Carbon gel monoliths with introduced straight microchannels for phenol adsorption

Abstract

Adsorption of phenol using carbon adsorbents in the form of a packed bed of particles inherently suffers from the incompatibility between low hydraulic resistance and short diffusion path length. In this work, carbon gel monoliths made from resorcinol–formaldehyde gels with introduced straight microchannels in the range of 60–160 µm were successfully synthesized using polyesters fibers as templates. The advantage of this synthesis method is that both channel size and channel density can be tuned independently. Introduced microchannels were effective in minimizing the pressure drop of a fluid flowing through the sample to less than a hundredth of beds packed with particles having the same diffusion path length. Synthesized monoliths also possess sufficient mechanical strength (more than 12 kg per monolith) to be activated to increase their adsorption capacity. Adsorption experiments of phenol in a continuous flow system show that synthesized monoliths can be used as effective adsorbents for phenol removal. The tunable channel size and channel density of the proposed synthesis method has the potential for the synthesis of monoliths which could be used to fulfill various process demands.