## 3 Results and Discussion
### Characteristics of Anb/C and Anb/AgNP/C Composites
All studied systems are characterized by low values of the determination coefficient 1-R\({}^{2}\) (mean 1.2 \(\times\) 10\({}^{-5}\)) and relative standard deviation SD(c)/c\({}_{\rm o}\) (mean 0.37%), (Table S1). Moreover, the high-quality optimization can be confirmed by no systematic deviations of put-together data, (Figure 6) as curves: deviations of concentration (\(\Delta c_{i}\))\(\sim\)square root of time (t\({}^{1/2}\)), where \(\Delta c_{i}=c_{i}\)\(c_{i}\)\(c_{\rm fit}\)(\(t_{i}\)). The next step of analysis of the kinetic data was an investigation of the approximation of the process using simple model-based equations as follows: first order (FOE), second order (SOE), and mixed 1.2 order (MOE) equations. None of the mentioned methods of optimization give as good results as a multiexponential equation. MOE and FOE deviations are, on average, 1.6 and 2.2 times worse than m-exp. ones (mean SD(c)/c\({}_{\rm o}\): 0.6 and 0.82 vs. 0.37%). The fitting parameters for SOE are much worse (mean SD(c)/c\({}_{\rm o}\): 4.5%) and are of systematic features. Since the FOE, SOE, and MOE equations relate to Langmuir kinetics, we also tried to use a fractal-like MOE equation, derived from MOE. This equation reflects a conception of fractality, so it seems more suitable for describing the kinetics of heterogeneous systems. The f-MOE equation includes in its assumptions a certain distribution of adsorption rates like in the case of the multiexponential equation. In the process of optimization using the f-MOE equation for all the studied systems, negative values of f\({}_{2}\) were obtained. Therefore, the f-MOE was reduced to the simple form of the f-FOE equation. In Figure 13, the dependences of various rate parameters from the f-FOE equation on 1/T for the adenosine adsorption from the one- and two-component solutions on the activated carbon RIAA are presented. Logarithms of (t\({}_{0.5}\)); (k\({}_{1}\)); and (k\({}_{1}\)/T) \(\sim\) (1/T) are characterized by ideal (R\({}^{2}\)\(\approx\)1) or satisfied linearity (R\({}^{2}\)=0.9346-0.9814), which allowed for the estimation of the adsorption activation energies. Obtained values from the given dependences equal: 14.53, 14.10, 11.63 kJ/mol and 22.63, 22.97, 20.50 kJ/mol for adenosine adsorption from the one- and two-component solutions, respectively. Thermodynamic constants, estimated based  
Figure 12: The dependences of the logarithm of average half-times on 1/T for adsorption of adenosine from the one- and two-component solutions on the activated carbon RIAA. Parameter t\({}_{05}\) was obtained numerically from the m-exp equation. on t\({}_{0.5}\) and k\({}_{1}\), are most similar and consistent with ones obtained from the m-exp equation parameters (14.87 and 22.56 kJ/mol). The fitting quality of f-FOE is close to that of the m-exp. equation-relative deviations and are only, on average, 1.4 times (mean SD(c)/c\({}_{0}\): 0.5%) worse. For a better presentation of the fitting quality using various kinetic equations, the experimental data, fitted lines (m-exp., FOE, SOE, MOE, and f-FOE), and their deviations in Weber-Morris linear coordinates for the exemplary systems are plotted in Figure S1 (Supplementary Materials). In Table S1, the parameters of considered kinetic equations are summarized. Finally, we analyzed whether the kinetics of adenosine adsorption on the activated carbon RIAA behaves following the intraparticle diffusion model (IDM). For this purpose, the experimental data were presented in Bangham's linear coordinates (Figure S2). However, despite obtaining high linearity of function, especially for one-component systems (R\({}^{2}\): 0.9947-0.9995) the values of slope parameters ranged from 0.7916-1.0501 instead of 0.5, which is typical for IDM. One can note that the linearity of the Bangham plot for the entire range of experimental data, mathematically is equivalent to the f-FOE kinetic equations: \(\frac{c}{c_{0}}=1-\exp\left[-(kt)^{s}\right]\), with \(s=p\) (\(p\)-fractality parameter) and \(c_{0}/c_{0}=0\).