Titration of weak base fibrous anion exchangers in the presence of complex-forming divalent cations

Curves of potentiometric titration of fully protonized fibrous ion exchangers with potassium hydroxide against the background of 1 M KCl in the presence of chlorides of Ni2+, Со2+, Сu2+ and Ca2+ were obtained. The ion exchangers were synthesized by modifying of industrial polyacrylonitrile fiber with diethylenetriamine and triethylenetetraamine and predominantly contained functional groups R-CO-NH- (CH2CH2NH)nH (n = 2 or 3) and a small amount of carboxyl groups. The sorption of Ni2+, Со2+, Сu2+ и Ca2+by ion exchangers was calculated from the data obtained depending on the pH of the medium. It was found that the investigated ion exchangers with high selectivity sorb heavy metal ions in a wide range of acidity of solutions (pH 2–9) due to the formation of metal-polymer complexes with polyamine functional groups. The maximum sorption capacity is 1.5–2.7 and 4–5 meq/g for ion exchangers with n = 2 and 3, respectively.

Indicator materials on the base of fibrous ion exchangers for visualizing of the sorption resource of the chemical air cleaning filters

On the base of fibrous ion exchangers, indicator materials were obtained for sorbates of an alkaline and acidic nature, intended to visualize the working time of the filter layer during ion exchange air purification. The optimal conditions for their production and operation were determined. The practical applicability for the manufacture of indicator cartridges for filters of deep air purification and personal protective equipment for human respiratory organs and skin with the aim of timely visualizing of the sorption resource depletion, due to the contrast and sensitivity of the color change, was demonstrated.

PREPARATION OF ION-EXCHANGE SOILS BASED ON WEEK DISSOCIATING FIBROUS ION EXCHANGERS

The perspectives of using ion-exchange soils for growing plants in zero-gravity field are described. Standard methods for obtaining ion-exchange soils are not suitable for weakly dissociating ion-exchangers. Methods for obtaining ion-exchange soil based on weakly dissociating fibrous ion exchangers are proposed. The method using concentrated solutions made it possible to obtain ion-exchange soils with a larger content of deficient ions (K+ , NO3 – ). The suitability of the obtained ion-exchange soils was confirmed by a biological experiment.