Enhanced swelling hydrogel of cellulose by adding fly ash

Coal combustion as a source of steam power generation produces waste in the form of fly ash, which is an environmental pollutant. Fly ash's properties are influenced by its mineral concentration, which implies that it differs significantly depending on the coal source. In this work, an environment friendly hydrogel is made from cellulose and fly ash to utilize coal waste. Environment-friendly hydrogel is used in various fields of science, such as health and agriculture. The preparation process involves two cellulose derivatives, Sodium Carboxymethyl Cellulose (CMC-Na) and Hydroxyethyl cellulose (HEC), in 2% distilled water with a 3/1 ratio of CMC-Na/HEC. Citric acid (CA) is a crosslinking agent, and it is commonly used in various cellulose derivatives because it has non-toxic properties. The polymerization occurs during heating in an oven at 80℃ for 8 hours. The percentage swelling ratio and FTIR measurements investigate the addition of CA variation at the range of 1.75%-5% and the variation of adding silica-based fly ash such as sodium silicate and nanosilica. The results showed that the best percentage swelling ratio with the lowest CA content and 5% nanosilica gave the highest swelling ratio at 5800%. Adding silica-based fly ash material affects the swelling ratio of the hydrogel.