Stringent laws on carbon emissions are being implemented every day globally. This has come at a time when the consequences of global warming are beginning to pinch. As a result, scholars have taken up the challenge to develop amicable solutions, since it’s nearly impossible to do away with fossil based fuels, upon which most of the world leading economies have been built from. Therefore, developing a chemical or physical system that can capture CO2 and store it, would provide a perfect solution to this dilemma. In line with this, amine scrubbing is the most widely used technique for carbon capture. Unfortunately, it has several drawbacks which inhibit its performance including corrosion, rate of uptake and high regeneration energy. Alternatively, solid absorbents have been put forward but their sensitivity to other components of the gas mixture and their current high cost hinder their commercialization. Researchers have therefore considered mitigating corrosion and enhancing the recyclability of amine absorbents.
To this effect, a team of researchers led by Dr. Colin Wood from the CSIRO, Energy, Australian Resources Research Centre conducted a study where amine solutions were infused in hydrogel particles (AIHs) and their the suitability for CO2 absorption under ambient conditions was investigated. The AIHs are essentially ‘dry’ and exhibit properties of solids despite being infused with significant quantities of liquid amine. In addition, they assessed and compared the absorption kinetics and recyclability of the proposed AIHs possesses and bulk amine solutions. Their work is currently published in the research journal, Journal of Materials Chemistry A.
The research technique employed for the CO2 uptake measurements were performed at room temperature and pressure. Next, Fourier transform infrared spectroscopy analysis spectra of the samples was obtained. They then proceeded to undertake thermal gravimetric analysis experiment of the samples. Lastly, the regeneration of the amine infused hydrogels (AIHs) was tested where multiple absorption–desorption cycles were performed to fully evaluate the recyclability.
The authors observed that the novel material rapidly captured CO2 and at a higher overall rate when compared with commonly used aqueous amine solutions under similar experimental conditions. Additionally, they realized that the proposed material could attain exceptional levels of CO2 uptake without the need for constant stirring. Moreover, they also noted that the hydrogel’s recoverability and reusability was excellent which reduced material cost.
In summary, the CSIRO researchers’ study successfully demonstrated the potential and effectiveness of amine infused hydrogels as absorbent for application in CO2 capture. Generally, it was seen that the proposed material could reach theoretical CO2 maximal uptake with a faster kinetics in comparison with bulk amine solutions due to the increased contact surface area. More so, the ability to regenerate the amine infused hydrogels is excellent. Altogether, this proof-of-concept study demonstrates that by using an inexpensive and readily available material (hydrogel), amine induced hydrogels show promise as a CO2 absorbent.
RESEARCH UPDATE: CSIRO researchers: Dr. Xingguang Xu (Postdoctoral fellow) and Dr. Colin Wood just recently advanced even further the carbon capture technology by generating a diverse range of alkali/amine infused hydrogels. The results were just reported in Environ. Sci. Technol., 2018, 52 (18), pp 10874–10882.
Xingguang Xu, Charles Heath, Bobby Pejcic and Colin D. Wood. CO2 capture by amine infused hydrogels (AIHs). Journal of Materials Chemistry A, 2018, volume 6, page 4829Go To Journal of Materials Chemistry A