scholarly journals Photocatalytic Degradation of Rhodamine B in Heterogeneous and Homogeneous Systems

2021 ◽  
Vol 49 (1) ◽  
pp. 9-16
Author(s):  
Asfandyar Khan ◽  
Zsolt Valicsek ◽  
Ottó Horváth
Keyword(s):  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Reaction Rate ◽  
Vibrio Fischeri ◽  
Antibacterial Property ◽  
Copper Ferrite ◽  
Experimental Conditions ◽  
Wide Ph Range ◽  
Bioluminescence Assay ◽  
Ph Range

This study focuses on the photocatalytic degradation of Rhodamine B (RhB) in heterogeneous and homogeneous photo-Fenton reactions. In the heterogeneous system, iron(II) doped copper ferrite CuII(x)FeII(1-x)FeIII2O4 nanoparticles (NPs) prepared in our previous work were employed as potential catalysts. The photodegradation of RhB was carried out in a quartz cuvette located in a diode array spectrometer. The experimental conditions such as pH, NPs dosage and H2O2 dosage with regard to the photocatalytic degradation of RhB were optimized to be 7.5, 500 mg/L and 8.9x10-2 mol/L, respectively. In addition, visible light-induced photodegradation of RhB was also carried out by using \ch{H2O2} over a wide pH range in the absence of heterogeneous photocatalysts. It was observed that the reaction rate significantly increased above pH 10, resulting in a faster rate of degradation of RhB, which may be attributed to the deprotonation of hydrogen peroxide. Furthermore, the potential antibacterial property of such catalysts against the Gram-negative bacterium Vibrio fischeri in a bioluminescence assay yielded inhibition activities of more than 60% in all cases.

scholarly journals Synthesis, Characterization and Application of Iron(II) Doped Copper Ferrites (CuII(x)FeII(1-x)FeIII2O4) as Novel Heterogeneous Photo-Fenton Catalysts

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 921 ◽  
Author(s):  
Asfandyar Khan ◽  
Zsolt Valicsek ◽  
Ottó Horváth
Keyword(s):  
Photocatalytic Degradation ◽  
Band Gap ◽  
Fine Particles ◽  
Diffuse Reflectance Spectroscopy ◽  
Type System ◽  
Copper Ferrite ◽  
Degradation Of Dyes ◽  
Wide Ph Range ◽  
Ph Range ◽  
Co Precipitation

The heterogeneous photo-Fenton type system has huge fame in the field of wastewater treatment due to its reusability and appreciable photoactivity within a wide pH range. This research investigates the synthesis and characterization of iron(II) doped copper ferrite (CuII(x)FeII(1-x)FeIII2O4 nanoparticles (NPs) and their photocatalytic applications for the degradation of methylene blue (MB) as a model dye. The NPs were prepared via simple co-precipitation technique and calcination. The NPs were characterized by using Raman spectroscopy, X-ray diffractometry (XRD), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS). SEM reveals the structural change from the spherical-like particles into needle-like fine particles as the consequence of the increasing ratio of copper(II) in the ferrites, accompanied by the decrease of the optical band-gap energies from 2.02 to 1.25 eV. The three major determinants of heterogeneous photo-Fenton system, namely NPs concentration, hydrogen peroxide concentration and pH, on the photocatalytic degradation of MB were studied. The reusability of NPs was found to be continuously increasing during 4 cycles. It was concluded that iron(II) doped copper ferrites, due to their favorable band-gap energies and peculiar structures, exhibit a strong potential for photocatalytic-degradation of dyes, for example, MB.

scholarly journals An Overview of Current Knowledge on the Properties, Synthesis and Applications of Quaternary Chitosan Derivatives

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2878
Author(s):  
Emanuelle Dantas Freitas ◽  
Celso Fidelis Moura Jr. ◽  
Jonas Kerwald ◽  
Marisa Masumi Beppu
Keyword(s):  
Water Solubility ◽  
Current Knowledge ◽  
Hydroxyl Groups ◽  
Phosphonium Salts ◽  
Experimental Conditions ◽  
Quaternized Chitosan ◽  
Wide Ph Range ◽  
Primary Amino ◽  
Ph Range ◽  
Low Solubility

