Chitosan is a polysaccharide consisting predominantly of unbranched chains of /l-( 1,4)-2-. amino-2-deoxy-D-glucose residues. It can be readily obtained by hydrolysis from chitin, which exists naturally in fungi and arthropods. Recently, the effective use of chitin and chitosan'), and their congeners2-4, for inorganic chromatography has been demonstrated, as they can act as excellent chelating agents. It was also found that the adsorption ability of chitosan is generally much higher than that of chitin. However, chitosan is known to be poor in mechanical properties in water, and the presence of free amino groups enhances its solubility, particularly in acidic media.

SUMMARY:The adsorption of bromine onto powdery chitin, chitosan and cellulose was studied in an aqueous bromine-potassium bromide solution at 30°C. Chitosan was found to show an excellent ability of adsorbing bromine as well as iodine. The chitosan film also exhibited high ability of adsorbing bromine both in methanol and in aqueous potassium bromide solutions. ZUSAMMENFASSUNG:Die Adsorption von Brom an pulverisiertem Chitin, Chitosan und an pulverisierter Cellulose wurde in einer wanrigen Brom-Kaliumbromidlosung bei 30 "C untersucht. Chitosan zeigte eine ausgezeichnete Fahigkeit, Brom und Jod zu adsorbieren. Der Chitosanfilm hat die Fahigkeit, Brom in Methanol und in wanriger Kaliumbromidlbsung zu adsorbieren.

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In this conference the generation and uses of high magnetic fields were reviewed. The fields of application ranged from bio-magnetics on the one hand to solid state and nuclear physics on the other. In this report the emphasis is on the methods of generating magnetic fields, both steady and pulsed, and on the latest developments with high critical field superconductors, Steady fields up to 130 k~ have been generated in conventional coils, while in liquid hydrogen-cooled coils fields of about 80 kG have been produced. At the time of the conference the highest field generated in superconducting solenoids was about 69 kG, using niobium-tin. The critical field curves of another material, vanadium-gallium, V,Ga, as far as they have been measured show the possibility of critical fields rising to 500 kG at 1" K.

The adsorption of iodine on chitosan was studied by physico-chemical methods. The scanning electron micrograph measurements of chitosan-iodine adducts showed that iodine molecules were adsorbed uniformly on the chitosan film when the film was treated with aqueous iodine-potassium iodide solution. The thermogravimetric analysis of the adducts revealed that the loss in weight began at about 19O"C, and that iodine molecules were thus well-complexed with chitosan. It was also found that the IR spectra of the chitosan films showed the amide I and amide I1 bands shifted to lower frequencies due to the iodine adsorption. The X-ray diffractometry of these adducts was further carried out, and it was found that the iodine adsorbed chitosan showed no crystalline pattern, different from that of the original chitosan which showed crystallinity in some extent. The chitosan recovered after desorbing iodine by immersion in aqueous sodium thiosulfate solution was amorphous. ZUSAMMENFASSUNG :Die Adsorption von Jod an Chitosan wurde mit physikalisch-chemischen Methoden untersucht. Die Rasterelektronenmikroskopie von Chitosan-Jod-Addukten zeigte, daI3 Jodmolekille gleichmaig a n einen Chitosan-Film adsorbiert wurden, wenn der Film mit wal3riger Jod-Kaliumjodid-Lilsung behandelt wurde. Die thermogravimetrische Anaiyse der Addukte zeigte, d d der Gewichtsverlust bei 190°C begann und dal3 die Jodmolekille gut mit Chitosan komplexiert waren. Die IR-Spektren der Chitosan-Fihe zeigten die Amidbanden I und 11, die durch die Jodadsorption zu geringeren Frequenzen verschoben wurden. Rontgenbeugung an den Addukten zeigte, da8 das Chitosan, das Jod adsorbiert hatte, keine kristallinen Anteile aufwies.Im Gegensatz d a m zeigte das ursprilngliche Chitosan bis zu einem gewissen Grad Kristallinitgt. Das durch Eintauchen in eine w l h i g e Thiosulfatldsung vom Jod befreite Chitosan war amorph.