460301 Ultralight, Reusable Cellulose Diacetate Aerogels for Selective Fluid Sorption

Monday, November 14, 2016: 12:30 PM
Lombard (Hilton San Francisco Union Square)
Anurodh Tripathi1,2, Saad A. Khan1 and Orlando J. Rojas2,3, (1)Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, (2)Forest Biomaterials, North Carolina State University, Raleigh, NC, (3)Department of Forest Product Technology, School of Chemical Technology, Aalto University, Helsinki, Finland

Uncontrolled oil or chemical spillage into fresh water can trigger a cascade of events including toxic loading and contamination of food resources, all of which are heavily detrimental to the ecosystem1,2. Widespread technologies proposed to deal with oil spills include oil skimming, in-situ burning, mechanical containment and utilization of dispersants, solidifiers and degrading microorganisms3–8. However, these methods are either inefficient or environmentally unfriendly. The need for efficient oil spill cleaning technologies was imminent in 2010 deep water horizon spill, one of the largest man-made disasters in the recent history, where oil gushed out in the Gulf of Mexico for straight 87 days, pouring out over 200 million gallons of crude oil9. In this type of scenario, the use of sorbents is attractive as they are easy to deploy and do not generate byproducts. There are three categories of sorbent materials: organic (milkweed, wood chips, rice straw, among others), inorganic (organo-clay, perlite and sand, zeolites, etc.) and synthetic (non-woven polypropylene mats, for example).10–12 However, they (1) suffer from low sorption capability (typically less than 10 g per gram of solid support); (2) are difficult to recover (they are not buoyant), and (3) are not biodegradable.

In recent years, aerogels have gained attention as sorbent materials because of their light weight and high pore volume. In this study, highly porous (99.7% air volume) and ultra-light (4.3 mg/ml density) cellulose ester aerogels were synthesized for unprecedented water uptake (45-90 g/g) while affording wet strength and mechanical robustness (maximum compressive stress and strain of 350 kPa and 92%, respectively). The high compression strains are generally achieved with carbon nanofiber aerogels but the 92% strain is higher than those of nanocellulose aerogel reported in literature. The compressive stress of 350 kPa is 100 times higher than the reported cellulosic aerogels (see Figure 1). The aerogels were further adjusted towards hydrophobicity and oleophilicity via chemical vapor deposition with an organo-silane species. The as-modified aerogel exhibited high oil retention (20-30 g/g aerogel) while maintaining mechanical integrity for fast oil cleanup from aqueous media under marine conditions.

Figure 1: a) Image of a 2 w/v% aerogel (density 4.3 mg/ml) on a dandelion leaf; b) Compressive stress-strain profile for 4 w/v% aerogels with the maximum compressive stress of 350 kPa and maximum strain of 92%. Inset: SEM image showing the radial cross-section of 4 w/v% CDA aerogel with a “honeycomb” like structure.

References:

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2.        Burton NHK, Musgrove  a. J, Rehfisch MM, Clark N a. Birds of the Severn Estuary and Bristol Channel: Their current status and key environmental issues. Mar Pollut Bull. 2010;61(1-3):115-123. doi:10.1016/j.marpolbul.2009.12.018.

3.        Fingas M. Oil Spill Science and Technology. Elsevier, Amsterdam. 2011;a.

4.        Fingas M. “In-situ burning” in Oil Spill Science and Technology. In: Elsevier. Gulf publishing company, New York NY; 2011:737-903.

5.        Michel J, Adams EE, Addassi Y, et al. Oil Spill Dispersants. Efficacy and Effects. Washington, DC; 2005.

6.        Rosales PI, Suidan MT, Venosa AD. A laboratory screening study on the use of solidifiers as a response tool to remove crude oil slicks on seawater. Chemosphere. 2010;80(4):389-395. doi:10.1016/j.chemosphere.2010.04.036.

7.        Correa M, Padron E, Petkoff I. The San Rafael De Laya oil spill : A Case of cleanup and remediation in Venezuela. In: International Oil Spill Conference.; 1997:932-935.

8.        Aldhous P, Hecht J. Beware long-term damage when cleaning up oil spills. New Sci. 2010;10(206):2765. doi:10.1016/S0262-4079(10)61464-9.

9.        Graham B, Reilly WK, Beinecke F, Boesch DF, Garcia TD, Murray C a. Deep Water: The Gulf Oil Disaster and the Future of Offshore Drilling.; 2011.

10.      Teas C, Kalligeros S, Zanikos F, Stournas S, Lois E, Anastopoulos G. Investigation of the effectiveness of absorbent materials in oil spills clean up. Desalination. 2001;140(3):259-264. doi:10.1016/S0011-9164(01)00375-7.

11.      Adebajo MO, Frost RL, Kloprogge JT, Carmody O, Kokot S. Porous Materials for Oil Spill Cleanup : A Review of Synthesis. J Porous Mater. 2003;(10):159-170. doi:10.1023/A:1027484117065.

12.      Carmody O, Frost R, Xi Y, Kokot S. Adsorption of hydrocarbons on organo-clays-Implications for oil spill remediation. J Colloid Interface Sci. 2007;305(1):17-24. doi:10.1016/j.jcis.2006.09.032.

 


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