Article pubs.acs.org/IECR
Saran-Derived Carbons for CO2 and Benzene Sorption at Ambient Conditions Aleksandra Dziura,† Michal Marszewski,‡ Jerzy Choma,† Luiz K. C. de Souza,‡,§ Łukasz Osuchowski,⊥ and Mietek Jaroniec*,‡ †
Institute of Chemistry, Military Technical Academy, 00-908 Warsaw, Poland Departament of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States § Laboratory of Catalysis and Oilchemistry, Department of Chemistry, ICEN, Federal University of Para (UFPA), Rua Augusto Corrêa, 01−Guamá, CEP 66075-110, Belém, Pará, Brazil ⊥ Military Institute of Chemistry and Radiometry, 00-910 Warsaw, Poland ‡
ABSTRACT: A series of microporous carbons was obtained through carbonization of Saran polymer (poly(vinylidene chlorideco-vinyl chloride)) at various temperatures. The resulting carbons were also activated with KOH to obtain highly microporous carbons. The activated carbons possessed well-developed porous structures: specific surface area in the range 1460−2200 m2/g, micropore volume in the range of 0.65−0.96 cm3/g, and ultramicropore volume in the range of 0.18−0.25 cm3/g. The welldeveloped porous structure of these carbons resulted in high CO2 and benzene uptakes: CO2 uptake of 6.7 mmol/g at 0 °C and 3.9 mmol/g at 25 °C (both at ca. 800 mmHg) and benzene uptake of 11.6 mmol/g at 20 °C (at a pressure close to the saturation vapor pressure). This study shows that simple but controlled carbonization and activation of commercially available polymers such as Saran can afford high surface area carbon sorbents for CO2 and benzene adsorption and for related environment remediation applications. Pierce et al.,10 as early as 1949, reported that a slow thermal treatment of Saran polymer up to 600 °C resulted in its burnoff of ca. 75% (thermal decomposition of the polymer involving release of low-mass hydrocarbons and hydrogen chloride). The resulting carbon material showed very low ash content of ca. 0.055 wt % and well-developed surface area of 2720 m2/g (measured by CCl4 adsorption). Subsequently, Lamond et al.11 investigated carbons derived from Saran 428 and Saran 489 (vinylidene chloride to vinyl chloride 90:10 mass ratio); both acquired from Dow Chemical Company. Carbonization was carried out at 1500 °C for 4 h with heating rate of 7.5 °C/min up to 1000 °C and 15−30 °C/min afterward. The resulting carbons exhibited very small pores between 0.45 and 0.57 nm. Other Saran-derived activated carbons were reported by Fernandez-Morales et al.12 Saran 872 was used as a carbon precursor and carbonized at various temperatures. Gas chromatography was used to assess adsorption properties of the resulting carbons toward number of hydrocarbon compounds. As a result, these carbons were proven to be effective molecular sieves for cyclohexane due to the small pore size (2400 m2/g) and large possible volume of ultramicropores (pores
