1:00 pm - 2:00 pm
3-18J Agricultural/Forestry Centre, University of Alberta, Edmonton AB
Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Ana Vidrio Sahagun. This seminar is open to the general public to attend.
MSc with Dr. Marleny Aranda Saldana.
Thesis Topic: Development of cellulose-based material from wheat straw using pressurized water + ethanol hydrolysis and high-intensity ultrasound treatments
The increasing demand of food containers, along with growing petroplastics concerns and Canada’s single-use plastic ban, caused 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 are mainly composed of cellulose, are produced annually. 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, alkaline hydrogen peroxide, with further fibrillation using high-intensity ultrasound (HIUS) to develop environmentally friendly 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 utilizing pressurized 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 industry.