Dear Utkarsh

I hope you can find your answer in the following review paper:

best regards

Randa

Yan model was developed empirically, based on statistical analysis of experimental data. so it does not have any physical assumption on the developed model.

Nevertheless, the maximum solid-phase concentration (q) can be estimated by an approximation of the Thomas model at 50% of bed saturation. (q = b*Co/M) , where "b" is the model parameter.

For the parameter "a" i don't know if it has physical meaning (i think it do not).

Best regards

The purpose of Yan model and Thomas model is the same. i.e., to evaluate the performance of column in terms of adsorption capacity. However, the Yan model gives more accurate value (i.e., with less error) of adsorption capacity of column because in Thomas model is limited by diffusion. That's why in most of the studies, the Yan model gives overestimated results than that of the Thomas model. The below reference can further help in this regard,

Article Effective defluoridation of industrial wastewater by using a...