Superabsorbent Hydrogel from Extracted Oil Palm Frond Waste Cellulose Using Microwave Irradioation for Cadmium Ion Removal from Aqueous Solution

This research report facile approach on dispersion of cellulose fiber extracted from oil palm frond waste in a “green-solution” prepared by using urea and sodium hydroxide while the polymerization is carried out using microwave to form hydrogels. Effects of adding cellulose was determined by comparing the swelling degree between 0% and 2% cellulose hydrogel. Results showed that swelling ratio enhanced by the presence of cellulose. SEM images exposed that hydrogel with cellulose has rough surface compared to the hydrogels without cellulose. The XRD demonstrated that cellulose hydrogel lost its crystallinity upon polymerization. The DSC analysis showed that upon polymerization the hydrogel has better heat stability compared to the raw oil palm frond cellulose fiber. The FTIR shows successful polymerization has occurred between polyacrylamide and cellulose with a reference to band at 1657.99 cm, which indicated the N–H bond. The capacity of cellulose hydrogel at different ratios to adsorb cadmium as a function of pH has also been carried out. Results showed that hydrogel made of 2% cellulose at pH 4 adsorbed the most cadmium. Therefore, this sorbent can potentially be used as Cd ion remover in aqueous solution.