Decolorization Of Methyl Orange Dye Research Articles

Effect of noble bacteria Ochrobactrum intermedium (Alhpa-22) on decolorization of methyl orange dye in a bioreactor

Abstract In this study Ochrobactrum intermedium (Alhpa-22) was isolated from petroleum refinery sludge and characterized by using 16rRNA. In experimentation, for decolrization of methyl orange dye an indigenous noble bacterial ochrobactrum intermedium (Alhpa-22) at 35 °C has been used in a bioreactor. The ochrobactrum bacterial decolorized methyl orange dye having the concentration of 50 mgL−1 by 87 % within 9 days, which is a very encouraging result. decolorization of methyl orange dye by the isolated bacteria was elucidated using a UV–Vis spectrophotometer. The experimental data were fitted first and zero order kinetics models which show degradation of dye follows first order kinetics in presence of Lysinibacillus fusiformis KLm1, bacterial ochrobactrum intermedium (Alhpa-22) and mix consortia of Lysinibacillus fusiformis KLm1 and ochrobactrum intermedium (Alhpa-22). The rate constant were estimated to be 0.017 h−1, 0.020 h−1 and 0.014 h−1 respectively. Due to its higher decolorizing capability these may be used for the bioremediation of methyl orange dye (azo dye).

Photocatalytic decolorization of methyl orange dye using SnO2-TiO2 nanocomposite particles synthesised by Ultrasonic Assisted Co-Precipitation Method

The ultrasonic-aided co-precipitation method was used to create SnO2-TiO2 nanocomposite particles. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and UV-vis spectroscopy were used to characterize the nanocomposite particles. XRD patterns revealed the crystalline structure of particles and the average particle size determined by Debye Scherrer’s equation was found to be 11.355, 4.9577, and 4.333 nm for TiO2 nanoparticles, SnO2 nanoparticles, and SnO2-TiO2 nanocomposites, respectively. The Ti, Sn, and O species were confirmed to exist by energy-dispersive X-ray spectroscopy (EDS). The UV absorption peaks at 288, 305, and 350 nm were attributed to SnO2, TiO2-SnO2, and TiO2 respectively. The photocatalytic aspect was investigated in a model organic contaminant (methyl orange). Data obtained by the above-mentioned characterization methods confirmed the superior photocatalytic activity of SnO2-TiO2 nanostructure than SnO2 or TiO2 alone.

Self-Sustained Three-Dimensional Macroporous TiO2-Graphene Photocatalyst for Sunlight Decolorization of Methyl Orange.

The development of highly efficient sunlight-driven photocatalysts has triggered increased attention due to their merit in effluent treatment through a chemically green approach. To this end, we present herein the synthesis and characterization of the TiO2/3D-GF/Ni hybrid emphasizing the main structural and morphological properties and the photodegradation process of a highly resistant aromatic azo dye, methyl orange, under both UV light and simulated sunlight. Three-dimensional (3D) graphene was grown by the thermal CVD method on the nickel foam and subsequently coated with thin films of anatase employing the sol-gel method. Thereafter, it was gratifyingly demonstrated that the hybrid nanomaterial, TiO2/3D-GF-Ni, was able to bring about more than 90% decolorization of methyl orange dye after 30 min under simulated sunlight irradiance. Moreover, the efficiency of the methyl orange decolorization was 99.5% after three successive cycles. This high-performance photocatalyst which can effectively decolorize methyl orange will most likely make a great contribution to reducing environmental pollution by employing renewable solar energy.

