Shravan Dommaraju

Email: srdn96@mail.missouri.edu

Chance Drewery Email: cmdr7f@mail.missouri.edu

Department of Chemistry

University of Missouri-Columbia

101 Schlundt Hall

521 S. College Ave

Columbia, MO 65211

USA

April 25, 2017

Dr. Rainer Glaser, Professor in Chemistry

Editor, Journal of Organic Chemistry

Department of Chemistry, University of Missouri-Columbia

Columbia, MO 65211

Re: REVISED

Carbon Capture, Utilization, and Storage: A New Method for Lower Temperature

Recovery of Carbon Dioxide from Sorbents Using Polyethoxyamines

By Shravan Dommaraju and Chance Drewery

Dear Dr. Glaser,

Thank you for your communication on April 20 with the peer reviews of our original

manuscript. We were pleased with their suggestions and have taken both of them into

consideration during our revision. We have prepared a revision and the changes made are

described below.

Major Changes

[M.1] Assessment of responses in regards to our abstract, materials & methods, and results &

discussion have left us in belief that we have constructed these sections in a manner that has a

common ground between our reviewers. Some changes were made as addressed later.

[M.2] The Reference heading has been moved so that it appears on the same page as the

references.

[M.3] A general review of reference formatting was conducted to ensure format follows that of

the JOC.

[M.4] Some small formatting, spelling, and grammar errors were corrected.

Response to Reviewer 1 (9)

2

[1.1] Reviewer requested further explanation of figures in this section. Prior explanation was

given in both paper and in figure titles. Further explanation was added to the figure titles.

[1.2] Concern was raised about the number of figures in the results and discussion section. Upon

review, we feel that both figures 3 and 4 are necessary. Figure 3 provides concise and easily

understood verification of mechanism. Figure 4 provides a comparison point between T-403 and

the comparison sorbents. This is necessary to demonstrate the superior performance of T-403.

Response to Reviewer 2 (G3)

[2.1] See [M.1]. The request asked us to include more detail in the abstract. We have added some

data to the abstract to be more specific to polyethoxyamine performance.

[2.2] Reviewer recommended the deletion of the “Discussion” sub-heading. Following your

suggestion, we further reviewed the Discussion sub-heading from page 16 and have removed it

to avoid confusion.

[2.3] Reference 4 may appear in an unusual format because we are citing the Intergovernmental

Panel on Climate Change. The last name of one of the authors is de Coninck which may seem

like a misspelling but we have ensured that she is being properly cited.

[2.4] Reference 16 was cited incorrectly, as issue information is only required for journals that

reset to page 1 for each issue. This is not the case for J. Phys. Chem. so the issue field has been

removed.

[2.5] We believe you meant to say reference 15 with regard to having a day, month, and year.

This source is a patent so this citation follows ACS standards for patents.

[2.6] The reviewer recommended that bolding of years be checked. Upon review, all references

published in journals, online articles with available publication date, and technical reports (Ref.

4) have bolded year fields, while the rest do not. This follows the ACS style guide.

We believe we have addressed all the comments and suggestions of the reviewers and are

thankful for their evaluations of our original submission. The revision has incorporated those

comments which prove to enhance the focus of our manuscript.

Best regards,

Shravan and Chance

1

Carbon Capture, Utilization, and Storage: A New Method for Lower Temperature ecovery

of Carbon Dioxide from Sorbents Using Polyethoxyamines

Shravan Dommaraju† and Chance Drewery†

†Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA

Email: srdn96@mail.missouri.edu; cmdr7f@mail.missouri.edu

2

Abstract

An inexpensive, novel polymer/silica sorbent system using Jeffamine® T-403 and fumed

silica for carbon capture has been characterized. After synthesis of the sorbent system, use of

Fourier Transform-Infrared (FTIR) Spectroscopy demonstrated the mechanism of sorption onto

the sorbent, with the peak corresponding to the primary amine diminishing under CO2

atmosphere. The T-403/silica sorbent system was also compared to sorbent systems consisting of

polyethylenimine (PEI) and polyethyleneglycol (PEG). The T-403/silica sorbent system

adsorbed 53.7 mg/g sorbent at industrial flue gas temperatures, approximately the same

proportion of CO2 as the PEI/silica (56.1 mg/g sorbent) and the PEI/PEG/silica system (67.3

mg/g sorbent). However, it adsorbed and desorbed at a faster rate, reaching half desorption in 4.3

minutes, and showed better percent regeneration, at 96.3 percent. The higher rate of sorption and

desorption, coupled with the lower temperatures used and better regeneration, indicates potential

widespread use as a carbon capture sorbent with minimal energy input, especially as compared to

current sorbent systems requiring additional heat for desorption and consistent maintenance and

replacement of the sorbent.

