Kecepatan Pelepasan Urea dari Controlled Release Fertilizer (CRF): Pengaruh Rasio Carboxymethylcellulose (CMC) – Karagenan

Beads of carboxymethylcellulose (CMC)-carrageenan for controlled release fertillizer matrix (CRF) are prepared based on different blend with CMC:carragenan weight ratio of 1:0, 1:0.5, and 1:1. CMC-carrageenan beads gel was chemically modified using glutaraldehyde solution (4%) as the crosslinker and applied to control the urea release rate. This research proposed mathematical model describing the mass transfer rate of urea release and determined the effect of ratio CMC-carrageenan blend on the parameters of urea release rate from the beads gel in water. The beads gel were crosslinked by beads gel immersion method and thermal curing at 110oC for 25 minutes. Urea was loaded in the beads gel. The rate release of urea from crosslinked beads gel in water was determined by measuring the concentration of urea in various time of immersion. Result showed that the mathematical model arranged could be describe the mass transfer rate of urea release. The release rate of urea was decreased with the increasing of carrageenan amount in ratio blend. The range constant mass transfer rate was around 0.0444/minute until 0.0528/minute, while the range equillibrium constant was around 0.000524 until 0.000897 gram of solid/mL. The optimum weight ratio CMC:carrageenan of 1:1 might be potential for urea controlled release