Degradation Of Naphthol Blue Black Research Articles

Hydrothermal synthesis of cadmium sulfide decorated reduced graphene oxide photocatalyst for the degradation of photostable naphthol blue black dye

Photocatalysis is being used for the mineralization of recalcitrant organic pollutants in water that cannot be treated with conventional methods. Cadmium sulfide decorated reduced graphene oxide (rGO-CdS) nanocomposite photocatalyst was synthesized by hydrothermal method and evaluated for the removal of a photostable textile azo dye, naphthol blue black (NBB) under ultraviolet light (UV-A, 365 nm). The rGO-CdS combination was opted for due to utilizing the narrow band gap (Eg = ~2.4 eV) of CdS and robust rGO support, capable of attracting organic pollutants to surface, bear, and protect CdS from photocorrosion. The formation of rGO-CdS was proved from the findings of physiochemical characterization UV–visible-, X-ray diffraction photoelectron, Raman, energy dispersive X-ray-spectroscopic, and scanning, transmission electron, and atomic force microscopic studies. The spherical CdS was decorated on the random shaped rGO sheets. Eg of CdS and rGO-CdS were 2.42 and 2.39 eV, respectively. After 2 h of light exposure, 2 g/L of rGO-CdS mineralized 95 % of NBB (2 × 10−4 mol/L). After 5 cycles, 80 % of photocatalytic efficiency was retained. In gas chromatography-mass spectrometry studies, 8 fragments of NBB were found after 1 h and confirmed that the degradation was mediated by photocatalytic dilapidation. The optimum pH for NBB degradation was 9. The rGO-CdS was found to be a potentially stable and reusable photocatalyst for environmental applications.

Outstanding performance of electro-Fenton/ultra-violet/ultra-sound assisted-persulfate process for the complete degradation of hazardous pollutants in contaminated water

This work focuses on the degradation of the hazardous azo dye Naphthol Blue Black (NBB) utilizing an innovative approach combining electro-Fenton (EF), ultra-violet (UV), and ultra-sound (US) processes while varying the operating parameters (concentration of iron and dye, pH, current intensity). Under the optimum experimental conditions, an excellent degradation efficiency of the NBB dye is achieved after 60 min, i.e., 98%, 95%, and 65% for EF, UV, and US processes, respectively. The addition of persulfate significantly improves the efficiency and accelerates the kinetics of the NBB degradation. Combining all processes assisted with persulfate achieved 99% NBB degradation within a very short contact time of 2 min and 98% reduction in COD after 55 min. The as-obtained outstanding performance associated with the synergistic effects of EF/US/UV alongside the addition of persulfate can be adopted to degrade other hazardous substances.

Galvano-Fenton Engineering Solution with Spontaneous Catalyst's Generation from Waste: Experimental Efficiency, Parametric Analysis and Modeling Interpretation Applied to a Clean Technology for Dyes Degradation in Water.

In this paper, the degradation of the diazo dye naphthol blue black (NBB) using the Galvano-Fenton process is studied experimentally and numerically. The simulations are carried out based on the anodic, cathodic, and 34 elementary reactions evolving in the electrolyte, in addition to the oxidative attack of NBB by at a constant rate of during the initiation stage of the chain reactions. The selection of the operating conditions including the pH of the electrolyte, the stirring speed, and the electrodes disposition is performed by assessing the kinetics of NBB degradation; these parameters are set to 3, 350 rpm and a parallel disposition with a 3 cm inter-electrode distance, respectively. The kinetics of in the electrolyte were monitored using the principles of Fricke dosimetry and simulated numerically. The model showed more than a 96% correlation with the experimental results in both the blank test and the presence of the dye. The effects of and concentrations on the degradation of the dye were examined jointly with the evolution of the simulated , , and concentrations in the electrolyte. The model demonstrated a good correlation with the experimental results in terms of the initial degradation rates, with correlation coefficients exceeding 98%.

