Abstract
The rapid growth of CO2 emissions in the atmosphere has attracted great attention due to the influence of the greenhouse effect. Aerogels’ application for capturing CO2 is quite promising owing to their numerous advantages, such as high porosity (~95%); these are predominantly mesoporous (20–50 nm) materials with very high surface area (>800 m2∙g−1). To increase the CO2 level of aerogels’ uptake capacity and selectivity, active materials have been investigated, such as potassium carbonate, K2CO3, amines, and ionic-liquid amino-acid moieties loaded onto the surface of aerogels. The flexibility of the composition and surface chemistry of aerogels can be modified intentionally—indeed, manipulated—for CO2 capture. Up to now, most research has focused mainly on the synthesis of amine-modified silica aerogels and the evaluation of their CO2-sorption properties. However, there is no comprehensive study focusing on the effect of different types of aerogels and modification groups on the adsorption of CO2. In this review, we present, in broad terms, the use of different precursors, as well as modification of synthesis parameters. The present review aims to consider which kind of precursors and modification groups can serve as potentially attractive molecular-design characteristics in promising materials for capturing CO2.
Highlights
Nanocellulose−silica aerogel can be prepared by the two-step gelation−impregnation process or one-step homogeneous dispersion and simultaneous gelation of nanocellulose and silica precursor such as TEOS and methyltrimethoxysilane
Amongst all types of aerogels, silica, carbon, polymer, and natural-based aerogels are mostly applied for environmental cleaning and capturing CO2, owing to their distinctive physicochemical properties
Considering the versatility of sol-gel processing, the microstructural patterns, composition, and surface chemistry of aerogels can be tailored by sol-gel parameters and different types of precursors for applications of CO2 capture
Summary
Class III sorbents are prepared served as starting materials for sol-gel precursors for silica aerogels, and undergo more by polymerizing an amine-rich polymer from the support surface, such as in situ or rapid hydrolysis than TEOS [17]. The sol-gel processes for hydrophilic (TEOS) and hydrophobic (MTMS) silica aerogels as a result of the hydrolysis and condensation mechanism are shown in Scheme. Sarawade et al produced sodium silicate-based hydrophobic aerogels with Na2SiO3 as a precursor and surface modification using trimethylchlorosilane (TMCS) by an ambient-pressure drying process [25]. As shown in Scheme 3, for each CO2 molecule, two amine functional groups require under dry conditions, one as a proton receptor and the other as a carbamate anion (a) and one amine functional group is required in the presence of water (b)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
