Adsorption dynamics of p-nitrophenol in structured fixed bed with microfibrous entrapped activated carbon

•The microfibrous entrapped activated carbon composites are used for PNP adsorption.•The HSDM is used for investigation adsorption dynamics.•Mass transfer has been enhanced in structured fixed bed.•Experimental and two theoretical results confirmed the conclusion.

Adsorption dynamics of p-nitrophenol (PNP) in the structured fixed bed filled with granular activated carbon in the inlet and microfibrous entrapped activated carbon composites in the outlet at various flow rates and inlet concentrations were studied. A modified version of the homogeneous surface diffusion model (HSDM) involving surface diffusion, film mass transfer and axial dispersion was proposed to simulate the adsorption dynamics of PNP in the structured fixed bed. The breakthrough curve of PNP in the structured fixed bed is steeper than that in the individual activated carbon fixed bed with the same bed height. The length of unused bed (LUB) of the structured bed decreases almost 20% compared with that of the individual bed. The model simulations indicate that intraparticle diffusion resistances, film mass transfer resistances and the resistance due to axial dispersion decrease by adding the microfibrous entrapped activated carbon composites in the outlet of the bed. The experimental and modeled results indicate that the mass transfer and utilization of bed capacity are enhanced by adding the microfibrous entrapped activated carbon composites in the outlet of the structured bed.