Application of Gamma Radiation for Removal of Organic Pollutants from Wastewater

The study of this research is focused on the possibility of using gamma radiation in order to decrease the concentration of polycyclic aromatic hydrocarbon (PAH) in effluents. The research was initiated with a concentration of 100ppm of synthetic naphthalene aqueous solution submitted to different absorbed doses. The HPLC analysis has shown that the dose of 30kGy degraded 99.96% of the naphthalene molecule. The identification program of NIST library has identified the by-products formed during the radiation process. Concerning the industrial effluent wastewater sample, we opted for analysis by GC-MS before and after gamma irradiation, to monitor the degradation of PAH and other pollutants from the refinery. The results show that in global view, gamma radiation decreases significantly the contaminated level, with the increase of the absorbed dose. In detailed view, the relative content of the naphthalene, 2,7 dimethyl in the effluent sample decreased with the increase of the absorbed dose. At the dose of 6 kGy the molecule was completely degraded. The COD of effluent sample presented a reduction of 58%, when 10 kGy dose was applied. After irradiation a secondary treatment, based on adsorption using a natural adsorbent, has to be applied in order to remove the by-products of radiation degradation, to get a better quality of effluent and consequently improve the environmental condition. (author)