تاثیر اندازه ذرات گرافیت بر ساختار حفرات و جذب گاز CO2 نانوساختار ایروژل گرافنی

صفایی, الهه; طالبی, زهرا; غفاری نیا, وحید

تاثیر اندازه ذرات گرافیت بر ساختار حفرات و جذب گاز CO2 نانوساختار ایروژل گرافنی

نوع مقاله : پژوهشی اصیل

نویسندگان

الهه صفایی ¹

زهرا طالبی ¹

وحید غفاری نیا ²

¹ داﻧﺸﮑﺪه ﻣﻬﻨﺪﺳﯽ نساجی، داﻧﺸﮕﺎه صنعتی اصفهان، اصفهان، ایران

² داﻧﺸﮑﺪه ﻣﻬﻨﺪﺳﯽ برق و کامپیوتر، داﻧﺸﮕﺎه صنعتی اصفهان، اصفهان،ایران

چکیده

جاذبهای جامد متخلخل به منظور جذب گاز دی اکسیدکربن به عنوان گازآلاینده و اثرگذار بر تغییرات جوی

محیط زیست مورد توجه محققان قرارگرفته اند. درتحقیق حاضر، از گرافن ایروژل به منظور جذب گاز دی-

اکسیدکربن استفاده شد. اثر پودر گرافیت اولیه بر فرایند اکسیداسیون گرافن اکساید و گروههای اکسیژنی روی سطح آن بررسی شد. سپس تاثیرمیزان اکسیداسیون برخودتجمعی نانوصفحات حین فرایند هیدروترمال و ساختارحفرات سلسله مراتبی گرافن ایروژل حاصل مورد بررسی قرارگرفت. دراین پژوهش از روش هامرز اصلاح شده برای سنتز گرافن اکسایدها و روش هیدروترمال و خشککردن انجمادی برای سنتز گرافن ایروژلها استفاده شد. به منظور مشخصه یابی گرافن اکسایدها از آزمونهای طیفسنجی مادون قرمز (FTIR) و پراش پرتوایکس ( XRD) استفاده شد. گرافن ایروژل ها با استفاده از آزمون های مختلف شامل جذب و واجذب نیتروژن، میکروسکوپ الکترونی روبشی ) (SEMمورد بررسی قرارگرفتند. درآزمون XRD اختلاف فاصله لایه ها بین گرافیت و گرافن اکساید نشان دهنده اکسیدشدن موفقیت آمیزصفحات گرافیت است. اختلاف شدت پیکهای اکسیژنی در آزمون FTIRناشی از اختلاف اندازه ذرات گرافیتها است. بطوری که شدت گروههای اکسیژنی بیشتر درگرافیت با اندازه ذرات کوچکتر مشاهده شد. بررسی ریخت شناسی گرافن ایروژلها اهمیت گروهای اکسیژنی در تشکیل ساختارسه بعدی سلسله مراتبی را نشان داد. افزایش گروههای اکسیژنی در نمونه با اندازه ذرات کوچکتر، ساختاری با دیوارههای نازکتر و تجمع کمترصفحات ایجاد کرده است.

نتایج حاصل نشان دادند که گرافیت با اندازه ذارت کوچک منجر به بهبود ساختار حفرات سلسله مراتبی ایروژل و افزایش میزان جذب گاز تا ۱/۰۴ mmol شد. ایروژل حاصل از ذرات گرافیت بزرگتر دارای جذب گازmmol

۰/۷۲است. استفاده از گرافیت با اندازه ذرات کوچکتر منجربه کنترل بهتر فرایند اکسیداسیون گرافن اکساید و

فرایند خودتجمعی گرافن ایروژل و سطح مخصوص مزو و میکرو بالا( ۱۱۲m2/gو ۱۱۵به ترتیب) شد.

کلیدواژه‌ها

گرافیت

گرافن اکساید

گرافن ایروژل

‌ جذب گازCO2

ساختار حفرات

موضوعات

غشاء

عنوان مقاله English

Effect of Graphite Source on Pore Structure and CO2 Adsorption of Graphene Aerogel

نویسندگان English

Elahe Safaei ¹

Zahra Talebi ¹

Vahid Ghafarinia ²

¹ Department of Textile Engineering, Isfahan University of Technology, Isfahan, Iran

² Department of Electrical and Computer Engineering, Isfahan University of Technology, Isfahan, Iran

چکیده English

Research subject: Global warming is the most important worldwide problem. CO₂ is one of the greenhouse gasses and its emission to the atmosphere causes global warming to increase. Porous adsorbents are great candidates for CO₂ adsorption and graphene aerogels are porous nanostructures with very low density and hierarchical porosity which is suitable for CO₂ adsorption. The source of pristine graphite for graphene oxide synthesis as a precursor plays a vital role in graphene aerogel nanostructure.

Research approach: In the current study, graphene oxide by modified Hummers method was synthesized with three different graphite sources. Graphene aerogels were prepared with synthesized graphene oxides via hydrothermal and freeze-drying methods to investigate their effect on graphene aerogel nanostructure. Finally, the CO₂ adsorption of graphene aerogels was evaluated. The samples were characterized by FTIR, XRD, SEM, and BET analysis.

Main results: The results indicated that the source of graphite has a significant role in the process of oxidation of graphene oxide by the modified Hummers method. XRD results of graphene oxides showed successful oxidation of graphite. The normalizing FTIR peaks of graphene oxides showed different intensities of oxygenated functional group peaks. FE-SEM results of graphene aerogels showed that less oxidation of graphite powder caused agglomeration of graphite plates and thick walls were formed. The macropore size in the structure of obtained aerogels (GAB and GAE) was 2.28 and 3.84 µm respectively which affected the CO₂ adsorption. Larger pores led to easier mass transfer of CO₂ molecules and higher CO₂ adsorption was achieved. Moreover, the high meso and micro surface area (111 and 115 m²/g respectively) in GAE increased CO₂ adsorption up to 1.04 mmol/g compared to GAB (0.724 mmol/g).

