Construction and photocatalytic properties toward rhodamine B of CdS/Fe_(3)O_(4) heterojunction

A simple two-step hydrothermal method synthesized four different CdS/Fe_(3)O_(4)photocatalysts with varying ratios of mass of CdS to Fe_(3)O_(4).The composition and morphology of the prepared samples were investigated using X-ray diffraction(XRD),Raman spectrum,X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).Solid UV reflectance spectra testing found that CdS/Fe_(3)O_(4)nanocomposites had good light absorption throughout the spectral range,promoting their photocatalytic properties.Under visible light irradiation,CdS/Fe_(3)O_(4)(2∶5)with a mass ratio of 2∶5 exhibited excellent photocatalytic perfor-mance,with a degradation rate of 98.8%for rhodamine B.Furthermore,after five cycles of photocatalytic degrada-tion reaction,the rhodamine B degradation rate remained at 96.2%,indicating that the photocatalysts have good pho-tocatalytic stability.

Photocatalytic Degradation of Rhodamine B by Recyclable Ag Br/Polypyrrole(PPy)Nano-Catalysts

We investigated the removal of the organic dye rhodamine B in wastewater with recyclable AgBr/polypyrrole(PPy)nano-photocatalysts.With PPy as an active base for electron transfer,and hexadecyltrimethylammonium bromide(CTAB)as both the soft-templating agent and the bromine source,a series of AgBr/PPy nano-photocatalysts containing various proportions of silver were prepared in a convenient one-step synthesis procedure.The synthesized catalysts were characterized by TG analysis to reveal that,in comparison with pure PPy,the interaction between PPy and AgBr led to increased thermal stability.Chemical combination of PPy and AgBr was observed through XRD and XPS analyses.For the morphology study,the AgBr particles were found to be well dispersed in the PPy nanowire network from SEM results.In the photodegradation experiments,up to 92%rhodamine B was degraded by the AgBr/PPy catalysts in the period of 1 hour under 254 nm UV light.The catalysts could maintain 60%catalytic efficiency after 3 cycles in the recyclability test.

Composite Activated Carbon from Canarium schweinfurthii/Polyethylene Terephthalate: Adsorption Test of Rhodamine B Dye Removal in Aqueous Solution

The present work deals on one hand with the valorization of wastes plastics, polyethylene terephthalate (PET) and Canarium schweinfurthii (CS) for the preparation of polyethylene terephthalate activated carbon (PETAC) and Canarium schweinfurthii/polyethylene terephthalate activated carbon (CS/PETAC). These adsorbents, on the other hand, were used for removal Rhodamine B (RhB) in an aqueous solution. PET and CS precursors were subjected to thermogravimetric analysis (TGA) and differential scanning colorimetry (DSC). Meanwhile PETAC and CS/PETAC were characterized using scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), X-ray fluorescence (XRF), Fourier transformed infrared spectroscopy (FT-IR) and nitrogen adsorption/desorption (N2-BET). The N2-BET results revealed an increase of the specific surface area from 6.75 m2/g to 1282.0 m2/g for PETAC and CS/PETAC. The results of characterization indicated the key role played by plastic wastes to enhance the structural and functional properties of CS/PETAC. The RhB removal from the aqueous solution onto PETAC and CS/PETAC was found to be independent of pH, with an optimal contact time of RhB removal within 10 min for materials. The non-linear adsorption isotherm data for the adsorption process showed that the Langmuir and Freundlich models best fitted the RhB adsorption onto PETAC meanwhile only the Freundlich adsorption isotherm gave the best fit for CS/PETAC according to the correlation coefficient value closed to unity. The pseudo-first and pseudo-second-order kinetic models best described the RhB dye removal on both adsorbents. Additionally, the Elovich model confirmed that chemisorption was the main mechanism followed. These findings proved that CS seeds and PET wastes are low-cost precursors that should be given an added value by transforming them into an outstanding carbon material for dye removal in liquid effluent.

