SINTESIS DAN KARAKTERISASI HIDROGEL SUPERABSORBEN BERBASIS SELULOSA DARI TONGKOL JAGUNG SEBAGAI PELEPAS UREA TERKENDALI (CONTROLLED-RELEASE OF UREA)

The low efficiency of fertilizers in agriculture contributes to disadvantage economic and environmental problems. Slow/controlled-release fertilizers can provide to the plant nutrients significantly longer than fertilizers commonly used by farmers. Corncob waste can be used as raw material for synthesis hydrogel cellulose as a controlled-release of Urea through a cross-linking process with epichlorohydrin in NaOH/urea aqueous systems. Enrichment of fertilizers in hydrogels is done through immersion by urea solutions. The structure and morphology were characterized by FTIR spectroscopy and scanning electron microscopy. The results showed the characteristics of urea were present in hydrogels. Addition of the carboxymethyl group to the hydrogel provides an increase in the ratio of swelling and absorption of urea and improves the surface and structure of the hydrogel. The measurement of urea released will be analyzed using UV-Visible Spectro. Fertilizer release by GEL-A-Urea was reached at 5.29% and GEL-B-Urea at 5.56% with a release time span of 15-180 minutes. The amount of release is also evaluated by variations in pH and temperature. Increased pH and temperature can accelerate the release of urea. Having a high water absorption capacity and the ability to release fertilizer nutrients will be very important for the application of hydrogels, especially slow-release and controlled-release fertilizer