Batch and Continuous Column Adsorption of p-Nitrophenol onto Activated Carbons with Different Particle Sizes

LEDESMA, BEATRIZ; SABIO, EDUARDO; GONZÁLEZ-GARCÍA, CARMEN MARIA; ROMAN, SILVIA; FERNANDEZ, MARIA EMILIA; BONELLI, P.R.; CUKIERMAN, ANA LEA

Processes

Multidisciplinary Digital Publishing Institute (MDPI)

Año: 2023 vol. 11 p. 2045 - 2067

The study focused on investigating the solvent adsorption of p-Nitrophenol (PNP) ontoactivated carbons for wastewater treatment. It explored the influence of adsorbate concentrationand adsorbent size on equilibrium isotherms and removal rates to develop efficient adsorptionprocesses. The study examined adsorption isotherms under equilibrium conditions utilizing boththe Langmuir and Double-Langmuir models and the Dubinin–Radushkevich equation. Remarkably,all the models demonstrated equally excellent fitting to the experimental data. Kinetics ofPNP adsorption were investigated using pseudo-first-order, pseudo-second-order, and intraparticlediffusion kinetic models. This provided insights into the dominant adsorption mechanism andmass transfer phenomena, aiding the design of efficient wastewater treatment processes. Strongcorrelations (correlation coefficients > 0.9) were found between the models and experimental datafor three types of activated carbons under batch conditions. This validation enhances the reliabilityand applicability of the models, supporting their practical use. The study also observed a slightincrease in maximum adsorption capacity (qmax) with decreasing particle size, although there isnot a significant difference: 340, 350, and 365 mgg􀀀1, for CB-L, CB-M, and CB-S, respectively. Thisinsight helps in selecting appropriate activated carbon for effective PNP removal, considering bothadsorption capacity and particle size. Furthermore, the analysis of PNP adsorption under dynamicconditions in fixed-bed columns highlighted the significance of inlet velocity and carbon mass indetermining breakthrough time, with particle size playing a secondary role. This information aids inoptimizing the design and operation of fixed-bed adsorption systems for efficient PNP removal. Insummary, this study’s significant contributions lie in enhancing our understanding of PNP adsorption in wastewater treatment. By investigating equilibrium isotherms, kinetics, and mass transfer phenomena, it provides validated models, insights into adsorption capacity and particle size, and practical guidance for dynamic adsorption systems. These findings contribute to the development of efficient and sustainable wastewater treatment methods