Photophysics of Auramine O adsorbed on solid clays

Valandro, Silvano R.; Poli, Alessandra Lima; Neumann, Miguel G.; Cavalheiro, Carla Cristina Schmitt

doi:10.1016/j.jlumin.2015.01.023

Cited by 17 publications

(22 citation statements)

References 24 publications

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“…5c). It is generally accepted in clay intercalation chemistry that ionic moiety first interact with the surface of clay layers (Neumann et al, 2002;Valandro et al, 2015), and then the ions at the edge of the clay particle gradually migrate into the interlayer space through concentration gradient.…”

Section: Transmission Electron Microscopy (Tem)mentioning

confidence: 99%

Systematic utilization of layered double hydroxide nanosheets for effective removal of methyl orange from an aqueous system by π-π stacking-induced nanoconfinement

Yamaguchi

Salles

et al. 2021

Journal of Environmental Management

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Systematic utilization of carbonated Mg-Al layered double hydroxide (LDH) nanosheets on methyl orange removal was investigated with a respect to particle dimension. LDHs with smallest dimension were synthesized carefully to have a small lateral size as well as high dispersibility. The other particles with medium and large sizes were prepared by hydrothermal treatment and urea hydrolysis to have larger size and higher crystallinity. According to kinetics and isotherm analyses, the smallest sized LDH showed effective adsorption of methyl orange (1250 mg/g-LDH) which was remarkable higher than the other LDHs with the larger lateral sizes. Compared with the larger lateral sized LDHs, the small sized ones were verified to utilize all the accessible adsorption sites of the nanosheets generating nanoconfinement of the methyl orange molecules. Transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD) patterns definitely indicated that the LDHs with ~40 nm of the lateral dimension could fully utilize the interlayer nanospace of the LDH. Monte-Carlo simulation suggested the intercalated methyl orange could be stabilized not only through electrostatic interaction with the LDH layer but also by π-π stacking between the methyl orange molecules, which is thought to be the driving force to replace carbonate anion.

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Section: Transmission Electron Microscopy (Tem)mentioning

confidence: 99%

Systematic utilization of layered double hydroxide nanosheets for effective removal of methyl orange from an aqueous system by π-π stacking-induced nanoconfinement

Yamaguchi

Salles

et al. 2021

Journal of Environmental Management

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“…This can be attributed to all fractions of yeasts being stained instantaneously after mixing, followed by a decrease cause by the major influence of fluorescent dye decay. It has also been reported that Auramine‐O decays when it is bound to cellulose (Simkovitch and Huppert ) and solid clays (Valandro et al ). The enhancement in fluorescence intensity is similar to a reported case for the mixing of Auramine‐O with htDNA and the amyloid fibril protein (Amdursky and Huppert ; Xu et al ).…”

Section: Discussionmentioning

confidence: 90%

Optimal fluorescent‐dye staining time for the real‐time detection of microbes: a study of Saccharomyces cerevisiae

et al. 2020

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Aims To provide information on the time‐dependent behaviour of microbe staining by fluorescent dyes in the order of seconds, which is important in terms of the recent rapid and online techniques for microbe measurements and/or environmental microbe analysis. Methods and Results For combinations of yeast (Saccharomyces cerevisiae) and typical dyes, including DAPI (4′,6‐diamidino‐2‐phenylindole) and Auramine‐O, a suspension of yeast cells in ultrapure water was injected into a dye solution in a micro cuvette placed inside a spectrofluorometer and the fluorescence intensity of the resulting solution was measured at 1 s intervals, starting immediately after the mixing and continued until the time for the maximum intensity using various concentrations of yeast and dyes. The relaxation time τ, which corresponds to ~63·2% of the maximum fluorescence intensity, was shown to decrease to below 1 s with increasing DAPI concentration, whereas it remained constant for 2–3 s with increasing Auramine‐O concentration, for example at a yeast concentration of 100 µg ml−1. Conclusions For the conditions of yeast >10 µg ml−1, DAPI >1 µg ml−1 and Auramine‐O >0·1 µg ml−1, τ could be adjusted to below 5 s to achieve a rapid and stable staining. Significance and Impact of the Study Design and operating conditions for rapid and online measurements of microbes can be optimized.

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“…S1E to S1I, Supporting material). This phenomenon known as meta-chromacy is ascribed to the formation of dye aggregates upon adsorption [39,40] and to stacking interaction between the aggre-gated dyes in which dye's electron cloud can be attracted toward a polar group on the material's surface. This interaction lowers the energy of highest occupied molecular orbital (HOMO) while empty and lowest unoccupied molecular orbital (LUMO) remains unaf-fected creating a higher energy difference between the orbitals and the transition occurs at higher energy thus at shorter wave length [41,42] .…”

Section: Uvevis-diffuse Reflectance Spectroscopy (Drs)mentioning

confidence: 99%

Dual-function hydrotalcite-derived adsorbents with sulfur storage properties: Dyes and hydrotalcite fate in adsorption-regeneration cycles

Stawiński

Węgrzyn

Freitas

et al. 2017

Microporous and Mesoporous Materials

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Thermal treatment of hydrotalcite at increasing temperatures resulted in formation of mixed oxides that exhibited different adsorption behavior toward anionic and cationic industrial dyes. The material annealed at 450 ○ C was characterized by the highest maximum adsorption capacity for both types of dyes. The adsorption was strongly pH dependent and for the anionic dye abatement low pH was favored whilst higher pH was more preferable for removal of the cationic dye. According to the equilibrium experiments, the maximum adsorption capacity increased from 179 ± 5 to 291 ± 8 mg g -1 in case of the anionic dye at pH 3.5 and from 6 ± 2 to 48 ± 2 mg g -1 in case of the cationic dye at pH 8.0, on starting and thermally treated material at 450 ○ C, respectively. Detailed characteristics of spent adsorbent and its reconstructed form revealed that after each cycle of adsorption and thermal regeneration the maximum adsorption capacity of the material decreased due to changes in the structure and accumulation of sulfur compounds. Evolution of specific surface area and porosity was correlated with annealing temperatures and behavior of dye's residues.

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Photophysics of Auramine O adsorbed on solid clays

Cited by 17 publications

References 24 publications

Systematic utilization of layered double hydroxide nanosheets for effective removal of methyl orange from an aqueous system by π-π stacking-induced nanoconfinement

Systematic utilization of layered double hydroxide nanosheets for effective removal of methyl orange from an aqueous system by π-π stacking-induced nanoconfinement

Optimal fluorescent‐dye staining time for the real‐time detection of microbes: a study of Saccharomyces cerevisiae

Dual-function hydrotalcite-derived adsorbents with sulfur storage properties: Dyes and hydrotalcite fate in adsorption-regeneration cycles

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