Microfiltration of Selective Polysaccharides Using Inexpensive Fuller's Earth-Based Ceramic Membranes

This study presents a microfiltration approach for separating polysaccharides using an unprecedented ceramic membrane made from affordable Fuller's earth. The membrane was created through uniaxial hydraulic pressing and sintered at 850 °C, resulting in a pore size of 0.176 μm, 39% porosity, and strong chemical and mechanical stability. Characterized comprehensively with Fourier transform infrared (FTIR) spectroscopy, optical microscopy, particle size analysis, and colorimetry, it effectively retained polysaccharides (cellulose and starch) while allowing the passage of monosaccharides (glucose) and disaccharides (sucrose). Microfiltration experiments performed in a dead-end setup under different pressures and concentrations showed flux rates from 212.18 to 225.97 L m^-2 h^-1 for cellulose-glucose mixtures and 218.84 to 222.91 L m^-2 h^-1 for cellulose-sucrose mixtures, with flux increasing linearly with pressure. Fouling analysis using Hermia's model identified complete pore blocking as the primary mechanism, except for starch-glucose mixtures, which followed the cake filtration model. These findings demonstrate the potential of locally sourced ceramic membranes for efficient, selective carbohydrate separation with promising applications in the food, pharmaceutical, and environmental industries.