热解气活化的活性炭对水体中甲萘威的吸附性能

Adsorption performance of carbaryl of wastewater on activated carbons prepared by pyrolysis gas activation

以生物质混合压缩颗粒为原料,在600~900℃活化温度下,循环利用热解气制备活性炭,考察热解气的活化作用及活性炭对农药甲萘威的吸附性能。结果表明:热解气具有明显的活化作用,经过活化的炭与热解炭相比孔结构更加发达,表面更加粗糙;活化温度对活性炭理化性质具有显著影响,随温度升高,活性炭芳香性升高,极性降低,含氧官能团逐渐减少,比表面积由239.00 m^2·g^(-1)增加到629.20 m^2·g^(-1),平均孔径由5.438 nm减小至3.005 nm;Freundlich模型能够很好地拟合活性炭对甲萘威的吸附等温线,随活化温度升高,活性炭吸附能力增大;吸附动力学更符合伪二级反应动力学模型,60 h内基本实现吸附平衡;当活化温度为800℃,单位原料对甲萘威的吸附量最大。

In this study, activated carbons （ACs） were prepared from mixed biomass pellet, which were activated by pyrolysis gas at the temperatures from 600℃to 900℃. Batch experiments were performed to investigate the activation effects of pyrolysis gas and adsorption properties of earbaryl onto ACs. The pyrolysis gas obviously promoted the development of pore structure, and the surface of carbons became rougher after activation process. With the increase of activation temperatures, the aromaticity of activated carbons increased, polarity and surface oxygen functional group decreased, SBET increased from 239.00 m2· g-1 to 629.20 m2 · g-1 and Dp decreased from 5. 438 nm to 3. 005 nm. Freundlich model well described adsorption isotherms of carbaryl on ACs, and the adsorption capacity of ACs increased with activation temperature. Pseudo-second order model more fit the adsorp- tion kinetics, and the adsorption nearly reached equilibrium within 60 h. The highest adsorption capacity yield was achieved at the activation temperature of 800 ℃.