Fabrication of Grafted Carboxymethyl Cellulose Superabsorbent Hydrogel for Water Retention and Sustained Release of Ethephon in Sandy Soil

The present study aimed to develop an efficient superabsorbent hydrogel for water conservation and slow release of Ethephon in sandy soil. Herein, carboxymethyl cellulose (CMC) was grafted via a free radical polymerization technique with acrylamide and 2-Acrylamido-2-methylpropanesulfonic acid (AMPS) as hydrophilic monomers. The developed CMC-g-(PAM-co-PAMPS) graft copolymer superabsorbent hydrogel was characterized by FTIR, TGA, and SEM analysis to prove the occurrence of the grafting process. Several factors affecting the grafting process were investigated, while maximum grafting (%) value reached 91%. Moreover, increasing AMPS ratio obviously improved the swelling degree of the developed hydrogel with a maximal value of 17,770%. Moreover, addition of 2% of hydrogel to sandy soil potentially enhanced the water retention by 47% compared to pure sandy soil which retained about 7% of water. Besides, increasing Ethephon ratio up to 20% significantly increased its loading (%) value up to 88%, while about 87% of Ethephon was released within 28 days in a slow and sustained manner. The results suggested that the fabricated grafted hydrogel can serve as nutrient carrier and amendment for sandy soil for advanced agricultural applications.