Characterization of the firing behaviour of an illite-kaolinite clay mineral and its potential use as membrane support

Abstract

The commercial value of any clay depends on its physical and chemical properties, these could help in tuning the characteristics of ceramic membrane supports required at extreme filtration conditions. The characteristics of two clay minerals named SA and CH were studied at various firing temperatures. The composition in oxides of both raw materials consisted of quartz (44.40 ± 0.60 to 46.98 ± 0.57 m%), alumina (13.16 ± 0.56 to 19.64 ± 0.48 m%), iron oxide (4.85 ± 0.46 to 6.37 ± 0.70 m %), and relatively smaller amounts of alkaline-earth oxides (3.34 ± 0.43 to 5.98 ± 0.33 m% calcium oxide and 1.98 ± 0.18 to 5.87 ± 0.34 m% for magnesium oxide). XRD of the investigated samples indicated the presence of kaolinite and illite as pure clay fractions in the clay mineral. SEM showed that the clay minerals were constituted from fine poorly crystalline particles with particles’ size more than 5 μm. The specific surface areas of the clay minerals were found to vary between 94.5 ± 6.3 to 138.6 ± 4.2 m 2 /g using methylene blue stain test, indicating that, the clay minerals fall within chlorite, illite, and kaolinite categories. The porosity of the clay supports made from both clays were found to be maximal with values of 23.45% ± 0.66 and 21.61% ± 0.60 for SA and CH clay materials respectively at 700°C. These values were a direct result of capillary movements of water in the specimen pores that were opened to the outside leading to the highest number macropores and mesopores in the specimen.

Characterization and Beneficiation of Ethiopian Kaolin for use in Fabrication of Ceramic Membrane

“…The values of mass loss were increased linearly from 500-900 o C and then increase marginally with increasing temperature to a maximum mass loss of 11.00 ± 0.09 %. Similar observations were reported in the literature [74].…”

“…An increase in final firing temperature leads to a decrease in the porosity of the flat ceramic bodies down to a value of 14.96 ± 0.62 %. A similar trend was reported in the literature for kaolin based ceramic specimens [1], [63], [88]- [90], [64], [76], [79], [81], [84]- [87] and other types of clay-based ceramic specimens [74], [78], [91], [92]. Finally, the porosity of a flat ceramic specimen is directly related to water absorption, both properties show a similar trend in the firing temperature range 700-1100 o C. The chemical stability was estimated in terms of weight loss after immersing the flat ceramic specimen in acid and alkali solution.…”

“…In the first stage, the porosity of the flat ceramic specimen increases from 29.24 ± 0.04 % to 36.54 ± 0.9 % when the firing temperature is increased from 500 to 700 °C while it decreases to 25.08 ± 0.55, 22.26 ± 0.3,19.63 ± 0.89, and 14.96 ± 0.62 % keeping the temperature to 800, 900, 1000, and 1100 °C, respectively. A similar trend was observed in the literature for kaolinite clay minerals [74]. The first stage of the curve (increased pattern) indicates an opening of the macropores and mesopores with temperature, whereas the second stage of the curve (decreased pattern) is caused by the fusing of the grains under the effect of heat and the particles tend to agglomerate with each other that enhance the densification of the flat ceramic bodies [82], [83].…”

“…Nevertheless, the prepared flat ceramic specimen offers good chemical stability in acidic (< 3% mass loss in acid solution) and excellent chemical stability in basic media (< 1% mass loss in alkali solution). The obtained results are comparable with kaolin based ceramic bodies [63], [76], [84], [88], [93] and other types of claybased ceramic bodies [74], [76], [91], [92], [94], [95]. Scanning electron microscopy (SEM) micrographs reported in Fig.…”

Synthesis of Graphene Oxide from Hydrogenated Diamond Like Carbon and Protein Immobilization onto It: Characterization and Study of Practical Utility

“…Preparation of Graphene Oxide and Immobilization of biomolecules onto the large smooth surface for biosensor applications has attracted significant attention in recent years around the Globe. Besides, immobilization of biomolecules [1] [2] [3] [4] onto surfaces of different material is essential in many fields of Chemical [5] [6], physical, biological sciences, including cell and molecular biology, medical diagnostics, analytical chemistry, tissue engineering, and bioprocess engineering. Since the discovery of the many advantageous properties of immobilized biomolecules, the challenges in this area have been to develop new support substrate materials with appropriate structures, surface morphology and functionality to widen the understanding of immobilized biomolecules.…”