Ye Zhang,Yong Gao,Peng Wang,Yichen Xu,Zhenming Yang,Jinsong Zhang
Membrane contactors have received considerable attention for extraction due to non-dispersive mass transfer through porous membranes. The past decades have seen the rapid development of organic hollow fiber membrane contactors, but very few studies have explored the applications of inorganic membranes in extraction, possibly due to their high costs. In this work, a novel SiC foam material with a hollow skeleton and microporous strut wall was used as a ceramic membrane contactor (HS-FCMC) for rare earths extraction. The foam's structure was characterized by scanning electron microscopy (SEM), X-ray micro-computed tomography (micro-CT), and mercury intrusion porosimetry (MIP). The flow and concentration fields inside and outside the foam cell were simulated by computational fluid dynamics (CFD), and the mass transfer through the ceramic membrane was analyzed. Based on the nitric acid–Ce 3+ /Pr 3+ –P507–kerosene chemical system, the extraction efficiency of Pr 3+ and Ce 3+ using the HS-FCMC reached 96.13% and 92.86%, respectively. A comparison study with poly tetra fluoroethylene (PTFE) hollow fibers was also conducted. The results indicate that the HS-FCMC is suitable for rare earths extraction due to the multiscale porous structure and chemical stability of the hollow-skeleton SiC foam. This research advances the knowledge of inorganic membrane extraction methods.
Capturing CO 2 from the flue gas in the power plant is an important measure to realize the low-carbon combustion of the fossil energy. This paper presents a novel technique which combines traditional methods of the chemical absorption, the physical adsorption and the membrane absorption. The ionic liquid ([TEPA][MIm]) is utilized to improve the CO 2 absorption performance and reduce the energy consumption. While the porous skeleton (ZIF-8) is added to the ionic liquid to reduce the viscosity while introducing the physical adsorption. Moreover, the hydrophobic ceramic membrane is utilized as the separation interface between the gas phase and the liquid phase, which can avoid the entrainment and overflow of the liquid phase while increasing the specific surface area. In terms of the material preparation and the characterization, the addition of ZIF-8 does not destroy the original chemical composition of [TEPA][MIm]. The average contact angle of the hydrophobic ceramic membrane is 140.55°, and the failure temperature is greater than 400 K, which conforms to the application situation of the power plant. In terms of the CO 2 capture and the desorption performance, the maximum CO 2 capture amount reaches 2.03 mol/mol. The temperature of complete desorption is 70 °C. Furthermore, the capture performance after five cycles can reach 80 % of the initial performance. The performance is better than that of the CO 2 capture technology utilizing the traditional monoethanolamine solution.
Jian Sun,Peng Xu,Dawei Gong,Xiangli Kong,Kaiyun Fu,Xianfu Chen,Minghui Qiu,Yiqun Fan
Increased atmospheric carbon dioxide (CO 2 ) concentration constitutes a growing environmental and health concern. The absorption of CO 2 from air requires a large gas–liquid contact area due to low driving force. Here, the membrane absorption was proposed to the removal of atmospheric CO 2 using a ceramic membrane contactor, while NaOH serves as absorbent, performance of ceramic membrane absorption was study. In hydrophilic membrane, NaOH concentration of 2 mol⋅L −1 has the best absorption performance, which serves as initial concentration in absorption cyclic process, and when NaOH utilization reaches 75 %, it still has great absorption performance. In addition, suitable gas and liquid operating parameters of this work were also confirmed as 1000 mL⋅min −1 and 1 mL⋅min −1 , respectively, corresponding mass transfer coefficient and CO 2 absorption flux is 2.6 mm⋅s −1 and 0.096 mol⋅m −2 ⋅h −1 , respectively. The great absorption stability shows the huge potential of ceramic membrane contactor application for direct air capture.
危险品化学品经营许可证（带存储）