Release of urea from cellulosic hydrogel coated urea granule: Modeling effect of crosslink density and pH triggering

ABSTRACT

Urea granules were coated with CMC-g-cl-PAA hydrogel by in situ spraying and polymerization technique with mean thickness of 0.24 mm. Water absorption capacity of hydrogel coated urea granules varied from 18.67 to 217.33 g/g depending on pH. Urea release was extended due to hydrogel coating and kinetic analysis at different pH (4.0, 7.0 and 9.2) revealed a sigmoid function as best fit model. The coated urea granules showed pH triggered release property with higher rate in alkaline medium and slower in acidic medium. The prepared hydrogel coated urea granules may find its application in integrated water and nutrient management strategies in agriculture.

Graphical Abstract

KEYWORDS:

• Urea
• hydrogel coating
• carboxymethyl cellulose
• triggered release formulations

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Additional information

Notes on contributors

Dhruba Jyoti Sarkar

Dhruba Jyoti Sarkar has been working extensively in the field of agrochemicals. He has expertise in developing controlled release agrochemical formulations including pesticides and fertilizers. He has also developed nanoformulations, triggered release formulations, etc. for better use efficiency of the same.

Tanumoy Bera

Tanumoy Bera has expertise in the field of nutrient dynamics in soil and other aspects of soil chemistry.

Anupama Singh

Anupama Singh has been working in the field of hydrogel chemistry and its application in agriculture. She has developed several agriculturally suitable hydrogels or superabsorbents for improving  input use efficiency in crop production.