3

Introduction

Carbon capture is the use of technologies to effectively bind CO2 in industrial settings

and from the atmosphere.1 Capturing CO2 emissions from fossil fuels, which are still the greatest

energy source for humans, would reduce the level of greenhouse gases in the atmosphere.2 Even

with advances in energy efficiency and clean technology, there is still need to reduce CO2

concentrations in the atmosphere.1 CO2 emissions are increasing and are at a current

concentration of over 400 ppm.3 Once captured, the CO2 must be handled in either of two ways,

utilization or storage.4 Carbon dioxide can be utilized in some way to reduce overall emissions or

stored to remove it from the environment over large periods of time.4 Captured CO2 currently has

some small scale uses in flame extinguishing, refrigeration, decaffeination of coffee, extraction

of edible oils, beverage carbonation, and formation of baking soda.2,5 In addition, CO2 has

applications in synthesis of biologically important molecules via algae.2,6 As it stands currently,

carbon capture, storage, and utilization require large energy inputs, such that they may be

emitting more CO2 than they are removing.7 This means that further research must still be

conducted into carbon capture, utilization, and storage techniques with an emphasis on reducing

energy inputs for the technology.7 Low energy capture, utilization, and storage techniques may

be more widely used in industry for lower cost and would remove more net CO2 from the

atmosphere, provided the efficiency of the technique remained the same.7

Current techniques for carbon capture include post-combustions capture, where CO2 is

separated from flue gas by the use of sorbents, pre-combustions capture, where CO2 is made

from carbon fuels in producing hydrogen gas as an energy source, and oxy-fuel combustion,

where increasing the concentration of O2 in the combustion chamber leads to a pure stream of

CO2 gas for capture.2 Amines are a type of sorbent being used and researched for capturing

4

CO2.8 Amines can bind to CO2 at room temperature and most can be regenerated (removal of the

CO2) at 85 ℃.8 Another sorbent being used for capture of CO2 is caustic soda (NaOH).3 Other

methods model capture after natural photosynthesis, a biological process which converts 100

billion tons of CO2 to biomass annually.9 One group has created a synthetic CO2 fixation

pathway called the CETCH cycle, which carboxylates with 37 times more efficiently that

RuBisCO, the enzyme responsible for fixation in photosynthesis.9 Carbon capture can be

conducted directly from power plant flue gases or in open air.8 Open air capture is more difficult

because the CO2 concentration is 300 times less in open air,8 but it has the advantage of being

location independent.3 Carbon capture techniques vary greatly, but the most common current

techniques involve amine sorbents for capture from flue gases, using temperature swings to

regenerate the sorbent and release the CO2.4 The current sorbent most commonly being used for

carbon capture is monoethanolamine (MEA). MEA has high reactivity and selectivity, is low-

cost, and has high sorption capacity, but it also has many drawbacks, including corrosion, high

cost of regeneration, and solvent loss. For example, a 31% MEA solution by weight requires

over 4.8 MJ energy input per kg CO2 captured, with over 80% of the energy cost coming from

cost to heat the solution and solvent loss.10 To handle these drawbacks, sorbent systems are being

investigated.11 Prior research tested polyethyleneimine (PEI) as a carbon capturing polymer

adsorbed onto silica, but the sorbent systems suffered from leaching of the polymer from the

silica. Longer chain polymers were able to adsorb less CO2 per gram sorbent, but leached less

frequently. Addition of polyethyleneglycol (PEG) improved the regeneration of the PEI sorbent

system.12 This is suspected to be due to the Lewis acid/base interactions between CO2 and the

ether functional groups of the PEG molecule, but the full mechanism is yet to be determined

fully.13 The T-403 molecule contains both ether sites and amine sites, so the PEG/PEI sorbent

5

system and the T-403 sorbent system may be acting with similar mechanism. Structures of T-

403, PEI, and PEG can be found in Scheme 1.

Scheme 1. Structures of Jeffamine T-403, polyethyleneglycol (PEG), and polyethylenimine

(PEI). All three compounds are used to bind CO2 as part of a polymer and silica sorbent system.

