Oxidative Degradation Of Rhodamine Research Articles

Oxidative degradation of Rhodamine B solution with nZVI persulfate activation

In this study, the researchers evaluated the use of nano-zero-valent iron (nZVI) activated persulfate (PS) for the degradation of Rhodamine B (RhB). The effects of various operating parameters such as initial pH, and dosages of PS, nZVI and citric acid (CA) on the removal rate of RhB were investigated. The results demonstrated that at a PS dosage of 5 mmol·L<sup>-1</sup>, nZVI dosage of 0.3 g·L<sup>-1</sup>, 0.1 mmol·L<sup>-1</sup> CA, and pH of 5, the degradation rate of RhB was 94.970%. The degradation and kinetic analysis of RhB using micron-scale zero-valent iron (mZVI) and nZVI revealed that nZVI exhibited higher activity with PS due to its smaller particle size. The activation of PS by nZVI is higher compared to mZVI, and the ineffective consumption is half that of the mZVI/PS system, the TOC removal rate increased by 18.65%. Kinetic analysis indicated that under the mentioned reaction conditions, the degradation process followed a pseudo-second-order reaction model, with the highest apparent reaction rate constant (kobs). The researchers also identified active radical species in the nZVI/PS system. Additionally, Gas Chromatography-Mass Spectrometry (GC-MS) analysis was used to detect reaction intermediates and propose a possible degradation pathway for RhB.

Effect of the presence of various natural organic matters on anodic oxidation of electrified carbon nanotube membrane.

The widespread adoption of electrified carbon nanotube membranes (ECM) requires to better understand process effectiveness according to limiting phenomena of natural organic matters (NOMs). In this study, the influences of various NOM fractions were investigated on the oxidative degradation of Rhodamine B (RhB) in ECM. The results showed the decolorizing efficiencies of RhB in the presence of humic acid (HA) were still above 96%, while bovine serum albumin (BSA) reduced firstly and then increased the decolorizing efficiencies of RhB. The decolorizing efficiencies of RhB with alginate (AA) were over 98% at the first 15 min but decreased gradually to 76% after 150 min. These different performances of HA, BSA and AA were mainly due to their influences on the electrochemical reactivity characterization of ECM. ECM with the BSA depositing layer showed the highest exchange current density (j0), while the AA depositing layer restrained electron-transfer activity of ECM. Cyclic voltammetry (CV) experiments showed that the partial electrooxidation of BSA would occur in ECM with its degradation product observed in the effluent. The variation of electrochemical reactivity characterization of ECM resulted into its electri-oxidation and electri-adsorption rates to be the largest with BSA, followed by AA and HA.

Mechanism and kinetic model of the oxidative degradation of Rhodamine B dye in aqueous solution by ultrasound-assisted Fenton's process

Mechanism and kinetic model of the oxidative degradation of Rhodamine B dye in aqueous solution by ultrasound-assisted Fenton's process

Solar driven photocatalytic degradation potential of novel graphitic carbon nitride based nano zero-valent iron doped bismuth ferrite ternary composite

The synthetic industry has destroyed the life span of human beings due to environmental pollution. The discharged organic pollutants can be degraded by many physicochemical techniques, among them the heterogeneous photocatalysis is distinctive. Nano zero-valent iron (NZVI) doped bismuth ferrite (BiFeO 3 ) nanoparticles were composited with g-C 3 N 4 to fabricate ternary NZVI@BiFeO 3 /g-C 3 N 4 semiconductor photocatalyst. The facile fabrication was achieved through the hydrothermal approach. The characterization techniques such as X-ray diffraction, Fourier transform infrared and Scanning electron microscopy equipped with energy dispersive X-ray was used. The analysis confirmed the successful fabrication of the photocatalysts. The energy bandgaps of the prepared photocatalysts were measured by the Tauc plot method using a UV–visible spectrophotometer. The energy bandgap values suggest that the insertion of g-C 3 N 4 improves the optical response of catalysts under visible light. The NZVI@BiFeO 3 /g-C 3 N 4 was employed against Rhodamine B dye for photocatalytic oxidative degradation under sunlight radiations. The influencing parameters like pH, NZVI@BiFeO 3 /g-C 3 N 4 concentration, oxidant dose, reaction time were optimized to obtain the best-suited conditions. Under optimized conditions (i.e. pH = 9, NZVI@BiFeO 3 /g-C 3 N 4 = 10 mg/100 mL, oxidant = 18 mM, Time = 120 min) the g-C 3 N 4 based composite photocatalyst showed ~97% oxidative degradation of Rhodamine B. Response surface methodology was used as a statistical tool to check the combinational effect of influencing parameters. • Hydrothermally synthesized composite (NZVI@BFO/g-C 3 N 4 ) was used for RhB degradation. • The ternary composite showed improved photocatalysis under sunlight. • Effective photocatalysis by NZVI@BFO/g-C 3 N 4 was due to the engineered heterostructure. • ~97% degradation of RhB was achieved within 120 min at room temperature.

