Thermodynamics of Sorption of Cu(II) from Aqueous Solutions by Modified Chitosan

The influence of the “aqueous solution of copper sulfate–hydrogel sorbent based on chitosan and silicon dioxide” heterophase system have been studied. The most important sorption characteristics of the process of extracting Cu(II) ions from aqueous solutions of CuSO4 in the linear coordinates of Langmuir and Freundlich, the theory of volumetric filling of micropores (TVFM at n = 2), and Temkin. The values of changes in thermodynamic potentials during the sorption extraction of Cu(II) cations from aqueous solutions in the temperature range of 298–333 K were obtained. In general, the process is thermodynamically spontaneous and exothermic; the characteristic curves of the sorbent indicate that the conditions of temperature invariance are met. The distribution of isosteric heats of sorption with increasing degree of surface filling was obtained.