Novel bio-based Pd/chitosan-perlite composite bead as an efficient catalyst for rapid decolorization of azo dye

Perlite that is a volcanic glass was applied along with chitosan to form chitosan-perlite beads through a facile procedure. The as-prepared beads were then cross-linked with glutaraldehyde and utilized as a bio-based supporting material for the immobilization of Pd nanoparticles via wet impregnation method. The resultant catalyst was characterized via XRD, SEM, TEM, ICP, TGA, FTIR and elemental mapping analysis and its performance was then appraised for decolorization of Methyl orange dye in aqueous media at ambient temperature in the presence of sodium borohydride as a reducing agent. The results established that scant amount of the catalyst, 1.5 mg, could promote the reaction in 2 min to decolorize the dye with yield = 100 %. Using the experimental data, activation energy, enthalpy, and entropy of the decolorization reaction were calculated to be 35.98 kJ/mol, 33.44 kJ/mol, −166.22 J/mol.K, respectively. The catalyst was recyclable up to eight runs with insignificant loss of catalytic activity and Pd leaching.

Photodecomposition of Urea in the Presence of Titanium Dioxide

Urea is used as a fertilizer, food supplement, and also as raw ingredient for the production of polymers and pharmaceuticals. If urea is not adequately processed, it can accumulate in the environment and pollute groundwater and surface water. Although urea is biodegradable, it has negative impacts on aquatic creatures in the long run. It courses eutrophication and algal blooms in waters. Therefore, as a feasible solution, the development of efficient photocatalysts for the breakdown of urea is essential. In this study, titanium dioxide (Merck 21 nm anatase) was used as a catalyst by applying a thin layer of TiO2 onto glass sheets (1 cm×1 cm), the active surface. Such coated glass sheets were placed in prepared 400 nm urea solution exposed to UV light for 120 minutes. The concentration of urea was detected 15 minutes time intervals for the kinetic analysis. Urea concentration with the UV exposure time was determined by the spectrophotometric method. This approach determines the amount of water soluble urea in the medium via fast, accurate, and low-cost manner. The urea was determined based on its ability to inhibit the reaction between bromate ion with HCl reaction. The reaction was monitored spectrophotometrically at 505 nm by decolorization of methyl orange dye with bromine and chlorine produced by the reaction products. Results indicate that urea decomposition in UV irradiated solutions were faster than in the dark under the same conditions. Approx. 22 wt.% of urea was degraded within 120 minutes of UV irradiation when compared to 3.9 wt.% decomposition with the dark condition experiment. In addition, titanium dioxide plated glass sheets proved to be stable in repeated urea degradation cycles.
 Keywords: Photocatalysis, Urea degradation, Titanium dioxide

Theoretical and experimental study of the photodegradation of methyl orange in the presence of different morphologies of Au-ZnO using Monte Carlo dynamic simulation.

Herein, a simple approach was formed based on synthesizing different morphologies of ZnO and Au-ZnO as photocatalyst. In this study, ZnO and Au-ZnO were synthesized via a co-precipitation method and fully characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). Three different ratios of Zn2+:OH- (1:2, 1:3, and 1:5) controlled the morphology of samples, which were made into spindle, star, and flower structures, respectively. Then, the photocatalytic activity was studied and compared. Their comparison showed that the flower morphology for ZnO and Au-ZnO was more effective in photocatalytic degradation and decolorization of methyl orange dye. Also, quantum and Monte Carlo (MC) calculations were carried out to investigate the adsorption of methyl orange (MO) molecules on ZnO(111) surface in the presence of Au or without Au in aqueous conditions by Monte Carlo adsorption locator simulations in the Materials Studio 2017 software. Au created a tendency to form a relatively strong interaction of MO with the ZnO(111) surface. The adsorption of MO on Au-ZnO(111) in the presence of Au was more significant than that of MO on ZnO(111), suggesting Au could significantly improve the reactivity of the methyl orange toward the ZnO(111).

