5% and 20%) in this study. Application of TiO₂ and DEA to the sludge samples in ambient environment was studied. Ten PAH (Σ₁₀ PAH) compounds were targeted and their average value in the sludge was found to be 4480 ± 1450 ng/g dry matter (DM). Total PAH content of the sludge was reduced by 25% in the ambient air environment. Meteorological conditions, atmospheric deposition, evaporation and sunlight irradiation played an effective role in the variations in PAH levels during the tests carried out in ambient air environment. Moreover, it was observed that when the ring numbers of PAHs increased, their removal rates also increased. Total PAH level did not change with the addition of 5% DEA and only 10% decreased with 5% TiO₂ addition. PAH removal ratios were 8% and 32% when DEA (20%) and TiO₂ (20%) were added, respectively. It was concluded that DEA was a weak photo-sensitizer yet TiO₂ was effective only at 20% dosage.

Keywords:

• Treatment sludge
• TiO₂
• diethylamine
• sunlight.

Acknowledgment

This work was supported by The Commission of Scientific Research Projects of the Uludag University with Project Number: UAP (M) 2009/20. The authors would like to thank to Melike Ballica for her tiresome efforts during laboratory studies.