Preparation of carbon aerogels with different pore structures and their fixed bed adsorption properties for dye removal

Controlled porosity carbon aerogels are prepared by a sol–gel polymerization method and the prepared materials are used as fixed bed adsorbents for dye removal. The influences of operating conditions and preparation factors on the adsorption of C. I. Reactive Red 2, as a model compound, from aqueous solution were investigated. Many column parameters were estimated at different stages and the Bed-Depth-Service-Time model was used to analyze the experimental data. The results showed that the adsorption bed capacity increased with increasing bed height, decreasing liquid flow rate and decreasing initial dye concentration. Moreover, the work indicated that the adsorption ability of the carbon aerogel could be controlled by adjusting the molar ratio of resorcinol to surfactant and carbonization conditions. In addition, the adsorption capacity could be improved when the carbon aerogel was activated by CO2. The reasons for the difference in adsorption ability could be related to the different pore structure characteristics of various samples.

► First exploration of the fixed bed adsorption properties of a carbon aerogel.
► The adsorption performance of carbon aerogel is highly dependent on the adsorption operating parameters.
► The adsorption behavior could be controlled by adjusting reactant ratios and carbonization conditions.
►  The adsorption ability may be improved when the carbon aerogel is activated by CO2.
► The adsorption ability of carbon aerogel is related to pore structure characteristics.