Decolorization of methyl orange dye by photo-Fenton process using silica gel/iron oxide catalyst

Decolorization of methyl orange dye by photo-Fenton process using silica gel/iron oxide catalyst

Polyaniline/ZnO composites prepared via a green route for sunlight-driven photocatalytic efficient decolorization of methyl orange dye

Polyaniline/ZnO composites prepared via a green route for sunlight-driven photocatalytic efficient decolorization of methyl orange dye

Degradation mechanism and toxicity reduction of methyl orange dye by a newly isolated bacterium Pseudomonas aeruginosa MZ520730

Methyl orange (MO) dye is recalcitrant in nature, hard to degrade and if released into the soil and aquatic resources could cause serious threats on environment and human health. MO is toxic to plant growth. Bacterial treatment may be a sustainable solution for its degradation and decolourization. In this work, a bacterium (RKS6) was isolated from textile industry wastewater and sludge samples and identified as Pseudomonas aeruginosa based on the 16S rRNA gene sequencing analysis. RKS6 showed more than 99% decolorization of MO dye (100 mg/l) and 96% reduction of total organic carbon (TOC) within 12 h, at 30 °C, pH 7 at static conditions. RKS6 also produced MnP enzyme of molecular weight ∼53 kDa as characterized by the SDS-PAGE analysis. Further, LC-MS analysis showed that MO dye was degraded into 4-[(4-aminophenyl) diazenyl] benzene sulfonate, 4, 2-((dihydroxymethyl) hyrazono-4) 5-benzene sulfonate, 4-(triazan-2-yl) benzene sulfonic, water and carbon dioxide by RKS6. Toxicity assessment showed that the solution treated by the bacterium allowed 90% seed germination indicating that RKS6 was effective in mineralization and detoxification of MO dye and can be effectively used in industrial wastewater treatment.

An efficient decolorization of methyl orange dye by laccase from Marasmiellus palmivorus immobilized on chitosan-coated magnetic particles

The oxidation activity of laccase on a broad range of substrates has attracted great interest in the development of technologies for industrial and environmental applications. In this work, a crude laccase from Marasmiellus palmivorus was immobilized onto chitosan-coated magnetic particles. The support was developed and characterized by X-ray diffraction, vibrating sample magnetometer (VSM), specific surface area, and pore size by BET/BJH method, and Fourier Transform Infrared Spectroscopy (FTIR). Magnetic particles retained approximately 30% of magnetization (19.5 emu/g) after enzyme immobilization. The highest activity of the immobilized crude laccase was 139.84 U.g dry support−1 (48.74% efficiency and 99% yield) when 25 mg protein. g dry support−1 were applied in the support previously activated with 90 mM glutaraldehyde. Enzyme immobilization was fast, reaching maximum recovered activity (36%) after 5 min of contact with the support. The optimum pH of the soluble and immobilized crude laccase was 5.5 and the optimum temperature varied between 40 and 50 °C for the soluble form and between 25 and 35 °C for the immobilized form. Immobilization increased the thermal stability of the enzyme by a factor of 1.33. Decolorization reaction of methyl orange dye using ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) as a mediator allowed 30 cycles of reuse with a percentage of decolorization above 60%.

Enhanced photocatalytic decolorization of methyl orange dye and its mineralization pathway by immobilized TiO2/polyaniline

An immobilized TiO2/polyaniline (TiO2/PANI) bilayer photocatalyst was fabricated to decolorize methyl orange (MO) dye in aqueous solution. The synergistic decolorization of MO occurred via photocatalysis by TiO2 top layer and adsorption by PANI sub-layer. The fabrication of the photocatalyst was pertaining to the loading of TiO2 (0.32–2.24 mg cm−2) and PANI (0.32–1.92 mg cm−2). Increasing the loading would increase the thickness of the layer whereas an increment in the adsorption rate constant would essentially increase the synergistic photocatalytic–adsorption in the decolorization of MO. The TiO2 and PANI layer loading was optimized at 1.27 and 0.63 mg cm−2, respectively. The optimized TiO2/PANI photocatalyst removed MO dye by four and three times more effectively than the TiO2 and PANI single layer, respectively. The aeration, which supplied the dissolved oxygen, was optimized at 40 mL min−1 of flow rate. The photocatalytic degradation mechanism of MO was initiated by the demethylation followed by the aromatic ring opening and ended with a complete oxidation of the aliphatic chain to become CO2 and H2O. The TOC and IC analyses confirmed the mineralization of MO.