Redox cycling of copper mediated by hydrazine: efficient catalyst systems for oxidative degradation of rhodamine B

Catalytic processes based on Fenton-like reactions on the degradation of organic pollutants have been improved by accelerating the redox cycling of metal ions. This work presents, at first, the results obtained for the heterogeneous degradation of rhodamine B (RhB) by copper ferrite (CuFe2O4) in presence of hydrogen peroxide (H2O2) and hydrazine (N2H4) as redox cycle accelerator. Atomic absorption spectroscopy showed small amounts of Cu2+ are leached from ferrite highlighting the influence of the homogeneous catalysis in the whole process. The data obtained for the homogeneous process using Cu2+ in solution containing both N2H4 and H2O2 indicated such system is highly efficient mineralizing 73% of RhB within only 10 min of reaction and having H2O and CO2 as major products. Using tert-butyl alcohol as radical scavenger, it was confirmed hydroxyl radical (HO•) is the active oxidant species regarding the RhB degradation. The homogeneous catalyst was applied to a real sample of textile effluent spiked with RhB and showed reasonable efficiency, although lower than that obtained for the standard solutions of RhB. This result was assigned to the interference of salts in the medium that react with HO• thus acting as radical scavenger.

Optimal H2O2 concentration in advanced oxidation over titanium dioxide photocatalyst

The oxidative degradation of Rhodamine B dye under ultraviolet irradiation was studied. The degradation rate was measured with using of smartphone camera. Photocatalytic degradation of the Rhodamine B dye over the P25-TiO2 catalyst has been found to accelerate substantially in the presence of hydrogen peroxide. The relationship between the photocatalytic degradation rate and H2O2 concentration has been studied. The optimal concentration of H2O2 has been found to in the range of 10-25 mM. The proposed mixture of P25 photocatalyst and H2O2 oxidizer can be used to remove organic pollutions from industrial waste water.

Mechanism and Kinetic Model of the Oxidative Degradation of Rhodamine B Dye in Aqueous Solution by Ultrasound-assisted Fenton’s Process

Mechanism and Kinetic Model of the Oxidative Degradation of Rhodamine B Dye in Aqueous Solution by Ultrasound-assisted Fenton’s Process

Copper- and Nitrogen-Codoped Graphene with Versatile Catalytic Performances for Fenton-Like Reactions and Oxygen Reduction Reaction

Copper- and nitrogen-codoped reduced graphene oxide material (Cu/N-rGO) was prepared with a hydrothermal method. Its versatile catalytic performances were demonstrated toward the oxidative degradation of rhodamine B (RhB) and oxygen reduction reaction (ORR). The Cu and N codoping of graphene enhanced not only its activation ability toward H2O2, but also its electrocatalytic ability for ORR. It was observed that the use of 3%Cu/N-rGO together with 40 mmol·L−1 H2O2 and 4 mmol·L−1 Na2CO3 could remove more than 94% of the added RhB (30 mg·L−1) in 20 min through a catalytic Fenton-like degradation. Quenching experiments and electron paramagnetic resonance (EPR) measurements indicated that the main reactive species generated in the catalytic oxidation process were surface-bound •OH. The modified graphene also showed good electrocatalytic activity for ORR reaction in alkaline media through a four-electron mechanism. On the electrode of Cu/N-rGO, the ORR reaction exhibited an onset potential of −0.1 V and a half-wave potential of −0.248 V, which were correspondingly close to those on a Pt/C electrode. In comparison with a Pt/C electrode, the 3%Cu/N-rGO electrode showed much greater tolerance to methanol. Such outstanding catalytic properties are attributed to the abundant active sites and the synergism between Cu and N in Cu/N-rGO.

EFFECT OF MELAMINE ACIDIC TREATMENT ON g-C3N4 PHYSICOCHEMICAL PROPERTIES AND CATALYTIC ACTIVITY

Heterogeneous photocatalysts are widely used for wastewater and natural water treatment from organic pollutants. In this paper, g-C3N4-based photocatalysts were synthesized by thermal condensation of melamine. The effect of melamine pretreatment with acetic acid on the physicochemical properties of g-C3N4 was studied using differential thermogravimetric analysis (DTA-TG), X-ray diffraction (XRD), FT-IR spectroscopy, scanning electron microscopy (SEM), and low-temperature nitrogen adsorption-desorption. The catalytic activity of synthesized photocatalysts was evaluated during the oxidative degradation of Rhodamine B in an aqueous solution under “soft” (type A) and “hard” (type B) UV irradiation.

