Hadi Shayesteh, Abdelhamid Sayari
High Resolution Image Download MS PowerPoint Slide Global warming has been exacerbated by the escalating emissions of greenhouse gases from fossil fuel power plants and other industrial and transportation sources. Postcombustion CO 2 capture by amine-containing materials has evolved into a burgeoning industry for mitigating point-source emissions. Nevertheless, the deployment of sustainable and biodegradable solid-supported amine adsorbents remains underexplored despite their tunable surface chemistry that can be leveraged for CO 2 adsorption. Therefore, the purpose of this study is to valorize lignin for CO 2 capture using a double amine functionalization method. Lignin was subjected to two separate grafting procedures: one with diethylenetriamine (DETA) to produce DETA-aminated lignin (DAL) and another procedure involving 3-aminopropyltrimethoxysilane (APTMS) and triaminosilane (TRI) to make APTMS- and TRI-grafted lignin. Subsequently, DAL was further grafted by TRI (TRI/DAL) to increase amine content and improve CO 2 capture. TRI/DAL was found to achieve a considerably higher CO 2 uptake than that of individually modified materials. In the presence of 15% dry CO 2 /N 2 at 25 °C, CO 2 uptake reached 1.31 mmol/g, representing a 72% increase compared to DAL (0.76 mmol/g) and more than 250% of TRI/Lignin-1 (0.37 mmol/g). Humidity further promoted CO 2 capture, with a CO 2 uptake of 1.84 mmol/g and an amine efficiency of 0.43 mol CO 2 /mol N at 55% relative humidity (RH). In addition to enhancing CO 2 uptake, the presence of moisture improved the cyclic stability of the material, with TRI/DAL retaining 97.5 and 95% of its initial capacity after ten cycles at 25 and 50 °C in the presence of 15% CO 2 /N 2 with 55% RH.