Synthesis, characterization and photocatalytic activity evaluation of TiO2 – ZnO nanocomposites: Elucidating effect of varying Ti:Zn molar ratio

The effect of ZnO content in TiO2-ZnO nanocomposites synthesized via sol-gel route was studied by varying the Ti:Zn molar ratios from 1:0.1 (TZ-1:0.1) to 1:1 (TZ-1:1). Phase transformation of anatase TiO2 to rutile and the ultimate formation of mixed oxides at the expense of rutile TiO2 and ZnO (ZnTiO3 and Zn2TiO4) were observed to occur in a Zn concentration dependent manner at a constant calcination temperature of 600 °C for 1 h. These phase transformations were concomitent with alterations in morphology and bandgap. Zn addition into the nanocomposites facilitated visible light activity at all the Ti:Zn molar ratios studied. Superior visible light photocatalytic decolorization of methyl orange dye, was observed in nanocomposites TZ-1:0.3 (Ti:Zn of 1:0.3) and TZ-1:0.4 (Ti:Zn of 1:0.4) that contained a blend of phases, predominated by rutile TiO2 and ZnTiO3 and not by the anatase phase. Analysis of reaction rate by fitting decolorization kinetics into the Langmuir – Hinshelwood model revealed that rate of decolorization under visible irradiation was significantly higher in TZ-1:0.4 (Langmuir-Hinshelwood rate constant, kLH of 6.8 × 10−2 min-1) than in TZ-1:0.3 (kLH of 5.3 × 10−2 min-1). However, the nanocomposite TZ-1:0.3 promoted greater extent of mineralization compared to TZ-1:0.4. Addition of Zn not only helped in tailoring the bandgap of the nanocomposites for facilitating visible light activity, it also affected photocatalytic decolorization and/or mineralization of methyl orange dye under both UV and visible irradiation by controlling the unique blend of phases existing in the nanocomposite.

Photocatalytic enhancement of immobilized TiO2-polyaniline bilayer (TiO2-PBL) system for decolorization of methyl orange dye

Immobilized TiO2-polyaniline (PANI) bilayer (TiO2-PBL) was fabricated on a glass plate for decolorization of methyl orange (MO). The thickness of TiO2-PBL was 25.55 μm with the ratio of 0.62:0.38 for TiO2 to PANI layer. It was observed that the TiO2-PBL system emitted less photoluminescence (PL) intensity than the TiO2 monolayer corresponding to better •OH radicals production with reduced band gap energy. The removal of MO from the solution after 90 min of treatment was 97% by TiO2-PBL and 53% by TiO2 monolayer which indicates the efficacy of the former system due to the synergistic photocatalytic-adsorption processes. The effect of prewashing (photoetching) of TiO2-PBL plate was pronounced as better removal efficiency of MO was observed for ten cycles under UV–vis and visible light irradiations. The results showed that the TiO2-PBL system has visible light active properties, reduces the recombination of photogenerated active species and enhances the photocatalytic oxidation of MO.

Effect of calcination temperature on the microstructure and electronic properties of TiO2–ZnO nanocomposites and implications on photocatalytic activity

TiO2–ZnO nanocomposites with a constant Ti:Zn molar ratio of 1:0.1 were prepared via sol–gel process followed by calcination at 300, 400, 500, 600, and 700 °C. The structural and compositional characterizations of these nanocomposites were performed through XRD, FTIR, SEM, and EDAX. Bandgap was measured using DRS. Photocatalytic performance of the nanocomposites was evaluated by decolorization of methyl orange dye under UV and visible irradiation with and without aeration. The results showed that increase in calcination temperature resulted in nanocomposites with well-defined morphology. Although the particle size increased with increase in calcination temperature, the crystallinity of the particles also increased, resulting in enhanced photocatalytic activity. A temperature-dependent anatase-to-rutile phase transformation was observed in TiO2–ZnO nanocomposite beyond 600 °C. The calcination temperature influenced both dye adsorption on the nanocomposites and also dye decolorization by photocatalysis. Even when present at low molar concentration, ZnO in the nanocomposite caused sufficient decrease in bandgap (2.6 eV) at temperatures as low as 400 °C, such that visible irradiation could cause dye decolorization. However, the best decolorization performance was observed in the presence of the nanocomposite calcined at 600 °C. Aerated systems showed better performance in all cases. Desorption of the dye remaining adsorbed on the nanocomposite at the end of the photocatalytic reaction, confirmed that adsorption accounted for only 6.6 and 3% of dye removal in the nanocomposites calcined at 600 °C with UV and visible irradiation, respectively. However, in other systems, ignoring adsorption may cause significant overestimation in photocatalytic loss of dye from the system.