Immobilization of copper oxide nanoparticles onto chitosan biopolymer: Application to the oxidative degradation of Naphthol blue black

In this study, copper oxide nanoparticles, prepared using pistacia vera hull extract, were immobilized onto chitosan. FT-IR spectrum of copper oxide-chitosan exhibited chemical shifting of the main peaks of the biopolymer indicating that hydroxyl and amino groups were reacted with copper oxide nanoparticles. SEM features showed spherical surface and physical stability of the composite. The shifting of the burning temperature in DTA from 278.5 °C to 212.6 °C in the composite proved the interaction between chitosan and copper oxide nanoparticles. The composite was applied for the oxidative degradation of naphthol blue black in the presence of H2O2. The change of copper oxide nanoparticles loading, time, dye concentration, temperature, and oxidant dose were studied. The degradation yield reached 86 % (C0 = 30 mg/L, T=20 °C, H2O2 = 8 mL/L). The activation energy (Ea), entropy (ΔS*) and enthalpy (ΔH*) were equal to 45.558 KJ. mol−1, −116.203 J mol−1 K−1 and 42.986 kJ mol−1, respectively.

Electrochemical oxidation of Naphthol Blue Black with different supporting electrolytes using a BDD /carbon felt cell

The electrochemical oxidation of Naphthol Blue Black (NBB) solution by means of anodic oxidation with electro-generated H2O2 (AO-H2O2) and Electro-Fenton (EF) was studied, using boron doped diamond (BDD)/ carbon felt (CF) cell. The experiments were carried out in NaCl and Na2SO4 as supporting electrolytes with initial concentration of 0.1 mM of NBB. The studied parameters were pH, applied current, concentration of Fenton catalyst, concentration of supporting electrolytes, and Cl-/SO42- mixture. The degradation of NBB was almost total when NaCl was used compared to Na2SO4, thanks to the electro-generated active chlorine (HClO/ClO-). The higher degradation is found with EF compared to AO-H2O2 process, the kinetic of degradation of NBB always follows a pseudo first-order reaction. The optimum conditions for the mineralization of NBB (i.e., 0.1 mM NBB, 50 mM Na2SO4 at pH 3.0, 0.1 mM Fe2+, and a current of 300 mA) were determined. These conditions yielded a total color removal in less than 10 min and 98% of total organic carbon (TOC) removal at 120 min electrolysis time. The biochemical oxygen demand/ Chemical oxygen demand (BOD/COD) ratio was decreased from 0.5 to 0.3, during the same timescales. Whereas, the mineralization current efficiency (MCE%) dropped from 21.5% to 0.05% in the electrolysis time range from 15-120 min suggesting the concomitant parasitic reactions. The evolution of nitrite NO2-, nitrate NO3-, ammonium NH4+, and sulfate SO42- concentrations were also followed as the end-products during the electrolysis.

Competition in sonochemical degradation of Naphthol Blue Black: Presence of an organic (nonylphenol) and a mineral (bicarbonate ions) matrix

This study is dedicated to high frequency (278 kHz) sonolytic degradation of organic micropollutants in a complex aqueous medium. A model matrix composed of Naphthol Blue Black (an azoic dye, NBB), of Nonylphenol (an endocrine disrupting compound, NP) and of bicarbonate ions was investigated in order to evaluate the influence of NP and/or bicarbonate ions on the kinetics of NBB sonolysis.It was found that the NBB has no significant effect on the NP sonodegradation kinetics whereas the NP considerably decreases the NBB degradation rate. Furthermore it was highlighted the presence of bicarbonate ions is a way to reach a more efficient NBB degradation rate at low micropollutant concentrations, even in the presence of NP. These preferential sonodegradation rates were explained by the zone where the sonoreaction takes place, which was correlated to the physico-chemical properties of the studied molecules.It was also proved the kinetic model of sonolytic degradation of NBB is modified by the presence of bicarbonate ions; the most suitable model in this case is the Serpone's model which assumes the degradation of the compound in the gas/liquid interface and in the solution.

