Siriphannon, Punnama

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Facile Preparation of Montmorillonite/Crosslinked Chitosan Containing Potassium Nitrate Nanocomposites as Eco-Friendly Slow Release Fertilizers
(2023-08-01)
Rukchonlatee, Suparat
;
Siriphannon, Punnama
Montmorillonite/tripolyphosphate crosslinked chitosan containing potassium nitrate nanocomposites (MMT/CS-KNO3-TPP) were synthesized by facile incipient wetness impregnation method. The MMT was impregnated stepwise with a mixture of protonated chitosan and KNO<inf>3</inf>, followed by a TPP solution to ionically crosslink with chitosan, resulting in MMT/CS-KNO3-TPP nanocomposites. The initial quantity of KNO<inf>3</inf> to MMT was varied from 0 to 10, 20, and 30 wt%, and the TPP crosslinker was varied according to TPP:chitosan weight ratios of 0:5, 1:5, and 3:5. The resultant MMT/CS-KNO3-TPP nanocomposites composed of the K+ and NO<inf>3</inf>− ions embedded in crosslinked chitosan which intercalated in the MMT basal spacing and covered on MMT external surface. The structure of these nanocomposites could effectively slow the K+ and NO<inf>3</inf>− releases, with the 72- hours cumulative released values (%R) ranging from 20–34% for K+ to 0.4–1.0% for NO<inf>3</inf>−. The MMT/CS-KNO3-TPP nanocomposites with higher TPP concentration could extend the K+ and NO<inf>3</inf>− release times. Total K+ release times were predicted to be in the range of 128–204 days. The presence of MMT/CS-KNO3-TPP nanocomposites in RD43 rice cultivation could promote the growth of RD43 seedlings and roots. Furthermore, the TPP crosslinked chitosan showed physical changes in distilled water, indicating its potential as a long-term nitrogen (N) and phosphorus (P) source for plant nutrients.
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Facile synthesis of chitosan/CuO nanocomposites for potential use as biocontrol agents
(2018-06-01)
Siriphannon, P.
;
Iamphaojeen, Y.
Chitosan/CuO nanocomposites (Chi/CuO) were prepared by facile and eco-friendly technique. The 2%w/v chitosan solution was mixed with 0.5 %w/w sodium tripolyphosphate (STPP), resulting in the formation of ionically crosslinked chitosan. The crosslinked chitosan was soaked in an aqueous solution containing 0.001, 0.01 or 0.1 mol/L CuSO<inf>4</inf>•5H<inf>2</inf>O for 24 hrs, in which the Cu2+ ions were absorbed into the chitosan network, forming as the chitosan/Cu2+ precursors. The chitosan/Cu2+ precursors were hydrothermally reacted in two different basic media, i.e. NaOH and NH<inf>4</inf>OH, at 100°C for 24 hrs, resulting in the nano-sized CuO crystals hydrothermally grew and embedded in the crosslinked chitosan matrix. The CuO grown in the NaOH possessed larger crystallite size and higher crystallinity than that in the NH<inf>4</inf>OH. In addition, the CuO crystallite size in the nanocomposites increased with the increase of initial concentration of Cu2+ starting agent due to the increase of Cu2+ quantity in the chitosan/Cu2+ precursors. The chitosan/CuO nanocomposites prepared by using 0.01 and 0.1 mol/L Cu2+ could exhibit the antibacterial activities after intimate contact with Staphylococcus aureus and Escherichia coli under JIS L 1902:1998 (Qualitative) test method, indicating their potential use as biocontrol agents.
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Soft solution growth of magnetite-maghemite nanocrystals in crosslinked chitosan templates and their superparamagnetic properties
(2022-01-01)
Vaewbundit, Sukanda
;
Siriphannon, Punnama
Crosslinked chitosan/iron oxide nanocomposites (CC/IO) were synthesized at low temperatures using aqueous systems, i.e. hydrothermal and refluxing methods. The CC templates derived from various concentrations of tripolyphosphate crosslinker were used as host materials. The Fe2+ and Fe3+ ions with 1:2 molar ratio were adsorbed into the CC templates by the swelling, allowing to form CC/Fe2+Fe3+ precursors. The CC/IO nanocomposites were created by treating the precursors in NaOH solution using hydrothermal and refluxing methods. The CC/IO nanocomposites contained magnetite-maghemite nanocrystals with quadrilateral shape of 10 − 14 nm embedded in the CC templates. Superparamagnetism was obtained in the CC/IO nanocomposites, which had maximum magnetization (M<inf>max</inf>) values ranging from 8.6 to 15.2 emu/g and coercivity and magnetic remanence values close to zero. The cell viability of CC/IO nanocomposites ranged from 80 to 89%, demonstrating high safety for mammal. The CC/IO nanocomposites were considered to be potential superparamagenetic candidates for alternative medical applications.
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Chitosan intercalated montmorillonite: Preparation, characterization and cationic dye adsorption
(2009-01-01)
Monvisade, Pathavuth
;
Siriphannon, Punnama
Chitosan intercalated montmorillonite (Chi-MMT) was prepared by dispersing sodium montmorillonite (Na+-MMT) into chitosan solution at 60 °C for 24 h. The Chi-MMT was characterized by XRD, XRF and FT-IR. The intercalation was accomplished via the ion-exchange of Na+ ions with -NH<inf>3</inf>+ of chitosan, resulting in the expansion of d<inf>001</inf> from 1.42 nm of Na+-MMT to 2.21 nm of Chi-MMT. The chitosan content in the Chi-MMT measured by TGA was about 17 mass%. The adsorption capacity of Chi-MMT was investigated in comparison with the starting Na+-MMT and chitosan using three different cationic dyes, i.e. basic blue 9 (BB9), basic blue 66 (BB66) and basic yellow 1 (BY1). The Chi-MMT showed the highest adsorption capacity in the range of 46-49 mg/g when the initial dye concentration was 500 mg/L, being equivalent to 92-99 wt.% of dye removal. The adsorption capacities of Chi-MMT for all basic dyes increased with an increase of initial dye concentration. An increase of adsorption capability of Chi-MMT was attributed to the existence of intercalate-chitosan. It could enlarge the pore structure of Chi-MMT, facilitating the penetration of macromolecular dyes, and also electrostatically interact with the applied dyes. These results indicated the competency of Chi-MMT adsorbent for basic dye adsorption. © 2008 Elsevier B.V. All rights reserved.

Siriphannon, Punnama

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