Influence of Drying Methods on Preparation and Adsorption Capacity of Cassava Starch-Based Carbon Aerogels

Abstract:

To study the influence of drying method on the structure and adsorption capacity of starch-based carbon aerosols，two types of aerogels were prepared by ambient pressure drying （AD） and freeze drying （FD） methods，using cassava starch as carbon source. Subsequently，two corresponding carbon aerogels were prepared by high temperature carbonization，using the obtained aerogels as precursors，respectively. Fourier Transform Infrared Spectroscopy，X-ray Diffractometer，Scanning Electron Microscopy and Automatic Gas Sorption Analyzer were employed to evaluate starch-based aerogels （SAs） and carbon aerogels （SCAs），and the adsorption capacity of SCAs on cationic dyes was also studied. Results indicated that the chemical and crystalline structures of two SAs were identical. However，more pores were observed in SA prepared by freeze drying （SA-FD），and its corresponding SCA （SCA-FD） had lager surface area （887.4 m2/g） and pore volume （0.444 cm3/g），as well as stronger adsorption capacity on cationic dyes. It suggested that freeze drying was superior to ambient pressure drying.