Thermodynamics of sorption processes of toxic components of organic nature from solutions on solid sorbents

Abstract

The sorbtion theory of components from inorganic and organic nature out of solutions on the boundary of hard substance-liquid phases has pure thermodynamic character. Adsorbing substance can be regarded as a special equilibrium phase having a limited volume, which can be characterized by entropy, enthalpy and energy of Gibbs.

 On the base of phenol and sulfonol sorbtion on the activated coal of KAD-iodine and anionite AB-17-OH out of waste waters with the variable concentration of sulphonyls from Sumgait plants Republic of Azerbaijan (at the interval 250–1000 mg/l) which many times exceeds MAC (0,1–5 mg/l), thermodynamic parameters of the process have been calculated: DS⁰, DH⁰, DG⁰.  It’s well-known, that significance of enthalpy DH⁰ can be determined either from temperature dependence of contant equilibrium, or through the energy of diffusion activation, as the rate of sorbtional processes, including the activated coals and anionite of AB-17-OH in most cases is determined by diffusion of substances in pores of the sorbents framework.  The significance of DH⁰ has been determined by the energy of diffusion activation according to the formula: DH⁰=E_a–RT, preliminary having calculated the data of effective coefficients of diffusion, which permitted us to make a conclusion that diffusional processes with phenol and sulfonol at the anionite AB-17-OH go much more slowly as compared with activated coal KAD-iodine.

 It has been established that G⁰ is reduced in all cases with the rise of filling in the sorbent surface. Besides, as compared with phenol, the adsorption of sulfonol on both sorbents enlarges with the rise of temperature, which is reflected by reducing DS⁰.  In all cases the obtained data of DH⁰ tenfold lower than the data typical for chemosorbtional processes (80 kJ/mol) that correspond to mechanism of physical sorbtion.