Oxidative degradation of Rhodamine B by Ag@CuO nanocomposite activated persulfate

In this study, the Ag@CuO nanocomposite was prepared by a simple chemical reaction, and successfully used as a persulfate activator in the oxidative degradation of Rhodamine B (RHB). The micromorphology, crystal structure, elemental composition and content, and chemical state of Ag@CuO nanocomposite were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray energy spectrum analysis (EDS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), and X-ray photoelectron spectroscopy (XPS), respectively. The activator possesses a minor particle agglomeration. The degradation efficiency and degradation kinetics of RHB were investigated by different catalysts activated persulfate and at different temperatures. The results revealed that the Ag@CuO nanocomposite has better catalytic activity for the activation of persulfate potassium to degrade RHB than the contrastive activators. The oxidative degradation of RHB is a pseudo-first order reaction, and the higher temperature is benefit for the RHB degradation. The Ag@CuO nanocomposite presented a long-term stability through the cycle experiment in the degradation of RHB.

Degradation of rhodamine B with manganese dioxide nanorods.

This is an investigation on oxidative degradation of rhodamine B (RhB) by manganese dioxide (MnO2) nanorods synthesized by redox co-precipitation method. Field emission scanning electron microscopy of MnO2 nanorods at an electron voltage of 10 kV revealed a rod-like morphology for the synthesized nanoparticles. Fourier transform infrared spectra exhibited characteristic peaks of MnO2. Surface area of MnO2 nanorods was 277 m2/g. Effect of various parameters like initial concentration and pH of RhB solution, time of contact between MnO2 nanorods and RhB, dosage of MnO2, and stirring speed on decolouration of RhB was evaluated in batch experiments. Rapid decolouration in the initial period of the reaction was observed due to the adsorption of RhB molecules onto the surface of MnO2 nanorods followed by oxidative degradation. Percentage decolouration decreased with increase in initial concentration and increased with increase in dosage, speed of stirring the mixture and with increase in pH up to pH 7. Near complete decolouration was achieved at a dose of 0.5 g/L of MnO2 nanorods from 20 mg/L RhB solution within 3 min. Observations fitted best to the pseudo second order kinetic model. This study could pave the way for development of cost-effective, nontoxic nanostructures for treatment of wastewaters containing RhB.

Photocatalytic Activity and Fluorescence of Gold/Zinc Oxide Nanoparticles Formed by Dithiol Linking.

Monolayer-protected gold nanoparticles (AuNPs) with average diameters of 2-4 nm have been covalently attached to zinc oxide nanorods using dithiol ligands. Electron microscopy and Raman spectroscopy show that ozone treatment or annealing at 300 or 450 °C increases the average diameter of the AuNPs to 6, 8, and 14 (±1) nm, respectively, and decomposes the organic layers to various degrees. These treatments locate the AuNPs closer to the nanorods. Heating and subsequent ozone exposure changes the color of the as-prepared nanocomposite powder from blue to purple due to oxidation of the outer layer of the AuNPs, and heating to 300 °C changes it to pink due to oxygen desorption. ZnO nanorods have a bimodal photoluminescence spectrum that consists of an ultraviolet excitonic peak and a visible, surface defect-related peak. Ozone treatment and annealing of the nanocomposite decreases the intensities of both peaks due to quenching by the AuNPs, but the visible peak is affected less. The photocatalytic efficiency of the nanocomposites toward oxidative degradation of rhodamine B has been measured and follows the order 300 °C > 450 °C > ozone treated ≈ as-prepared ≈ bare ZnO. The greater efficiency of the annealed samples likely arises from decreased electron-hole pair recombination rates.

Oxidative degradation of Rhodamine B in aqueous solution using Fe/PANI nanoparticles in the presence of AQS serving as an electron shuttle

In this study, core-shell Fe0@polyaniline (PANI) nanoparticles were synthesized to remove Rhodamine B (RhB) in aqueous solution. The Fe0/PANI composites were characterized by X-ray diffraction, Fourier transform infrared spectra, and transmission electron microscopy. The performances of Fe0/PANI on the activation of molecular oxygen for the removal of RhB were investigated, and the effects of operating parameters, such as Fe0/PANI dosage, RhB initial concentration, and pH value on RhB removal were also discussed. The results indicated that the Fe0@PANI/O2 process exhibited significantly higher reactivity than did the Fe0/O2 process for the degradation of RhB. The oxidative degradation of RhB was further promoted by the presence of anthraquinone-2-sulfonic acid sodium salt working as an electron shuttle. In addition, the reaction mechanism was discussed by measuring the concentrations of Fe(II), and total Fe formed in the system and examining scavenging effect by tert-butyl alcohol and copper chloride. The redox mediating function of PANI was also revealed by the UV–vis spectra. The stability of Fe0@PANI showed that it is a potential nanomaterial for the environmental remediation.

