Activated Carbons for the Removal of Low-Concentration Gaseous Toluene at the Semipilot Scale

The present paper focuses on the removal of low-concentration gaseous toluene by adsorption on activated carbons (AC) at the semipilot plant scale. The performance of AC prepared by chemical and physical activation is analyzed and compared with a commercial AC. Our results have shown similar shapes for the breakthrough curves in the physically AC and the commercial AC, close to ideality, and similar lengths of the mass transfer zone, despite their different pore size distributions. This behavior is mostly related to a strong adsorbate-adsorbent interaction for the three AC, whereas this interaction has proved to be weaker in the chemically activated ones. The narrow micropore volume influences the breakthrough and saturation times, and a simple kinetic model has been used to fit the experimental data leading to good prediction of the adsorption capacities. A mathematical model, suitable for diluted concentrations, has been used to simulate the breakthrough curves. This model has proved to be useful to fit curves at laboratory scale and predict the adsorption behavior at larger scales.