کلیدواژه‌ها English

Graphite

Graphene oxide

Graphene Aerogel

Porous Structure

CO2 Adsorption

1. Shrivastava, S., et al., An experimental investigation of the CO2 adsorption performance of graphene oxide forms. International Journal of Refrigeration, 96, 179-190, 2018.
2. Dinda, Srikanta, and Premanath Murge. "Porous material for CO2 capture: preparation, performance evaluation, and analysis of adsorption isotherms." Journal of Porous Materials 30.1 ,115-126, 2023.
3. Korkmaz, S. and İ.A. Kariper, Graphene and graphene oxide based aerogels: Synthesis, characteristics and supercapacitor applications. Journal of Energy Storage, 27,101038, 2020.
4. Nassar, G., et al., A review on the current research on graphene-based aerogels and their applications. Carbon trends, 4, 100065, 2021.
5. Kim, J.H., et al., Building with graphene oxide: effect of graphite nature and oxidation methods on the graphene assembly. RSC advances, 11(6), 3645-3654, 2021.
6. Shojaeenezhad, S.S., M. Farbod, and I. Kazeminezhad, Effects of initial graphite particle size and shape on oxidation time in graphene oxide prepared by Hummers' method. Journal of Science: Advanced Materials and Devices, 2(4),. 470-475, 2017.
7. Sieradzka, M., et al., Insight into the effect of graphite grain sizes on the morphology, structure and electrical properties of reduced graphene oxide. Journal of Materials Research and Technology, 9(4), 7059-7067, 2020.
8. Caglayan, Hatice Pelin, et al. "Effect of Surface Characteristics of Graphene Aerogels and Hydrophilicity of Ionic Liquids on the CO2/CH4 Separation Performance of Ionic Liquid/Reduced Graphene Aerogel Composites." ACS Applied Nano Materials 6.3 , 2203-2217, 2023.
9. Liu, Y., M. Xiang, and L. Hong, Three-dimensional nitrogen and boron codoped graphene for carbon dioxide and oils adsorption. RSC advances, 7(11), 6467-6473 ,2017.
10. Wu, J., X. Qiu, and S. Chen, Preparation and characterization of an amine-modified graphene aerogel for enhanced carbon dioxide adsorption. Journal of Materials Science, 57(3), 1727-1737, 2022.
11. Mahmoudi, E., et al., Distinguishing characteristics and usability of graphene oxide based on different sources of graphite feedstock. Journal of colloid and interface science, 542, 429-440, 2019.
12. Zhu, Yanbin, et al. "An improved Hummers method to synthesize graphene oxide using much less concentrated sulfuric acid." Chinese Chemical Letters 33.10 , 4541-4544, 2022.
13. Wang, F., et al., Facile synthesis of ultra-light graphene aerogels with super absorption capability for organic solvents and strain-sensitive electrical conductivity. Chemical Engineering Journal, 320: p. 539-548, 2017.
14. Bardestani, R., G.S. Patience, and S. Kaliaguine, Experimental methods in chemical engineering: specific surface area and pore size distribution measurements—BET, BJH, and DFT. The Canadian Journal of Chemical Engineering, 97(11): p. 2781-2791, 2019.
15. Garcia-Bordeje, E., et al., Control of the microstructure and surface chemistry of graphene aerogels via pH and time manipulation by a hydrothermal method. Nanoscale, 10(7): p. 3526-3539, 2018.
16. Al-Gaashani, R., et al., Effects of preparation temperature on production of graphene oxide by novel chemical processing. Ceramics International, 47(7): p. 10113-10122, 2021.
17. Muniyalakshmi, M., K. Sethuraman, and D. Silambarasan, Synthesis and characterization of graphene oxide nanosheets. Materials Today: Proceedings, 21: p. 408-410, 2020.
18. Raeburn, J., A.Z. Cardoso, and D.J. Adams, The importance of the self-assembly process to control mechanical properties of low molecular weight hydrogels. Chemical Society Reviews, 42(12): p. 5143-5156, 2013.
19. Sui, Z.-Y., et al., Preparation of three-dimensional graphene oxide–polyethylenimine porous materials as dye and gas adsorbents. ACS applied materials & interfaces, 5(18): p. 9172-9179, 2013.
20. Singh, G., et al., Emerging trends in porous materials for CO 2 capture and conversion. Chemical Society Reviews, 49(13): p. 4360-4404, 2020.
21. Chowdhury, S. and R. Balasubramanian, Three-dimensional graphene-based porous adsorbents for postcombustion CO2 capture. Industrial & Engineering Chemistry Research, 55(29): p. 7906-7916, 2016.
22. Jiang, Min, et al. Hierarchically porous graphene/ZIF-8 hybrid aerogel: preparation, CO2 uptake capacity, and mechanical property." ACS applied materials & interfaces 10.1: 827-834, 2018.
23. Hsan, Nazrul, et al. "Chitosan grafted graphene oxide aerogel: Synthesis, characterization and carbon dioxide capture study." International journal of biological macromolecules, 125: 300-306, 2019.
24. Balasubramanian, Rajasekhar, and Shamik Chowdhury. "Recent advances and progress in the development of graphene-based adsorbents for CO 2 capture." Journal of Materials Chemistry A 3.44: 21968-21989, 2015.
25. Wörmeyer, Kai, Mohammad Alnaief, and Irina Smirnova. "Amino functionalised Silica-Aerogels for CO 2-adsorption at low partial pressure." Adsorption 18: 163-171, 2012.