Development of cellulose-based material from wheat straw using a combination of pressurized water and ethanol and high-intensity ultrasound treatments

• Author / Creator

  Vidrio Sahagun, Ana Xochitl

• The increasing demand for food containers, along with growing petroplastics concerns and Canada's single-use plastic ban, led to an interest in replacing petroplastics with renewable, biodegradable materials like cellulose. Wheat is one of the main cereal crops produced in Canada, and thus, large amounts of wheat straw, which is mainly composed of cellulose, is produced annually. Recently, cellulose and cellulose-based materials have been demonstrated to have potential as packaging materials. To isolate cellulose, conventional treatments that involve corrosive and toxic solvents have been used. The objectives of this thesis were to study cellulose isolation processes from wheat straw, including pressurized water + ethanol mixtures and alkaline hydrogen peroxide, with further fibrillation using high-intensity ultrasound (HIUS) to develop sustainable materials for potential food packaging applications. Furthermore, the effect of the incorporation of calcium carbonate and glycerol on the materials chemical properties was also studied. The samples treated with subcritical water and pressurized 20% aqueous ethanol (20% EtOH) showed the highest and the lowest contents of cellulose and hemicellulose, respectively. However, the pressurized 20% EtOH treatment removed more lignin. Therefore, the combination of pressurized 20% EtOH and alkaline hydrogen peroxide for 2.5 h resulted in a cellulose-rich solid residue with a cellulose content of 85.48±0.65%. Then, the bleached solid residue was dispersed and subjected to HIUS treatments up to 1200 W for 6, 13, and 20 min, resulting in a wide range of micro/nanofibers. The addition of calcium carbonate in the cellulosic micro/nanopapers produced a significant change in the water interactions with the cellulosic matrix. This research contributed to the understanding of cellulose isolation from wheat straw utilising pressurised water + ethanol mixtures hydrolysis, along with the generation of valuable co-products such as phenolics, carbohydrates, and minerals, hence fostering a circular economy in the wheat production and processing industry.

• Subjects / Keywords

  • wheat straw
  • SCW
  • pressurized fluid
  • cellulose
  • food-packaging
  • sustainability

• Graduation date

  Fall 2023

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-44vg-cw08

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.