Preparation And Characterization Of The New Carbon Aerogels

As new carbon materials, carbon aerogels have outstanding properties of highspecific surface area, high porosity, good conductivity and low thermal conductivity,which make carbon aerogels as electrode adsorb ions well in the water, and havebroad prospects in electrosorption technology. Resorcinol as raw materials can obtainthe carbon aerogels with larger specific surface area, so favored by researchers.Commonly used preparation technology of carbon aerogels make resorcinol andformaldehyde as raw materials, and prepare via a sol-gel process, solvent replacement,ambient pressure and carbonization process. But the gel time of preparation process islonger, and the hardness of carbon aerogels is lower. Address these problems,phloroglucinol are joined in the raw materials of resorcinol. Compared with resorcinol,phloroglucinol have more reactivity point in the structure, which not only improve thereaction speed and shorten the gel time, but also can enhance the network structure ofcarbon aerogels. This topic discusses the research work of carbon aeroge ls withphloroglucinol, resorcinol and formaldehyde as materials.In the paper, the nanoscale carbon aerogels were prepared with the raw materialsof phloroglucinol, resorcinol and formaldehyde under the action of catalyst via thesol-gel method. Change the synthetic conditions, including the content ofphloroglucinol, concentration of reactants, the type and content of catalysts, canprepare PRF carbon aerogels in different process conditions. Then the microstructureof PRF carbon aerogels were characterized by instruments. The detail of researchcontent are as follows:(1) PRF carbon aerogels were prepared by sol-gel method. The results showedthat after carbonization, the specific surface area and quantity adsorbed improveobviously, and average pore volume and pore size decrease. Compared with RFcarbon aerogels, the specific surface area, average pore volume and quantity adsorbedof PRF carbon aerogels are larger.(2) PRF carbon aerogels were prepared through changing the content ofphloroglucinol (nP/nR). The results showed that the larger of content, the smaller ofspecific surface area and average pore volume of carbon aerogels. When theproportion of nP/nRis1:7, the carbon aerogels have concentrated pore structure whichis favourable to the electric adsorption desalination experiments. (3) PRF carbon aerogels were prepared by changing the concentration ofreactants. The samples were characterized and the results indicated that the structureof carbon aerogels become loose and the conductivity decrease with the increase ofconcentration. The structure of carbon aerogels are mesoporous-oriented. The carbonaerogels with the reactant concentration of45%have higher specific surface area andquantity adsorbed, and have concentrated pore size distribution and uniform networkstructure.(4) PRF carbon aerogels were prepared by changing the catalyst type. Themicrostructure characterization showed that the addition of catalysts make thestructure compact, the specific surface area increase and the resistivity decrease. WithNa2CO3as catalyst, PRF carbon aerogels have the highest specific surface area andlowest resistivity.(5) PRF carbon aerogels were prepared through changing the content ofcatalysts(nR/nC). The results showed that with the increase of nR/nC, the average poresize and resistivity increase. When the is800, the carbon aerogels have higher specificsurface area and larger adsorption capacity, and the electrical conductivity is good.(6) The electrosorption experiment showed that the adsorption capacity of PRFcarbon aerogels electrode is11.25mg/g.