Decolorization Rate Of Methyl Orange Research Articles

Hibiscus sabdariffa assisted green fabrication of reduced graphene oxide and its application for methyl orange removal: Optimization employing response surface methodology

Eco-friendly fabrication of reduced graphene oxide (rGO) is of paramount importance among various carbon nanostructures. In the current research, sustainable preparation of rGO via aqueous extract of Hibiscus sabdariffa L. calyces as the green reducer of graphene oxide (GO) without utilizing hazardous chemical agents was described. The structural characteristics of the GO and rGO were studied utilizing Fourier transform infrared (FT-IR) spectroscopy, UV–Visible spectrophotometry, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The prepared nanostructure was applied as the potential adsorbent for effective methyl orange (MO) decolorization and degradation in aqueous solution. The effect of numerous independent parameters on the decolorization process involving rGO dosage, H2O2 volume, process time, and temperature were assessed and optimized via Box-Behnken design/response surface methodology BBD/RSM). A second-order model was proved to express the decolorization efficiency (D %) responses with high values of R2 and adjusted R2. Under optimal condition, the decolorization rate of MO using rGO was higher than 99 % in contact time of 31 min. The reusability of rGO for the MO removal manifested good efficiency in up to five cycles of recyclability. The findings of this research illustrate the feasibility of Hs based rGO as a suitable adsorbent for effective decolorization of MO dye from aqueous medium.

Natural tea polyphenol functionalized graphene anode for simultaneous power production and degradation of methyl orange dye in microbial fuel cells.

The microbial fuel cell (MFCs) has dual functions, capable of achieving dye decolorization and synchronous power generation. Despite these advantages, the MFCs have faced challenges related to low electron transfer efficiencies and limited dye treatment capacity in wastewater applications. This work introduces an innovative approach by employing reduced graphene oxide-modified carbon cloth (TP-RGO@CC) anodes, utilizing tea polyphenols as the reducing agent. This modification significantly enhances the hydrophilicity and biocompatibility of the anodes. The MFC equipped with the TP-RGO@CC anode demonstrated a remarkable increase in the maximum power density, reaching 773.9 mW m-2, representing a 22% improvement over the plain carbon cloth electrode. The decolorization rate of methyl orange (50 mg L-1, pH 7) reached 99% within 48 h. Biodiversity analysis revealed that the TP-RGO@CC anode selectively enriched electrogens producing and organic matter-degrading bacteria, promoting a dual mechanism of dye decolorization, degradation, and simultaneous electro-production at the anode. This work highlights advanced anode materials that excel in effective pollutant removal, energy conversion, and biomass reuse.

Expansion of carbon source utilization range of Shewanella oneidensis for efficient azo dye wastewater treatment through co-culture with Lactobacillus plantarum.

Shewanella oneidensis has demonstrated excellent potential for azo dye decolorization and degradation. However, in anaerobic environments, S. oneidensis has a narrow carbon source spectrum, which requires additional electron donors, such as sodium lactate. This increases the practical application costs for wastewater treatment. Here, we aimed to expand the carbon source utilization range of S. oneidensis FJAT-2478 by co-culturing it with Lactobacillus plantarum FJAT-7926, leveraging their commensalism relationship to develop a metabolic chain. Results showed that a 1:2 initial ratio of L. plantarum FJAT-7926 to S. oneidensis FJAT-2478 achieved a 97.16% decolorization rate of methyl orange when glucose served as the sole carbon source. This co-culture system achieved a decolorization rate comparable to that obtained using sodium lactate as an electron donor and was significantly higher than that achieved by L. plantarum FJAT-7926 (7.88%) or S. oneidensis FJAT-2478 (6.89%) alone. After undergoing five cycles, the co-culture system continued to exhibit effective decolorization. It was demonstrated that the co-culture system could use common and inexpensive carbon sources, such as starch, molasses, sucrose, and maltose, to decolorize azo dyes. For instance, 100mg/L methyl orange could be degraded by over 98.05% within 24h. The results indicated that the degradation rates of methyl orange were higher when L. plantarum was inoculated first, followed by a subsequent inoculation of S. oneidensis after 2h. The co-culturing of L. plantarum FJAT-7926 and S. oneidensis FJAT-2478 proved to be an effective strategy in treating azo dye wastewater, expanding the potential practical applications of S. oneidensis.