Proposed methods of interaction are highlighted by color.

Here we report that use of Jeffamine® T-403, a polyethoxyamine, in a silica sorbent

system, provides a low-cost, readily available, and stable sorbent for CO2 capture that

regenerates CO2 with minimal temperature input. The T-403/silica system is chemically selective

6

for CO2 and regenerates sorbent using only a vacuum and at a temperature of 45 ℃, as compared

to the higher temperatures required of the PEI and PEI/PEG systems. In addition, T-403/silica

sorbent systems have higher regeneration speeds and desorb a higher percentage of CO2 relative

to the PEI and PEI/PEG systems. Problems associated with MEA, such as long-term stability and

high cost of regeneration,10 were reduced with T-403 as well. Polyethoxyamines are available for

implementation in industry, as large-scale preparation of a Jeffamine T-403/silica sorbent system

is extremely cost effective, since Jeffamines are available in bulk quantities at low prices. The

price for 18 metric tons of T-403 can be as low as $2/kg T-403.14

Materials and Methods

Preparation of Materials

Polyethoxyamines can be synthesized using static beds, which catalyze amination of

branched polyethers.15 Formation of polyethoxyamines has been conducted on an industrial

scale. Jeffamines®, such as T-403, a type of polyethoxyamine, were purchased from Huntsman

International, LLC based in The Woodlands, Texas. In addition, methanol (>99.9%),

polyethylenimine (PEI, Mw ~25,000), polyethyleneglycol (PEG, Mw ~400), polyvinylacetate

(PVAc, Mw ~150,000), polymethylmethacrylate (PMMA, Mw ~35,000), and fumed silica powder

were obtained from Sigma Aldrich (St. Louis, MO). Structures of these polymers can be found in

the supplementary information. Gases used in the experiment, CO2 and N2, were bought from

Air Gas.

Sorbent Preparation

The standard method for preparation of the polymer/silica sorbent using an illustrated

example of T-403 on 14 nm fumed silica. A predetermined weight of 14 nm fumed silica was

7

measured out and placed inside a pre-cleaned vial and dispersed in methanol. A stock solution of

T-403 in methanol was freshly prepared. Depending on the desired polymer-to-weight ratio, the

appropriate volume of T-403/methanol solution was added to the silica dispersion to achieve the

desired T-403/silica ratio based on weight. The dispersion was stirred for a least 1 hour, followed

by heating at 45°C to evaporate the methanol. This leaves the T-403 coated silica as a white,

powdery material.

CO2 Capture and Regeneration Tests

In order to measure the CO2 sorption capability of the polymer/silica systems, 0.5 g of

each polymer/silica powder was placed in a vial. The sorbent was then blanketed with glass wool

so that the nanoparticles would not be lost in the upcoming steps. The vial was sealed with a

septum lined cap. A needle connected to vacuum was inserted through the septum, and the

sorbent was dried under vacuum for three hours at 90 ℃. Using a manifold, a branched piece of

glassware with multiple openings, the sorbent was placed under nitrogenous atmosphere with N2

gas. Immediately afterward, the sample was held at 45 ℃ and 1 atmosphere, unless otherwise

indicated. The vial was weighed, to measure the mass of the sorbent and N2 atmosphere in the

vial. Two needles were introduced into the septum, with one connected to CO2 gas and the other

providing an exit route for the added CO2. Each sorbent was exposed to CO2 gas atmosphere at

45 ℃ and 1 atm for 1 hour, unless otherwise specified. At this point, the vial was weighed again,

to measure the mass of sorbent, adsorbed CO2, and the CO2 atmosphere. A correction factor was

applied to the mass to account for the difference in molecular weight of CO2 and N2. All total

sorption data can be found in the supplementary information.

In addition to testing the capabilities of various sorbents, the carbon sorption capabilities

of neat Jeffamines, meaning Jeffamines not adhered to silica, was also tested. A vial was filled

8

with a measured mass of each polymer, followed by weighing of the vial. CO2 gas was bubbled

through the Jeffamine polymers, and the mass of the vial was taken again after 1 hour of CO2

bubbling. The amount of CO2 adsorbed by the neat Jeffamines was determined by the increase in

mass of the vial.

For regeneration studies, the sorbents were adsorbed as described above. Following

sorption, the samples were put into a ~1 torr atmosphere at 45 ℃ for 1 hour, unless otherwise

indicated. The vial was weighed again to determine the amount of CO2 that became desorbed.

