State Key Laboratory of Coal Combustion, College of Energy and Power Engineering, Huazhong University of Science and Technology

气候变化的加剧要求更加绿色高效的碳减排技术和产品的开发。固废和生物质衍生的常规CO2碳质吸附剂材料吸附效果较差，需要进行额外的活化改性以提升多孔炭的吸附性能。本工作以废纸为原料，经过简单预处理和溶胶凝胶炭化工艺，得到微孔高度发达的超微孔废纸碳气凝胶，探究了不同种类废纸和制备温度的影响。对材料的理化特性和CO2吸附性能进行了表征和测试，结果表明，废纸碳气凝胶的孔隙结构发达，呈类蜂窝状。打印纸为原料，800 ℃下制备的废纸碳气凝胶具有大比表面积1369.94 m2/g、高孔容0.59 cm3/g和孔径为0.4−0.8 nm的超微孔。无需改性，0 ℃时的CO2吸附量为247 mg/g，对应CO2/N2吸附选择性为11，25 ℃时的动力学吸附量为151 mg/g，七次吸脱附循环的平均波动幅度小于5%，对烟气CO2（10%）的捕获量为42 mg/g。废纸碳气凝胶展现出优异的CO2吸附性能和再生稳定性，优于固废和生物质衍生的常规炭材料。本工作也为固废处置和资源化利用提供了新思路。

The intensification of climate change requires the development of greener and more efficient carbon abatement technologies and products. Conventional CO2 carbonaceous adsorbent materials derived from solid waste and biomass feedstocks are poorly adsorbed and often require additional activation pore making and functional group introduction to enhance the adsorption performance of the porous carbon, which inevitably results in further growth of the process and further increase in energy consumption. In the work carried out in this paper, different kinds of waste paper were used as raw materials, and after a simple pretreatment and sol-gel carbonization process, highly developed microporous hierarchical porous carbon aerogels were prepared; moreover, KOH could be introduced in situ and activation pore-making could be accomplished synchronously during pyrolysis, which avoided the additional energy consumption of the two-step method. Thermogravimetric (TG), scanning electron microscopy (SEM), specific surface area and pore size analyzer (BET), Fourier transform infrared spectrometer (FT-IR) and fixed bed adsorption rig were used to characterize and test the thermal weight loss properties of the waste paper aerogels, the physicochemical properties of the waste paper carbon aerogels and the CO2 adsorption properties, respectively, and the results show that the main thermal weight loss process of the waste paper aerogels occurs at around 300 ℃, and is accompanied by the appearance of miscellaneous peaks of heat loss in the low pyrolysis temperature region, and the final mass residual rate is slightly higher than that of cellulose. Scanning electron microscopy showed that the pore structure was well developed and relatively homogeneous, and the surface openings showed a honeycomb-like structure. The printing paper carbon aerogel DYZ-800 prepared at a pyrolysis temperature of 800 ℃ has an ultra-high specific surface area of 1369.94 m2/g (94.28% of microporous specific surface area), a pore volume of 0.59 cm3/g (85.34% of microporous pore volume), and a pore-size distribution that is close to the kinetic diameter of CO2 molecules (0.4−0.8 nm and containing a large number of super-micropores with a size of 0.7 nm). The results of FT-IR tests revealed the effects of different waste paper types and pyrolysis temperatures on the carbon aerogel skeleton and chemical groups of waste paper, with sample DYZ-800 having a more stable carbon skeleton and a relatively high content of carbon-oxygen (C−O) groups. The maximum CO2 adsorption capacity of DYZ-800 without modification was 247 mg/g at 0 ℃ (1 bar) and 151 mg/g at 25 ℃ (1 bar), and the CO2/N2 adsorption selectivity was 11. The average fluctuation after 7 adsorption and desorption cycles was less than 5%, which showed good regeneration stability. The capture of CO2 at 10% flue gas concentration on a fixed-bed adsorption bench could also reach 42 mg/g (25 ℃, 1 bar). Among the three different adsorption kinetic models selected, the Bangham pore diffusion model had an excellent fit, demonstrating the great contribution of the well-developed pore structure of waste paper carbon aerogels in the CO2 kinetic adsorption process. Taken together, these results show that the waste paper carbon aerogel possesses excellent physicochemical properties, and the presence of a large number of micropores (especially ultra-micropores) enables it to exhibit excellent CO2 adsorption performance, which is superior to that of conventional solid waste and biomass-based carbon materials. All these indicate that the carbon aerogel prepared in this work has great advantages in carbon capture and potentials for further improvement, and this work also provides new ideas for solid waste disposal and resource utilization.

国家自然科学基金（52176187，52306245），浙江大学能源清洁利用国家重点实验室开放基金（ZJUCEU2022008）和国家资助博士后研究人员计划（GZB20230235）资助

顾锦阳, 张雄, 张俊杰, 邵敬爱, 张世红, 杨海平, 陈汉平. 超微孔废纸碳气凝胶的制备及其CO2吸附性能研究[J]. 燃料化学学报（中英文）, 2024, 52(9): 1336-1347.

GU Jinyang, ZHANG Xiong, ZHANG Junjie, SHAO Jingai, ZHANG Shihong, YANG Haiping, CHEN Hanping. Preparation of ultra-microporous waste paper carbon aerogel and its CO2 adsorption performance[J]. Journal of Fuel Chemistry and Technology, 2024, 52(9): 1336-1347.