Highly active P25@Pd/C nanocomposite for the degradation of Naphthol Blue Black with visible light

TiO2-P25 supported Pd/C (P25@Pd/C) composite was prepared by the solid state dispersion method. The prepared composite was characterized by XRD, Raman, PL, SEM and DRS measurements. The photocatalytic activity of the composite was tested towards Naphthol Blue Black (NBB) azo dye degradation under visible light. The photocatalytic activity of P25 was highly influenced by Pd/C. Almost complete degradation was achieved with P25@Pd/C in 120 min, and found to be more efficient when compared with pristine Degussa-P25. The composite was reused in four cycles without loss of activity. A mechanism was proposed for NBB degradation by P25@Pd/C composite under visible light.

Solar and visible active amino porphyrin/SiO2[sbnd]ZnO for the degradation of naphthol blue black

Although SiO2 falls in the category of insulator, we used 70% SiO2 and 30% of ZnO mixture for photocatalytic application. SiO2ZnO was prepared by a simple solid dispersion method, before making a mixture of oxides; SiO2 and ZnO were prepared by a sol-gel and physical grinding methods, respectively. The prepared SiO2ZnO was chemically modified with 5,10,15,20-meso-tetra-(para-amino)-phenyl-porphyrin (TPAPP) and used for the degradation of an azo dye naphthol blue black (NBB) under direct sunlight as well as visible light. Before making a TPAPP/SiO2ZnO composite, the surface modification of SiO2ZnO was carried out with glycidoxypropyltrimethoxy silane (GPTMS) which acts as a coupling agent. The TPAPP modified SiO2ZnO was characterized by FT-IR, XRD, SEM, FE-SEM with elemental mapping, EDS and DRS measurements. A mechanism was proposed for NBB degradation by TPAPP/SiO2ZnO under sun light. The catalyst was found to be reusable.

Persulfate-enhanced sonochemical degradation of naphthol blue black in water: Evidence of sulfate radical formation

This work explores the effect of persulfate (PS) on the sonochemical degradation of organic pollutants taking naphthol blue black (NBB), an anionic diazo dye, as a substrate model. The sonolytic experiments were conducted in the absence and presence of PS under various experimental conditions including acoustic power (10−80W), frequency (20 and 585kHz) and saturating gas (argon, air and nitrogen). Experimental results showed that PS decomposition into sulfate radical (SO4−) takes place by sonolysis and increasing PS concentration up to 1g/L would result in an increase in the NBB degradation rate. It was found that the PS-enhanced effect was strongly operating parameters dependent. The positive effect of PS decreased with increasing power and the best enhancing effect was obtained for the lowest acoustic power. Correspondingly, the PS-enhanced effect was more remarkable at low frequency (20kHz) than that observed at high frequency ultrasound (585kHz). Nitrogen saturating gas gave the best enhanced effect of PS than argon and air atmospheres. Theoretical (computer simulation of bubble collapse) and experimental measurements of the yields of free radical generation under the different experimental conditions have been made for interpreting the obtained effects of PS on the sonochemical degradation of the dye pollutant. The experimental findings were attributed to the fact that radical-radical recombination reactions occur at faster rate than the radical-organic reaction when the concentration of free radicals is too high (at higher sonochemical conditions).

Sonolytic degradation of naphthol blue black at 1700 kHz: Effects of salts, complex matrices and persulfate