Chitosan, a chitin-derivative polysaccharide, known for its non-toxicity, biocompatibility and biodegradability, presents limited applications due to its low solubility in neutral or basic pH medium. Quaternization stands out as an alternative to modify this natural polymer, aiming to improve its solubility over a wide pH range and, consequently, expand its range of applications. Quaternization occurs by introducing a quaternary ammonium moiety onto or outside the chitosan backbone, via chemical reactions with primary amino and hydroxyl groups, under vast experimental conditions. The oldest and most common forms of quaternized chitosan involve N,N,N-trimethyl chitosan (TMC) and N-[(2-hydroxy-3-trimethyl ammonium) propyl] chitosan (HTCC) and, more recently, quaternized chitosan by insertion of pyridinium or phosphonium salts. By modifying chitosan through the insertion of a quaternary moiety, permanent cationic charges on the polysaccharide backbone are achieved and properties such as water solubility, antimicrobial activity, mucoadhesiveness and permeability are significantly improved, enabling the application mainly in the biomedical and pharmaceutical areas. In this review, the main quaternized chitosan compounds are addressed in terms of their structure, properties, synthesis routes and applications. In addition, other less explored compounds are also presented, involving the main findings and future prospects regarding the field of quaternized chitosans.

Photocatalytic degradation of methyl orange, methylene blue and rhodamine B with AgCl nanocatalyst synthesised from its bulk material in the ionic liquid [P6 6 6 14]Cl

2016 ◽  
Vol 75 (1) ◽  
pp. 128-140 ◽  
Author(s):  
Borja Rodríguez-Cabo ◽  
Iago Rodríguez-Palmeiro ◽  
Raquel Corchero ◽  
Rosario Rodil ◽  
Eva Rodil ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Ionic Liquid ◽  
Methyl Orange ◽  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Silver Chloride ◽  
Bulk Material ◽  
Experimental Conditions ◽  
Agcl Nanoparticles

The photocatalytic degradation of wastewater containing three industrial dyes belonging to different families, methyl orange (MO), methylene blue (MB) and Rhodamine B (RhB), was studied under UV-Vis irradiation using synthesised silver chloride nanoparticles. The nanocatalyst was prepared by a dissolution/reprecipitation method starting from the bulk powder and the ionic liquid trihexyl(tetradecyl)phosphonium chloride, [P6 6 6 14]Cl, without addition of other solvents. The obtained catalyst was characterised by UV-Vis absorbance, X-ray powder diffraction, transmission electron microscopy and scanning electron microscopy. The decolourisation of the samples was studied by UV-Vis absorbance at the corresponding wavelength. Starting from 10 ppm dye solutions and 1 g L−1 of the synthesised AgCl nanoparticles, degradation efficiencies of 98.4% for MO, 98.6% for MB and 99.9% for RhB, were achieved in 1 h. The degradation mechanisms for the different dyes were studied. Comparison with other frequently used nanocatalysts, namely P-25 Degussa, TiO2 anatase, Ag and ZnO, highlights the strong catalytic activity of AgCl nanoparticles. Under the same experimental conditions, these nanoparticles led to higher (more than 10%) and faster degradations.

scholarly journals A Comparison Study on Fluorescence Properties of Formononetin and Ononin

2021 ◽  
Author(s):  
Jinjin Cao ◽  
Fang Lv ◽  
Ting Liu ◽  
Luchen Niu ◽  
Bocong Han ◽  
...  
Keyword(s):  
Fluorescence Enhancement ◽  
Alkaline Condition ◽  
Excitation Wavelength ◽  
Comparison Study ◽  
Spectral Difference ◽  
Experimental Conditions ◽  
Pyrone Ring ◽  
Wide Ph Range ◽  
Alkaline Conditions ◽  
Ph Range

