Encapsulated Urea-Kaolinite Nanocomposite for Controlled Release Fertilizer Formulations
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Date
2015-05-20
Journal Title
Journal ISSN
Volume Title
Publisher
Hindawi Publishing Corporation,
Abstract
Urea controlled release fertilizer (CRF) was prepared via kaolinite intercalation followed by gum arabic encapsulation in an attempt
to reduce its severe losses associated with dissolution, hydrolysis, and diffusion. Following the beneficiation, the nonkaolinite
fraction decreased from 39.58% to 0.36% whereas the kaolinite fraction increased from 60.42% to 99.64%. The X-ray diffractions
showed that kaolinite was a major phase with FCC Bravais crystal lattice with particle sizes ranging between 14.6nm and 92.5 nm.
Theparticle size varied with intercalation ratioswithmethanol intercalated kaolinite >DMSO-kaolinite > urea-kaolinite (KPDMU).
Following intercalation, SEM analysis revealed a change of order from thick compact overlapping euhedral pseudohexagonal
platelets to irregular booklets which later transformed to vermiform morphology and dispersed euhedral pseudohexagonal
platelets. Besides, dispersed euhedral pseudohexagonal platelets were seen to coexist with blocky-vermicular booklets. In addition,
a unique brain-form agglomeration which transformed into roundish particles mart was observed after encapsulation. The
nanocomposites decomposed between 48 and 600∘C. Release profiles showed that 100% of urea was released in 97 hours from
KPDMU while 87% was released in 150 hours from the encapsulated nanocomposite.The findings established that it is possible to
use Pugu kaolinite and gum arabic biopolymer to prepare urea CRF formulations.
Description
Keywords
nanocomposites, Kaolinite-urea