A set of studies necessary to determine the suitability of a fibrous anion exchanger with ternary amino groups based on industrial polyacrylonitrile fiber Nitron C as a component of ion substrates was carried out. A laboratory-prepared ion exchanger sample had a working exchange capacity equal to 0.9 meq/g for the nitrate anion, which limits the biological productivity of the substrate for growing plants, in the physiological pH range = 5.5–7.5 and the concentration of the equilibrium nutrient solution is 0.02 eq/l. This capacity is at the level of the best granular ion exchangers and significantly exceeds the capacity of the previously used fibrous ion exchangers for growing plants in zero gravity conditions on space stations in 1970–1994 (Mir, Soyuz TM-10 – TM-17). The synthesized ion exchanger is a polyampholyte and contains three types of ion exchange groups, has high hydrophilicity and mechanical properties that allow it to be processed into textiles and used for any purpose, in which fibrous ion exchangers can be used (air and water purification, human protection means, etc.).

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.

A mathematical model for description of the sorption capacity of ion exchangers on alkaline compounds protonizable in aqueous solutions (exemplified by ammonia, mono-, diand triethylamine) was proposed. The Henry’s constants for these substances were experimentally determined. The model accounts for the concentration and acid-base properties of the sorbate, relative air humidity, acid-base properties and exchange capacity of the ion exchanger, as well as spatial availability of functional groups for interaction under conditions of limited permeability of polymeric ion exchanger. The applicability of the model is illustrated by processing the experimental results on the sorption of ammonia and ethylamines by fibrous carboxylic and sulfonic cation exchangers. Good agreement between the calculated and experimental data is observed.

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.

New ion exchangers based on polyacrylonitrile fiber were obtained by catalytic amination of nitrile groups with tetraethylenepentaamine and pentaethylenehexaamine. Chelating ion exchangers with aminodiacetic functional groups were obtained on the base of these materials. The acid-base parameters of the functional groups of obtained ion exchangers were determined by potentiometric titration: initial polyampholytes have a high anion exchange capacity (E b = 4.5–5.5 m-eq/g) distributed between three types of groups with pK a equal to 3.3, 6.2 and 9.2, and a cation exchange capacity with E a ≈ 1 m-eq/g and pK a ≈ 10.7; chelating ion exchangers on their base contain three types of acid groups with pK a approximately equal to 3.5, 6.0, 10.5 and two types of anion-exchange groups with pK a equal to 2.0 and 6.0. Initial polyampholytes have a high efficiency in the processes of air purification from acidic impurities (experimental data for sulfur dioxide), chelating ion exchangers – in the processes of water purification from heavy metal ions.

A new method for the catalytic preparation (using copper salts) of the anion exchanger with ternary amino groups has been developed. The best conditions for synthesis of this ion exchanger, such as catalyst and aminating agent (dimethylamino propylamine) concentrations and process time, have been found. The acid-base properties of functional groups have been determined by potentiometric titration. By the analysis of isopiestic curves, water-holding capacity of the anion exchanger has been estimated and these results used for determination of the anion exchanger applicability for air purification. The experimental sorption results show the practical applicability of the ion exchanger for air purification from acidic impurities (on the example of sulfur dioxide sorption) in a wide range of relative humidity.

A new kind of sulfonic cation exchanger based on carbonized fiber modified with poly(styrene-divinylbenzene) was prepared by radiation grafting. The structural features and thermal stability of the cation exchangers prepared were studied.

The catalytic properties of the fibrous sulfonic acid cation exchanger FIBAN K-1 in methyl tert -amyl ether synthesis are studied as a function of its water content. Reducing the degree of hydration of the cation exchanger to <2 H 2 O molecules per SO 3 H group diminishes the proportion of the desired product in the catalysate. According to 13 C NMR data, protonation of methylbutenes in the air-dry cation exchanger phase (which contains 4 H 2 O molecules per SO 3 H group) involves [ n H 2 O] ⋅ H + species and is accompanied by olefin hydration and the formation of protonated tert -amyl alcohol.

The distribution of acid centers with respect to their strength in sulfocationite granules and fibers with different cationic compositions was studied using a new variant of the thermal desorption method. The in fraction of strong acid centers was found to increase as the exchange capacity of the H-form of dehydrated (120 degrees C, 2 h) sulfocationite grew. The acid properties of sulfocationites with exchange cations of various natures correlated with their catalytic activity.

Distribution in strength of the acid centers in sulfonic cation in the form of exchanger granules and fibers was studied by the novel modification of the thermal desorption method.

A new method for determining the thermal stability of sulfocationites is proposed. The method is based on the heating of an air-dry ionite sample in an inert gas flow that carries the gaseous products of the thermal decomposition of the ionite into a KMnO4 solution and thereby decolorizes it.

The swelling behavior of the H-form of a fibrous sulfonated cation exchanger (FIBAN K-1) and beaded sulfonated exchangers (KU-2-8 and Dowex msm 31) in the components of the reaction mixture of methyl tert-amyl ether synthesis was studied.

The 1H and 13C NMR spectra of granulated carboxylic cationite MAC-3 and fibrous anionites FIBAN (A-5, A-7, and A-9) have been investigated. The dependence of the chemical shifts and times of spin–spin relaxation of the water protons and carbon nuclei of MAC-3 on the water content in a sample has been investigated. A comparison of the carbon spectra of polyelectolytes and FIBAN fibrous anionites swollen in water has been made. It is shown that the carbon spectra of the ionites swollen in water represent fairly narrow lines practically for all groups of the skeleton, and therefore the structure of the ionites can be analyzed using a high-resolution NMR.