Facile Postprocessing Alters the Permeability and Selectivity of Microbial Cellulose Ultrafiltration Membranes

• Published in: Environmental science & technology 2020-10, Vol.54 (20), p.13249-13256
• Main Authors: Holland, Marcus C, Eggensperger, Christina G, Giagnorio, Mattia, Schiffman, Jessica D, Tiraferri, Alberto, Zodrow, Katherine R
• Format: Article
• Language: English
• Subjects: Accessibility; Addition polymerization; Biofilms; Bleaches; Cellulose; Chemical properties; Chemical treatment; Contact angle; Extracellular polymers; Filtration; Fourier transforms; Hydrogen Peroxide; Impurities; Infrared analysis; Infrared spectroscopy; Membrane filtration; Membrane permeability; Membranes; Membranes, Artificial; Microorganisms; Particle size; Permeability; Polymers; Scanning electron microscopy; Selectivity; Sodium hydroxide; Sodium hypochlorite; Thermogravimetric analysis; Ultrafiltration; Water filtration; Water purification; X-ray diffraction
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.0c00451

Water filtration membranes produced sustainably through microbial cellulose production can have filtration properties altered through facile chemical treatments. Microbial cellulose is an effective membrane filtration medium, and pristine microbial membranes can serve as ultrafiltration membranes with a permeability of 143 L m h bar and a particle size cut off of 35 nm. As living biofilms, these membranes consist of microbial cellulose, bacteria, and extracellular polymers. Thus, additional biofilm components may reduce the intrinsic permeability of the cellulose. Here, microbial membranes were treated with hydrogen peroxide (H O ) and sodium hypochlorite (NaOCl, liquid bleach) to remove impurities present in microbial cellulose and increase membrane permeability. For example, permeability increased from 143 to 257 L m h bar with treatment by 0.3% H O for 12 min. The membranes were also treated with sodium hydroxide (NaOH) to increase membrane selectivity, and the particle size cutoff was reduced from 35 to 10 nm post-treatment with 0.8% NaOH for 20 min. Scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, contact angle goniometry, and X-ray diffraction were used to characterize the physical and chemical properties of the membrane matrix. Facile chemical treatments provide a significant degree of flexibility to tailor microbial membranes to meet specific needs. Microbial membrane production is inherently accessible, and this study furthers that accessibility by utilizing only readily available components to treat microbial membranes and expand their potential applications.