Development of Adsorbents for Selective Carbon Capture: Role of Homo- and Cross-Coupling in Conjugated Microporous Polymers and Their Carbonized Derivatives

Abstract

Selective adsorption of CO2 from natural gas results in increased calorific value, decreased gas volume, and reduced corrosion. For this purpose, the development of high-performance adsorbents with regard to both adsorption capacity and CO2/CH4 selectivity receives great attention. Herein, two new conjugated microporous polymers (CMPs) were prepared by Yamamoto homocoupling and Sonogashira–Hagihara cross-coupling reaction. The significant role of homo- and cross-coupling in CMPs in selective CO2 separation was investigated. Notably, the cross-coupled CMP (NUT-15, NUT means Nanjing Tech University) shows CO2 uptake around twice that of homocoupled CMP (NUT-14) under the analogous conditions. Furthermore, the importance of KOH-activation and temperature-controlled carbonization in efficient CO2 capture was studied. For this, NUT-15 was further subjected to carbonization and highly active porous carbons (PCs) were obtained. It is noteworthy that PC-800 with high carbonization yield (78%) and suitable pore structure demonstrates excellent CO2 uptake (5.4 mmol·g–1) and selectivity (22.0) over CH4 at 273 K and 1 bar. Such CO2 uptake is higher than those of some benchmarks including activated carbon (2.8 mmol·g–1), PTz4 (3.6 mmol·g–1), and UTSA-50a (4.6 mmol·g–1) at 273 K and 1 bar. The high production yield, excellent CO2 uptake, and high selectivity make the present PCs promising candidates for selective CO2 separation from natural gas.

High-Performance Biomass-Derived Activated Porous Biocarbons for Combined Pre- and Post-Combustion CO2 Capture

“…For example, microporous carbon derived from pyrolysis of mesitylene-based polymer and NUT-15 polymer adsorbs 6.16 and 5.4 mmol of CO 2 g −1 at 0 °C and 1 bar which is far less than the CO 2 adsorption for LSB1-800 under similar conditions. 37,38 For LSB1-800, the contribution of micropores to the total surface area and total pore volume are 87% and 81%. The presence of narrow micropores results in enhanced interactions between the adsorbent and adsorbate at low pressures.…”

Increasing the surface area and CO2uptake of conjugated microporous polymersviaa post-knitting method

“…20 In the past few years, many CMPs and HCPs with tunable nanopores, [21][22][23][24] various functional units [25][26][27][28][29][30] and a wide range of raw materials, [31][32][33] have been prepared. Additionally, to further improve the CO 2 uptake of these polymers, some commonly modified methods have been developed including carbonization, [34][35][36][37] post-functionalization [38][39][40][41] and composite processes. 42 However, CMPs and HCPs are still limited by the synthetic issue of the low surface area, which also brings about a large barrier to CCS technologies.…”

Development of High Yielded Sn-Doped Porous Carbons for Selective CO2Capture

“…8 In addition, the effect of KOH-activation and activation temperature is discussed. 16 Thermal study demonstrates that NUT-16 has high yield in nitrogen than in air atmosphere. In nitrogen, NUT-16 predominantly decomposes at approximately 450 °C.…”

“…It has been reported that the presence of heavy metals such as Sn significantly enhances the thermal stability of polymers than their analogues without heavy metals, leading to high carbonization yield of porous carbons . In addition, the effect of KOH-activation and activation temperature is discussed . Thermal study demonstrates that NUT-16 has high yield in nitrogen than in air atmosphere.…”