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The thermokinetics was investigated and the enthalpy of sorption of Zn(II) ions from solutions of different concentration with VION KN-1 carboxyl chemisorption fibres (Na form) was determined. It was found that the time of attaining sorption equilibrium and the value of ∆H of sorption of Zn(II) ions is a function of their concentration in the solution. The results obtained can be used to determine the energy consumed in sorption of Zn(II) and effectively using KN-1 fibre in treatment of aqueous and gas-air media to remove heavy metal ions.There is now sufficiently extensive information on synthetic ion exchangers and the effect of the physical and chemical nature of the ion exchangers on the sorption process [1][2][3][4]. VION chemisorption fibre materials, which have a three-dimensional chemical network, have been investigated least. In comparison to granular ion exchangers, they have a high sorption rate, more developed surface, and high hydrolytic stability. High mechanical strength and stability in toxic and aggressive media are especially valuable properties of the fibres. Due to their specific features, VION fibres are widely used in sorption processes for treatment of aqueous and gaseous media.The synthesis and basic characteristics of VION KN-1 carboxyl-containing ion-exchange fibre fabricated by saponification of Nitron polyacrylonitrile fibre crosslinked with hydrazine hydrate were described in [2].VION KN-1 carboxyl-containing chemisorbent was made from polyacrylonitrile fibre by treating it with an aqueous solution containing 8-15 wt. % hydrazine and 1-2 wt. % sodium hydroxide for 2.0-2.5 h at a temperature of 90-100°C [5]. This treatment of Nitron fibre increases the rate of synthesis of the product. In addition, the VION KN-1 carboxyl-containing fibre obtained with this method has higher strength characteristics in comparison to the separate method, which allows reducing the amount of wastes in processing it into textiles.The VION KN-1 fibre used in the experiment has the following physicochemical and mechanical properties: Active group COONa SEC for 0.1 N HCl, mole/dm 3 4.6 Breaking strength, cN/tex 8 Elongation, % 30 Loss of strength in loop, % 4 Linear density, tex 0.808VION KN-1 fibre has high sorption properties with respect to heavy metals and radionuclides. The energy of the sorption reaction (enthalpy) of Zn(NO 3 ) 2 was determined to identify the cause of its high affinity for transition metal ions.Samples of Zn(II) with a concentration of 2.5, 3.5, 5, 7.5, and 10 mmole/dm 3 were used for the experiment. The weighed portion of fibre was 0.2±0.01 g.The studies were conducted on a MID-200 differential heat-conducting microcalorimeter at 298 K. The error of the calorimetric measurements did not exceed 2%. The experimental method consisted of the following. A stainless steel calorimeter

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