Thermal Processing Effects on on Biomass Ash Utilization for Ceramic Membrane Fabrication

Biomass carbon-rich ash is proposed as a sustainable alternative in the production of ceramic materials. This study investigated this waste product, combined with kaolin and alumina for the production of ceramic membranes. The formulations were defined based on the Al 2 O 3 -SiO 2 -MgO ternary diagram with 51 wt% biomass ash, 36 wt% kaolin, and 13 wt% alumina. The shaping of the green body samples was conducted by using the uniaxial pressing method at 40 MPa and sintering at temperatures ranging from 1050 to 1150 °C. Several properties, such as morphology, porosity, pore diameter, mechanical strength, and chemical resistance, were investigated. It was revealed that the increase in temperature occasioned decreased porosity and water absorption; conversely, it increased bulk density, pore size, diametrical shrinkage, and flexural strength. Moreover, the samples demonstrated minimal weight loss (<0.6 wt.%) in acidic and basic solutions. The samples with porosity ranging from 31.5% to 44.4%, pore size from 1.0 μm to 1.5 μm, and flexural resistance from 9.0 MPa to 21.0 MPa were tested for pure water flux at 1.0 bar and an enhanced flux at a higher temperature, attributed to increased pore size resulting from higher sintering temperatures, was observed. The best-performing sample was sintered at 1050 °C with an average flux of 1716.8 L.h −1 .m −2 . Also, according to TGA/DTA data, these membranes have greater stability. These membranes are suitable for the treatment of effluents and contribute to reducing environmental impact and increasing sustainability by promoting the efficient utilization of resources.