Hydrogel derived from hybrid water hyacinth carboxymethyl cellulose and banana peels pectin hydrogel via citric acid crosslinking

Abstract

Water hyacinth (WH) is a major pest in aquifer and likewise of banana peel waste that pollutes the environment. WH and banana peels have potential to produce carboxymethyl cellulose (CMC) as well as pectin. Both CMC and pectin are applicable for fabrication of hydrogels that focus on the natural ingredients for their use as food packaging materials. The application of CMC and pectin as a hydrogel material are splendid for increasing its mechanical, biodegradable and environment-friendly properties. This study determined the effect of citric acid as a cross-linking agent on the swelling properties of CMC-pectin based hydrogels and investigated their functional groups. Preparation of hybrid CMCpectin hydrogels was started by extracting WH cellulose. Through bleaching and dehemicellulose process. Cellulose was modified into CMC in two steps, alkalization and carboxymethylation. At the alkalization stage, the cellulose was mixed with NaOH 10% solution. For carboxymethylation, natrium chloroacetate (Na-CA) was added and stirred at 55°C for 3.5 hrs. Fabrication of hydrogel was mixed with 5% ratio 70:30 (w/w.%) of CMC:pectin. Citric acid (CA) was added as the cross-linking agent with concentrations of 5%, 10%, and 15% on heat treatment. The result of hybrid bio-hydrogels (HBH) was a sheet form film of semi-transparent, and brownish in color. HBH CMC/pectin with the addition of a cross-linking agent in the form of citric acid (5%) gave the highest swelling ability (6.64 wt., within 1 hr). Also, the presence of carboxyl bonds with hydroxyl groups was observed via Fourier transformed infrared spectrometry (FTIR) analysis.