promising in CO2 capture form combustion flue gas. Page 3 of 35. ACS Paragon Plus Environment. Industrial & Engineering Chemistry Research. 1. 2. 3. 4. 5. 6.
Article Cite This: Ind. Eng. Chem. Res. 2017, 56, 14115-14122
pubs.acs.org/IECR
Efficient CO2 Capture by Nitrogen-Doped Biocarbons Derived from Rotten Strawberries Limin Yue,† Linli Rao,† Liwei Wang,† Linlin Wang,‡ Jiayi Wu,† Xin Hu,*,† Herbert DaCosta,§ Jie Yang,† and Maohong Fan∥ †
College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, PR China College of Engineering, Zhejiang Normal University, Jinhua 321004, PR China § Math, Science, and Engineering Division, Illinois Central College, 1 College Drive, East Peoria, Illinois 61635, United States ∥ Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071, United States ‡
S Supporting Information *
ABSTRACT: In this study, rotten strawberries were used as carbon precursor to prepare nitrogen-doped porous biocarbons for CO2 capture. The sorbents were synthesized by hydrothermal treatment of rotten strawberries, followed by KOH activation. The nitrogen in the resulting sorbents is inherited from the rotten strawberry precursor. This series of samples demonstrates high CO2 uptake at 1 bar, up to 4.49 mmol g−1 at 25 °C and 6.35 mmol g−1 at 0 °C. In addition to narrow micropore volume and nitrogen content, the pore size of narrow micropores also plays a key role in determining the CO2 capture capacity under ambient conditions. Furthermore, these sorbents possess stable reusability, moderate heat of CO2 adsorption, quick CO2 adsorption kinetics, reasonable CO2/N2 selectivity, and high dynamic CO2 capture capacity under simulated flue gas conditions. All these merits along with the zero-cost and wide availability of rotten strawberry precursor make this type of sorbent highly promising in CO2 capture from combustion flue gas. petroleum coke,29−31 carbon-rich polymer,32,33 wood,34 and various biomass sources.35−42 In light of their wide availability, low cost, and renewability, biomass-derived porous carbons have obtained significant attention and showed great potential for CO2 capture under ambient conditions. For example, Mokaya and co-workers synthesized a series of Jujun grass and Camellia japonica-derived porous carbons.39 The maximum CO2 uptake at 25 °C and 1 bar was up to 5.0 mmol/g for these carbonaceous sorbents. In another work, they reported even higher CO2 adsorption capacity under the same testing conditions, i.e., 5.8 mmol/g, for porous carbons prepared from sawdust and lignin.43 Sevilla et al. also prepared porous carbon using sawdust as the precursor, and the maximum CO2 uptake was 4.8 mmol/g under 25 °C and 1 bar.44 Deng et al. developed pine nut shell-derived porous carbons, with the maximum CO2 uptake of 5.0 mmol/g at 25 °C and 1 bar.45 As one of the most commonly consumed fruits, strawberry is rich in nutritional value and contains a variety of vitamins that are beneficial to human health. Strawberries also have plentiful output; the strawberry production of China in market year
1. INTRODUCTION CO2 is one of the most dominant greenhouse gases, and its emission has a key responsibility in global warming.1 To mitigate CO2 emission, different techniques have been extensively researched including amine scrubbing,2 membrane separation,3 and ionic liquid absorption,4 to name a few. Among the various CO2 capture technologies, adsorption via solid adsorbents shows great promise due to its merits of low capital investment, simple operation, low energy consumption, and avoidance of equipment corrosion.5−10 A key factor for the success of this technique is to find sorbents with superior CO2 adsorption properties, such as high CO2 uptake and CO2/N2 selectivity, rapid CO2 adsorption kinetics, medium heat of adsorption, and outstanding chemical and mechanical stability. Among various solid porous sorbents such as carbons,11−17 silica,18,19 porous metal oxide,20 zeolites,21 metal organic frameworks (MOFs),22,23 and porous polymers,24,25 porous carbonaceous sorbents have revealed great promise in CO2 capture. The advantages of porous carbons include easy synthesis; low production cost; large accessible surface area; easy control of porosity; favorable surface chemistry; low chemical reactivity; high chemical, thermal, and mechanical stability; and high resistance to moisture.11,14,17 An attractive feature for porous carbons is that they can be synthesized from readily available and low-cost precursors, such as coal,26−28 © 2017 American Chemical Society
Received: Revised: Accepted: Published: 14115
July 2, 2017 September 4, 2017 November 8, 2017 November 8, 2017 DOI: 10.1021/acs.iecr.7b02692 Ind. Eng. Chem. Res. 2017, 56, 14115−14122
Article
Industrial & Engineering Chemistry Research 2011−2012 was estimated to be 2 100 000 tons.46 Fresh strawberries are available from late November to June. However, strawberries are not easy to preserve; any slight collision, even slight touch by fingers, could damage the skin and further lead to its decomposition. Rotten strawberries are usually discarded, which further increases the environmental impact. It would be of high value if this waste biomass source could be used to achieve more valuable adsorbents. In fact, there are approximately up to 7.68 g of carbohydrates, including sugar and dietary fibers, per 100 g of strawberries, making it a potential carbon precursor. In addition, strawberry contains a variety of vitamin B, such as thiamine (B1), ribofavin (B2), niacin (B3), pantothenic acid (B5), and vitamin B6, and some amount of proteins, which is attractive with respect to the potential addition of nitrogen within the carbon structure. In this study, hydrochar is first obtained by hydrothermal treatment of rotten strawberries, and then the resulting hydrochar was activated by KOH to synthesize nitrogendoped porous carbons. Compared with the tedious postsynthesis nitrogen-doping process reported in previous studies,29,30,38,47 synthesis of N-enriched porous carbon by one-step KOH activation of hydrochar can further reduce the sorbent preparation costs. The effect of two preparation parameters, i.e., activation temperature and KOH/hydrochar, on the porous properties and surface chemical properties will be investigated. The goal is to synthesize carbonaceous sorbents with high amounts of narrow micropores (
