Insights of CO2 Adsorption Performance of Amine Impregnated Mesoporous Silica (SBA-15) at Wide Range Pressure and Temperature Conditions

R. Ullah, M. Atilhan*, A. Canlier, S. Aparicio, C. T. Yavuz*
Int. J. Greenh. Gas Control, 43, 22-32, (2015). DOI: 10.1016/j.ijggc.2015.09.013.

Beside IGCC, efficient storage and transportation of CO₂ and other gases require pressurize conditions. CO₂ and other gases adsorption on solid sorbents at high pressure and various temperatures are extremely important as long as the environmental purification via gas capture and separation and gas transpiration are concern. The main objective of the present research was to investigate the effect of amine impregnation on the CO₂, methane and nitrogen adsorption capacity of mesoporous silica (SBA-15). Ordered mesoporous silica (SBA-15) was prepared and modified with ammonium hydroxide solution to introduce NH₂ functional groups within the pores of materials to produce modified SBA-15 (MSBA-15). The newly prepared materials were characterized with X-ray diffraction analysis, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) analysis were performed to measure pore volume as well as the surface area of both the unmodified and modified samples. Results revealed that the crystal structures of SBA-15 were matched with that of MSBA15; yet, pore volume of the modified material was almost reduced to 50% of the pristine material indicating amine loading into the pore channels. Importantly, gas sorption capacity was investigated at 200 bars and three different temperatures of 318 K, 328 K, and 338 K by using state-of-the-art gravimetric Rubotherm® magnetic suspension sorption apparatus. Gas sorption experiments showed that modified mesoporous silica adsorbed 1.6164 mmol/g of CO₂ at 1 bar which is almost double than that of 0.6462 mmol/g adsorbed by unmodified material. Quantitative selectivity of both the materials varied as CO₂, CH₄ and N₂.

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Highly Stable Nanoporous Sulfur bridged Covalent Organic Polymers for Carbon Dioxide Removal

H. A. Patel, F. Karadas, J. Byun, J. Park, E. Deniz, A. Canlier, Y. Jung,* M. Atilhan*, C. T. Yavuz*
Adv. Funct. Mater., 23, 2270–2276 (2013). [DOI] [pdf]

Carbon dioxide capture and separation requires robust solids that can stand harsh environments where a hot mixture of gases is often found. Herein, the first and comprehensive syntheses of porous sulfur-bridged covalent organic polymers (COPs) and their application for carbon dioxide capture in warm conditions and a wide range of pressures (0–200 bar) are reported. These COPs can store up to 3294 mg g−1 of carbon dioxide at 318 K and 200 bar while being highly stable against heating up to 400 °C. The carbon dioxide capacity of the COPs is also not hindered upon boiling in water for at least one week. Physisorptive binding is prevalent with isosteric heat of adsorptions around 24 kJ mol−1. M06–2X and RIMP2 calculations yield the same relative trend of binding energies, where, interestingly, the dimer of triazine and benzene play a cooperative role for a stronger binding of CO₂ (19.2 kJ mol−1) as compared to a separate binding with triazine (13.3 kJ mol−1) or benzene (11.8 kJ mol−1).

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High capacity carbon dioxide adsorption by inexpensive covalent organic polymers

H. A. Patel, F. Karadas, A. Canlier, J. Park, E. Deniz, Y. Jung, M. Atilhan*, C. T. Yavuz*
J. Mater. Chem., 22, 8431-8437, (2012). [DOI] [pdf]

With 5616 mg/g, COP-1 sets the new world record for the highest CO₂ capture capacity

At infinite selectivity, COP-2 holds the world record in CO₂/H₂ separation

Efficient CO₂ scrubbing without a significant energy penalty remains an outstanding challenge for fossil fuel-burning industry where aqueous amine solutions are still widely used. Porous materials have long been evaluated for next generation CO₂ adsorbents. Porous polymers, robust and inexpensive, show promise as feasible materials for the capture of CO₂ from warm exhaust fumes. We report the syntheses of porous covalent organic polymers (COPs) with CO₂ adsorption capacities of up to 5616 mg/g (measured at high pressures, i.e.200 bar) and industrially relevant temperatures (as warm as 65 ^oC). COPs are stable in boiling water for at least one week and near infinite CO₂/H₂ selectivity is observed.

Top five in CO₂ capture capacity*:
1. COP-1: 5616 mg/g
2. MOF-210: 2870 mg/g
3. NU-100: 2315 mg/g
4. PPN-4: 2121 mg/g
5. COP-2: 2086 mg/g

*These capacities reflect the highest recorded values, regardless of the conditions. In addition, according to our recent high pressure data on common solids, we believe the rankings won't change much even if the pressures are raised. 

+ This paper was published as is in 16 days after initial receipt

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