Mussabek Gauhar, Baktygerey Saule, Taurbayev Yerzhan, Yermukhamed Dana, Zhylkybayeva Nazym, Zaderko Alexander N, Diyuk Vitaliy E, Afonin Sergii, Yar-Mukhamedova Gulmira, Mariychuk Ruslan T, Grishchenko Liudmyla M, Kaňuchová Mária, Lisnyak Vladyslav V
Nanotechnological Laboratory of Open Type, Al-Farabi Kazakh National University 050040 Almaty Kazakhstan.
Institute of Information and Computational Technologies 050012 Almaty Kazakhstan.
RSC Adv. 2024 Sep 12;14(40):29052-29071. doi: 10.1039/d4ra04883k.
According to the proposed pyrolytic method, granular activated carbon (AC) Norit 830 W was functionalized by thermal treatment of AC in hydrofluorocarbon (HFC) gases, pentafluoroethane and 1,1,1,2-tetrafluoroethane, at 400-800 °C. This method does not require activation by plasma and photons. Chemical and elemental analysis showed that the pyrolytic treatment provides a loading of 2.95 mmol (5.6 wt%) of fluorine per gram of AC. Nitrogen adsorption measurements indicated that the microporous structure contracted when AC was treated with HFC at temperatures above 400 °C. Thermogravimetry, Fourier transform infrared spectroscopy (FTIR) with attenuated total reflectance (ATR), and X-ray photoelectron spectroscopy (XPS) demonstrated the evolution of oxygen-containing and fluorine-containing groups to more thermostable groups with treatment temperature. The fluorine-containing groups grafted at high temperature, above 600 °C exhibited the highest thermal stability up to 1250 °C in dry argon. From the data of XPS and solid-state F nuclear magnetic resonance spectroscopy data, the grafted fluorine exists in several types of grafted F-containing groups, the HFC residues. By changing the thermal regime of fluorination, the composition of fluorine-containing groups on a carbon surface can be regulated. Isolated fluoroalkyl groups can be grafted at temperatures of 400-500 °C, while at 600 °C and above, the semi-ionic fluorine groups increase significantly. The hydrophobized surface demonstrated the ability to effectively decompose HO in methanol solutions.
根据所提出的热解方法，颗粒状活性炭（AC）Norit 830 W通过在400-800°C的氢氟烃（HFC）气体（五氟乙烷和1,1,1,2-四氟乙烷）中对AC进行热处理而功能化。该方法不需要通过等离子体和光子进行活化。化学和元素分析表明，热解处理每克AC提供2.95 mmol（5.6 wt%）的氟负载量。氮吸附测量表明，当AC在400°C以上的温度下用HFC处理时，微孔结构收缩。热重分析、带有衰减全反射（ATR）的傅里叶变换红外光谱（FTIR）以及X射线光电子能谱（XPS）表明，随着处理温度的升高，含氧和含氟基团演变成更具热稳定性的基团。在600°C以上高温接枝的含氟基团在干燥氩气中高达1250°C时表现出最高的热稳定性。根据XPS和固态F核磁共振光谱数据，接枝的氟存在于几种类型的接枝含F基团中，即HFC残基。通过改变氟化的热条件，可以调节碳表面含氟基团的组成。在400-500°C的温度下可以接枝分离出的氟烷基，而在600°C及以上，半离子氟基团显著增加。疏水化表面显示出在甲醇溶液中有效分解HO的能力。
