Investigation of spent bleaching earth (SBE) based ceramic membrane through sintering method

Ceramic membrane is a separation technology that has advantages in mechanical, thermal, and chemical strength, and is environmentally friendly. This study aims to develop a ceramic membrane based on solid waste from the manufacturing of palm oil known as spent bleaching earth (SBE), focusing on how composition and sintering time affect the final membrane's physical properties. SBE was prepared through an extraction process using n-hexane and acetone solvents, then mixed with zeolite and polyvinyl alcohol (PVA) as additives. The membranes were molded and sintered at 750°C for 2 to 4 hours. Characterization included linear shrinkage analysis, density, water absorption, porosity, X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), and Thermogravimetric Analysis (TGA). The results showed that increasing the composition of SBE in the mixture led to an increase in porosity (up to 29.55%) and water absorption (up to 16.29%), but reduced the membrane density (down to 1.56 g/cm 3 ). Longer sintering time (4 hours) also increased porosity and water absorption compared to 2 hours sintering. XRF analysis showed that the dominant components in the membrane were SiO₂, O, CaO, and Al₂O₃. XRD identified the main mineral phases as quartz, dolomite, and anorthite. TGA confirmed that the largest mass loss occurred below 600°C, indicating the membrane's capacity to withstand extreme temperatures. Thus, the use of SBE as a ceramic membrane raw material offers a sustainable solution for industrial waste management and the production of low-cost filtration materials.