No abstract

No abstract

Cellulose Nanocrystals (CNC) are explored to stabilize oil/water emulsions for their ability to adsorb at the oil/water interface. In this work, the role of electrostatic forces in the CNC ability to stabilize oil/water emulsions is explored using canola oil/water and hexadecane/water as model systems. Canola oil/water and Hexadecane/ water (20/80, v/v) emulsions were stabilized with the addition of CNCs using ultrasonication. Emulsion droplet sizes range from 1 to 4 μm as measured by optical microscopy. It is found that CNC can stabilize oil/water emulsions regardless of their charge density. However, reducing the surface charge density, by adding salts and varying pH, can reduce the amount of CNC's required to form a stable emulsion. Just by adding 3 mM Na+ or 1 mM or less Ca+2 to a CNC suspension, the amount of CNC reduced by 30% to stabilized 2 mL of Canola oil. On the other hand, adding salt increases the emulsion volume. The addition of 100 mM Na+ or the reduction of pH below 2 leads to the aggregation of CNC; emulsions formed under these conditions showed gel-like behavior. This work shows the potential of nanocellulose crystal in stabilizing food and industrial emulsions. This is of interest for applications where biodegradability, biocompatibility, and food grade requirements are needed.

No abstract

No abstract

Porous ZnO/cellulose nanofiber (CNF) composites were synthesized to investigate their photocatalytic degradation of methylene blue (MB) dye (a persistent organic pollutant model) under a UV lamp and sunlight. UV/vis analysis indicated that complete photodegradation was achieved in about 10 min under natural sunlight with low UV intensity (between 1500 and 2900 μW/cm–1 of UVA/B). Scanning electron microscopy, Fourier transform infrared, Brunauer–Emmett–Teller, X-ray diffraction, and small-angle X-ray scattering characterization of the composite were consistent with flower/plate morphology ZnO nanomaterials of similar size to the CNF fiber diameter distributed in the matrix. The catalyst with 0.3 M Zn­(Ac)2 and 1.5 wt % CNF loading was the sample with the highest MB photodegradation efficiency of >99% in less than 10 min. This study provides proof-of-concept of a simple, sustainable, ecofriendly, and industrially scalable approach to synthesize extremely efficient ZnO/CNF photocatalysts for the degradation of organic pollutants. Catalyst performance showed greater dye degradation with a function of irradiation time as compared to state-of-the-art catalysts reported in the literature.

Four different cellulose nanofibers samples were prepared from northern bleached softwood kraft fibers. Fiber diameter distributions were measured from SEM images. Fiber aspect ratios ranging from 84 to 146 were estimated from fiber suspension sedimentation measurements. Three samples had heterogeneous distributions of fiber diameters, while one sample was more homogeneous. Sheet forming experiments using filters with pores ranging from 150 to 5 lm showed that the samples with a heterogeneous distribution of fiber dimensions could be easily formed into sheets at 0.2% initial solids concentration with all filter openings. On the other hand, sheets could only be formed from the homogenous sample by using 0.5% or more initial solids content and a lower applied vacuum and smaller filter openings. The forming data and estimated aspect ratios show reasonable agreement with the predictions of the crowding number and percolation theories for the connectivity and rigidity thresholds for fiber suspensions.

In present work, a cellulose aerogel filer with excellent performance in oil/water separation was presented.