(417b) Development of Highly Porous Carbon from Polyvinylidene Fluoride for CO2 Adsorption

In the increasing awareness of abnormal climate changes, carbon dioxide (CO₂) emissions from the use of fossil fuels have been considered as the major contributing greenhouse gas. Therefore, the reduction of CO₂ has become an important environmental concern, and various approaches such as absorption, adsorption, and membrane separation have been employed in CO₂ capture. In recent times, technology designed to capture CO₂by adsorption has received considerable attention due to its easy regeneration and low energy consumption without producing unfavorable by-products or any polluted sorbent.

Commercial adsorbents such as activated carbon, zeolite, and metal-organic frameworks (MOFs) have been widely used in CO₂ adsorption. Although zeolites and MOFs have high CO₂adsorption capacities, they substantially lose their adsorption abilities in humidified conditions due to their hydrophilic characteristics [1-2]. On the other hand, porous carbonaceous materials are hydrophobic and have additional advantages of high surface area, thermal and chemical stability, and relatively low cost.

In this study, polyvinylidene fluoride (PVDF) was used to synthesize porous carbon for CO₂ adsorption. PVDF has been known to process porous structure with high surface area and pore volume during carbonization at high temperature [3], indicating great potential in CO₂ adsorption. Therefore, highly porous carbons were prepared for CO₂ capture from the PVDF carbonized at high temperature in the range 400–800 °C, and the effects of carbonization temperature on the characteristics and CO₂ adsorption behavior of prepared carbon materials were investigated. The carbonized PVDFs showed high surface area and pore volume more than 1000 m²/g and 0.4 cm³/g, respectively, and the significant increase of these textural properties was predominantly attributed to the evolution of narrow micropores (< 0.7 nm).

The CO₂ adsorption uptake of the carbonized PVDF was measured by CO₂ adsorption isotherm at different temperatures. The maximum CO₂ adsorption capacities at the temperature of 0 and 25 °C were 5.27 and 3.59 mol/kg, respectively under atmospheric pressure. The carbonized PVDFs also showed excellent recyclability, easy regenerability, and rapid adsorption/desorption kinetics, providing potential possibility in continuous CO₂capture processes. The characteristics of the carbonized PVDFs were further analyzed by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Raman spectroscopy, and element analysis.

[1] Sunho Choi, Jeffrey H. Drese, and Cristopher W. Jones, Adsorbent materials for carbon dioxide capture from large anthropogenic point sources. ChemSusChem 2009, 2, 796-854.

[2] Abdelhamid Sayari, Youssef Belmabkhout, and Rodrigo Serna-Guerrero, Flue gas treatment via CO₂ adsorption. Chemical Engineering Journal 2011, 171, 760-774.

[3] Bin Xu, Shanshan Hou, Mo Chu, Gaoping Cao, and Yusheng Yang, An activation-free method for preparing microporous carbon by the pyrolysis of poly(vinylidene fluoride). Carbon 2010, 48, 2812-2814.