Recycling of exposed photographic X-ray films and recovery of silver using Bromelain

Recycling of exposed photographic X-ray films and recovery of silver using Bromelain

Author(s): K. V. Radha & C. Arun
Abstract:
In the present work an environmentally friendly recycling system to peel away the base coat from the X-ray film by using an enzyme was developed. Bromelain, a proteolytic enzyme extracted from the waste apex of pineapple was used for stripping the silver layer on the exposed film by hydrolysis of gelatin. The collected film can be reused for the manufacturing of X-ray film or other materials like fabrics, packaging films, recording tapes, and soft-drink bottles. The silver recovery conditions were optimized and the slurry obtained from the treatment of X-ray with Bromelain was analyzed using a scanning electron microscope.

The slurry was smelted in the presence of flux (Na2CO3) in a furnace to recover 99.9% pure silver.

Thus it helps in the recycling of X-ray film and recovery of silver without any harm to the environment.
Keywords:
waste management, X-ray films, waste pineapple apex, Bromelain, recovery of silver, metal ion concentration, gelatin, smelting, EDAX.
1 Introduction:
Silver is a rare, precious, naturally occurring metal, often found deposited as a mineral ore in association with other elements.

Fifty percent of silver produced is used in photographic and imaging materials.

Silver is unique in its ability to react with light to produce images in applications such as photography and radiography (X-rays).

Major emissions of silver are from the manufacture and disposal of certain photographic and X-ray films. X-rays films used in medical applications are made of a plastic sheet (polyester film) coated with a thin coating of gelatin (protein) impregnated with silver grain.

X-ray films are normally discarded by incineration and chemical ...

Pages: 10
Size: 4,357 kb
Paper DOI: 10.2495/SW100391

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