Studies on the Slow Release of Urea and Water from Malonic Acid Crosslinked Sodium Carboxymethylcellullose–Hydroxyethyl Cellulose Superabsorbent Hydrogel for Potential Applications in Agriculture Sector

Superabsorbent hydrogels prepared from cellulose derivatives are gaining applications in the agricultural sector for controlled and slow release of nutrients and water to prevent nutrient loss and facilitate the prudent use of water. The present work reports the synthesis of superabsorbent hydrogel based on two cellulose derivatives, sodium carboxymethyl cellulose (CMCNa) and hydroxyl ethyl cellulose (HEC) with malonic acid (MA) as the crosslinker. The ratio of the two cellulose derivatives as well as the concentration of the crosslinker were varied to find out the most suitable ratio to yield the hydrogel with highest water retention capacity and most efficient encapsulation and slow release of urea. Hydrogel synthesized from HEC and CMCNa in the ratio 1:3 in the presence of 1% MA as the crosslinker had shown the best results. Further a comparative study with another crosslinker citric acid was also investigated and found that malonic acid crosslinked hydrogel showed better results.