Anion Exchanger and a method for treating a fluid

#The present invention relates to a new anion exchanger, especially an anion exchanger with excellent heat resistance and a method for treating a fluid using it.

#Prior to the present invention, anion exchangers have been widely used as adsorbents for a variety of ionic substances. As anion exchanging groups, primary, secondary and tertiary amines and quarternary ammonium salts can be cited, but among them, those of the trimethylbenzylammonium type, where trimethylamine is bound with a benzyl group of a polymonovinyl aromatic compound through a covalent bond, exhibit excellent ion exchange ability and are widely used.

#However, these trimethylbenzylammonium salt type exchangers gradually decompose even at room temperature and the decomposition speed of the ammonium salt becomes significant especially at 60.degree. C. or higher.

#In the examples that follow the exchange capacity (milli-equivalent) was measured as follows. 50 ml of 0.1N hydrochloric acid was added in 0.5 g of OH.sup.- type anion exchanger and the mixture was shaked for 4 hr. 5 ml thereof is taken out and 5 ml of 0.1N sodium hydroxide aqueous solution was added and the mixture was titrated using 0.1N hydrochloric acid. Specific electric resistance, total organic carbon, atomic-absorption spectrum and inorganic anion were respectively measured by means of AQ-11 type specific resistance meter manufactured by DKK Co., Ltd., Automatic analyzer TOC 710 type manufactured by Toray Engineering Co., Ltd., Z8000 flameless atomic-absorption spectroscope manufactured by Hitachi Ltd., and Model IC500P ionchromatoanalyzer manufactured by Yokogawa Hokushin Electric Works, Ltd. Quantitative analyses of iodine gas and hydrogen cyanide gas were performed using Kitagawa-type gas detector.

#A multi-core islands-in-a-sea type composite fiber (undrawn) in which the sea component (polystyrene)/the island component (polyethylene)=50/50; number of islands was 16; the fiber diameter was 34 .mu., was cut into a cut fiber of 0.5 mm in length. 10 parts by weight of the cut fibers were added to a crosslinking liquid consisting of 50 parts by volume of a commercially available reagent grade sulfuric acid, 5 parts by volume of water and 2 parts by weight of paraformaldehyde and reacted at 60.degree. C. for 4 hr. The fibers were washed and dried. Then, the resulting crosslinked fibers were added to a chloromethylation liquid consisting of 3 parts by volume of chloromethyl ether, 8 parts by volume of tetrachloroethane and 0.15 part by volume of stannic chloride and reacted at 50.degree. C. for 4 hr to obtain chloromethylated fibers 1 part by weight of these chloromethylated fibers was added to a reaction liquid consisting of 2 parts by weight of triethylenediamine and 15 parts by volume of N,N-dimethylformamide and reacted at 60.degree. C. for 4 hr to obtain triethylenediamine type anion exchange fibers of formula (I) of the present invention.

#Hot water treatment at 100.degree. C. and dry treatment at 80.degree. C. on the obtained anion exchange fibers (OH type) were performed and exchange capacities before and after the treatments were measured. The obtained results were summarized in Table 1.