Absorption spectra of the sulphite and sulphate ions

Karim, S. Mujtaba; Samuel, R.

doi:10.1007/bf03035583

Cited by 8 publications

(3 citation statements)

References 6 publications

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“…A decrease in transmittance at shorter wavelengths was especially pronounced for S100T40. Previous studies on free-standing ChNF and CNC films have observed absorbance in the UV tailing into the visible spectrum caused by light absorption of amide in ChNWs (at ∼230 nm) and sulfate ester groups in CNCs (at ∼270 nm), 48–50 and the decrease in transmittance for S100T40 was attributed to keto or carboxyl groups formed by the oxidation of hydroxyl groups. 51 Due to the notable yellowing at higher temperatures, the upper limit of T spray was selected to be 100 °C.…”

Section: Resultsmentioning

confidence: 90%

Optimization of spray-coated nanochitin/nanocellulose films as renewable oxygen barrier layers via thermal treatment

Shen

Young

et al. 2022

Mater. Adv.

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Section: Resultsmentioning

confidence: 90%

Optimization of spray-coated nanochitin/nanocellulose films as renewable oxygen barrier layers via thermal treatment

Shen

Young

et al. 2022

Mater. Adv.

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“…Most original and recycled suspensions had high transmittances, except rCNC2, as shown in Figures b and S2. The transmittance became lower at shorter wavelengths due to the absorbance in the UV tailing into the visible spectrum by sulfate half-ester groups in CNC (∼270 nm) and amide groups in ChNW (∼230 nm). − For recycled single-layer coatings, e.g., rCNC1, rChNW1, and rblend, their average transmittance in the range of 350–800 nm slightly increased from 78 to 85, 82 to 85, and 69 to 72% in comparison to the original materials, respectively. The rCNC1 and rblend showed higher transmittance at shorter wavelengths compared to the original materials but lower transmittance at longer wavelengths; however, the rChNW1 compared to the original ChNW showed the opposite phenomenon.…”

Section: Resultsmentioning

confidence: 99%

Aqueous-Based Recycling of Cellulose Nanocrystal/Chitin Nanowhisker Barrier Coatings

Shen

Yang

et al. 2023

ACS Sustainable Chem. Eng.

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Multilayer films consisting of nanocellulose and nanochitin as oxygen barrier coatings and a conventional petroleum-based moisture barrier plastic as the substrate have been widely studied for food packaging applications. A challenge with enabling recycling of such hybrid multilayer materials is separating the coating from the substrate. In this work, we studied multilayer films consisting of poly(ethylene terephthalate) (PET) as a model substrate with chitin nanowhiskers (ChNWs) and cellulose nanocrystals (CNCs) as bilayer barrier coatings. Dissolution in aqueous media at different pH values was utilized for coating removal. PET coated with bilayers of recycled CNC and ChNW had an oxygen permeability (OP) of 6.6 cm 3 •μm/m 2 /day/kPa. It had a 27% increase compared to PET with the original bilayer coatings (5.2 cm 3 •μm/m 2 /day/kPa) while still provided a 62% reduction compared to uncoated PET (17.3 cm 3 •μm/m 2 /day/ kPa). Additionally, single-layer coatings of CNC were recycled for up to three runs, and no significant difference was found in the OP values for the films with recycled CNC coatings. This study demonstrates a pathway for recycling of the relatively expensive coating, which may provide a more sustainable solution for production of food packages.

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“…4 ). Additionally, the CNAs and CNSs surface was treated with a sulfate ester group, and the sulfate ion displayed a comparable absorption peak at about 284 nm 71 . Therefore, the carboxyl and sulfate group coupled to CNA and CNS particles can be responsible for the absorption peak at 284 nm for the CNA and CNS suspensions.…”

Section: Resultsmentioning

confidence: 99%

Green synthesis of cellulose nanocrystal/ZnO bio-nanocomposites exerting antibacterial activity and downregulating virulence toxigenic genes of food-poisoning bacteria

Dawwam

Al–Shemy

El-Demerdash³

2022

Sci Rep

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Recently, cellulose nanocrystals (CNs) have attracted wide attention owing to their superior properties compared to their bulk materials. For example, they represent an outstanding model for fabricating green metallic/metal oxide nanoparticles (NPs). In this study, two CNs (carboxylated CNs and sulfated CNs) extracted from agro-wastes of palm sheath fibers were used as templates for the facile and green synthesis of ZnO NPs by employing the sono-co-precipitation method. The obtained nanomaterials were characterized using TEM, EDX, UV–visible, DLS, FT-IR, and XRD analysis. As a result, the size and concentration of synthesized ZnO NPs were inversely proportional to one another and were affected by the CNs utilized and the reaction temperature used. Contagious diseases incited by multifarious toxigenic bacteria present severe threats to human health. The fabricated bio-nanocomposites were evaluated in terms of their antimicrobial efficacy by agar well diffusion method and broth microdilution assay, showing that CN–ZnO bio-nanocomposites were effective against the tested Gram-negative (Escherichia coli and Salmonella) and Gram-positive (Listeria monocytogenes and Staphylococcus aureus) bacteria. The influence of the subinhibitory concentrations of these suspensions on the expression of the most critical virulence toxin genes of the tested strains was effective. Significant downregulation levels were observed through toxigenic operons to both fabricated CN–ZnO bio-nanocomposites with a fold change ranging from 0.004 to 0.510, revealing a decline in the capacity and virulence of microorganisms to pose infections. Therefore, these newly fabricated CNS–ZnO bio-nanocomposites could be employed rationally in food systems as a novel preservative to inhibit microbial growth and repress the synthesis of exotoxins.

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Absorption spectra of the sulphite and sulphate ions

Cited by 8 publications

References 6 publications

Optimization of spray-coated nanochitin/nanocellulose films as renewable oxygen barrier layers via thermal treatment

Optimization of spray-coated nanochitin/nanocellulose films as renewable oxygen barrier layers via thermal treatment

Aqueous-Based Recycling of Cellulose Nanocrystal/Chitin Nanowhisker Barrier Coatings

Green synthesis of cellulose nanocrystal/ZnO bio-nanocomposites exerting antibacterial activity and downregulating virulence toxigenic genes of food-poisoning bacteria

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