z Materials Science inc. Nanomaterials & Polymers Determination of Mechanical Properties of Composite Supports Used in Catalytic Membranes for Hydrogen Production and Separation C. Utku DENİZ and F. Nihal TÜZÜN* [a] This study includes the determination of mechanical properties involving equibiaxial flexural strength, elastic modulus, strain and hardness for composite supports developed to be used in catalytic membranes in order to produce and separate hydro- gen. Composite supports are fabricated by mixing acidic, neutral and basic activated alumina types and sodium silicate binder. Three different Si /Al ratios are employed in the study. After preparing the support samples, they are calcined at the temperatures of 600 0 C and 1200 0 C for 11 hours and 22 hours respectively. At the end of calcination, equibiaxial flexural strength, elastic modulus, strain, hardness and solid density of supports are tested for both temperatures. Generally, higher mechanical properties and solid density results are obtained at 600 0 C and it is found that neutral alumina gives the best mechanical properties and solid density for Si /Al ratio of 0.648 at 600 0 C. 1. Introduction Development of new support materials in membrane technol- ogy have a great interest because of their utility in separation processes showing differences according to industries. Re- cently, alumina-based ceramic supports have attracted much attention owing to high-temperature durability, higher me- chanical strength, easy availability and a smooth surface. These advantages make them desirable for membrane and catalytic applications. [1–4] Mechanical properties containing flexural strength, com- pressive strength, hardness and a flexural modulus of supports are also another significant subject in membrane technology due to the enhancement of withstanding the stresses occurred by the pressure difference applied on them. [5–6] There are several types of researches in literature dealing with the mechanical properties of alumina-based ceramic supports used in membranes and catalytic applications. [7–11] However, results attained exhibited discrepancies resulted from the fabrication method, type of binder employed and sintering processes in a wide range. [7–11] A binder must be used to bring and bind the alumina particles together for obtaining sufficient mechanical properties in supports.Amount of binder used is effective in providing acceptable mechanical strength. Since, small content reduces the toughness, whereas, excess amount results in blocking the pores. The most preferred binder in ceramic industry is silica due to resistivity to high temperature. [12] The sintering temperature is also another parameter affecting the mechanical properties of supports. In general, flexural strength, flexural modulus and compressive strength increase as calcination temperature and Si/Al ratio increase in ceramic type supports fabricated. [1,7] It was met with some researches in literature dealing with the mechanical properties of porous ceramic supports em- ployed in membranes. Wang et al, Qin et al. and Chang et al. studied with porous membrane supports especially alumina, [13–15] Namvar-Mahboub et al. developed SiO 2 support, [16] while porous silicon carbide ceramic support was explored by Yang et al. [17] It was found that SiO 2 had poor alkaline resistance and SiC indicated low oxidation and alkali resistance at high temperatures. Dong et al. and Zhou et al. investigated porous cordierite supports [18–20] and Al 2 O 3 –TiO 2 membrane supports was worked by Qi et al. [21] It was detected that Al 2 O 3 –TiO 2 and cordierite had also poor acid resistance, demonstrated low mechanical strength. Among those supports, alumina support took much attention due to its high hardness, chemical and wear resistance. [22] In this study, it was objected to developing alumina supports having enough mechanical strength in membrane applications. Even though, a lot of research was made about supports used in hydrogen production, there was limited amount of knowledge for mechanical strength of those supports in literature. This work will provide a contribution to the literature via filling the gaps about the subject and creates a difference from other works done. For this reason, three types of activated alumina(acidic, basic and neutral) were tried with varying the Si/Al molar ratio at three different content and two different calcination temperatures. Effect of those variations and porosity on mechanical properties involving equibiaxial flexural strength, compression strength, hardness and elastic modulus were investigated. [a] Dr. C. U. DENİZ, Prof. Dr. F. N. TÜZÜN Engineering Faculty of Hitit University, Department of Chemical Engineer- ing, 19030, ÇORUM, TURKEY E-mail: nihaltuzun@yahoo.com Supporting information for this article is available on the WWW under https://doi.org/10.1002/slct.201904838 Full Papers DOI: 10.1002/slct.201904838 2892 ChemistrySelect 2020, 5,2892–2901 © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim