磷酸微波活化多孔生物质炭对亚甲基蓝的吸附特性

以甘蔗渣为原料，采用微波辅助H3PO4活化法制备富含含氧酸官能团的中孔生物质炭。通过扫描电子显微镜SEM、傅立叶变换红外光谱FT-IR等技术对生物质炭物理化学性质进行表征，并通过静态实验法，探讨炭样对亚甲基蓝的吸附行为及热力学性质。结果表明，H3PO4活化制备蔗渣生物质炭的适宜条件为浸渍比1：1，烘干时间10h，活化功率900W，活化时间22min，在此条件下制得的生物质炭得率为39．2％，碘值为817mg／g，亚甲基蓝值为229mg／g，为国家一级品标准的1．7倍。红外光谱分析表明，炭样表面以羟基、羰基、羧基等酸性官能团为主。静态吸附实验表明，Freundlich方程与Redlich—Peterson方程能较好地描述等温吸附行为，表现为优惠吸附。热力学研究表明，吸附吉布斯自由能（△G0）〈0，说明吸附反应是自发过程，而吸附标准焓变（△H0）〉70KJ／mol，表明亚甲基蓝在制备炭样上的吸附是吸热反应，升温有利于吸附，且化学反应在吸附过程中发挥了重要作用。

Adsorption characteristics of methylene blue onto biomass-based porous activated carbons by microwave assisted H3PO4 activation

Mesoporous biomass-based activated carbons containing acidic groups were prepared with ba- gasse as raw materials by microwave assisted H3PO4 activation. Surface properties of the prepared biomass-based carbons were performed using FTIR spectroscopy and SEM. The adsorption and thermodynamic behavior of meth- ylene blue on the carbons was investigated by conducting a series of batch adsorption experiments. The results show that under the conditions of impregnation ratio of 1： 1, stoving time of 10 h, activation power at 900 W and activation time of 22 rain, the yield of prepared activated carbon is 39.2% , the amount of iodine value adsorption of activated carbon is 817 mg/g,while the amount of methylene blue value adsorption of activated carbon is 229 mg/g, which is 1.70 times of the national l~＇standard sample of activated carbon. The FTIR experiment shows that the surfaces of activated carbons are dominated by acidic functional groups such as hydroxy, carbonyl and carboxyl. The isotherm adsorption behavior was found to fit well with both Freundlicb and Redlich-Peterson equa- tions. The adsorption process is concluded to be a kind of favorable adsorption. The negative change in free ener- gy （△G0） and positive change in enthalpy （△H0） indicated that the adsorption was a spontaneous and endother- mic process. The high value of the adsorption enthalpy △H0 （ 〉 70 kJ/mol） also indicated that the chemical reac- tion was involved and played an important role in the methylene blue adsorption on the carbon.