Aboulfazl Barati - Chemical Engineering Department, Faculty of Engineering, Arak University, Arak, Iran
Alireza Matini - Chemical Engineering Department, Faculty of Engineering, Arak University, Arak, Iran
Taghi Miri - Chemical Engineering Department, Faculty of Engineering, Arak University, Arak, Iran
Mohammad Hossein Haddad - Chemical Engineering Department, Faculty of Engineering, Arak University, Arak, Iran

To improve fertilizer use efficiency and minimize its negative impact on environment, a slow-release micro nutrient fertilizer with water-retention was prepared. Starch was used as skeletal material in copolymerization on which acrylic acid monomer can be grafted to form superabsorbent composite. Zinc nitrate was introduced to provide zinc nutrient. This article discusses the swelling kinetics of polymer matrix composite and release dynamics of zinc nitrate (micro nutrient fertilizer) from hydrogels. The prepared hydrogels showed enormous swelling in aqueous medium and displayed swelling characteristics which were highly dependent on the chemical composition of the hydrogel (amount of crosslinker, starch and organomodified montmorillonite), pH and ionic strength of the medium. Structure, morphology and the amounts of released micro nutrient was checked by FTIR, XRD, SEM and UV- Spectrophotometer. The results showed that the product with slow-release and water-retention capacity, being economical, nontoxic in soil and environment-friendly, could be found good application in agriculture and horticultural.

Micro nutrient, Montmorillonite, Hydrogels, Water retention, Release dynamics