| Autor: |
Ng, H.K. Melvin, Lim, G.K., Leo, C.P. |
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| Zdroj: |
Journal of Environmental Chemical Engineering; Feb2021, Vol. 9 Issue 1, pN.PAG-N.PAG, 1p |
| Abstrakt: |
The quenching of carbon dots (CDs) is affected by surface functional groups and other factors. Since CDs were also immobilized into thin films as a sensor, the effects of film properties on their photoluminescence should be investigated. In this work, N-doped CDs (NCDs) were immobilized in polyvinyl alcohol (PVA) thin films for tartrazine detection. Using a microwave-assisted hydrothermal method, amorphous NCDs were successfully produced. NCDs were blended into the PVA dope solution containing microfibrillated cellulose (MFC). An excessive amount of NCDs caused the undesired interaction and mutual reabsorption between the NCDs, resulting in self-quenching. Dimethylaminoethyl acrylate (DMAEMA) was added as copolymer to reduce the swelling ratio by about 50%. The reduction of water uptake subsequently reduced the tartrazine adsorption and the quenching of NCDs. Contradictory, the addition of TiO 2 nanoparticles improved the tartrazine adsorption and the NCDs quenching. The thin film also exhibits photocatalytic properties for analyte removal. The linear Δ F and the unchanged absorbance spectra of PVA/DM3/NCD/TiO 2 thin film indicate dynamic quenching at low tartrazine concentration (< 10 µM), attaining a limit of detection of 4.66 µM. The overlapping spectrum between the analyte absorbance and NCDs film emission spectra showed possible inner filter effects or fluorescence resonance energy transfer quenching mechanism. ga1 • N-doped carbon dots (NCDs) were immobilized in PVA thin film. • DMAEMA copolymerization reduced swelling and surface ratio of the PVA film. • TiO 2 nanoparticles improved tartrazine adsorption and quenching of NCDs. • Dynamic quenching occurred at low tartrazine concentration (<10 µM). • The photoluminescent intensity of the film was recovered after 4 h of UV cleaning. [ABSTRACT FROM AUTHOR] |
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