Evaluating the Impact of Tailored Water Wettability on Performance of CO2 Capture

The growing emission of CO2 is a severe cause of concern due to its adverse impact on the environment and climate change worldwide. In the past, various approaches, including synthesis of porous materials and amino modifications, were adopted for efficient and direct separation of CO2 from flue gas. Recently, hydrophobicity has been introduced to protect some of the highly potent porous materials and membranes from high humidity and aqueous exposures. While these approaches remained successful in removing CO2 from flue gas, the exact role of hydrophobicity towards CO2 separation is not yet validated in the literature. In this current study, an amine-amplified chemically reactive coating on fibrous cotton has been unprecedentedly developed for facile tailoring of different water wettability through the 1,4-conjugate addition reaction under ambient conditions. Further, these amine-amplified interfaces having tailored water wettability were extended to investigate independently the role of: (a) amine amplification and (b) hydrophobicity on the performance of CO2 separation at room temperature and atmospheric pressure. The increased hydrophobicity on the amine-amplified interface played an important role in improving the CO2 uptake from 24 mmol/L (water contact angle (WCA) of 86 degrees) to 63 mmol/L (WCA of 151 degrees). However, superhydrophobic coating that lacked the amine amplification process displayed a poor (7 mmol/L) CO2 separation performance. Thus, controlled amalgamation of amine amplification and bioinspired superhydrophobicity in fibrous cotton lead to a synergistic impact towards efficient CO2 separation at ambient temperature and pressure, irrespective of the level of humidity present during the course of the experiments. Thus, this current study would allow to design a more potent CO2 removal material by strategic association of porosity, amine modulation, and liquid wettability.