This process was repeated multiple times at 45 ℃ to determine how the sorbents performed under

cycling. Measurement of repeated sorption and desorption of CO2 serves as a better indicator of

potential success as a sustainable and reusable sorbent for large-scale carbon capture. If a sorbent

absorbs and desorbs exceptionally in the first cycle, but quickly loses sorption function, then it

will not be best suited for use in industrial carbon capture.

Sorption capacity of the T-403/silica sorbent is provided in Figure 1 at different

temperatures. This shows ability of the T-403/silica sorbent to adsorb relatively large amounts of

CO2 at low temperatures. In an industrial power plant, 45 ℃ is attainable for a sorbent without

additional heating, and thus does not require energy input for carbon capture. In addition, the

sorbent easily desorbs CO2 in a vacuum without requiring cooling, as shown in the

supplementary information.

Spectral characterization

FTIR characterization was performed on a Nicolet 4700 using a Thermo Smart Performer

germanium crystal Attenuated Total Reflectance (ATR) attachment. For each sample, 36 scans

were performed with a resolution of 6 cm-1. FTIR was performed to determine that T-403

obtained had the proper functional groups to properly adsorb CO2, specifically the primary amine

9

functional group. In addition, FTIR was performed on adsorbed T-403 to check that the primary

amine functional group was lost, since CO2 sorption will eliminate primary amines. This allows

verification of the carbon capture mechanism, and the data can be found in the supplementary

information.

Kinetic Analysis

Finally, kinetic analysis was performed on the T-403/silica sorbent. A sample was dried

under vacuum at 90 ℃ for 3 hours using a needle inserted through a septum-liner cap. The mass

of the uncapped vial was measured. The vial was recapped and 2 needles were inserted into the

septum. One needle allowed CO2 gas flow in at a rate of 65 mL min-1. The other needle allowed

pressure relief where gas could exit the vial. Gas flow rate was monitored with an Aalborg model

GFC17 model mass flow controller. Every 30 seconds, the vial was uncapped and the mass of

the vial was taken until the mass no longer changed. This mass corresponds to the maximal

sorption of CO2, as the T-403/silica system will eventually saturate with CO2 until the point

where no more CO2 can adsorb under these conditions.

Figure 2 demonstrates the faster speed of sorption for the T-403/silica sorbent system.

Faster saturation with CO2 presents better applications in carbon capture, especially in capture

from flue gas, as more carbon can be captured in a shorter amount of time, with less investment

into the sorbents. Further sorption capacities and speeds can be found in the supplementary

information.

10

Figure 1. CO2 adsorption capacity for the T-403/silica system under varying temperature

conditions. The ratio of the mass of adsorbed CO2 in mg to the mass of sorbent in g was

measured and plotted against the temperature of each trial. T-403 is prepared in a 1:1 ratio to

silica. 14 nm fumed silica nanoparticles were used.

11

Figure 2. Kinetic analysis of CO2 sorption. Each curve measures the amount of CO2 captured

per gram of Jeffamine polymer in the vial. Each sorbent was measured at 30 second intervals to

measure the amount of adsorbed CO2. Study was performed at 45 ℃ with CO2 flow rate into the

vial at a rate of 65 mL/min.

12

Results and Discussion

Jeffamines considered for CO2 capture

The Jeffamines D-230, EDR-148 (Scheme 2), and T-403 were tested for a polymer/silica

CO2 sorption material. Based on data and observations collected for the neat Jeffamines, they

had the capability of adsorbing CO2. Sorption occurred at rates of 135, 131 and 76 mg of CO2

per gram of polymer, respectfully, but needed a solid nanosilica support system to avoid

increased viscosity and eventual solidification (observed in D-230 and T-403). T-403 is

noticeably different in that it contains three primary amine groups instead of two, like the other

Jeffamines that we investigated. This structural feature allows for the T-403 polyethoxyanime to

bind the CO2 molecule using only its components. Scheme 3 illustrates this.

Scheme 2. Jeffamine® structures used.

Scheme 3. Binding of T-403 with CO2.

