Abstract:
Photographic film is widely applicable in the world in medical institution, printing
industry, photo shop, biochemical laboratory and others but after used it is thrown away
without any proper treatment. Since it has silver halide, waste X-ray film contributes for
environmental pollution. This environmental issue motivates to perform the research
work focused on recovery of silver from waste photographic film for economic benefit
and environmental protection. The application of biocatalyst for treatment of silver
recovery is economically cheap and environmental friendly option. Bromelain enzyme is
one type of biocatalyst and found in pineapple plant which used for remove gelatin
component on the surface of X-ray film; then after silver will be stripped (extracted) from
such wastes. After extracted silver obtained purification (smelting) process was followed
by addition of sodium carbonate and borax as purifying agent. The mixture was inserted to furnace at 965oC; the melted silver was decanted and quenched. Bromelain enzyme depends on parameters i.e. temperature (35, 45 and 55) oC, pH (4.5, 6.5 and 8.5) and time
(10, 20, and 30) minutes were taken for analysis; and these were optimized to get
maximum efficiency of enzyme on silver recovery. Expert design software version 6.0.0
was used for analysis by taking 3 factors, 3 levels and 2 replications. The analysis
showed that 0.54 grams of silver were maximum efficiency attained from extracting 60
grams of waste X-ray film using Bromelain enzyme as bio- catalyst. The efficiency of
Bromelain enzyme (pineapple juice) is somehow greater than chemical striping of
sodium hydroxide (NaOH) (0.52 grams per 60 grams of X-ray film) and papain (0.48
grams).