Synthesis of InSb nanocrystals in an air atmosphere and their photocatalytic activity from near-infrared to ultra-violet

We report a new facile route to prepare indium antimonide (InSb) nanocrystals (NCs) in air and at ambient pressure. Spherical cubic zinc blende InSb NCs with an average size of 5nm were synthesized and spontaneously separated through a rapid microwave-assisted one-pot reaction. The photocatalytic activity of obtained product was investigated by the decolorization of methyl orange dye under near-IR, visible light, and UV irradiation. This novel synthetic pathway may improve existing applications and suggest new opportunities for studying III-V semiconductor nanomaterials.

Photocatalytic Decolorization of methyl orange dye using nano-photocatalysts

Environmental contamination, which is growing around the world, is a serious problem can not to be neglected. Among all contaminations, water pollution is a major problem. Azo dyes are one of the largest groups of pollutants found in the drinking water, coming from, and the food and textile industries. TiO2/Fe3O4 and TiO2/Fe2O3 nanocomposites with various ratios were synthesized by an ultrasonic-assisted deposition-precipitation method and their UV-light decolorization of methyl orange (MO) dye was investigated. The effect of Fe3O4/TiO2 and Fe2O3-TiO2 nanocomposites ratio on the photocatalytic activity and magnetic property of the nanocomposites was studied by comparing their decolorization curves and magnetism in the presence of magnet, respectively. The results revealed that the decolorization efficiency of 1 wt% Fe3O4/TiO2 nanocomposite reached about 40% within 60 min UV irradiation at room temperature. However, this sample showed the least magnetism. Also, the ability of synthesized nanocomposites in holding the adsorbed methyl orange dye on their surface and the effect of pH were investigated.

Copper modified exchanger for the photodegradation of methyl orange dye

AbstractA Cu modified hybrid exchanger was synthesized by loading Cu(II) onto the sulfonic acid sites of the C-145 cation exchanger by passing CuSO4 solution followed by treatment with sodium hydroxide to deposit the copper hydroxide particles. Each hybrid sorbent particle is essentially a spherical macroporous cation exchanger bead within which agglomerates of nanoscale hydrated Cu oxide particles have been uniformly and irreversibly dispersed using a simple chemical–thermal treatment. The obtained material was characterized using X-ray diffraction, energy-dispersive X-ray spectroscopy and scanning electron microscope. The obtained materials were applied for the photo-decolorization of methyl orange as a member of the azo dye family, in an aqueous medium using UV irradiation (λ = 254 nm) under different experimental conditions. The effect of catalyst concentration and pH on the decolorization of methyl orange dye was investigated. The decolorization of methyl orange dye has been followed using UV–vis spe...

Heterogeneous Fenton process using steel industry wastes for methyl orange degradation

Steel industry wastes (iron-containing waste) could be used as a Fenton-catalyst for the decolorization of methyl orange dye. Various reaction conditions were investigated including catalyst concentration, hydrogen peroxide concentration and pH value. The obtained results indicated that the dye degradation rate increases with increasing catalyst and hydrogen peroxide (H2O2) concentrations and with decreasing pH value. Over 98 % decolorization of the dye was achieved within 30 min at optimum reaction conditions; 200 mg/L catalyst and 34 mM H2O2 concentrations at pH 2 for 20 mg/L initial dye concentration. Reaction kinetics was also carried out to determine the order of reaction in both catalyst and H2O2 concentrations. Stability and reusability of Iron-containing waste were investigated. The iron-containing waste as catalyst can be reused several times with nearly same efficiency of Fenton-like oxidation of MO.

