Study on removal of silver and polyethylene terephthalate from exposed radiography films using enzyme protease

Abstract

In the proposed method, crude enzymes extracted from waste dry leaves of 15 different plants showing protease activity were used for removal of silver from exposed medical X-ray film by hydrolysis of gelatin. Optimum operating pH and temperature for crude protease extract was found to be 7 and 50\xa0°C, respectively. The X-ray film before and after protease treatment was analysed using FTIR (Fourier-transform infrared spectroscopy) and EDS (Energy-Dispersive X-Ray Spectroscopy). The slurry obtained after smelting process analysed using EDS shows 99.8% of silver recovery. The result confirms that the enzyme extraction process recovers silver and PET (polyethylene terephthalate) in eco-friendly treatment methodology when compared to conventional chemical treatment process.