Fabrication of a monoclinic/hexagonal junction in WO_3 and its enhanced photocatalytic degradation of rhodamine B

A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction（XRD）,scanning electron microscopy（SEM）,high-resolution transmission electron microscopy（HRTEM）,X-ray photoelectron spectroscopy,and N2 adsorption-desorption were used to characterize the crystalline phase,morphology,particle size,chemical composition,and surface area of the WO3 samples.The formation of hexagonal（h-WO3） and monoclinic（m-WO3） crystal structures of WO3 at different temperatures or different times was confirmed by XRD.m-WO3 is formed at 600 ℃,while m-WO3 starts to transform into h-WO3 at 800℃.However,h-WO3,which forms at 800℃,may transform into m-WO3 by increasing the calcination temperature to 1000℃.SEM results indicate that m-WO3 particles exhibit a bulky shape with heavy aggregates,while h-WO3 particles exhibit a rod-like shape.Moreover,m-WO3 crystals are sporadically patched on the surface of the h-WO3 rod-like particles,resulting in the exposure of both m-WO3 and h-WO3 on the surface.It is observed that the monoclinic phase（m-WO3）/hexagonal phase（h-WO3） junction was fabricated by tuning the calcination temperature and calcination time.The relative ratios between m-WO3 and h-WO3 in the phase junction can readily be tailored by control of the calcination time.The photocatalytic activities of WO3 with different crystalline phases were evaluated by the photocatalytic degradation of rhodamine B as a model pollutant.A higher photocatalytic activity was observed in the WO3 sample with the m-WO3/h-WO3junction as compared with the sample with only m-WO3.The improvement of photocatalytic activity can be attributed to the reduction of the electron-hole recombination rate owing to the formation of the phase junction,whose presence has been confirmed by HRTEM and photoluminescence spectra.

Microwave photocatalytic degradation of Rhodamine B using TiO_2 supported on activated carbon:Mechanism implication

The photocatalytic degradation of Rhodamine B （RhB） was carried out using TiO2 supported on activated carbon （TiO2-AC） under microwave irradiation. Composite catalyst TiO2-AC was prepared and characterized using X-ray diffraction （XRD）, transmission electron microscopy （TEM） and Brunauer-Emmett-Teller （BET）. In the process of microwave-enhanced photocatalysis （MPC）, RhB （30 mg/L） was almost completely decoloured in 10 min, and the mineralization efficiency was 96.0% in 20 min. The reaction rate constant of RhB in MPC using TiO2-AC by pseudo first-order reaction kinetics was 4.16 times of that using Degussa P25. Additionally, according to gas chromatography/mass spectrometry （GC/MS） and liquid chromatography/mass spectrometry （LC/MS） identification, the major intermediates of RhB in MPC included two kinds of N-de-ethylation intermediates （N,N-diethyl-N＇-ethyl-rhodamine （DER））, oxalic acid, malonic acid, snccinic acid, and phthalic acid, maleic acid, 3-nitrobenzoic acid, and so on. The degradation of RhB in MPC was mainly attributed to the destruction of the conjugated structure, and then the intermediates transformed to acid molecules which were mineralized to water and carbon dioxide.

Electrochemical oxidation of rhodamine B by PbO_2/Sb-SnO_2/TiO_2 nanotube arrays electrode

A PbO2/Sb-SnO2/TiO2 nanotube array composite electrode was successfully synthesized and its electrochemical oxidation properties were investigated.Field-emission scanning electron microscopy(FE-SEM)and X-ray diffraction(XRD)results showed that the PbO2 coating was composed of anα-PbO2 inner layer and aβ-PbO2 outer layer.Accelerated life measurement indicated that the composite electrode had a lifetime of 815 h.Rhodamine B(RhB)was employed as a model pollutant to analyze the electrocatalytic activity of the electrode.The effects of initial RhB concentration,current density,initial pH,temperature,and chloride ion concentration on the electrochemical oxidation were investigated in detail.Inductively coupled plasma atomic emission spectroscopy(ICP-AES)results suggested that the concentration of leached Pb^2+in the electrolyte during the electrocatalytic oxidation process can be neglected.Finally,the degradation mechanism during the electrocatalytic oxidation process was proposed based on the results of solid-phase micro-extraction-gas chromatography-mass spectrometry(SPME-GC-MS).The high electrocatalytic performance of the composite electrode makes it a promising anode for the treatment of organic pollutants in aqueous solution.