A facile synthesis of CuO nanowires and nanorods, and their catalytic activity in the oxidative degradation of Rhodamine B with hydrogen peroxide

In this study, a new and facile solution-phase route to prepare CuO nanowires and nanorods with the assistance of salicylic acid was reported. Compared with the commercial CuO nanoparticles, both the CuO nanowires and nanorods exhibited significantly improved catalytic activity in the degradation of Rhodamine B with H2O2, which may result from their special one dimensional nanostructures. The apparent activation energy of Rhodamine B oxidation with H2O2 in the presence of the CuO nanowires and nanorods was 30.95kJ·mol−1 and 32.07kJ·mol−1, respectively, which was much lower than that in the absence of catalysts.

Oxidative Degradation of Rhodamine B Catalysed by Copper Oxide Nanoparticles in Aqueous Medium

In the present work , copper oxide nanoparticles are synthesized by wet sol – gel method using sodium hydroxide as the precipitating agent and starch as the capping agent. Size characterization of the nanoparticle was done by TEM, XRD and FT – IR. The as prepared nanoparticles are used as catalyst in the degradation Rhodamine B dye using hydrogen peroxide.The effects of H2O2 dosage, medium pH, solution temperature, and the dye compositions on the degradation kinetics of rhodamine B have been studied. The pH=4 and temperature = 40◦c are the optimized conditions.

Photocatalytic Degradation of Nanometer TiO<sub>2</sub> Sol Composed Fabric to Dye

The TiO2 sol was prepared via sol-gel method. A new reaction system and the relevant technical route were adopted, and TiO2 colloidal sol containing nanoctrystalline anatase was prepared at low temperature, which directly had photocatalytic activity without the typical high-temperature treatment in traditional sol-gel method. The structure and property of Nanometer TiO2 were characterized by Particle Size Distribution, what is more, its effects of ratio of reactants on the catalytic proporty of nanometer TiO2 were analyzed. Nano-TiO2 sol as loaded on the surface of fabric using finishing method，thus nano-TiO2 finished fabrics were obtained and used as photocatalysts for oxidative degradation of Rhodamine B in water. Some factors affecting degradation such as the TiO2 content, dye concentration and reuse of the nano-TiO2 finished fabrics were investigated with respect to the decoloration value. The results showed that increasing molar ratio of water to n-butyl titanate led to a smaller particle size nano-TiO2 sol. Nanometer TiO2 sol composed fabrics have a very good photocatalytic activity on the degradation of dyes, and can be resued for sevral circles. Increasing TiO2 content on the fabric and decreasing the dye concentration led to higher decoloration of the dyes in solution.

Oxidative degradation of dye pollutants over a broad pH range using hydrogen peroxide catalyzed by FePz(dtnCl 2) 4

The oxidative degradation of rhodamine B (RhB) with hydrogen peroxide activated by iron(II) tetra-(5,6-dichloro-1,4-dithiin)-porphyrazine (abbreviated as FePz(dtnCl 2) 4) was studied by means of UV–Vis spectra, GC–MS and TOC analysis, in which the effects of pH, light, concentration of hydrogen peroxide and the degraded products of the RhB were investigated. The results indicate that FePz(dtnCl 2) 4 was found to exhibit high catalytic activity to activate hydrogen peroxide for the oxidative degradation of RhB and good stability over a broad pH range under visible light irradiation ( λ > 420 nm). The conversions of RhB in 80 min were 99%, 85%, 52% and the TOC removals in 240 min were 91%, 64%, 18% when the initial solutions pHs were 2, 7, 11, respectively. HO radicals were testified to generate in the biomimetic catalytic system both at pH 2 and 7 by means of spin-trapping electron spin resonance. However, control experiment with scavenging of HO radicals displayed the quite different results at pH 2 and 7. Based on experiment results together with theoretic deduction, a mechanism for RhB oxidation involving two kinds of reactive oxidizing species was proposed, the homolytic cleavage generating the HO radicals and the heterolytic cleavage generating the Pz +Fe IV O radicals.