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UPSI Digital Repository (UDRep)
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| Abstract : Universiti Pendidikan Sultan Idris |
| The aim of this study is to modulate the controlled release properties of zinc hydroxide nitrate?sodium dodecylsulphate?bispyribac (ZHN?SDS?BP) nanocomposite, by coating the nanocomposite using chitosan. This study was conducted as part of an effort to reduce the environmental problems caused by the over-use of pesticides. The characterisation study shows that chitosan had been successfully coated onto the outer surface of the ZHN?SDS?BP (BP concentration of 0.05�M) without changing the types of ions intercalated in its interlayer gallery. The chitosan-coated nanocomposite, ZHN?SDS?BP?Chi also possesses a better thermal stability compared to the uncoated nanocomposite. Owing to the polycationic, hygroscopic nature, and gelation ability of chitosan, the chitosan coating was found to significantly prolong the release of bispyribac. The ZHN?SDS?BP?Chi showed a better performance in releasing pesticides, with prolonged release time ranging from 462 to 5349�min, compared to 74 to 4117�min for the uncoated nanocomposites. The release kinetic studies reveal that the release of bispyribac from the ZHN?SDS?BP?Chi is controlled by a pseudo-second-order kinetic model, thus signifying that the release mechanism is via dissolution and ion-exchange processes. The potential of chitosan in slowing the release of BP from ZHN?SDS?BP?Chi will hopefully contribute to minimise the risk of pollution resulting from the excessive use of pesticides. ? 2020, Institute of Chemistry, Slovak Academy of Sciences. |
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