title: Environment-oriented low-cost porous mullite ceramic membrane supports fabricated from coal gangue and bauxite.
abstract: Porous mullite ceramic supports for filtration membrane were successfully fabricated via recycling of coal gangue and bauxite at sintering temperatures from 1100 to 1500°C with corn starch as pore-forming agent. The dynamic sintering behaviors, phase evolution, shrinkage, porosity and pore size, gas permeation flux, microstructure and mechanical property were systematically studied. A unique volume-expansion stage was observed at increased temperatures from 1276 to 1481°C caused by a mullitization-crystal-growth process. During this stage, open porosity increases and pore size distributions broaden, which result in a maximum of nitrogen gas flux at 1400°C. The X-ray diffraction results reveal that secondary mullitization took place from 1100°C and the major phase is mullite with a content of ∼84.7wt.% at 1400°C. SEM images show that the as-fabricated mullite supports have a porous microstructure composed of sintered glassy particles embedded with inter-locked mullite crystals, which grew gradually with increasing temperature from rod-like into blocky-like morphologies. To obtain mullite membrane supports with sufficient porosity and acceptable mechanical strength, the relationship between porosity and mechanical strength was investigated, which was fitted using a parabolic equation.
authors.affiliation: Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, PR China; Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo, PR China; School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, PR China.
authors.forename: Qikai
authors.initials: Q
authors.lastname: Lü
authors.affiliation: School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, PR China.
authors.forename: Xinfa
authors.initials: X
authors.lastname: Dong
authors.affiliation: Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, PR China; Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo, PR China.
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, PR China; Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo, PR China. Electronic address: ycdong@iue.ac.cn.
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Dong
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry*; D002516:Ceramics; D003032:Coal Mining; D003365:Costs and Cost Analysis; D004787:Environmental Pollution / Q000517:prevention & control; D005374:Filtration; D007220:Industrial Waste; D008567:Membranes, Artificial; D016062:Porosity; D059027:Recycling / Q000379:methods
chemical_list: D000538:Aluminum Silicates; D007220:Industrial Waste; D008567:Membranes, Artificial; C049037:aluminosilicate; D000537:Aluminum Oxide
keywords: Ceramic membrane; Coal gangue; Mechanical strength; Porous mullite; Waste recycling