Discipline: Ecology Environmental and Earth Sciences
Subcategory: Environmental Engineering
Melisa Stewart - Prairie View A&M University
Co-Author(s): Hongbo Du, Prairie View A&M University, Prairie View, TX
There has been an increase in greenhouse gas emissions in the atmosphere particularly starting with the second half of the 20th century, which has been attributed mostly to various human activities. The effects of these gases on the environment and global climate has caused a growing concern especially on carbon dioxide (CO2) emissions and its contribution as a greenhouse gas causing increased warming of our atmosphere. As such, there are many studies currently underway to identify methods to reduce the CO2 emissions from flue gases. These methods are for carbon capture at three stages; pre- combustion, post-combustion and oxyfuel process. This study aims to discuss available technologies with different solvent and solid absorbents for post combustion capture of CO2. Polyethyleneimine (PEI) is the most promising when considered among many available technologies of solid absorptions. PEI impregnated protonated titanate nanotubes (PTNTs) are being investigated as a suitable solid absorption media for post-combustion capture of CO2 from flue gas after coal combustion. To analyze the temperature effects on performance of the potential CO2 absorbent, the following procedure was used: PTNTs were synthesized by mixing of 3g of TiO2 powder with 120 mL 10 M aqueous solution of sodium hydroxide (NaOH) by magnetic stirring. The slurry was then treated in polytetrafluoroethylene-lined auto-clave for 24 h at temperatures 130°C 140°C and 150 °C respectively. The recovered precipitate was washed in 0.1 M hydrochloric acid (HCl) to achieve a pH of 1.6. Deionized (DI) water was used to wash the precipitate to a neutral pH and the filtered residue was dried in a vacuum oven overnight at 100°C. The result yielded PEI impregnated PTNTs in a 50:50 ratio, going forward identified as PEI-PTNTs-50. In analyzing the PTNTs as well as the PEI-PTNTS-50 using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it was found that the nano-tubular structures were achieved with hydrothermal synthesis, dilute acid wash and DI water wash; the nanotubes were maintained after PEI was loaded; and the diameter of nanotubes in the length of 200-400 nanometers (nm) were observed in several nm varying with synthesis temperatures. In the following CO2 absorption experiments, PEI-PTNTS-50 demonstrated good absorption capacity compared to the currently available technologies. From this, we see that there is a promise for use of PEI-PTNTS-50 as a solid media for carbon capture at an industrial scale, which will be in our future study.Melisa Stewart-Emerging Researchers National .docx
Funder Acknowledgement(s): Funding is provided by 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 AWRD to PVAMU.
Faculty Advisor: Raghava Kommalapati, email@example.com