Pectin-based surperabsorbent hydrogels crosslinked by some chemicals: synthesis and characterization

Synthesis of superabsorbent hydrogels from pectin was investigated using three kinds of crosslinkers, CaCl(2), ethylene glycol diglycidyl ether (EGE), and glutaraldehyde (GA). Among them, GA was the most suitable to attain high absorbency, reaching ca. 500 g/g in pure water. On the contrary, hydrogels crosslinked by CaCl(2) and EGE absorbed much less water, their maximum absorbency was around 200 g/g and 40 g/g, respectively. Absorbency in 0.9% NaCl solution of hydrogel crosslinked by GA was as low as 15 g/g, which indicates absorbency of hydrogels in the present study is sensitive to salt concentration. Biodegradability of pectin-based hydrogels in activated sludge at 25 degrees C for 18 days was 60-65%.