氨水改性活性炭对沼气吸附脱碳的实验研究

EXPERIMENTAL STUDY ON ADSORPTION AND DECARBONIZATION OF BIOGAS BY ACTIVATED CARBON MODIFICATED BY AMMONIA

针对沼气吸附法脱碳提质所用活性炭进行改性研究,以氨水为改性剂,探讨改性剂浓度和改性时间对活性炭脱碳效果以及其表面化学结构的影响。实验结果表明:1)经过氨水改性处理后的活性炭呈酸性官能团减少,呈碱性官能团增加,同时引入含氮官能团,改性后活性炭的表面疏水性增强,极性发生变化,增强对气体的吸附能力;2)在改性剂浓度5%~25%范围内,氨水浓度为10%,改性时间为12 h,改性效果最佳,活性炭比表面积由413.2 m^(2)/g增至502.7 m^(2)/g,增加21.66%,微孔容积增加39.47%,达到最大值0.735 cm^(3)/g,总孔容积增加54.33%,达到最大值0.963 cm^(3)/g,微孔孔径增大13.06%,达到1.307 nm;3)模拟沼气(CH4体积占比60%,CO_(2)体积占比40%)吸附脱碳实验显示,改性最佳的活性炭处理使样品气中甲烷含量增加19.96%,由未改性活性炭的76.30%达到91.53%。

The modification of activated carbon used in biogas decarburization and purification through adsorption method was studied,and ammonia used as modifier.The effect of modifier concentration and modification time on the decarburization effect of activated carbon and its surface chemical structure was investigated.The results shown that:1)After the treatment with ammonia water,the activated carbon showed less acid functional groups and more alkaline functional groups.At the same time,the introduction of nitrogencontaining functional groups made the surface hydrophobicity of the modified activated carbon enhanced,the polarity changed,and the adsorption capacity of the gas was enhanced;2)In the concentration range of modifier concentration 5%-25%,the concentration of ammonia water is 10%,the modification time is 12 h,and the modification effect is the best.The specific surface area of activated carbon increases from 413.2 m^(2)/g to 502.7 m^(2)/g,21.66% is increased,the micropore volume increased by 39.47% to a maximum of 0.735 cm^(3)/g,the total pore volume increased by 54.33% to a maximum of 0.963 cm^(3)/g,and the pore diameter increased by 13.06% to 1.307 nm;3)Simulated biogas(CH4volume accounts for 60%,CO_(2) volume accounts for 40%)adsorption decarburization experiments showed that the best modified activated carbon treatment increased the methane content in the sample gas by 19.96%,and reached 91.53% from 76.30% of the original activated carbon.