Chitosan hydrogel films as a template for mild biosynthesis of CdS quantum dots with highly efficient photocatalytic activity

Cadmium sulfide (CdS) semiconducting quantum dots (QDs) were prepared using in situ synthesizing method in crosslinked chitosan hydrogel films under relative mild experimental conditions and characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results confirmed that crosslinked chitosan hydrogel films provided a confined matrix for CdS QDs growth in uniform size through chelation and electrostation between cadmium ions and amino groups in chitosan chains. The CdS QDs/chitosan composite films exhibited a highly efficient photocatalytic activity for decolorization of methyl orange (MO) solution under visible light irradiation. The good linearity relationship between ln(C0/Ci) and irradiation time (t) indicated that the decolorization of MO dye under present experimental conditions followed pseudo-first-order kinetics. These results suggested that CdS QDs/chitosan composite films were suitable material for potential application in decolorization of organic dye pollutants under visible light irradiation.

Photo degradation of Methyl Orange an azo dye by Advanced Fenton Process using zero valent metallic iron: Influence of various reaction parameters and its degradation mechanism

Advanced Fenton process (AFP) using zero valent metallic iron (ZVMI) is studied as a potential technique to degrade the azo dye in the aqueous medium. The influence of various reaction parameters like effect of iron dosage, concentration of H 2O 2/ammonium per sulfate (APS), initial dye concentration, effect of pH and the influence of radical scavenger are studied and optimum conditions are reported. The degradation rate decreased at higher iron dosages and also at higher oxidant concentrations due to the surface precipitation which deactivates the iron surface. The rate constant for the processes Fe 0/UV and Fe 0/APS/UV is twice compared to their respective Fe 0/dark and Fe 0/APS/dark processes. The rate constant for Fe 0/H 2O 2/UV process is four times higher than Fe 0/H 2O 2/dark process. The increase in the efficiency of Fe 0/UV process is attributed to the cleavage of stable iron complexes which produces Fe 2+ ions that participates in cyclic Fenton mechanism for the generation of hydroxyl radicals. The increase in the efficiency of Fe 0/APS/UV or H 2O 2 compared to dark process is due to continuous generation of hydroxyl radicals and also due to the frequent photo reduction of Fe 3+ ions to Fe 2+ ions. Though H 2O 2 is a better oxidant than APS in all respects, but it is more susceptible to deactivation by hydroxyl radical scavengers. The decrease in the rate constant in the presence of hydroxyl radical scavenger is more for H 2O 2 than APS. Iron powder retains its recycling efficiency better in the presence of H 2O 2 than APS. The decrease in the degradation rate in the presence of APS as an oxidant is due to the fact that generation of free radicals on iron surface is slower compared to H 2O 2. Also, the excess acidity provided by APS retards the degradation rate as excess H + ions acts as hydroxyl radical scavenger. The degradation of Methyl Orange (MO) using Fe 0 is an acid driven process shows higher efficiency at pH 3. The efficiency of various processes for the de colorization of MO dye is of the following order: Fe 0/H 2O 2/UV > Fe 0/H 2O 2/dark >Fe 0/APS/UV > Fe 0/UV > Fe 0/APS/dark > H 2O 2/UV ≈ Fe 0/dark > APS/UV. Dye resisted to degradation in the presence of oxidizing agent in dark. The degradation process was followed by UV–vis and GC–MS spectroscopic techniques. Based on the intermediates obtained probable degradation mechanism has been proposed. The result suggests that complete degradation of the dye was achieved in the presence of oxidizing agent when the system was amended with iron powder under UV light illumination. The concentration of Fe 2+ ions leached at the end of the optimized degradation experiment is found to be 2.78 × 10 −3 M. With optimization, the degradation using Fe 0 can be effective way to treat azo dyes in aqueous solution.