Preparation of anion exchangers from beech sawdust and wheat straw
1999
Simkovic, I.
Beech sawdust, extracted sawdust, wheat straw and extracted straw were quaternized and crosslinked in the presence of sodium hydroxide in one step with 1,3-bis(3-chloro-2-hydroxypropyl)imidazolium hydrogen sulfate or with 3-chloro-2-hydroxypropyltrimethylammonium chloride/epichlorohydrin optionally in the presence of ammonium hydroxide. Under optimal conditions the first system gave much higher yields and amounts of incorporated nitrogen into the water-insoluble residue than the combination of epichlorohydrin and monofunctional quaternizing agent with or without ammonium hydroxide. In the absence of ammonium hydroxide, slightly better results were obtained. There is a correlation between nitrogen content and exchange capacity of anion exchangers as determined by elemental analysis after recycling with sodium hydroxide. hydrochloric, sulfuric or phosphoric acid. When wheat straw was modified, slightly better results were obtained than on beech sawdust although both materials are suitable for this application.
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