Linear and Non-Linear Regression Analysis for the Adsorption Kinetics of SO2 in a Fixed Carbon Bed Reactor-A Case Study

Here, we determined the kinetic parameters of SO2 adsorption on unburned carbons from lignite fly ash and activated carbons based on hard coal dust. The model studies were performed using the linear and non-linear regression method for the following models: pseudo first and second order, intraparticle diffusion, and chemisorption on a heterogeneous surface. The quality of the fitting of a given model to empirical data was assessed based on: R-2, R, Delta q, SSE, ARE, chi(2), HYBRID, MPSD, EABS, and SNE. It was clearly shown that the linear regression more accurately reflects the behaviour of the adsorption system, which is consistent with the first-order kinetic reaction-for activated carbons (SO2 + Ar) or chemisorption on a heterogeneous surface-for unburned carbons (SO2 + Ar and SO2 + Ar + H2O(g) + O-2) and activated carbons (SO2 + Ar + H2O(g) + O-2). Importantly, usually, each of the approaches (linear/non-linear) indicated a different mechanism of the studied phenomenon. A certain universality of the chi(2) and HYBRID functions has been proved, the minimization of which repeatedly led to the lowest SNE values for the indicated models. Fitting data by any of the non-linear equations based on the R or R-2 functions only cannot be treated as evidence/prerequisite of the existence of a given adsorption mechanism.

Automated summary

In this study, the kinetic parameters of SO2 adsorption on unburned carbons and activated carbons were determined using linear and non-linear regression methods. The fitting quality of different models was assessed and it was found that linear regression is more accurate in reflecting the behavior of the adsorption system. Different mechanisms were observed for the two types of carbons.