Abstract In this work, reasons for the spectral difference between two isoflavones, Formononetin (F) and ononin (FG), are explained in the viewpoint of molecular structure through a comparison study of the fluorescence features of the two. The fluorescence enhancement of FG in hot alkaline condition is reported for the first time. For F, there was almost no fluorescence under acidic conditions, but when pH>5, its fluorescence began to increase with increasing pH due to the proton ionization of 7-OH. In the range of pH 9.3-12.0, the anion form of F produced a fairly strong and stable fluorescence with maximum excitation wavelength (λex) of 334 nm and emission wavelength (λem) of 464 nm, its fluorescence quantum yield (Yf) was measured to be 0.042. And for FG, its aqueous solution fluoresced weakly in a wide pH range until it was placed under hot alkaline conditions, which was presumed to the cleavage reaction of the γ-pyrone ring in FG by observing a significant fluorescence at λex / λem =288 / 388nm, and Yf was determined to be 0.020. The fluorescence sensitization methods of F and FG both exhibit low limits of detection (2.60 ng·mL-1, 9.30 ng·mL-1) and wide linear ranges (0.0117-1.86 μg·mL-1, 0.0146-2.92μg·mL-1). Although the structural relationship between F and FG is glycoside and aglycone, FG cannot be translated to F by glucoside hydrolysis under hot alkaline condition, the fluorescence enhancement mechanisms of the two are essentially different. The fluorescence difference between the two under different experimental conditions lays the foundation for future fluorescence quantitative analysis.

Heterogeneous Photocatalytic Discoloration/Degradation of Rhodamine B with H2O2 and Spinel Copper Ferrite Magnetic Nanoparticles

2014 ◽  
Vol 67 (4) ◽  
pp. 609 ◽  
Author(s):  
Ariadna Flores ◽  
Karina Nesprias ◽  
Paula Vitale ◽  
Julia Tasca ◽  
Araceli Lavat ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Uv Light ◽  
Synergetic Effect ◽  
Copper Ferrite ◽  
H2o2 Concentration ◽  
Experimental Conditions ◽  
Secondary Pollution ◽  
Uv Light Irradiation ◽  
Degradation Reaction ◽  
Catalyst Dosage

The discoloration/degradation of the artificial dye Rhodamine B (RhB) was investigated using advanced oxidation technologies. Aqueous solutions of RhB containing spinel copper ferrites (CuFe2O4) as a heterogeneous catalyst were exposed to UV irradiation/hydrogen peroxide. Under these experimental conditions the discoloration/degradation of RhB is strongly promoted by copper ferrites, reaching 95 % discoloration of the dye in 10 min and 97 % degradation in 200 min. The influence of the catalyst amount, H2O2 concentration, light source, and UV light intensity were studied. Optimum concentrations of H2O2 and catalyst dosage were found for the RhB degradation reaction. The catalyst had high magnetic sensitivity under an external magnetic field, which allowed its magnetic separation from water avoiding secondary pollution processes, and its recycling. A markedly synergetic effect of spinel copper ferrite and UV light irradiation was observed for the RhB discoloration/degradation with H2O2 as a green oxidant.

scholarly journals Facile Production of a Fenton-Like Photocatalyst by Two-Step Calcination with a Broad pH Adaptability

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 676
Author(s):  
Siyang Ji ◽  
Yanling Yang ◽  
Xing Li ◽  
Hang Liu ◽  
Zhiwei Zhou
Keyword(s):  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
Active Oxygen Species ◽  
Oxygen Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Wide Ph Range ◽  
Calcination Method ◽  
Ph Range