Coral-like TiO2/organosilane hybrid particles with rapid adsorption of methyl orange

TiO2/Bis[3-(trimethoxysilyl)propyl]amine (BTMSPA) hybrid particles with a coral morphology were prepared using a facile method and used for the removal of methyl orange (MO) dye from wastewater. The structure of the TiO2/BTMSPA particles and the adsorption mechanism for MO were analyzed. Meanwhile, the adsorption isotherms and kinetics of MO on the particles were also studied. During the preparation of the TiO2/BTMSPA hybrid adsorbent, some of the BTMSPA linked the TiO2 particles to form a skeleton, while the remaining BTMSPA grew in situ on the TiO2 surface into nanopapillae, forming a micro/nano-porous coral-like structure. The secondary amine group in BTMSPA acted as an adsorbent via a single molecular layer chemisorption mechanism. In a neutral environment, the decolorization rate of MO was 83.3% after 1 min, eventually reaching 91.2 %. The maximum adsorption capacity was determined to be 90.3 and 369.3 mg/g under neutral and acidic conditions, respectively. Furthermore, the hybrid particles also showed excellent performance for the removal of other anionic dyes and such as methyl blue and amaranth red, with a 100 % decolorization rate. The adsorbent had good universality and excellent regeneration performance after an alkaline washing step.

Fe–N complex biochar as a superior partner of sodium sulfide for methyl orange decolorization by combination of adsorption and reduction

To enhance the decolorization of methyl orange (MO), Fe–N complex biochar (Fe-N-BC) was developed as an accelerator in the sodium sulfide (Na2S) reduction system. The decolorization effect and mechanism of MO in the Fe-N-BC/Na2S composite system were studied. Surface pore analysis, Raman spectroscopy, FT-IR, XPS, and electrochemical analysis were used to characterize Fe-N-BC and unmodified biochar (BC). These results demonstrated that Fe-N-BC had better adsorption performance (specific surface area 463.46 m2 g−1) and electron transfer capacity than BC. By adding Fe-N-BC to the Na2S reduction system for MO, it was found that the decolorization of MO was greatly improved (increased by 93%). Besides, the effects of critical factors such as the initial concentration of Na2S, the dosage of Fe-N-BC, pH value, and temperature on the decolorization rate of MO were evaluated. Through the analysis of the action mechanism, the cooperation mode of Fe-N-BC and Na2S was to form an infinite cycle of adsorption-reduction-regeneration, so as to realize the rapid decolorization of MO. On the one hand, Fe-N-BC could adsorb MO and Na2S on its surface to increase the contact opportunity; on the other hand, it could act as a redox mediator to accelerate the electron transfer of the reduction reaction. In addition, the degradation of MO by Na2S was also an in-situ regeneration of Fe-N-BC. These findings may provide a feasible method to decolorize azo dyes quickly by cooperating with chemical reducing agents from a new perspective.

The Investigation of Microstructure, Photocatalysis and Corrosion Resistance of C-Doped Ti–O Films Fabricated by Reactive Magnetron Sputtering Deposition with CO2 Gas

By employing carbon dioxide as one source of reaction gases, carbon-doped Ti–O films were fabricated via reactive magnetron sputtering deposition. The chemical bonding configurations and microstructure of the films were analyzed by Raman spectrum and SEM, respectively. The effect of pH on the photocatalytic activities of the films was determined via evaluation of the decolorization rate of methyl orange under alkali, acid and neutrality conditions using UV light irradiation. Electrochemical impedance spectroscopy and potentiodynamic polarization tests were employed to determine the anti-corrosion properties. Compared with the C-free Ti–O film, the C-doped Ti–O films exhibit superior corrosion resistance. Furthermore, the results of the photodegradation experiment suggest that the C-doped Ti–O films have excellent photocatalytic activities and, for methyl orange, those with higher carbon content exhibit hyper-photodegradative effect under the alkali condition.

Facile Preparation of Granular Copper Films as Cathode for Enhanced Electrochemical Degradation of Methyl Orange.

In this paper, granular copper films (GCFs) were prepared through electrodeposition in CuSO4 solution containing triethanolamine, and the films were used as electro-Fenton-like cathodes for degradation of methyl orange (MO). The effects of triethanolamine concentration, pH value, current intensity and temperature on the morphology of the films, as well as the MO decolorization ratio (DR), were investigated in detail. Results show that when the concentration of triethanolamine is 0.2 wt%, the prepared GCF exhibits the best performance. Under room temperature and neutral conditions, no external O2 or catalyst, MO is completely decolorized after 240 min. Compared with the commonly used carbon cathode, the GCF cathode can increase the MO decolorization rate by approximately 70.9%. The kinetics of the electrochemical degradation reaction is also discussed.

