Jia Yanfei,Wei Jianwen,Yuan Yuan,Geng Linlin,Chen Siqi,Liao Lei
A stable and effective amine-modified adsorbent for CO 2 capture was prepared with the impregnation method using the ZSM-5/SBA-16 (ZS) as support and the tetraethylenepentamine (TEPA) as modifier. The CO 2 adsorption performance was investigated by thermal gravimetric analysis (TGA) in mixed gases (15% CO 2 and 85% N 2 ) at 30–90 °C. At 60 °C, the ZS displayed the highest CO 2 adsorption capacity of 2.80 mmol g −1 at 60% TEPA loading. The adsorption kinetics analysis showed that the adsorption process of amine-modified ZS was dominated by both physical and chemical adsorptions. After five cycles of adsorption/desorption, ZS-T-60 kept better stability with the equilibrium adsorption capacity of the composite material was 2.486 mmol g −1 , which was 11.1% lower than the original adsorption capacity. The composite material ZS showed good CO 2 capture ability, indicating the promising future of these adsorbents for CO 2 adsorption from actual flue gas after desulfurization. Graphical abstract
An amine-modified ZSM-5/SBA-16 (ZS) micro-/mesoporous composite was synthesized for CO 2 capture using nonionic tri-block copolymer pluronic (F127) as a template, tetraethyl orthosilicate (TEOS) as a silicon source and ZSM-5 zeolite as part of silicon aluminum source by embedding method. The amine-bifunctionalized samples were prepared by first grafting with aminepropyltriethoxysilane (APTES) and then impregnating with different concentrations of tetraethylenepentamine (TEPA). The amine efficiency, adsorption kinetics, thermal stability, regeneration performance and the effects of impregnated amine loadings (30–60%) and temperatures (30–90 °C) on the CO 2 adsorption performance were investigated using a thermal gravimetric analyzer (TGA) in the mixed gases (15 vol% CO 2 and the balance of N 2 ). The best adsorbent after modification of ZSM-5/SBA-16 composite material was screened to study CO 2 adsorption mechanism and adsorption kinetics. With the increase of the TEPA amount, the adsorption capacity of amine-bifunctionalized material first increased and then decreased. At 90 °C, the bifunctionalized ZSM-5/SBA-16 displayed the highest CO 2 adsorption performance of 1.630 mmol/g at the TEPA loading of 55%. The CO 2 adsorption mechanism of the bifunctionalized material was the synergistic effect of physical adsorption and chemical adsorption. After five adsorption/desorption cycle regenerations, the saturated adsorption capacity of the composite material was 1.496 mmol/g, which was only 8.2% lower than the original adsorption capacity. The composites exhibited good CO 2 adsorption performance, indicating the promising industrial applications for CO 2 capture form actual flue gas after desulfurization.
Solid amine adsorbents hold promising application prospects in the realm of industrial flue gas decarbonization. Nevertheless, there remains a need for substantial improvement in the cycling stability of solid amine adsorbents. Additionally, the competitive adsorption mechanism of solid amine adsorbents pertaining to flue gas components lacks thorough verification. In this study, amine-grafted micro-mesoporous ZSM-5/SBA-16 adsorbents were synthesized to improve the CO 2 adsorption capacity and investigate the effect of impurity gases on CO 2 adsorption. Various characterization techniques, including X-ray diffraction (XRD), thermogravimetric analysis (TGA), N 2 adsorption, and elemental analysis, were employed to analyze the properties of the adsorbents. The loading analysis of the micro-mesoporous molecular sieve revealed that ZS-A-2.0 exhibited the highest CO 2 adsorption capacity of 41.39 mg/g. Mass spectrometry was utilized to evaluate the co-adsorption experimentation involving multicomponent gases. The breakthrough curves of CO 2 displayed dual stages at low concentrations, suggesting the simultaneous occurrence of physical and chemical adsorption throughout the entire adsorption process. Based on temperature programming desorption (TPD) and in situ Fourier transform infrared spectroscopy (FTIR), the results indicated a notable enhancement in CO 2 adsorption due to the presence of H 2 O. Conversely, the presence of SO 2 and NO exhibited adverse effects on CO 2 adsorption, consequently hindering the formation of carbamate and (RNH 3 ) 2 CO 3 adsorption products. This study presents, for the first time, a comprehensive investigation into the interactive adsorption mechanism and product distribution between CO 2 and impurity gases. The findings presented herein provide valuable insights and essential support for practical flue gas applications.
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