Altwala Afnan, Mokaya Robert
School of Chemistry, University of Nottingham University Park Nottingham NG7 2RD UK
Department of Chemistry, College of Science Al-Zulfi, Majmaah University Al-Majmaah 11952 Saudi Arabia.
RSC Adv. 2022 Jul 12;12(31):20080-20087. doi: 10.1039/d2ra02661a. eCollection 2022 Jul 6.
This work explores the use of a less corrosive activating agent, potassium oxalate (PO), in combination with difficult to activate carbonaceous matter for the preparation of activated carbons. The design of the study allowed a fuller understanding of the workings of PO compared to hydroxide (KOH) activation, and also optimised the preparation of highly microporous carbons with exceptional CO storage capacity under low pressure (≤1 bar) conditions at ambient temperature. The PO activated carbons have a surface area of up to 1760 m g and are highly microporous with virtually all of the surface area arising from micropores. The porosity of the PO activated carbons can be readily tailored towards having pores of size 6-8 Å, which are highly suited for CO storage at low pressure (, post-combustion capture). At 25 °C, the PO activated carbons can store up to 1.8 and 5.0 mmol g of CO at 0.15 bar and 1 bar, respectively. On the other hand, KOH activated carbons reach a higher surface area of up to 2700 m g, and store up to 1.0 and 4.0 mmol g of CO. This work demonstrates that PO may be used as a mild, less corrosive and less toxic activating agent for the rational and targeted synthesis of biomass-derived activated carbons with tailored porosity. The targeted synthesis may be aided by careful selection of the biomass starting material as guided by the O/C ratio of the biomass.
本研究探索了使用腐蚀性较小的活化剂草酸钾（PO）与难以活化的含碳物质相结合来制备活性炭。与氢氧化钾（KOH）活化相比，该研究设计能更全面地了解PO的作用原理，还优化了在环境温度下低压（≤1巴）条件下具有出色CO储存能力的高微孔碳的制备。PO活化的活性炭比表面积高达1760 m²/g，具有高度微孔结构，几乎所有比表面积都来自微孔。PO活化活性炭的孔隙率可轻松调整为具有6 - 8 Å大小的孔隙，这非常适合在低压下储存CO（用于燃烧后捕获）。在25°C时，PO活化的活性炭在0.15巴和1巴下分别可储存高达1.8和5.0 mmol/g的CO。另一方面，KOH活化的活性炭比表面积更高，可达2700 m²/g，可储存高达1.0和4.0 mmol/g的CO。这项工作表明，PO可作为一种温和、腐蚀性较小且毒性较低的活化剂，用于合理且有针对性地合成具有定制孔隙率的生物质衍生活性炭。通过根据生物质的O/C比仔细选择生物质原料，可辅助进行有针对性的合成。
