Discipline: Ecology Environmental and Earth Sciences
Subcategory: Environmental Engineering
Melisa Stewart - Prairie View A&M University
Co-Author(s): Hongbo Du and Raghava R. Kommalapati, Prairie View A&M University
In recent history, there has been great concern about global warming and its correlation with greenhouse gases. Of great concern is the increase in carbon dioxide (CO2) in the atmosphere, where it is found to be the most abundant greenhouse gas. CO2 levels have increased by almost 40% since the industrial revolution due to various anthropogenic sources such as the burning of fossil fuels e.g. coal for the generation of electricity at power plants. In order to decrease CO2 emissions from such sources, there has been much research in recent years on its capture and storage. Research methodologies have shown that CO2 can be captured using various techniques, two of which are: absorption using aqueous amines and adsorption using solid adsorbents. Aqueous amine absorbents such as the alkanolamine monoethanolamine (MEA) are currently being used to capture CO2 from power plant flue gas through chemical absorption processes. However, there are a number of disadvantages found with this method, which includes: large energy requirements for the regeneration of the absorbent, loss of the absorbent due to evaporation and that the amine corrodes the equipment. As an alternative, solid adsorbent systems are currently being researched and developed as possible replacements for the aqueous amine processes.
In this study, the aim is to discuss the different available solvent and solid technologies for the capture of CO2 through post-combustion. Of these technologies being considered, polyethyleneimine (PEI) shows the most promise. As a suitable media for post-combustion CO2 capture from flue gas after combustion of coal, PEI impregnated protonated titanate nanotubes (PTNTs) are being investigated. The objectives of this research are: to synthesize the solid adsorbent of PTNTs, functionalized with polyethyleneimine (PEI) to yield PEI-PTNTs to capture CO2 from coal power plant flue gas; to characterize samples using scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) and to analyze the effects of temperature on both the CO2 adsorption capacity and synthesis of protonated titanate nanotubes (PTNTs). It is hypothesized that with increase in synthesis temperature and increased nanotube size, there will be increased CO2 adsorption. Hydrothermal process was employed followed by dilute acid and deionized water wash to yield PTNTs. Polyethylenimine (PEI) was added to PTNTs using the wet impregnation method to yield PEI-PTNTs. PTNTs and PEI-PTNTs were analyzed and characterized using SEM, XRD and TEM. From SEM, tubular structures were observed as PTNTs with lengths of 200-400nm. TEM showed these nanotubes had open ends with internal diameter of 8nm and outer diameter of 10nm. From XRD, the crystalline phases present in the samples were observed.
Funder Acknowledgement(s): DOE grant to Dr. Kommalapati DOE Project title (Grant No.:FE0023040): Combustion Carbon Capture Using Polyethyleneimine Functionalized Titanate Nanotubes. Partial funding is also provided from NSF CREST AWARD to PVAMU.
Faculty Advisor: Raghava Kommalapati, firstname.lastname@example.org
Role: All the synthesis was done by me; however, the analyses were done at another University.