The Effects of Synthesis Conditions on the Carbon Capture Capacity of Polyethylenimine Impregnated Protonated Titanate Nanotubes

Capture and storage of carbon dioxide emitted from power plants, which burn fossil fuels, is one of the best ways to mitigate climate change. Polyethylenimine (PEI) impregnated protonated titanate nanotubes (PEI-PTNTs) are efficient amine-modified solid adsorbents for post combustion carbon capture. This study is to investigate the effects of synthesis conditions of titanate nanotubes on the carbon capture capacity of PEI-PTNTs. PTNTs are synthesized using hydrothermal treatment of TiO₂ anatase powder at different temperatures and in different days, followed by washing with dilute HCl solution and deionized water. PEI-PTNTs are prepared by loading PEI (M.W. = 10,000) onto PTNTs at a weight ratio of 1:1 using a wet impregnation process. PTNTs and PEI-PTNTs are characterized using transmission electron microscopy, porosity and surface area analysis, powder X-ray diffraction, and Fourier transform infrared spectroscopy. CO₂ adsorption is conducted at 75 °C using simulated flue gas, and CO₂ desorption is performed at 110 °C by purging the adsorbent with dry nitrogen gas. CO₂ adsorption experiments demonstrate that the PEI-PTNTs synthesized at 130 °C within 3 or 5 days, have the highest CO₂ capture capacity. These optimized PEI-PTNTs have a significant potential to capture CO₂ from power plants.