Nanocomposite PAAm/methyl cellulose/montmorillonite hydrogel: Evidence of synergistic effects for the slow release of fertilizers

Nenhuma Miniatura disponível

Data

2013-08-07

Autores

Bortolin, Adriel
Aouada, Fauze A. [UNESP]
Mattoso, Luiz H. C.
Ribeiro, Caue

Título da Revista

ISSN da Revista

Título de Volume

Editor

Resumo

In this work, we synthesized a novel series of hydrogels composed of polyacrylamide (PAAm), methylcellulose (MC), and calcic montmorillonite (MMt) appropriate for the controlled release of fertilizers, where the components presented a synergistic effect, giving very high fertilizer loading in their structure. The synthesized hydrogel was characterized in relation to morphological, hydrophilic, spectroscopic, structural, thermal, and kinetic properties. After those characterizations, the application potential was verified through sorption and desorption studies of a nitrogenated fertilizer, urea (CO(NH2)2). The swelling degree results showed that the clay loading considerably reduces the water absorption capability; however, the hydrolysis process favored the urea adsorption in the hydrogel nanocomposites, increasing the load content according to the increase of the clay mass. The FTIR spectra indicated that there was incorporation of the clay with the polymeric matrix of the hydrogel and that incorporation increased the water absorption speed (indicated by the kinetic constant k). By an X-ray diffraction technique, good nanodispersion (intercalation) and exfoliation of the clay platelets in the hydrogel matrix were observed. Furthermore, the presence of the montmorillonite in the hydrogel caused the system to liberate the nutrient in a more controlled manner than that with the neat hydrogel in different pH ranges. In conclusion, excellent results were obtained for the controlled desorption of urea, highlighting the hydrolyzed hydrogels containing 50% calcic montmorillonite. This system presented the best desorption results, releasing larger amounts of nutrient and almost 200 times slower than pure urea, i.e., without hydrogel. The total values of nutrients present in the system show that this material is potentially viable for application in agriculture as a nutrient carrier vehicle. © 2013 American Chemical Society.

Descrição

Palavras-chave

controlled release of fertilizer, hydrogel nanocomposites, hydrolysis process, montmorillonite clay, polyacrylamide, Absorption capability, Controlled release, Hydrogel nanocomposites, Hydrolysis process, Montmorillonite (MMT), Montmorillonite clay, Sorption and desorptions, X-ray diffraction techniques, Clay minerals, Desorption, Fertilizers, Fourier transform infrared spectroscopy, Hydrolysis, Metabolism, Nanocomposites, Nutrients, Polyacrylates, Urea, X ray diffraction, Hydrogels

Como citar

Journal of Agricultural and Food Chemistry, v. 61, n. 31, p. 7431-7439, 2013.