![Figure 2: Relation between the water permeability (Kp) of a clay-based low-cost ceramic membrane and the mean particle diameter of used starch (data from [26]).](/figures/figure-2-relation-between-the-water-permeability-kp-of-a-3u30mumx.webp)
Q2. What have the authors contributed in "Low-cost ceramic membranes: a research opportunity for industrial application" ?
This work exhaustively reviews the raw materials, ceramic compositions and variables of the manufacturing processes used in the development of these membranes, with special emphasis on their numerous potential industrial applications.
Q3. What are the future works in "Low-cost ceramic membranes: a research opportunity for industrial application" ?
The driving force of this research activity has been the clear possibility of lowering the cost of current ceramic membranes, based on ceramic oxides, maintaining, as far as possible, their performance. Broadly speaking, regarding the starting compositions employed, there are two main different branches: compositions based on advanced ceramics ( e. g. those containing alumina ) with potential applications in very aggressive media and compositions exclusively based on traditional ceramics with applications with lower demanding performance. Low-cost ceramic substrates can be used directly as microfiltration membranes. The potential applications of low-cost ceramic membranes cover virtually all applications of commercial ceramic membranes obtained with pure oxides.
Q4. What is the main method of deposition for selective layers?
Dip-coating is the main deposition method for selective layers where conventional compositions are used to follow the low-cost philosophy by means of a higher intensity milling.
Q5. What are the advantages of mullite-based ceramic membranes?
Mullite-based ceramic membranes represent one of the best alternatives to alumina due to their excellent properties such as low thermal expansion and conductivity, excellent thermal shock resistance and high thermal, chemical and mechanical stability [39,40].
Q6. What can be used to reduce the pore size of the membranes?
selective layers can also be applied to them, which reduce the effective pore size of the membranes and allow them to be used in other separation processes.
Q7. What are the characteristics of low-cost ceramic membranes?
Tests with synthetic aqueous solution containing microbial charge revealed good membrane selectivity with a microorganism rejection higher than 90 %.and those based on low-cost raw materials incorporating selective layersLow-cost ceramic membranes possess the characteristics of ceramic materials: chemical stability, high mechanical resistance, brittleness, thermal and electrical insulation, etc.
Q8. What is the method for the separation of oil-water emulsions?
Among all the available separation technologies, membrane filtration is one of the most promising methods for the separation of water-oil emulsions, due to its advantages: no chemical additives are needed to break the emulsions, it has high efficiency in the elimination of COD and the installations are compact and automated.
Q9. What are the developed industrial separation processes that make use of membrane technology?
The most developed industrial separation processes that make use of membrane technology are microfiltration, ultrafiltration, nanofiltration, reverse osmosis and electrodialysis.
Q10. What are the factors influencing the thickness and morphology of the resulting layer?
Other factors influencing the thickness and morphology of the resulting layer are the viscosity and density of the suspension, as well as the speed of substrate extraction.
Q11. What are the characteristics of the firing cycles for selective layer sintering?
Some reported characteristics of the firing cycles for selective layer sintering are as follows: slow heating rate (1-4 ºC∙min-1) to avoid cracking, maximum sintering temperature lower than that of the substrate and dwell time between 1-2 hours.
Q12. What is the advantage of using low-cost ceramic membranes for the recovery of whey?
the use of low-cost ceramic membranes for the recovery of whey has a twofold advantage: increase the profits of the farmer and reduce pollution of river water.
Q13. What is the main ingredient in the production of low-cost ceramic membranes?
in recent years there has been an increase in the number of studies valuing wastes in the production of low-cost ceramic membranes, as a main ingredient with diverse functionality or as a pore forming material, depending on the nature of the waste used.
Q14. What is the effect of starch on the microstructure of low-cost ceramic membranes?
The properties of low-cost ceramic membranes are determined by their composition (nature and proportion of raw materials and additives), the content and type of pore-forming materials and the firing cycle (sintering temperature and dwell time).
Q15. What is the main reason why the research on low-cost membranes has been intense?
Although research activity on low-cost membranes has been intense in recent years, due to the numerous potential applications in the industry, very few studies have attempted to correlate the microstructural characteristics of sintered substrates with their functional properties, due to the fact that the use of natural minerals (clay, kaolin, etc.) as raw materials makes it difficult to model the intricate microstructure of these membranes [1,24].
Q16. What is the role of pore formers in the ceramic membrane?
Very commonly, pore former materials are indispensable for the ceramic membrane to obtain the necessary pore size and porosity for the intended application.