Influence of the Pyrolysis Temperature and TiO2-Incorporation on the Properties of SiOC/SiC Composites for Efficient Wastewater Treatment Applications

Abstract

This study focuses on the development of porous ceramer and SiOC composites which are suitable for microfiltration applications, using a mixture of polysiloxanes as the preceramic precursor. The properties of the membranes—such as their pore size, hydrophilicity, specific surface area, and mechanical resistance—were tailored in a one-step process, according to the choice of pyrolysis temperatures (600–1000 °C) and the incorporation of micro- (SiC) and nanofillers (TiO2). Lower pyrolysis temperatures (<700 °C) allowed the incorporation of TiO2 in its photocatalytically active anatase phase, enabling the study of its photocatalytic decomposition. The produced materials showed low photocatalytic activity; however, a high adsorption capacity for methylene blue was observed, which could be suitable for dye-removal applications. The membrane performance was evaluated in terms of its maximum flexural strength, water permeation, and separation of an oil-in-water emulsion. The mechanical resistance increased with an increase of the pyrolysis temperature, as the preceramic precursor underwent the ceramization process. Water fluxes varying from 2.5 to 370 L/m2·h (2 bar) were obtained according to the membrane pore sizes and surface characteristics. Oil-rejection ratios of 81–98% were obtained at an initial oil concentration of 1000 mg/L, indicating a potential application of the produced PDC membranes in the treatment of oily wastewater.

Ceramic-like membranes without sintering via alkali activation of metakaolin, blast furnace slag, or their mixture: Characterization and cation-exchange properties

“…However, it has been observed that the surface area of AAMs improves upon successive exposure to water and ion-exchange or by using a higher radius alkali cation in the synthesis (i.e., for example K silicate instead of Na silicate): in those cases, specific surface area can reach values of 100-300 m 2 g -1 (Melar et al, 2015;Skorina, 2014). The specific surface areas of the selective layers of conventional ceramic membranes can be > 600 m 2 g -1 (Ji et al, 2022) but they tend to decrease upon increasing the sintering temperature (e.g., a SiOC/SiC membrane had specific surface area of tens of m 2 /g when sintered at 800-1000 °C) (Fontão et al, 2022). The cumulative pore volume (Fig.…”

Effect of Sintering Temperature on the Microstructure Behavior of Gelcasted Porous Ceramics Using Cassava Starch as Pore Template

“…Porous ceramics provide the opportunity to combine high porosity with crucial properties such as high thermal conductivity, high strength, and chemical stability, which are essential for industrial applications and development. The implementation of the materials includes catalytic support [1][2], removal of heavy metal ions or azo dyes from wastewater [3][4], thermal insulators [5], combustion analyzers [6], and membrane for microfiltration [7]. However, due to pricey raw materials and production techniques, the usage of porous ceramics in more widespread applications is restricted [8].…”