Characterization of Jeffamine sorbents

All polymer/silica sorbents used were analyzed using FTIR to confirm the polymers

presence on the silica support. The silica support has a characteristic strong, broad, IR absortion

band at 1110 cm-1 with a broad shoulder at 1180 cm—1. The T-403 has characteristic C-O-C

stretches in the 1000 – 1400 cm-1 region, C – H anti-symmetric and symmetric stretches from

13

2850 – 2990 cm-1, and N – H bands at 3100 – 3400 cm-1 (stretching), 1590 cm-1 (deformation),

and 750 – 850 cm-1 (wagging). The FTIR spectrum clearly allows us to see the T-403/silica

forming a composite by evidence of the sample containing band characteristics of both.

Sorption and desorption of Jeffamines

We compared the sorption and desorption rates of all three Jeffamines that we had

selected by running them in a 1:1 (w/w) ratio of polymer/silica. Our results indicated that T-403

was best for sorption of CO2. To further test T-403, we tested the ratios of T-403/silica at 1:2

(w/w) and T-403/silica at 2:1 (w/w) ratios. These results showed poor performance which is

noted in the supplemental information. The weight of CO2 sorption in mg per gram of Jeffamine

shows that T-403 is the clear decision for polymer/silica Jeffamine (Figure 2).

To confirm the sorption of the CO2 on T-403, ATR-FTIR was used to analyze the

polymer/silica with and without the sorption of CO2 as shown in Figure 3 on the following page.

The absorbance of T-403/silica (red curve) and T-403/silica after CO2 sorption (green profile)

confirms the absorption of CO2, leading to the formation of carbamate.16 The absorbance

increases in the range of 1335 - 1430 cm-1 and ~1564 cm-1 are indicate the symmetric and

asymmetric CO2 stretches arising from carbamate. Additionally, the T-403/silica with CO2

sorption contains peaks consistent with NH3 deformations seen for amine/carbamate species and

the disappearance of the N-H stretch at 3370 cm-1.

14

Figure 3. FTIR spectra of T-403/silica with (green) and without (red) the sorption of CO2. The

loss of the N-H stretch is noted by the * in the inset.

Comparison of T-403 to PEI and PEI/PEG

The sorbent T-403/silica and PEI/silica were tested along with different combinations of

the Lewis base modifiers to see how these modifiers affected the sorption capacity of the sorbent.

Table 1 shows the theoretical maximal CO2 sorption capacity of the T-403 is less than half that

of the PEI sorbent. Despite this difference, the PEI only performed a few mg higher than the T-

403, and was well short of its theoretical maximal sorption capacity while the T-403 was able to

capture over 70% of its theoretical maximal sorption capacity. The regeneration studies further

displayed the T-403 with a percent regeneration of 96.3% with only 4.3 minutes to reach its t50%

15

Table 1. CO2 sorption capacities of sorbents from this study. Sorption capacity and percent

regeneration were at 45°C.

regeneration. The PEI/silica sorbent was only able to regenerate 20.8 % and had a t50%

regeneration of 30.1 minutes. The PEI’s best sorption was when combined with PEG400, at 67.3

mg CO2 g-1, but still only had a 35.0% regeneration with a t50% of 14.9 minutes. Additional data

of different combinations of sorbents can be found in the supporting information.

The CO2 sorption of T-403 and PEI is expected to involve carbamate formation, CO2

mass transfer through the polymers, and possible Lewis acid – base formation. The

supplementary information shows CO2 sorption over time for T-403 and PEI-based sorbents.

sorbent

theoretical

maximal CO2

sorption

capacity (mg

CO2 g−1)

experimental

CO2 sorption

capacity (mg

CO2 g-1)

% of theor.

max.

sorbed

%

regeneration

(10 min of N2)

t50%

regen.

(min)

T-403:silica

1:1 75.2 53.7 ± 3.6 71.4 96.3 ± 2.5 4.3

PEI:silica

0.5:1 169 56.1 ± 5.1 33.2 20.8 ± 1.8 30.1

PEI:PEG400:silica

0.5:0.5:1 128 67.3 ± 6.8 52.6 35.0 ± 5.9 14.9

16

Figure 4. CO2 sorption over time for T-403 and PEI-based sorbents with and without Lewis base

modifiers.

The PEI:silica sorbent had the highest theoretical maximal CO2 sorption capacity of all

the combinations of polymers and Lewis base modifiers we tried. Despite this maximal capacity,

the PEI was unable to match the percent of theoretical maximal capacity that the T-403 achieved.

We were able to find that the PEI:PEG400:silica sorbent was able to capture more CO2 than the

PEI:silica sorbent did by itself. The combination of T-403 with Lewis base modifiers gave

different trends than the PEI. This is due to the T-403 already having a PEG-like backbone.