Photocatalytic degradation of Rhodamine B under visible light with Nd-doped titanium dioxide films

Microporous titanium dioxide films were prepared by the sol-gel methods on glass substrates, using tetrabutyl titanate as source material. In order to absorb the visible light and increase the photocatalytic activities, different concentrations of neodymium ions (Nd/Ti molar ratio was 0.5%, 0.7%, 0.9%, and 1.1% respectively) were added into the sol. X-ray diffraction (XRD), X-ray photoelectron spectros-copy (XPS), and atom force microscopy (AFM) were applied to characterize the modified films. A kind of typical textile industry pollutant (Rhodamine B) was used to evaluate the photocatalytic activities of the films under visible light. The results showed that the activities of the films were improved by doping Nd ions into the sol.

Green Oxygenation Degradation of Rhodamine B by Using Activated Molecule Oxygen

Iron(II) tetra-(1,4-dithin)-porphyrazine, (FePz(dtn)4) is able to activate molecule oxygen for oxygenation degradation of rhodamine B (RhB) in an extensive pH region without light excitation. Experiments indicate that the RhB can be degraded nearly 52% in alkaline aqueous solution, bubbling with dioxygen for seven hours in the presence of FePz(dtn)4 and the hydrogen peroxides as an active intermediate were determined by DPD method. The catalyst is recyclable and the catalyst activity was maintained after 10 recycles.

Detection of intermediates in the TiO_2-assisted photodegradation of Rhodamine B under visible light irradiation

The photocatalytic degradation of dye Rhodamine B （RhB） in the presence of TiO2 nanostdpe or P25 under visible light irradiation was investigated. The degradation intermediates were identified using Infrared spectra （IR spectra）, ^1H nuclear magnetic resonance （^1HNMR） spectra, and gas chromatography-mass spectroscopy （GC-MS）. The IR and the ^1HNMR results showed that the large conjugated chromophore structure of RhB was efficiently destroyed under visible light irradiation in both the photocatalytic systems （TiO2 nanostfipe or P25 and Rhodamine B systems）. GC-MS results showed that the main identified intermediates were ethanediotic acid, 1,2-benzenedicarboxylic acid, 4-hydroxy benzoic acid and benzoic acid, which were almost the same in the TiO2 nanostdpes and P25 systems. This work provides a good insight into the reaction pathway（s） for the TiO2-assisted photocatalytic degradation of dye pollutants under visible light irradiation.

Studies on the Recognition Interaction of Rhodamine B and DNA by Voltammetry

The recognition interaction of Rhodamine B(RB) with DNA was studied in a Britton-Robinson (B-R) buffer solution with pH=7.5 at a glassy carbon electrode by electrochemical techniques. RB shows an irreversible oxidation peak at +0.92 V(vs. SCE). After the addition of DNA in the RB solution, the peak current of RB decreased apparently without the shift of the peak potential. The electrochemical parameters such as the charge transfer coefficient α and the electrode reaction rate constant k s of the interaction system were carefully studied. The parameters did not change before and after the addition of DNA, which indicated that an electrochemical non-active complex had been formed, so the concentration of RB in the solution decreased and the peak current decreased correspondingly. The binding ratio of RB to DNA was 2∶1 with a binding constant of 2.66×10 9.

Simultaneous Determination of Fluorescein, Rhodamine 6G and Rhodamine B in Turbid Solution by Polarization Variable-Angle Synchronous Fluorescence Spectrometry

Polarization variable-angle synchronous fluorescence spectrometry was proposed to determine samples in turbid solution. A mixture of fluorescein, rhodamine 6G and rhodamine B was used to evaluate the technique. The background caused by scattering light was decreased remarkably. The limits of detection were 0.6 ng/ml for fluorescein, 2.3 ng/ml for rhodamine 6G and 4.1 ng/ml for rhodamine B, respectively.