In the present work, the effect of salts (NaCl and Na2SO4), complex matrices (natural water and seawater) and persulfate ions on the sonochemical degradation of an acidic diazo dye, naphthol blue black (NBB), in water at 1700kHz was clarified. Additionally, the influence of initial dye concentration and liquid temperature on the extent of NBB sonolytic removal was investigated. It was found that the NBB degradation rate increased with increasing the initial substrate concentration in the range 3–15mgL−1. Significant enhancements in the NBB degradation rates were observed at high liquid temperatures: 96.5% of NBB was removed at 65°C after 45min of sonication while only 51% was reached at 25°C. The presence of salts (NaCl or Na2SO4) has a beneficial effect on NBB degradation. The degradation rate of NBB in the presence of 0.5 and 1M NaCl was 3–6 times higher than that obtained without salt. Interestingly, faster degradation rates of NBB were observed in complex matrices. The complete destruction of NBB required 40min in seawater and 60min in natural water instead of 210min in distilled water. The addition of persulfate (PS) ions improved substantially the sonochemical degradation of NBB through the ultrasonic (US) generation of sulfate radical (SO4–), which is more efficient toward the degradation of NBB. The system US/PS resulted in 100% NBB removal within only 60min of ultrasonic treatment.

Sonochemical degradation of naphthol blue black in water: Effect of operating parameters

In this work, the sonochemical degradation of naphthol blue black (NBB), an acidic diazo dye, in water was investigated. The effects of several operating parameters such as initial NBB concentration, acoustic intensity, ultrasonic frequency, nature of the dissolved gas and solution pH on the degradation of the dye were carried out. The obtained results showed that ultrasound completely destroyed NBB (5mgL−1) after 45min of sonication and most of the chemical oxygen demand was eliminated after 90min of treatment. It was found that the initial rate of sonolytic degradation increased with increasing the initial NBB concentration. The fitting of the experimental data by a heterogeneous Langmuir-kinetics model showed that NBB degraded mainly at the interfacial region of the bubble by hydroxyl radical (OH) attack. The degradation rate of the dye increased substantially with increasing acoustic intensity in the range of 0.44–3.58Wcm−2 and decreased with increasing frequency in the range of 585–1140kHz. The rate of NBB degradation decreased in the order of Ar>air>N2. The significant degradation was achieved in acidic conditions (pH 2) where the initial degradation rate was 1.37 and 1.66 higher than those observed at pH 6 and pH 10, respectively.

Comprehensive experimental and numerical investigations of the effect of frequency and acoustic intensity on the sonolytic degradation of naphthol blue black in water

In the present work, comprehensive experimental and numerical investigations of the effects of frequency and acoustic intensity on the sonochemical degradation of naphthol blue black (NBB) in water have been carried out. The experiments have been examined at three frequencies (585, 860 and 1140kHz) and over a wide range of acoustic intensities. The observed experimental results have been discussed using a more realistic approach that combines the single bubble sonochemistry and the number of active bubbles. The single bubble yield has been predicted using a model that combines the bubble dynamics with chemical kinetics consisting of series of chemical reactions (73 reversible reactions) occurring inside an air bubble during the strong collapse. The experimental results showed that the sonochemical degradation rate of NBB increased substantially with increasing acoustic intensity and decreased with increasing ultrasound frequency. The numerical simulations revealed that NBB degraded mainly through the reaction with hydroxyl radical (OH), which is the dominant oxidant detected in the bubble during collapse. The production rate of OH radical inside a single bubble followed the same trend as that of NBB degradation rate. It increased with increasing acoustic intensity and decreased with increasing frequency. The enhancing effect of acoustic intensity toward the degradation of NBB was attributed to the rise of both the individual chemical bubble yield and the number of active bubbles with increasing acoustic intensity. The reducing effect of frequency was attributed to the sharp decrease in the chemical bubble yield with increasing frequency, which would not compensated by the rise of the number of active bubbles with the increase in ultrasound frequency.

Glycine-assisted synthesis of mesoporous TiO2 nanostructures with improved photocatalytic activity

Glycine modified TiO2 nanostructures (G-TiO2) were synthesized by a simple glycine-assisted hydrothermal post-treatment of titanate nanotubes. The as-prepared products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and N2 adsorption–desorption measurement. The results showed that G-TiO2 nanostructures were anatase crystalline phase and were composed of lots of nanorods and nanoparticles with small diameters. Nitrogen sorption analysis revealed that the obtained G-TiO2 nanostructures exhibited a big pore size. Moreover, the products expressed high photocatalytic performance for degradation of Naphthol Blue Black.