Although the mechanism is not fully understood, the PEI:Lewis base modifier:silica sorbents

show that the addition of a Lewis base site to the amine polymer allows it to better bind the CO2.

Modifiers like PEG have actually been used for the removal of CO2 and have even been

combined with amine compounds and shown to have the same effect.17

We tested the regeneration abilities of the sorbents at 45°C with slight vacuum. The PEI

was only able to regenerate 20.8% and the PEI:PEG400 only performed mildly better at 35.0%

regeneration. The T-403 was able to regenerate 96.3% and at only a half max of only 4.3 minutes

compared to the 30.1 and 14.9 for PEI and PEI:PEG400, respectfully. These findings further

17

support the need to a new step towards development of a T-403 sorbent system to be tested in

flue like conditions to show that the sorbent system will hold up.

Conclusion

The T-403 based sorbent is able to perform well under test conditions. The T-403

polymer/silica has a modest theoretical maximal CO2 sorption capacity at 75.2 but is able to

experimentally absorb 71.4% of that under favorable thermodynamic conditions of only 45°C.

The T-403 further supports its credibility by having one of the highest regeneration abilities at

around 96% with a T50% of just 4.3 minutes. The importance of an economically favorable

sorption system is that companies would not have additional strain of high heat systems whose

heating cost accounts for a sizable portion of their entire capture cost.

The T-403/silica sorbent would be able to operate at the temperature of the gas flue due

to its low heat requirements and with its low regeneration time, companies will be able to capture

more frequently meaning less downtime for a system or capture unit of a system. The Jeffamine

T-403 is already a commercially available polyethoxyamine that can also be produced with the

right system in place which could further reduce the cost of creating the system long term. The

T-403 polymer is evidence enough that the need for more research into economically favorable

systems may help sway companies to invest in these technologies.

Supplementary Material Available

The appendix contains more information on the characterization of T-403 and other

sorbents. FTIR data is presented for T-403, silica, T-403/silica system, and the T-403-CO2/silica

system. In addition, sorption and desorption data for a wide range of sorbents is given in the

appendix.

18

References

1 American Institute of Chemical Engineers. What is CCUS?.

(http://www.aiche.org/ccusnetwork/what-ccus. Accessed 30 Jan. 2017).

2 Hunt, A. J.; Sin, E. H. K.; Marriott, R.; Clark, J. H. Generation, Capture, and Utilization of

Industrial Carbon Dioxide. ChemSusChem 2010, 3, 306-322.

3 Eisenberg, A. The New York Times. Pulling Carbon Dioxide Out of Thin Air.

(http://www.nytimes.com/2013/01/06/business/pilot-plant-in-the-works-for- carbon-

dioxide-cleansing.html. Accessed 29 Jan. 2017) 2013.

4 Rubin, E.; Meyer, L.; de Coninck, H. IPCC Special Report: Carbon Dioxide Capture and

Storage. Cambridge University Press 2005, 18-50.

5 Harrabin, R. The Guardian. Indian firm makes carbon capture breakthrough.

(http://www.theguardian.com/environment/2017/jan/03/indian-firm-carbon-capture-

breakthrough-carbonclean. Accessed 27 Jan 2017).

6 Cole, A.J.; Mata, L.; Paul, N.A.; de Nys, R. Using CO2 to enhance carbon capture and biomass

applications of freshwater macroalgae. Bioenergy 2014, 6, 637-645.

7 Petrakopoulou, F.; Tsatsaronis, G. Can Carbon Dioxide Capture and Storage from Power Plants

Reduce the Environmental Impact of Electricity Generation? Energy Fuels 2014, 28,

5327-5338.

8 Kintisch, E. MIT Technology Review. Can Sucking CO2 Out of the Atmosphere Really Work?.

(https://www.technologyreview.com/s/531346/can-sucking- co2-out-of-the-atmosphere-

really-work/. Accessed 27 Jan. 2017)

9 Gong, F.; Li, Y. Fixing carbon, unnaturally. Science 2016, 354, 830-831.

19

10 Singh, P.; Swaaij, W. P. M. V.; Brilman, D. W. F. Energy efficient solvents for CO2

absorption from flue gas: Vapor liquid equilibrium and pilot plant study. Energy Proc.

2013, 37, 2021−2046.

