From isnv@ars-grin.gov Mon Sep 13 13:15:08 1999 Date: Mon, 13 Sep 1999 10:07:02 -0400 From: ARS News Service To: ARS News List Subject: Nut Shells on Tap for Industrial Clean Up [ The following text is in the "iso-8859-1" character set. ] [ Your display is set for the "US-ASCII" character set. ] [ Some characters may be displayed incorrectly. ] STORY LEAD: Nut Shells on Tap for Industrial Clean Up ----------- ARS News Service Agricultural Research Service, USDA Jan Suszkiw, (301) 504-1630, jsuszkiw@asrr.arsusda.gov September 13, 1999 ----------- Macadamia, pecan and almond shells are of little commercial value other than the nuts' natural packaging--or livestock bedding. But U.S. Department of Agriculture scientists are converting the shells into powerful industrial clean-up tools in the form of granular activated carbons (GACs). GAC uses run the gamut, from fish tank filters and water purifiers, to waste-water treatment, soil remediation and gas chromatographic analysis. In the U.S., such applications consume over 300 million pounds of carbons annually--over half the 600 million pounds used worldwide. What makes them so useful is a highly porous surface that draws heavy metals like lead and organic compounds like toluene and benzene. Both are common ingredients in fuels, dyes and paints. Once they escape into the environment, however, they can become contaminants. Many GAC products are made from coconut shells and coal, though both are costly. Coal also is a nonrenewable resource. Chemists Wayne Marshall and Linda Wartelle are testing discarded nutshells as a more plentiful and inexpensive alternative. Both work at the Agricultural Research Service's Southern Regional Research Center in New Orleans, La. ARS is USDA's chief scientific agency. Colleague Chris Toles, formerly ARS, is now at Northeastern University in Boston. Under a microscope, nutshell carbons resemble tiny, pockmarked asteroids. But one gram can have 900 square meters of surface area, a plus in adsorbing metals or chemicals with low molecular weights, like benzene. In comparative studies with six commercial carbons, use of macadamia GACs produced a three to four-fold increase in the ability of a standard EPA air sampling procedure to detect benzene at concentrations of 100 parts per billion. A longer story appears in the September issue of Agricultural Research magazine, and on the Web at: http://www.ars.usda.gov/is/AR/archive/sep99/carb0999.htm ---------- Scientific contact: Wayne Marshall, ARS Commodity Utilization Research Unit, Southern Regional Research Center, New Orleans, phone (504) 286-4356, fax (504) 286-4367, marshall@commserver.srrc.usda.gov. ---------- This item is one of the news releases and story leads that ARS Information distributes on weekdays to fax and e-mail subscribers. You can also get the latest ARS news on the World Wide Web at http://www.ars.usda.gov/is/pr/thelatest.htm. * Feedback and questions to ARS News Service via e-mail: isnv@ars-grin.gov. * ARS Information Staff, 5601 Sunnyside Ave., Room 1-2251, Beltsville MD 20705-5128, (301) 504-1617, fax 504-1648.