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United States Department of Agriculture

Agricultural Research Service

Title: Chemical Strategies for Producing Anion Exchangers from Lignocellulosic Residues to Be Used for Removing Textile Dyes from Wastewater

item Laszlo, Joseph

Submitted to: Society of Chemical Industry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 7, 1995
Publication Date: N/A

Interpretive Summary: The byproducts generated by the processing of crops such as sugarcane bagasse and wheat straw can be used to clean the wastewater produced by textile manufacturing operations. We explored various ways to alter these byproducts to enhance their ability to bind textile dyes. Introducing positive charges into the byproducts allows them to bind a large amount of dye. Depending on the type of chemistry used to introduce positive charge into the byproducts, the resulting dye-binding materials varied greatly in their ability to bind dye, production cost, and potential compostability. There was no clearly superior material, each had certain benefits and disadvantages.

Technical Abstract: The presence of textile dyes in the wastewater effluents of dyehouse operations is problematic. Difficulties in treating these effluents arise because of the great variety of dyes and co-solutes present. None of the traditional wastewater-treatment methods are satisfactorily effective in decolorizing these effluents in a cost-effective, environmentally-sound, manner. Because most types of textile dyes are negatively charged, anion-exchange resins could effectively treat dye-containing wastewaters. Low-cost anion-exchange resins can be prepared from the lignocellulosic byproducts generated during the processing of agricultural products. These biomass-based exchangers very effectively decolorize textile wastewater and can be disposed of by composting or incineration. Several agricultural byproduct chemical modification strategies were explored. The simplest approach, using ammonia and epichlorohydrin, produced a high-capacity, weak kanion exchanger. Dye bound to only a small fraction of the exchanger site present in ammonia-epichlorohydrin derivatized material. Treatment of agricultural byproducts with N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride and epichlorohydrin produced a high-capacity, strong anion exchanger. All of the exchange sites were able to bind dye. Other successful quaternization/crosslinking chemistries investigated were reaction with imidazole and epichlorohydrin, and treatment with 1,3-bis(3-chloro-2-hydroxypropyl)imidazolium hydrogensulfate. Many types of crop byproducts such as soybean hulls, sugarcane bagasse, and wheat straw can be derivatized using these chemistries and employed for dye removal, so this technology can exploit regionally available agricultural byproducts.

Last Modified: 5/5/2015
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