11 Hao, G.P.; Li, W.C.; Lu, A.H. Novel porous solids for carbon dioxide capture. J. Mater.

Chem. 2011, 21, 6447-6451.

12 Goeppert, A.; Meth, S.; Prakash, G.K.S.; Olah, G.A. Nanostructured silica as a support for

regenerable high-capacity organoamine-based CO2 sorbents. Energy Environ. Sci. 2010,

2, 1949-1960.

13 Kazarian, S.G.; Vincent, M.F.; Bright, F.V.; Liotta, C.L.; Eckert, C.A. Specific Intermolecular

Interaction of Carbon Dioxide with Polymers. J. Am. Chem. Soc. 1996, 118, 1729-1736.

14 Huntsman International, LLC. Personal Communication. 2011.

15 Fang, L.; Dong, X; An, S.; Guan, D.; Wang, S.; Bi, J.; Cui, Q.; Zheng, J. Production Method

for Continuously Synthesizing Polyether Amines through Static Bed. Chinese Patent

104693434A, June 10, 2015.

16 Danon, A.; Stair, P. C.; Weitz, E. FTIR Study of CO2 Adsorption on Amine-Grafted SBA-15:

Elucidation of Adsorbed Species. J. Phys. Chem. C 2011, 115, 11540-11549.

17 Tanthana, J.; Chuang, S. S. C. In Situ Infrared Study of the Role of PEG in Stabilizing Silica-

Supported Amines for CO2 Capture. ChemSusChem. 2010, 3, 957-964.

S1

Supporting Information

Carbon Capture, Utilization, and Storage: A New Method for Lower Temperature

Recovery of Carbon Dioxide from Sorbents Using Polyethoxyamines

Shravan Dommaraju† and Chance Drewery†

†Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA

Email: srdn96@mail.missouri.edu; cmdr7f@mail.missouri.edu

S2

Table of Contents

Structure of Polyvinylacetate and Polymethylmethacrylate..…………………………………….S3

ATR-FTIR Spectra Characterizing CO2 bound T-403………………………………………..….S4

ATR-FTIR Spectra Characterizing T-403/Silica system…………………………………………S5

Comparison of Jeffamine Sorption Capacities……….……...……………………….…………..S6

Comparison of Various Polymer Sorption Capacities……………………………………………S7

Comparison of Jeffamine Regeneration Capacities..……………………………………………..S8

Comparison of Various Polymer Regeneration Capacities………………………………………S9

Comparison of Average Percent Regeneration after 10 minutes………………………………..S10

Bibliography……………………………………………………………………………………S11

S3

Scheme S1. Polyvinylacetate (PVAc) and Polymethylmethacrylate (PMMA) are polymers

containing Lewis base sites. These sites are denoted in the scheme with the color red.

S4

Figure S1. ATR-FTIR spectra of T-403 showing before and after exposure to CO2. The inset

shows the true graph with the * denoting the loss of the NH stretching, which is lost upon CO2

binding.

S5

Figure S2. ATR-FTIR spectra for 14 nm silica (blue), neat T-403 (green), and T-403/14 nm

silica (1:1, w/w) sorbent (red). The inset shows the presence of a primary amine stretch present

in the T-403 polymer, denoted by *, showing an availability of a CO2-reactive amine for both.

S6

Figure S3. Comparison of the CO2 sorption capacities of various Jeffamine/nanosilica sorbents.

This data shows the sorption of CO2 by T-403/14 nm silica sorbent in a 1:1, w/w ratio to be the

highest rate.

S7

Figure S4. CO2 sorption capacities for each polymer sorbent tested in this study

S8

Table S1. CO2 sorption capacities and percent regeneration for various sorbents which were used

to test the sorption and regeneration

S9

Table S2. CO2 Sorption Capacities for Sorbents in This Study and Previously Reported

Literature

S10

Figure S5. The Average percent regeneration of sorbent after 10 minutes of N2 flow of 66

mL/min at 45°C and time to reach 50% regeneration of sorbent.

S11

Bibliography

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Polyethoxyamines as Low-Cost, Reversilbe Carbon Dioxide Sorbents. J. Colloid Interface Sci.

2012, 385, 154-159.

Zhu, J.; Baker, S. N. Lewis Base Polymers for Modifying Sorption and Regeneration Abilities of

Amine-Based Carbon Dioxide Capture Materials. ACS Sustainable Chem. Eng 2014, 2, 2666-

2674.