分子模拟研究活性炭表面官能团对丙酮吸附的影响

Molecular Simulation Study on Influence of Surface Functional Groups of Activated Carbon on Acetone Adsorption

目的从分子层面解释不同含量和种类的表面官能团对丙酮在活性炭中吸附的影响,从而了解不同浓度丙酮吸附应选择活性炭的种类。方法利用蒙特卡洛法模拟氧含量为3 wt%,5 wt%,10 wt%,20wt%,加入官能团分别为羟基、羧基、羰基的活性炭,在303 K下对丙酮的吸附。结果在1.0 nm孔中,当丙酮浓度为10 ppmv时,除加入羧基使氧含量为20 wt%外,加入各种含量和种类的官能团对丙酮的吸附都是有利的。当丙酮浓度为1000 ppmv时,除加入羰基使氧含量为10 wt%外,加入官能团对丙酮的吸附都是不利的。结论当丙酮浓度低于10 ppmv时,选用1.0 nm氧含量为5 wt%官能团为羟基的活性炭吸附效果最好。对于浓度大于1000 ppmv的丙酮,选用孔径为1.5 nm氧含量为10 wt%官能团为羧基的活性炭吸附效果最好。

Objective To investigate the effects of the type and amount of functional groups on acetone adsorp- tion in activated carbon at molecular level, and give suggestions on the choice of adsorbent used to adsorb ace- tone of different concentration. Methods GCMC simulation was used to calculate adsorption isotherms of ace- tone in adsorbents with different pore size and functional groups at 303 K. The type of functional groups insert- ed in adsorbents were hydroxyl, carbonyl and carboxyl respectively and oxygen content was 3 wt% , 5 wt% , 10 wt% and 20 wt% respectively. Results In 1.0 nm pore, when acetone concentration was 10 ppmv, different type and amount of functional groups were beneficial to acetone adsorption except the adsorbent with carboxyl groups whose oxygen content was 20%. When acetone concentration was 1000 ppmv, functional groups had disadvantage on acetone adsorption expect adsorbent with carbonyl groups whose oxygen content was 10 wt%. Conclusion When acetone concentration is lower than 10 ppmv, the 1.0 nm adsorbent with 5 wt% oxygen content and hydroxyl groups is the best. When acetone concentration is higher than 1000 ppmv, 1.5 nm adsorbent with 10 wt% oxygen content and carboxyl groups is the best.