Bozhen Wu,Xuejiao Song,Dongchen Zheng,Qianyun Tan,Yong Yao,Fa-Qian Liu
Under favorable regeneration conditions (120 °C, 100% CO2), ultrafast adsorption kinetics and excellent long-term cycle stability are still the biggest obstacles for amine-based solid CO2 adsorbents. Inspired by natural wood, a biochar with a highly ordered pore structure and excellent thermal conductivity was prepared and used as a carrier of organic amines to prepare ideal CO2 adsorbents. The results showed that the prepared adsorbent has a very high adsorption working capacity (4.23 mmol CO2·g–1), and its performance remains stable even after 30 adsorption–desorption cycles in the harsh desorption environment (120 °C, 100% CO2). Due to the existence of the hierarchical structure, the adsorbent exhibited ultra-fast adsorption kinetics, and the reaction rate constant is 37 times higher than that of traditional silica. This adsorbent also showed a very low regeneration heat of 1.64 MJ·kg–1 (CO2), which is especially important for the practical application. Therefore, these biochar-based adsorbents derived from natural wood make the CO2 capture process promising.
The synthesis of high-quality two-dimensional covalent organic frameworks (2D COFs) under mild conditions is crucial for their wide scale industrial application. Therefore, the advancement of the unidirectional diffusion synthesis (UDS) method has garnered significant attention. A comprehensive understanding of the diffusion dynamic occurring between the two phases is vital for optimizing reaction times and enhancing the growth conditions of highly crystalline COF films. In this work, we employed the UDS method, explored through various characterization tests, to fabricate 2D COFs on commercial PAN ultrafiltration membranes. Our study shows that the COF layer forms on one side contacting with the organic phase, regardless of whether the front side of the PAN-based film is exposed to the aqueous or organic phase. Through the different reaction times, it was found that the 2-min treatment yielded the optimal performance, with a pure water permeability coefficient of approximately 98 L·m −2 ·h −1 ·bar −1 , along with a retention rate of exceeding 95 % for both CR and AR 120. Furthermore, it surpassed the interfacial polymerization method in terms of both stability and retention capacity for EBF molecules with molecular weights under 500 g·mol −1 .