Onions Soak Up Heavy Metals

Onion Soaks Up Heavy Metals With Waste Food

Dec. 10, 2012 — Onion and garlic waste from the food industry could be used to mop up hazardous heavy metals, including arsenic, cadmium, iron, lead, mercury and tin in contaminated materials, according to a research paper published in the International Journal of Environment and Pollution.

  The waste from the processing and canning of onion could possibly be used to remove toxic materials from contaminated objects, including industrial waste. A team is studying how the “acidity or alkalinity, contact time, temperature and concentration of the different materials” could optimize the ability for the onions to filter the metal for industrial scale decontamination. It was found that at 50 degrees Celsius, or 122 Fahrenheit, and a pH of 5 is the most optimal conditions for clean-up processes. The onions extract lead.
        The absorbed metals can be released into a collecting vessel using nitric acid, and so the biomass can be reused. "The technique appears to be industrially applicable and viable," they suggest. "This may provide an affordable, environmental friendly and low maintenance technology for small and medium scale industries in developing countries."

http://www.sciencedaily.com/releases/2012/12/121210112345.htm