Use of monolithic silicon carbide aerogel as a reusable support for development of regenerable CO 2 adsorbent† Yong Kong, ab Xiaodong Shen, * ab Sheng Cui ab and Maohong Fan * cd Monolithic silicon carbide aerogel (MSiCA) was firstly used as a reusable support to develop a novel CO 2 adsorbent, i.e. amine functionalized monolithic silicon carbide aerogel (AFMSiCA). Used or exhausted AFMSiCA was separated, treated and re-functionalized by amine to form RF-MSiCA. CO 2 capture performance of the resulting adsorbents was investigated in a 1% CO 2 flow stream. The results revealed that CO 2 adsorption capacities of AFMSiCA at different temperatures ranging from 25 to 75  C showed little change, indicating that the resulting adsorbent is well-adapted to temperature. The adsorption rate is affected by the combined effect of CO 2 adsorption and desorption. Benefiting from the highly unique properties of the aerogel (e.g. high surface area and large pore volume), MSiCA-based adsorbents are dynamic in their CO 2 adsorption process. MSiCA could be readily recovered and reused at least 12 times without significant loss of CO 2 adsorption performance. The resulting adsorbents presented good stability during cyclic adsorption–regeneration tests. MSiCA is exceptional in practical application for CO 2 capture due to its excellent reusability and the regenerability of its amine functionalized counterparts. Introduction Concentrations of CO 2 in the atmosphere are increasing at an accelerating rate, a phenomenon that has drawn signicant attention because of its link to climate change. CO 2 capture and sequestration (CCS) is a promising way to control CO 2 emis- sions. 1 Among available techniques, amine scrubbing is the current state-of-the-art technology for CO 2 capture on an industrial scale. However, this approach shows signicant shortcomings, including corrosion, oxidative degradation, high energy consumption for regeneration, and secondary pollution resulting from its high volatility. 2 Hence, porous adsorbents functionalized with amines have been extensively studied for CO 2 capture because they can overcome the shortcomings of an aqueous amine scrubbing technique. 3 Recent investigations have focused on using aerogels as new CO 2 capture materials, due to their unique physical properties such as low densities, high surface areas and porosities. 4 Moreover, the microstructures and elemental compositions of aerogels can be tailored using solution chemistry via a process known as the sol–gel method. 5 Therefore, aerogel-based CO 2 adsorbents have been extensively developed recently. Cui et al. achieved a high CO 2 adsorption capacity in 10% CO 2 mixture stream by using silica aerogel modied with 3-aminopropyltriethoxysilane (APTES). 6 Begag et al. developed hydrophobic amine function- alized aerogels by graing amine groups onto silica backbone and achieved 1.43 mmol g 1 CO 2 sorption capacity in simulated ue gas. 7 Linneen et al. found that 1 g silica aerogel immobi- lized with tetraethylenepentamine (TEPA) could adsorb 3.5 mmol CO 2 under a dry 10% CO 2 /Ar stream. 8 Wang et al. found that 1 g silica aerogel can adsorb 3.3 mmol CO 2 from pure CO 2 at 25  C and 1 atm. 9 Masika developed a carbon aerogel for CO 2 capture, the CO 2 adsorption capacity obtained in pure CO 2 at 25  C and 1 bar was only 2.2 mmol g 1 although the carbon aerogel has a high surface area of 1100 m 2 g 1 . 10 Alhwaige et al. devel- oped chitosan hybrid aerogels for CO 2 capture, the CO 2 adsorption capacity in pure CO 2 at 25  C is up to 4.15 mmol g 1 . 11 Lin et al. successfully developed hydrophobic silica aer- ogel membranes for CO 2 capture. 12 We have developed a novel aerogel adsorbent based on amine hybrid silica aerogel via facile sol–gel route and supercritical drying, its CO 2 adsorption capacity of at 25  C and 1 atm in a 1% CO 2 mixture stream is as high as 5.55 mmol g 1 . 13 All these reports indicate that aerogels have a promising prospect in CO 2 capture. Silicon carbide (SiC) has high hardness, excellent thermal stability and superior chemical inertness, 14 therefore, its aerogel counterpart can be promisingly used for CO 2 capture. Bhatia a College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, P. R. China. E-mail: xdshen@njtech.edu.cn; Tel: +86-25-8358-7234 b State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China. E-mail: xdshen@njtech.edu.cn; Tel: +86- 25-8358-7234 c Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, WY 82071, USA. E-mail: mfan@uwyo.edu; Tel: +1-307-766-5633 d School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA. E-mail: mfan3@mail.gateche.edu; Tel: +1-404-385-4577 † Electronic supplementary information (ESI) available. See DOI: 10.1039/c4ra11261j Cite this: RSC Adv. , 2014, 4, 64193 Received 26th September 2014 Accepted 10th November 2014 DOI: 10.1039/c4ra11261j www.rsc.org/advances This journal is © The Royal Society of Chemistry 2014 RSC Adv. , 2014, 4, 64193–64199 | 64193 RSC Advances PAPER Published on 11 November 2014. Downloaded by University of Wyoming on 29/03/2016 15:24:15. View Article Online View Journal | View Issue