3. Goodness of fit

To determine the kinetic model that best describes the interaction between the adsorbent and solute, the goodness of fit is used. The coefficient of correlation (R<sup>2</sup> ), sum-of-squared errors (SSE), average relative error, Spearman's correlation coefficient, non-linear chi-square test, hybrid fractional error function, Marquardt's percent standard deviation, and standard deviation of relative errors are some of the error functions that have been employed to study model fit. Table 1 summaries the error function [4, 14–17].
