New waste recycling techniques could turn the discarded shells of pecans, almonds and other nuts into a prized commodity: activated carbons. Millions of microscopic pores riddle the structure of activated carbons, enabling them to adsorb many different chemical compounds and certain metals that sometimes contaminate air or water. Coal is the standard material for making the carbons, but it's a limited resource. Now research shows that carbons made from nutshells work just as well, if not better. This could spell good news for commercial nut growers and processors. They dispose of the nutshells at high cost or sell them for $2 to $10 a ton as a low-value commodity such as mulch. But the nutshells could find a niche in a global market that now consumes 600 million pounds of activated carbons annually—half of this in the U.S. Carbon uses run the gamut from fish tank filters and wastewater treatment plants to mining operations. Another application is air monitoring. In one comparative study with six commercial adsorbent products, one type of nutshell carbon resulted in a three- to four-fold increase in benzene adsorption for a standard EPA air sampling method. Benzene is used in fuels, dyes, solvents and many other products. But it becomes a contaminant upon escape into the environment. The scientists are now seeking to establish a cooperative research and development agreement with a commercial partner.
Southern Regional Research Center, New Orleans, LA
Wayne Marshall, (504) 286-4207, marshall@commserver.srrc.usda.gov

A new textile processing technique could breathe economic life into linters—short, curly cottonseed hairs that now have low commercial value. Linters usually get shaved off the seed at the cutting mill once the longer, more slender staple fibers have been removed at the cotton gin. Staples undergo further processing and finishing for use in clothing, towels and other fabrics. Linters, however, are ground into a pulp for making paper. One reason is that linters don't readily process into a cohesive sheet, or batt, without unraveling. ARS textile engineers tackled the problem with a technique that forces linters to wrap around staple fibers in the batt. Absorbent wipes, cosmetic pads and other nonwoven products made from the new blend offer the same look, feel and quality as commercial products containing 100 percent staple fibers. Incorporating linters helps reduce the costs of raw materials and of bleaching—a key processing step. Unbleached linters cost about 18 cents per pound versus 80 cents or higher for staples. Bleached linters cost about 50 centers a pound versus $1.35 for staples. The researchers are now seeking a commercial partner to refine the technology.
Southern Regional Research Center, New Orleans, LA
D.V. Parikh, (504) 286-4541,parikh@nola.srrc.usda.gov