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  • 1
    Online Resource
    Online Resource
    Walter de Gruyter GmbH ; 2019
    In:  Open Chemistry Vol. 17, No. 1 ( 2019-06-01), p. 365-380
    In: Open Chemistry, Walter de Gruyter GmbH, Vol. 17, No. 1 ( 2019-06-01), p. 365-380
    Abstract: This study investigates the potential of N -octyl chitosan derivatives, namely N -octyl- O -sulfate chitosan (NOOSC), N -octyl- N -succinyl chitosan (NONSC) and N -octyl- O -glycol chitosan (NOOGC) as amphiphilic carrier agents for atrazine in water-insoluble herbicide formulations. The N -octyl chitosan derivatives were characterised using several analytical instruments such as Fourier Transform Infrared (FTIR) Spectrometer, CHNS-O Elemental Analyser (CHNS-O), Transmission Electron Microscope (TEM), Thermogravimetric Analyser (TGA), Differential Scanning Calorimeter (DSC) and Fluorescence Spectrometer. The encapsulation of atrazine by N -octyl chitosan derivatives was studied using a High Performance Liquid Chromatography (HPLC). The FTIR spectra of N -octyl chitosan derivatives confirmed the presence of hydrophobic and hydrophilic groups on chitosan backbone. TEM images revealed that N -octyl chitosan derivatives have formed self-aggregates with a spherical shape. The CMC values for N -octyl chitosan derivatives were between 0.06 and 0.09 mg/mL. The encapsulation efficiency (EE) values for amphiphilic chitosan were greater than 90%. The release profiles showed different release behaviour of pure herbicide in solution as compared to atrazine-loaded N -octyl chitosan derivatives. Results suggest that the chitosan derivatives offer promising characteristics that enable them to act as effective carrier agents for atrazine. In conclusion, the application of N -octyl chitosan derivatives could reduce the use of organic solvents in herbicide formulations by 37.5%.
    Type of Medium: Online Resource
    ISSN: 2391-5420
    Language: Unknown
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2019
    detail.hit.zdb_id: 2825411-9
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  • 2
    In: Open Chemistry, Walter de Gruyter GmbH, Vol. 17, No. 1 ( 2019-09-25), p. 788-797
    Abstract: Andrographis paniculata Ness is one of the plants that is under explored and could contain potentially active substances to serve as an antimalarial. Structure investigation of major compounds that have responsibility for the antimalarial activity of Andrographis paniculata Ness ’s n-hexane extract is very important so that it is known whether the antimalarial activity is synergistic or from the major compounds. Menthol and dioctyladipate as major component from n-hexane extract of Andrographis paniculata Ness have been succesfully isolated using simple and inexpensive methods. The solvent system used are n-hexane : ethyl acetate (10:1) and n-hexane: chloroform (10:3) consecutively either for column or preparative thin layer chromatography. FT-IR, 1 H-NMR and GC-MS were used to determine the structure of compounds. The activity of n-hexane extract, menthol and dioctyladipate related to the inhibition of heme polymerization have been done comprehensively. The inhibition of heme polymerization activity of isolate compounds and n-hexane extract are classified to a good level (dioctyl adipate IC 50 = 1.15 ± 0.41 mg/mL, menthol IC 50 = 0.31 ± 0,01 mg/mL, and n-hexane extract IC 50 = 0.07 ± 0.03 mg/mL) and potentially as antimalarial. From the IC 50 , the antimalarial activity of Andrographis paniculata Ness ’s n-hexane extract is working synergistically, not by the major compounds.
    Type of Medium: Online Resource
    ISSN: 2391-5420
    Language: Unknown
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2019
    detail.hit.zdb_id: 2825411-9
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  • 3
    In: Green Processing and Synthesis, Walter de Gruyter GmbH, Vol. 11, No. 1 ( 2022-04-12), p. 345-360
    Abstract: Water pollution has become one of the most serious environmental issues recently, especially in relation to chemical-containing wastewater. Uncontrolled industrial waste, including large amounts of dye-containing wastewater from textile industries, needs intensive attention. In this work, the synthesis of Fe 3 O 4 @SiO 2 nanocomposite biogenic silica from Salacca zalacca leaf ash was conducted for the photo-Fenton-like degradation of dye waste. The use of Salacca zalacca leaf ash and the nanoflake form is the novelty of this work. The physicochemical characterization of the material was conducted using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and diffuse reflectance UV-visible spectroscopy (UV-DRS) analyses, and photocatalytic activity of material was investigated in wet peroxidation of rhodamine B and batik wastewater. The results showed homogeneously dispersed Fe 3 O 4 in SiO 2 support with a nanoflake form, and a crystallite size of 44.9 nm was obtained. XRD investigation revealed the single phase of Fe 3 O 4 , which is consistent with the TEM analysis. The bandgap energy of 2.21 eV was reported from UV-DRS measurements, which influenced the increasing photocatalytic activity and reusability of the nanocomposite compared to pure Fe 3 O 4 . The photocatalyst showed the maximum degradation efficiency (DE) of 99.9% after 60 min, and the reusability feature was expressed, as there was an insignificant change in the DE over the fifth cycle of use. The material exhibited photocatalytic oxidation of batik wastewater as the removal of total suspended solids, chemical oxygen demand, and color reached 95.55%, 89.59%, and 90.00%, respectively.
    Type of Medium: Online Resource
    ISSN: 2191-9550
    Language: English
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2022
    detail.hit.zdb_id: 2645923-1
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