Search

Amphetamine-type stimulants are among the most prevalent and widespread commonly abused drugs. Amphetamine and its derivatives were detected in aquatic environment. This study aimed to demonstrate experimentally the ability of γ-irradiation combined with persulfate anions (S 2 O 8 2– ) to degrade and mineralize the amphetamine in aqueous solution. An initial amphetamine concentration of 125 µM in distilled water was completely degraded by a γ-ray dose of 2.8 kGy. Generation of the sulfate radical (SO 4 •– ) from the fast reaction of added S 2 O 8 2– with hydrated electrons ( e aq − ; k eaq − / S2 O8 2– = 1.1×10 10 M −1 s −1 ) improved the efficiency of amphetamine degradation and mineralization. A γ-ray dose of 0.667 and 0.350 kGy in the absence and presence of S 2 O 8 2– anions degraded 90% of the amphetamine, respectively. For γ-ray/free O 2 and γ-ray/S 2 O 8 2– systems, 11.5 and 7 kGy was required for 50% amphetamine mineralization, respectively. Addition of HCO 3 – anions lowered the amphetamine degradation yield, whereas N 2 gas, SO 4 2– , and Cl – anions had a negligible effect. [ABSTRACT FROM AUTHOR]

Abstract Cadmium sulfide (CdS) thin films were deposited on p-type Si substrate by thermal evaporation to fabricate the CdS/p-Si heterojunction. Gamma irradiation has been used to modify the microstructural, optical and electrical characteristics of CdS/p-Si heterojunction of various doses in the range (0–80 kGy). X-ray diffraction measurements of the gamma irradiated show the reduction in crystallinity of the CdS thin films. While scanning electron microscope images depicted the average CdS particle size was found to be increased with increasing the gamma irradiation dose. Photoluminescence results revealed that at the specific dose of gamma irradiation was found to create the yellow emission in interstitial sites to the valence band. The I–V characteristics showed the current transport properties effected by the different gamma doses. The values of barrier height, saturation current and ideality factor for the CdS/p-Si heterostructure varied due to the causes like inhomogeneities in the interfacial, defect density, charge distribution on interfacial and interfacial layer thickness after gamma irradiation. The gamma irradiation induced effects and the possible mechanism in CdS/p-Si heterojunction is discussed. [ABSTRACT FROM AUTHOR]