Enhanced Photocatalytic Denitrification Rhodamine Bover In2O3/Bi24O31Br10 Nanocomposites under Visible Light Irradiation

A novel In203/Bi24O31Br10 composite photocatalyst, where In2O3 nanoparticleswith the diameter of about 5-10 nm were tightly attached on the surface of Bi24O31Br10 plates, wasprepared by using hydrolysis, impregnation method and post-thermal process. Photocatalyticactivity was evaluated by the degradation of Rhodamine B under the visible light irradiation.Effects of the contents of In203 nanoparticles on the optical property and photocatalytic activity of In203/Bi24O31Br10 composite were also investigated. Compared with neat In203 and Bi24O31Brlomaterials, 15In203/Bi24O31Br10 composite exhibits the best photocatalytic activity owing to theefficient separation of photogenerated electron and hole pairs, which is evidenced byphotoluminence spectra. More than 95% of Rhodamine B solution can be degraded by15In203/Bi24O31Brlo sample in 30 min.

Determination of Rhodamine B in Food Using HPLCUV Method

[ Objective] The aim was to establish a method for the determination of Rhodamine B in food by HPLC-UV. [ Metkod] Rhodamine B was extracted with acetone/hexane from food samples. After concentrated and purified by alumina cartridge, the Rhodamine B content in the food was determined by using high performance liquid chromatography with ultraviolet visible detector. [ Result] Within tile concentration range of 0.005 - 2.000 mg/kg, the peak area of Rhodamine B presented good linear relation with the concentration, and the related coefficient was 0.999 98. With high average recovery rate, the detection limit of the method was 0.005 mg/kg[ Concision] It is a fast and accurate method with high sensitivity to detect Rhodamine B in food.

Ag-Co3O4：Synthesis,characterization and evaluation of its photo-catalytic activity towards degradation of rhodamine B dye in aqueous medium

Synthesis,characterization of Co_3O_4 and Ag-Co_3O_4 composites and evaluation of their photo-catalytic activities towards photo-degradation of aqueous solution of rhodamine B dye under irradiation of visible light have been described in this paper.Co_3O_4 was prepared by solid phase mechano chemical process using Co(NO_3)_2·6H_2O and NH_4 HCO_3 as precursor materials.Ag was deposited on Co_3O_4 from AgNO_3 using Calotropis gigantea extract as reducing agent.XRD,SEM and FTIR were used for characterization of prepared composites.Photo-catalytic efficiencies of as-prepared Co_3O_4 and Ag-Co_3O_4 were evaluated for aqueous phase photo-degradation of rhodamine B.It was found that deposition of Ag on Co_3O_4 highly enhanced the photo-catalytic activity of Co_3O_4.Photo-catalytic degradation followed the Eley–Rideal mechanism.About 100% and 91% photo-degradation of 40 ml dye solution achieved at 313 K in 90 and 120 min over 0.05 g of Ag-Co_3O_4 as photo-catalyst using 100 and 200 mg·L^(-1) as initial concentration of dye respectively.

Electrochemical Studies of the Recognition Interaction of Rhodamine B with DNA

The recognition interaction of rhodamine B (RB) with DNA was studied in pH 7.5 Britton-Robinson (B-R) buffer solution by electrochemical techniques. An irreversible oxidation peak at glassy carbon electrode was obtained at +0.92V (vs. SCE). After the addition of DNA into the RB solution, the peak current of RB decreased apparently without the shift of peak potential. The electrochemical parameters such as the charge transfer coefficient a and the electrode reaction standard rate constant ks of RB in the absence and presence of DNA were determined, which did not change, indicating that a non-electroactive complex was formed, so the concentration of RB in the solution decreased and the peak current decreased correspondingly.

