Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

Materials

Ruihua Mu¹  Haiyun Hou¹  Jing Yang²  Lunwei Wang²  Yingming Guo² 

[1] School of Environment & Chemical Engineering, Xi’an Polytechnic University, Xi’an 710048, China;School of Urban Planning and Municipal Engineering, Xi’an Polytechnic University, Xi’an 710048, China;

关键词: cobalt-doped;    hydrothermal stability;    activation energy;    H₂ perm-selectivities;    regenerated;   

DOI  :  10.3390/ma14154188

来源: DOAJ

【 摘 要 】

Methyl-modified, cobalt-doped silica (Co/MSiO₂) materials were synthesized by sol-gel technique calcined in N₂ atmospheres, and membranes were made thereof by coating method. The effects of Co/Si molar ratio (n_Co) on the physical-chemical constructions of Co/MSiO₂ materials and microstructures of Co/MSiO₂ membranes were systematically investigated. The gas permeance performance and hydrothermal stability of Co/MSiO₂ membranes were also tested. The results show that the cobalt element in Co/MSiO₂ material calcined at 400 °C exists not only as Si–O–Co bond but also as Co₃O₄ and CoO crystals. The introduction of metallic cobalt and methyl can enlarge the total pore volume and average pore size of the SiO₂ membrane. The activation energy (E_a) values of H₂, CO₂, and N₂ for Co/MSiO₂ membranes are less than those for MSiO₂ membranes. When operating at a pressure difference of 0.2 MPa and 200 °C compared with MSiO₂ membrane, the permeances of H₂, CO₂, and N₂ for Co/MSiO₂ membrane with n_Co = 0.08 increased by 1.17, 0.70, and 0.83 times, respectively, and the perm-selectivities of H₂/CO₂ and H₂/N₂ increased by 27.66% and 18.53%, respectively. After being steamed and thermally regenerated, the change of H₂ permeance and H₂ perm-selectivities for Co/MSiO₂ membrane is much smaller than those for MSiO₂ membrane.

【 授权许可】

Unknown