Binary adsorption breakthrough curves in fixed bed: Experiment and prediction

• Activated carbon was used to adsorb phenol and PNP from aqueous solutions.
• Adsorption isotherm data of phenol and PNP were fitted by different models.
• Binary adsorption isotherm is predicted by the ideal adsorbed solution theory.
• Binary adsorption breakthrough curves were measured and predicted by wave theory.
• IAST plus wave theory is a tool to predict binary adsorption breakthrough curves.

Phenolic compounds are extensively used as raw materials in a wide variety of manufacturing processes and thus result in wastewaters containing phenolic compounds. In order to design a fixed-bed carbon adsorption process for wastewater containing phenol and p-nitrophenol, batch and column adsorption tests at 250 °C were performed to measure the adsorption isotherms and breakthrough curves of phenol and p-nitrophenol, respectively. The Freundlich adsorption isotherm model for single-component systems was found to correlate the adsorption equilibrium data better than the Langmuir model. Algorithms for applying the ideal adsorbed solution theory along with the Langmuir and Freundlich adsorption isotherm models were derived to predict the p-nitrophenol–phenol binary adsorption data. Compared with the experimental data, the Freundlich model along with the ideal adsorbed solution theory can best predict the binary adsorption data with the least errors. Thus, the wave propagation theory along with the ideal adsorbed solution theory using the Freundlich isotherm model was applied to predict the breakthrough curves of binary adsorption satisfactorily. This study demonstrates a novel methodology to predict the binary adsorption breakthrough curves using the adsorption isotherm model, the ideal adsorbed solution theory, and the wave propagation theory.