Preparation and characterization of low cost porous ceramic membrane support from kaolin using phase inversion/sintering technique for gas separation: Effect of kaolin content and non-solvent coagulant bath
Graphical abstract
Introduction
The combination of excellent thermal and chemical stabilities has made ceramic membranes as an attractive alternative to polymeric membranes (Fung and Wang, 2014, Harun et al., 2014, Hubadillah et al., 2014, Kingsbury and Li, 2009, Othman et al., 2010, Paiman et al., 2015). These advantages have resulted in ceramic membranes to show better durability under harsh condition such as gas separation application (Donelson et al., 2014, Isobe et al., 2007, Li and Hwang, 1992). Consequently, porous ceramic membrane support has received intensive attentions because of their advantages being used in a broad range of applications (Bouzerara et al., 2006, Isobe et al., 2013, Miao, 1999, Smart et al., 2013). Pore size distribution, total porosity ratio, surface quality and mechanical strength are among the major properties of the development of ceramic membrane support. The addition of top layer on the support which will be applied in the subsequent preparation steps is of crucial importance to the integrity of ceramic membrane.
Conventionally, most ceramic membrane support are usually made from expensive metal oxides such as alumina, zirconia, titania or a combination of these oxides. However, significant efforts have been made in recent years in membrane technology to develop new porous ceramic support from kaolin (Bouzerara et al., 2006, Bouzerara et al., 2012, Emani et al., 2014, Sarbatly, 2011). Kaolin is one of the most widely clay materials and has an important role in numerous industrial applications, such as provides low plasticity and high refractory properties (Bouzerara et al., 2006); and preferred raw material for porous ceramics (Ganesh and Ferreira, 2009). It may however be noted that most of the studies on kaolin were aimed at water and wastewater application (Bouzerara et al., 2006, Sahnoun and Baklouti, 2013) and no attempt has been made for gas separation.
Preparation of ceramic membrane using phase inversion technique is an emerging method for producing asymmetric ceramic membrane. In 2009, Li et al. had reported on the formation of macrostructures in a ceramic membrane from alumina using phase inversion technique is due to the hydrodynamically unstable viscous fingering (Kingsbury and Li, 2009). Three years later, Wang and Lai extended this work by investigating the effect of different non-solvent coagulant bath to distinguish characteristics according to the rules of the viscous fingering theory (Wang and Lai, 2012). In 2011, Sarbatly discovered that ceramic membrane from kaolin can be successfully prepared by phase inversion technique (Sarbatly, 2011).
Concerning to the costing problem in fabrication of porous ceramic membrane support toward gas separation application, therefore, this work aims to provide a thorough investigation on two important fabrication parameters toward the quality of prepared porous ceramic membrane support from kaolin material. Firstly, this paper continues the effort of two works (Sarbatly, 2011, Wang and Lai, 2012) to investigate the effect of non-solvent coagulant bath toward the fabrication of low cost ceramic membrane support using phase inversion technique. The composition for ceramic membrane support was adapted by work of Sarbatly (Sarbatly, 2011). Secondly, this study was also examined the effect of non-solvent coagulant bath. In this regard, it shall be noted that all supports will promote different morphologies according to previous studies. In this study, ceramic membrane support's characteristics which are surface roughness, pore size distribution, porosity and mechanical strength have been investigated. The gas separation performance will also be investigated in term of gas permeation and selectivity.
Section snippets
Materials
Kaolin powder with particle size ranging from 0.3 μm to 0.8 μm purchased from BG Oil Chem Sdn Bhd was used as the ceramic particles. Polyethersulfone (PESf) (UDEL) was used as the polymer binder, while N-methylpyrrolidone (NMP, QRëC™) was used as the solvent.
Preparation of ceramic suspension
The kaolin powder and PESf were dried in an oven overnight at 60 °C to remove all moisture. Then, NMP and Arlacel was stirred at temperature of 60 °C prior to the addition of the kaolin powder. The suspension was then stirred for 48 h by using
Ceramic membrane support morphology
The kaolin ceramic membrane supports were prepared with ceramic dope suspensions consisting of 54.0 g, 67.5 g, 81.0 g and 94.5 g kaolin contents, and immersed into three different types on non-solvent coagulant bath (distilled water, ethanol, and mixture of 70% NMP and 30% distilled water). The cross-section images of the prepared ceramic supports at different kaolin contents and immersed into distilled water as coagulant bath are shown in Fig. 3. As can be seen, ceramic support prepared at 54.0 g
Conclusion
Symmetric and asymmetric kaolin ceramic supports prepared from phase inversion technique were obtained by varying two parameters which are kaolin content and non-solvent coagulant bath. In this study, not all ceramic supports consist common structures obtained by phase inversion technique (finger-like structure and sponge-like voids). Finger-like structure obtained when immersed into distilled water, dense layer on top of the support can be obtained by immersion into ethanol while mixture of
Acknowledgements
The financial support from the Ministry of Higher Education with Research Grants Scheme vot A022 is acknowledged with gratitude. The award of Master study to SKH by Yayasan Sultan Iskandar Foundatio is also gratefully acknowledge. The authors would like to thank Mr Fazlannuddin Hanur bin Harith, for support with gas performance testing.
References (29)
- et al.
Porous ceramic supports for membranes prepared from kaolin and doloma mixtures
J. Eur. Ceram. Soc.
(2006) - et al.
Permeation and strength characteristics of macroporous supports for gas separation produced by co-sintering mixtures of α-alumina and kaolin
J. Membr. Sci.
(2014) - et al.
Cross flow microfiltration of oil–water emulsions using kaolin based low cost ceramic membranes
Desalination
(2014) - et al.
Nickel aluminate spinel reinforced ceramic hollow fibre membrane
J. Membr. Sci.
(2014) - et al.
Influence of raw material type and of the overall chemical composition on phase formation and sintered microstructure of mullite aggregates
Ceram. Int.
(2009) - et al.
Comparison of out-of-plane tensile moduli of CFRP laminates obtained by 3-point bending and direct loading tests
Compos. Part A: Appl. Sci. Manuf.
(2014) - et al.
Gas permeability and mechanical properties of porous alumina ceramics with unidirectionally aligned pores
J. Eur. Ceram. Soc.
(2007) - et al.
Preparation and gas permeability of the surface-modified porous Al2O3 ceramic filter for CO2 gas separation
J. Asian Ceram. Soc.
(2013) - et al.
A morphological study of ceramic hollow fibre membranes
J. Membr. Sci.
(2009) - et al.
Formation of micro-channels in ceramic membranes – spatial structure, simulation, and potential use in water treatment
J. Membr. Sci.
(2015)