Synthesis and azo dye photodegradation activity of ZrS2–ZnO nano-composites

ZrS2–loaded ZnO (ZrS2–ZnO) nano-composites were synthesized by the precipitate-thermal decomposition method. The coexistence of ZrS2 increased the absorbance of ZnO in UV region. X-ray photoelectron spectroscopic analysis revealed Zr in the form of Zr4+. The prepared catalysts were used for degradation of an industrial pollutant azo dye, naphthol blue black (NBB), under UV light. It was found that the uptake of 11.4wt% ZrS2 on ZnO was very efficient for NBB removal and its photocatalytic activity was more efficient than ZnO, ZrS2 and TiO2 catalysts. The optimum pH for efficient degradation of NBB was 6.5. Based on the energy levels of ZrS2 and ZnO, a mechanism was proposed for the higher efficiency of ZrS2–ZnO under UV light. This catalyst was reusable.

Solar photocatalytic degradation of Naphthol Blue Black

The solar photocatalytic activity of AgBr–ZnO was investigated for the degradation of Naphthol Blue Black (NBB) in aqueous solution. Removal of azo dyes from wastewater is a challenging process, since these dyes are nonbiodegradable. Presence of a visible light absorbing component, AgBr, makes this catalyst solar active. AgBr–ZnO is found to be more efficient than commercial ZnO and prepared ZnO for solar degradation of NBB azo dye. The effects of operational parameters, such as the amount of photocatalyst, dye concentration, and initial pH on photo mineralization have been analyzed. The optimum pH and catalyst amount for the efficient removal of dye are found to be 11 and 3 g L−1, respectively. Increase of initial dye concentration decreased the degradation rate. The mineralization of NBB has also been confirmed by chemical oxygen demand measurements. The higher photocatalytic activity of AgBr–ZnO towards NBB degradation in solar light is explained by a mechanism involving band energy levels of AgBr and ZnO. The catalyst was found to be reusable.

Highly active WO3–Ag–ZnO photocatalyst driven by day light illumination

The WO3 loaded Ag–ZnO (WO3–Ag–ZnO) was successfully synthesized by precipitation–decomposition method. The catalyst was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) images, energy dispersive spectrum (EDS), transmission electron microscope (TEM), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), cyclic voltammetry (CV) and BET surface area measurements. The photocatalytic activity of WO3–Ag–ZnO was investigated for the degradation of Naphthol Blue Black (NBB) in aqueous solution using solar light. WO3–Ag–ZnO is found to be more efficient than Ag–ZnO, WO3–ZnO, Ag–WO3, WO3, commercial ZnO, bare ZnO, TiO2–P25 and TiO2 (Merck) at pH 9 for the mineralization of NBB dye. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization of NBB dye have been analyzed. The mineralization of NBB has been confirmed by Chemical Oxygen Demand (COD) measurements. A degradation mechanism is proposed for the degradation of NBB under solar light. This catalyst is found to be reusable.

Solar-light-assisted photocatalytic degradation of NBB dye on Zr-codoped Ag–ZnO catalyst

Zr-codoped Ag–ZnO (Zr–Ag–ZnO) was successfully synthesized by the precipitation–decomposition method. The catalyst was characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive spectra (EDS), diffuse reflectance spectra, photoluminescence spectra, cyclic voltammetry, and Brunauer–Emmett–Teller (BET) surface area measurements. The photocatalytic activity of Zr–Ag–ZnO was investigated for the degradation of Naphthol Blue Black (NBB) in aqueous solution using solar light. Codoping shifted the absorbance of ZnO to the entire visible region. Zr–Ag–ZnO is found to be more efficient than Ag–ZnO, Zr–ZnO, commercial ZnO, prepared ZnO, TiO2-P25, and TiO2 (Merck) at pH 9 for mineralization of NBB under solar light. The influence of operational parameters such as the amount of photocatalyst, dye concentration, and initial pH on photomineralization of NBB has been analyzed. Mineralization of NBB was confirmed by chemical oxygen demand (COD) measurements. A mechanism is proposed for the degradation of NBB under solar light. The catalyst is found to be reusable.

