Tailored cellulose acetate/deep eutectic solvent composite membranes with microcrystalline cellulose for efficient...

Clarification is a critical step in orange juice processing to enhance visual quality, stability, and shelf life. Conventional clarification methods often rely on chemical additives and are labor-intensive, which can compromise juice quality. To address these limitations, this study developed sustainable, high-performance composite membranes based on Cellulose Acetate (CA), selected for its excellent biodegradability and renewable origin. The CA matrix was modified using Deep Eutectic Solvents (DES) and Microcrystalline Cellulose (MCC), which functions as a hydrophilic reinforcing filler. The novelty of this work lies in the synergistic application of 'oxaline' DES (synthesized from choline chloride and oxalic acid) as both a pore-forming agent and a dispersion-enhancing medium that effectively prevents MCC agglomeration within the CA matrix. Membranes were fabricated via the non-solvent induced phase separation (NIPS) technique and evaluated for morphology, mechanical strength, and clean water permeability (CWP). The optimized membrane (DMAc-DES/M2) exhibited a high CWP of 4042.52 L/m²·h·bar, a water contact angle of 68.56° indicating improved hydrophilicity, and sufficient tensile strength of 6.16 MPa. Capillary flow porometry confirmed a mean pore size of 0.3941 μm, classifying the structure as a microfiltration membrane. In orange juice clarification trials, this membrane achieved a flux of 8.67 L/m²·h and 100% rejection of suspended solids and alcohol-insoluble solids while preserving essential nutritional attributes. These results affirm the potential of DES-MCC-modified CA membranes as effective, eco-friendly, and high-performance alternatives to commercial polyethersulfone and polysulfone membranes for industrial juice processing.