The Synthesis And Analysis Of Hemp Cloth Activated Carbon Fibers

Activated carbon fibers have been investigated by many scientists all over the world as a new kind of highly effective, active fibrous adsorbent and environmental material. In this work, hemp cloth was used to synthesize activated carbon fibers with different porous structure by chemical activation and chemical-physical activation. The surface texture, chemical structure, surface energy distribution and microcosmic figures were characterized by N2adsorption analysis at low temperature, Fourier transform infrared spectra(FTIR), density functional theory(DFT) and scanning electron microscopy(SEM), indicating the carbonization and activation mechanism of the samples.The results showed that the textile characteristics of the chemical activation samples were influenced enormously by activation temperature. The yield of the samples was decreased with increasing activation temperature or time, and the specific surface area was increasing with the activation temperature up to800℃and then decreasing at900℃. The pore size distribution was centralized in micropore region, with a small fraction of mesopores, but without macropores. The surface energy distribution was very wide, suggesting that there are several adsorption sites with different surface energy, and the surfaces are very heterogeneous.The chemical-physical activation samples showed different variation of the surface texture and iodine adsorption amounts. The structure and function of the samples were affected by activation time and activating agents. The H3PO4-CO2and ZnCl2-CO2activation samples were typical micropore materials. The pore size distribution was centralized in micropore region, with a small fraction of mesopores, but without macropores. The iodine amounts were increasing with the activation time to a certain point and then decreasing. The ZnCl2-steam activation samples with activation time over20min were mesopore materials, with a reasonable amount of mesopore and macropore.The microcosmic figures of the hemp cloth activated carbon fibers prepared by different activating agents existed great difference. The fibers of H3PO4, ZnCl2, ZnCl2-CO2and ZnCl2-steam activation samples were strip homodromous array, with wide gap among fibers. But the H3PO4-CO2activation sample was strip homodromous array, with very narrow gap. The roughness concentration of the fiber surface was also different, slick or not slick. This further supported the activation mechanism of different activation methods.