Solar assisted photocatalytic degradation of Naphthol Blue Black dye using Ce 1− xMn xO 2

The photocatalytic degradation of textile diazo dye Naphthol Blue Black has been investigated using sunlight and Ce 1− x Mn x O 2 ( x = 0, 0.1, 0.2, 0.3 and 1.0) samples. Ce 1− x Mn x O 2 samples were synthesized by co-precipitation method and characterized by XRD, FTIR, thermal techniques and surface areas. Some solid-state studies, such as magnetic susceptibility, electrical resistivity and diffuse reflectance studies were undertaken. The extent of decolourization of the dye was determined by UV–vis spectroscopy. CeO 2 forms solid solution with Mn upto 30 mol% maintaining fluorite structure.

Photoelectrochemical mineralization of textile diazo dye pollutants using nanocrystalline WO 3 electrodes

Photoelectrochemical degradation processes of Naphthol Blue Black (NBB) dye in aqueous solutions were investigated seeking an effective method of degrading textile diazo dyes. Nanocrystalline WO 3 film on a Pt mesh electrode was used as the photoanode for photoelectrochemical degradation of NBB dye. Higher rates of NBB degradation were observed in chloride-containing environments than in sulfate solutions. A strong pH dependence of the NBB dye degradation rate has been found in chloride media. The pH dependence follows the trend of decreasing oxidizing power of electron holes, h VB,s, trapped at the surface of WO 3 particles, with increasing solution pH. In the low pH range (1.0–4.5), photooxidation of the medium favors the formation of Cl and Cl 2 − radicals which are powerful oxidants for the NBB dye. In alkaline solutions, the formation of OH radicals is predominant over Cl and Cl 2 − radicals but the kinetics of NBB degradation is much slower than in acidic media. In sulfate solutions, the rate of NBB photodegradation is slower than in chloride media. Evidently, the lower oxidizing power of the dipersulfate ion S 2O 8 −2 being the oxidant in this environment, is the limiting factor. The intermediates of the NBB dye degradation were detected using HPLC analysis. Possible dye degradation mechanism is proposed.

Photoelectrochemical degradation of naphthol blue black diazo dye on WO 3 film electrode

Photoelectrochemical degradation of a textile diazo dye, naphthol blue black (NBB), has been investigated using different semiconductor electrodes. A higher photoelectrocatalytic activity has been observed for WO 3 film electrodes, prepared by electrodeposition, than for TiO 2 nanoparticulate film electrodes. By annealing of the WO 3 film deposited on a Pt substrate, we were able to increase the photodegradation rate of NBB, owing to the reduced losses due to the electron–hole recombination. This treatment also increased the long-term photostability of the electrode. The effect of the supporting electrolyte was examined using NaCl, NaClO 4, KNO 3, and Na 2SO 4 solutions. The highest NBB degradation rate was found in the acidic Cl − medium. With increasing solution pH, the degradation rate decreased to a lower level indicating a change in the NBB photodecomposition mechanism. The reaction is of the first order with respect to NBB in the concentration range up to ca. 6×10 −5 M NBB. The apparent rate constants for the photoelectrocatalytic degradation of NBB in 0.5 M NaCl+8.8×10 −5 M NBB solution, on a WO 3 film electrode at E=1.08 V versus SCE, are 1.302×10 −4 and 3.41×10 −5 cm −2 s −1, under illumination with ultraviolet and visible light, respectively. It has been found that the mechanism of the sub-band excitation with the dye self-sensitization is a minor degradation path for NBB, while the main path involves the electron–hole generation and heterogeneous oxidation with participation of valence-band electron holes. The latter reactions involve oxidation of solution components with generation of powerful oxidants, such as the OH , Cl 2 −, and Cl radicals, being directly responsible for the fast dye decomposition.