Comparison of Copper-crosslinked Carboxymethyl Cellulose Versus Biopolymer-based Hydrogels for Controlled Release of Fertilizer

This work deals with evaluating the hydrogel prepared from copper-crosslinked carboxymethyl cellulose as a controlled release system of fertilizer. In this respect, the behavior of gel was compared with gels prepared from polycationic biopolymer (trimethyl chitosan; Tri.M.Ch), individual or as a crosslinking agent of carboxylate-containing cellulose derivatives (CMC) and oxidized cellulose nanoparticles (OC.NPs). The swelling behavior of gel was preliminarily examined as a key factor for gel application. It is worth noting that the swelling capacity of CMC-Cu(II) gel was very higher (2350% at 250 min) than other gels (Tri.M.Ch, CMC-Tri.M.Ch and OC.NPs.Tri.M.Ch), where their swelling capacities ranged 100-300%. Moreover, it provided more sustained release rate of monoammonium phosphate (MAP-fertilizer) loaded hydrogels, similar to CMC-Tr.M.Ch, with maximum similar to 87-88%; while the gels of Tr.M.Ch. and Tr.M.Ch.-OC.NPs achieved maximum release reached 96-100%. The release of MAP from the hydrogels was followed by a Fickian or quasi-Fickian diffusion mechanism. The trend of hydrogels for MAP release was reflected in the nutrition value (NPK) of onion planted on gel-treated sand loamy soil. [GRAPHICS]

Automated summary

The study evaluated the hydrogel prepared from copper-crosslinked carboxymethyl cellulose as a controlled release system of fertilizer, showing high swelling capacity and sustained release rate, with a Fickian or quasi-Fickian diffusion mechanism for fertilizer release. The performance of the hydrogel was reflected in the nutrition value of onion planted in gel-treated soil.