A novel heterogeneous Fenton-like photocatalyst, Fe-doped graphitic carbon nitride (Fe-g-C3N4), was produced by facile two-step calcination method. This Fe–g–C3N4 catalyzed rhodamine B degradation in the presence of H2O2 accompanied with visible light irradiation. transmission electron microscopy(TEM), x-ray diffraction (XRD), FT-IR, x-ray photoelectron spectroscopy (XPS), and photoluminescence fluorescent spectrometer (PL) characterization analysis methods were adopted to evaluate the physicochemical property of samples. It can be observed that the Fe-g-C3N4 exhibited excellent photocatalytic Fenton-like activity at a wide pH range of 3–9, with rhodamine B(RhB) degradation efficiency up to 95.5% after irradiation for 45 min in the presence of 1.0 mM H2O2. Its high activity was ascribed to the formation of Fe–N ligands in the triazine rings that accelerated electron movement driving the Fe(III)/Fe(II) redox cycle, and inhibited photo-generated electron hole re-combinations for continuous generation of reactive oxygen species by reactions between Fe(II) and H2O2. The main active oxygen species were hydroxyl radicals, followed by superoxide radicals and hole electrons. This produced catalyst of Fe–g–C3N4 shows excellent reusability and stability, and can be a promising candidate for decontamination of wastewater.

scholarly journals Kinetics and mechanisms of EDTA photocatalytic degradation withTiO2under different experimental conditions

2001 ◽  
Vol 3 (4) ◽  
pp. 193-199 ◽  
Author(s):  
Paola A. Babay ◽  
Carina A. Emilio ◽  
Rosana E. Ferreyra ◽  
Eduardo A. Gautier ◽  
Raquel T. Gettar ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Photocatalytic Degradation ◽  
Reaction Rate ◽  
Initial Rate ◽  
Uv Light ◽  
Degradation Process ◽  
Kinetic Regime ◽  
Experimental Conditions ◽  
Initial Ph ◽  
Limiting Values

The photocatalytic degradationof EDTA overTiO2has been analyzed to establish the influence of oxidants on the reaction rate, the nature of the intermediates and the kinetic regime. Degussa P-25 suspensions containing EDTA at initial pH 3 in different concentrations were irradiated under near UV light. A Langmuirian behavior was observed.O2at saturation concentrations was found to be crucial for EDTA degradation. The rapid depletion of EDTA was not accompanied by a corresponding TOC decrease, indicating formation of refractory intermediates. An enhancement in TOC reduction could be achieved by keeping pH constant or by hydrogen peroxide addition. Addition of Fe(III) caused a remarkable increase on the initial rate of EDTA consumption and also on TOC decrease. Changes in both parameters clearly increased under the simultaneous addition of Fe(III) andH2O2, until limiting values.Some of the possible intermediates of EDTA degradation were evaluated in the filtered solution. So far, glycine, ethylenediamine, ammonium, formaldehyde, and formic, iminodiacetic, oxalic, oxamic, glycolic and glyoxylic acids have been identified in different proportions, depending on the experimental conditions. Different degradationpathways are proposed. Inthe presence of Fe(III), photo-Fenton reactions would contribute also to the degradation process.

Removing dye Rhodamine B from aqueous medium via wet peroxidation with V-MCM-41 and H2O2

2009 ◽  
Vol 59 (3) ◽  
pp. 565-571 ◽  
Author(s):  
Deyong Wu ◽  
Mingce Long ◽  
Chao Chen ◽  
Yahui Wu ◽  
Weimin Cai ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Visible Light Irradiation ◽  
Rhodamine B ◽  
Mesoporous Structure ◽  
Heterogeneous Fenton ◽  
Bet Method ◽  
Wide Ph Range ◽  
Ph Range ◽  
Tetraethyl Silicate ◽  
Mcm 41

A new heterogeneous Fenton-like system, consisting of V-MCM-41 catalyst and hydrogen peroxide, was proved to be effective in removing recalcitrant dye Rhodamine B (RhB) in aqueous solutions. V-MCM-41 was prepared following a direct hydrothermal procedure with tetraethyl silicate and ammonium metavanadate as precursor. The mesoporous structure has been characterized by XRD, and the specific surface area was determined as x m2 g−1 according to BET method. The catalytic reaction can proceed in a relatively wide pH range from acidic to alkaline. And the visible light irradiation cannot promote the reaction process. In addition, the mechanism implication for V-MCM-41 as a Fenton-like catalyst has been discussed.

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