The prospect of ever-stricter clean-water standards has industry looking for less expensive ways to remove toxic chemicals. Now, scientists at the Agricultural Research Service's Southern Regional Research Center in New Orleans think that the by-products from cereal and oilseed crops could remove toxics from wastewater at bargain-basement prices.
Results from the first six months of a three-year research effort have found that soybean hulls plucked more than 90% of the zinc found in a test sample. That's comparable efficiency to the oil-based resins and activated charcoal now used to treat toxic effluent. And at just 4~ a pound, soy is dirt cheap compared with commercial ion exchange resins ($2 to $10 a pound) and activated charcoal (at least 50~ a pound).
Now, researchers must figure out how to prevent the hulls from breaking down during the filtration process and how to remove the toxic metals from the soy-based resin for reuse. And although distilled soy hulls are expected to work on other toxic metals besides zinc, soy's ability to absorb toxic organic compounds, such as methanol, remains to be tested.