On the underestimated effect of the starch ash on the characteristics of low cost ceramic membranes

Abstract

Starches are commonly used as a pore generator in the fabrication of low-cost ceramic membranes, since they are cheap, innocuous, environmentally friendly and easy to burn.Nevertheless, the influence of starches residues (ashes) generated during its burning off is dismissed. The present study analyses the influence of the starch ashes, generated by six different starches of similar particle size, on the characteristics of low-cost ceramic supports. The results indicated that starches gave rise to different amounts of ashes ranging from 0.17 to 0.71 wt%. In addition, these ashes contained some chemical 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2 elements in their composition, such as sodium, potassium or calcium, which can act as fluxes in the ceramic composition, modifying the characteristics of the obtained supports (mainly open porosity, water permeability and pore size distribution). It has also been observed that when the ash content grows the effect of the fluxing elements on the evolution of the microstructural features of the ceramic membrane (porosity, pore size or permeability) becomes more significant. Finally, tortuosity was calculated with a simple model derived from the Hagen-Poiseuille equation; the obtained data showed that tortuosity factor and its evolution with dwelling time were also affected by the starch ashes. *Manuscript Click here to view linked References

Low-cost ceramic membranes: A research opportunity for industrial application

“…This figure shows the variation of air permeability with sintering (dwelling) time for a clay-based low-cost ceramic membrane composition prepared from the same amount of starch but of different nature. As observed, the figure highlights that there is a nonnegligible effect of the starch ash on the sintering behavior and consequently on membrane microstructure and permeability [27].…”

“…In their work, Lorente-Ayza et al [25] determined that the experimental data of water permeability fit the Hagen-Poiseuille equation confirming the significant contribution of coarse pores generated by starch to membrane permeability. In addition, the effect of starch particle size as well as the influence of fluxing elements present in the starch ashes were also showed by Lorente-Ayza et al in [26] and [27] respectively.…”

“…Recently Lorente-Ayza et al have reported a complete research on the effect of starch on the microstructure of low-cost ceramic membranes [25][26][27]. The research includes the effect of the nature, amount and particle size of the starch on the microstructure and permeability of different low-cost ceramic membrane compositions.…”

Structures, Properties, and Performances—Relationships of Polymeric Membranes for Pervaporative Desalination

“…In past days, inorganic membranes were merely used to work under highly contaminated feed environment and at high temperature, wherein the polymeric membranes did not work properly. However, the discovery of low-cost ceramic membranes containing clays and organic pore formers has reinvigorated the frequent use of ceramic-based inorganic membranes in the commercial scale [246,247,248,249]. In fact, in the modern era, syntheses of new inorganic-based composite membranes, such as MOF, CNT, and graphene and its derivatives, have gained a high impact for the pervaporative desalination of wastewater.…”

Improvement of the Electrochemical Behavior of (Sb, Sn, Cu)O Ceramic Electrodes as Electrochemical Advanced Oxidation Anodes

“…In addition, starches also introduce impurities in the system, whose proportion and characteristics are function of their origin. [33] Conversely, high quality petroleum coke has a very low level of impurities and its mechanical behavior during pressing allows shaping the green electrodes by dry-pressing without defects. In order to analyze the viability of petroleum coke as pore generator, a series of (Sb,Sn,Cu)O electrodes with 3 different coke contents, was synthetized.…”