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United States Department of Agriculture

Agricultural Research Service

Title: Quaternized Agricultural by-Products As Anion Exchange Resins

Authors
item Wartelle, Lynda
item Marshall, Wayne

Submitted to: Journal of Environmental Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 3, 2004
Publication Date: January 13, 2006
Citation: Wartelle, L.H., Marshall, W.E. 2006. Quaternized agricultural by-products as anion exchange resins. Journal of Environmental Management. 78(2):157-162

Interpretive Summary: Low-cost alternatives to expensive synthetic anion exchange resins are needed as regulations for discharge of toxic anions become more rigorous. The focus of this study was the chemical modification of realily available, low-cost agricultural by-products to anion exchange resins. The by-products tested were almond shells, corn cobs, corn stover, cottonseed hulls, oak chips, oat hulls, peanut shells, pecan shells, rice hulls, rice straw, soybean hulls and sugarcane bagasse. Resins were prepared through the quaternization of a series of twelve agricultural by-products, which is a reaction designed to add a positive charge to the surface of the by-product. The modified by-products were compared by using them to adsorb phophates from simulated wastewater. Quaternized corn stover and soybean hulls showed the highest phosphate adsorption. Modified by-products were compared to two commerically available anion exchange resins.

Technical Abstract: Low-cost alternatives to expensive synthetic anion exchange resins are needed as regulations for discharge of toxic anions become more rigorous. The focus of this study was the chemical modification of readily available, low-cost agricultural by-products to anion exchange resins. Resins were prepared through the quaternization of a series of twelve agricultural by-products with N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride. Phosphorus adsorption assays were conducted at pH 3, 7 and 11 in order to compare anion exchange properties among the by-products. The highest adsorption took place at pH 3 for most of the modified by-products. Quaternized corn stover and soybean hulls showed the highest phosphorus adsorption at 0.75 mmoles/g and 0.65 mmoles/g respectively at pH 3. Modified by-products were compared to two commercially available anion exchange resins. The ability of these modified by-products to adsorb phosphorus was compared to the content of different polymeric constituents. There was an inverse linear relationship between the lignin:cellulose ratio of the starting material and phosphorus adsorption. Lignin content may be a predictor of the ability of a by-product to become an effective anion exchange resin through modification with N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride.

Last Modified: 10/30/2014
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