Energy Transfer and Electron Transfer in Composite System of Carbon Quantum Dots/Rhodamine B Molecules

In this work, we investigated the energy transfer (EnT) and electron transfer (ET) processes as well as their relationship in the carbon quantum dots/rhodamine B (CQDs/RhB) including o-CQDs/Rh B and m-CQDs/RhB systems by using photoluminescence spectroscopy in combination with steady-state and transient absorption spectroscopy. We found that the ET process is negligible in the o-CQDs/RhB system with an EnT efficiency as high as 73.2%,while it becomes pronounced in the m-CQDs/RhB system whose EnT efficiency is lower than 33.5%. Such an interplay of En T and ET processes revealed in the prototypical composite system consisting of carbon quantum dots and dye molecules would provide helpful insights for applications of relevance to exciton quenching.

Photocatalytic degradation kinetics in Rhodamine B dye degradation with poriferous TiO_2 photocatalyst

A type of poriferous TiO2 material was prepared using cetyl trimethyl ammonium bromide as a template agent and butyl tetra titanate as a precursor. Through studying the photocatalytic kinetic activity of Rhodamine B photocatalytic degradation reaction with a UV-1601PC ultraviolet-visible spectrophotometer, the photocatalytic degradation process of Rhodamine B was found to not correspond to the first-order kinetic process completely. According to the reaction phenomenon, the photocatalytic degradation process of Rhodamine B with poriferous TiO2 involved two irreversible reactions. The kinetic model was tested using experimental data.

The stimulated Raman scattering competition between solute and solvent in Rhodamine B solution

The competition between the stimulated resonance Raman scattering （SRRS） of Rhodamine B （RhB） and the stimulated Raman scattering （SRS） of ethanol （C2H50H） is observed at the RhB in C2H5OH solution. For different concentrations of the solution, the peak wavelengths of the SRRS, the amplified spontaneous emission （ASE）, the fluorescence and the absorption of RhB are different. The SRRS of RhB and the SRS of C2H50H are simultaneously generated when the concentration of the solution is 10-5 mol/L and the energy of the excitation laser is 20.4 mJ. Otherwise, only either the SRRS of RhB or the SRS of C2H5OH is generated. The SRRS can be amplified by the ASE gain when the SRRS is near the peak of the ASE, and the peak wavelength of the SRRS coincides with the wavelength of the maximal intensity ASE.

Experimental study on the degradation of Rhodamine B by hydrodynamic cavitation technique

Hydrodynamic cavitation is a new technique in wastewater treatment processes. The degradation of Rbodamine B was studied on a 220 liters hydrodynamic cavitation setup using multiple hole orifice plates in this paper. The experimental results showed that Rhodamine B was really decomposed by hydrodynamic cavitation. Some factors influencing degradation effect i.e. geometric parameters and operation conditions also were discussed. It was concluded there was the optimal ratio of total area of holes to crosssectional area of the pipe and the rate constant increased with a reduction in the value of the modified cavitional number.

Monolithic Mesh-Type Fe-Pd/γ-Al₂O₃/Al Bifunctional Catalysts for Electro-Fenton Degradation of Rhodamine B

A novel Fe-Pd bifunctional catalyst supported on mesh-type γ-Al2O3/Al was prepared and applied in the degradation of Rhodamine B (RhB). The monolithic mesh-type Fe-Pd/γ-Al2O3/Al bifunctional catalyst could be separated from the solution directly and could synthesize H2O2 in situ. The characterization results showed that Fe could improve the dispersion of Pd0, and the electronic interactions between Pd and Fe could increase the Pd0 contents on the catalyst, which increased the productivity of H2O2. Furthermore, DFT calculations proved that the addition of Fe could inhibit the dissociation of O2 and promote the nondissociative hydrogenation of O2 on the surface of Fe-Pd/γ-Al2O3/Al, which resulted in the increasement of H2O2 selectivity. Finally, the in-situ synthesized H2O2 by Pd was furtherly decomposed in situ by Fe to generateOH radicals to degrade organic pollutants. Therefore, Fe-Pd/ γ-Al2O3/Al catalysts exhibited excellent catalytic activity in the in-situ synthesis of H2O2 and the degradation of RhB due to the synergistic effects between Pd and Fe on the catalyst. It provided a new idea for the design of bifunctional electro-Fenton catalysts. Ten cycles of experiments showed that the catalytic activity of Fe-Pd/γ-Al2O3/Al catalyst could be maintained for a long time.