热改性对柱状活性炭脱硫能力的影响

在N2保护下采用不同温度对柱状活性炭进行热改性,得到了5种改性活性炭(AC-1～AC-5),将改性前后的活性炭(AC)分别置于含有SO2且有水蒸气和氧气存在的条件下进行脱硫试验,利用气体吸附仪和扫描电镜对改性前后活性炭表面的物理性质进行了表征.试验结果表明,当改性温度为700～900℃时,改性后活性炭的脱硫能力随着改性...

Effect of thermal modification on desulfurization capacity of column activated carbon

Five kinds of modified activated carbons (AC-1 to AC-5) were obtained by thermal modification of columnar activated carbons at different temperatures under the protection of N₂. The activated carbons (AC) before and after modification were placed in the condition containing SO₂ and in the presence of water vapor and oxygen respectively for desulfurization experiment. The physical properties of activated carbon surface before and after modification were characterized by gas adsorption apparatus and scanning electron microscope. The experimental results show that when the modification temperature is 700-900 ℃, the desulfurization ability of the modified activated carbon increases with the increase of the modification temperature, when the modification temperature is 900 ℃, the desulfurization ability of the activated carbon is the strongest, when the modification temperature is 1 100 ℃, the desulfurization ability of the activated carbon decreases obviously. Gas adsorption apparatus of the proceeds of the BET the results of the analysis, and scanning electron microscopy the results show that activated carbon part was blocked in the process of heating channel is opened, increase its adsorption surface area, to improve the initial activated carbon desulfurization rate is good, but too high temperature will destroy the original structure of aperture, activated carbon in AC-4 and AC-5 samples of the desulfurization ability becomes poor. In addition, temperature-programmed desorption technology (TPD) was used to analyze the pH content of activated carbon samples from AC to AC-4. The results showed that there was a good proportional linear relationship between the ph content of strong alkali center on the surface of activated carbon and its desulfurization ability. By comparing the samples AC-2 and AC-3, it can be found that under the condition of little difference in the physical properties of activated carbon, the improvement of its desulfurization ability mainly benefits from the change of surface chemical properties, especially the enhancement of alkalinity. At the same time, through the Boehm titration and combined with Fourier transform infrared spectrometer (FTIR) of activated carbon samples AC and AC-3 the surface acidic functional groups of change were analyzed, and found that the thermal modified activated carbon surface carboxyl, lactone and decrease in the number of hydroxyl groups, shows that heat treatment can make the surface acidic functional groups of activated carbon decomposition, is helpful to promote its desulfurization ability.