Azo dye degrading bacteria tolerant to extreme conditions inhabit nearshore ecosystems: Optimization and degradation pathways

Nearshore ecosystems are transitional zones, and they may harbor a diverse microbial community capable of degrading azo dyes under extreme environmental conditions. In this study, thirteen bacterial strains capable of degrading eight azo dyes were isolated in nearshore environments and characterized using high throughput 16 S rRNA sequencing. The results of this study demonstrate that the biodegradability of azo dyes was influenced by their chemical structure and position of functional groups as well as the type of bacteria. The decolorization rate of Methyl Orange (95%) was double that of the heavier and sterically hindered Reactive Yellow 84 (<40%). Shewanella indica strain ST2, Oceanimonas smirnovii strain ST3, Enterococcus faecalis strain ST5, and Clostridium bufermentans strain ST12 demonstrated potential application in industrial effluent treatment as they were tolerant to a wide range of environmental parameters (pH: 5–9, NaCl: 0–70 g L−1, azo dye concentration: 100–2000 mg L−1) including exposure to metals. Analysis of the transformation products using GC-MS revealed that different bacterial strains may have different biotransformation pathways. This study provides critical insight on the in-situ biotransformation potential of azo dyes in marine environments.

Efficient and synergistic decolourization and nitrate removal using a single-chamber with a coupled biocathode-photoanode system

With the continuous development of the chemical industries, synergistic removal of carbon and nitrogen contaminants has drawn much attention. In this work, a novel strategy for the synergistic removal of methyl orange (MO) and nitrate was developed in a single reactor by combining a TiO2/g-C3N4 nanosheet/graphene photoanode and denitrifying biofilm cathode. Under xenon light illumination, the photocatalytic MO decolorization rate exceeded 90% (the initial concentration of MO was as high as 100 mg·L−1) with a biocathode potential bias of −0.5 V vs Ag/AgCl; additionally, the decolourization rate apparently followed first-order kinetics with a constant of 0.11 ± 0.02 h−1. The improved MO decolourization rate was mainly because the biocathode effectively enhanced the charge separation of the photogenerated charge at the TiO2/g-C3N4 nanosheet/graphene photoanode interface. In the meantime, the effluent nitrate was lower than 1 mg·N·L−1 at a biocathode potential of −0.5 V vs Ag/AgCl. The results indicated that the coupled biocathode-photoanode system could serve the purpose of simultaneously degrading MO and accomplishing nitrate reduction. Considering the sustainability of sunlight and the use of a biocathode, the coupled biocathode-photoanode system is a promising alternative for the simultaneous removal of biorefractory organics and nitrate.

Preparation and visible light responsive photocatalytic activity of Fe3O4/Ni-Al-Ce LDH/Bi2WO6 composites

Novel Fe3O4/Ni-Al-Ce LDH/Bi2WO6 composites were prepared through a hydrothermal method and co-precipitation method. The morphologies and structures of the photocatalysts were characterized by XRD, Raman, TEM, UV-vis-DRS, BET surface area and VSM techniques. The photocatalytic performances of the photocatalysts were investigated by the decolorization of methyl orange (MO) under visible-light irradiation. The results showed that the Fe3O4/Ni-Al-Ce LDH/Bi2WO6 composites exhibited greater photocatalytic activities compared to pure Bi2WO6 and the Ni-Al-Ce LDH; the decolorization rate of MO was 87% within 60 min under visible-light irradiation. The decolorization efficiency of the composite material remained at 71% after 4 recycling runs, showing improved stability. Furthermore, the experimental results also showed that the photocatalytic reactions for the composites followed first-order reaction kinetics. Therefore, the Fe3O4/Ni-Al-Ce LDH/Bi2WO6 composites were photocatalysts with high efficiencies and stabilities for a photocatalytic reaction of an organic pollutant, and this study provides a new, effective method for the development of wastewater treatment.

微波辐照废木屑制备活性炭及处理甲基橙废水的研究

以常见的木材厂废木屑作为原料，通过微波辐照以Na2CO3为活化剂，制备废木屑活性炭。利用Design expert软件中水平设计和响应面分析法对微波条件下废木屑制备活性炭进行了优化，经过逐步回归分析建立了微波时间、木屑细度、固液比以及活化剂浓度对活性炭的产率和对甲基橙脱色力影响的二次回归模型。产率和脱色率的回归方程的决定系数分别达到了0.9866和0.9978。得到较优的碳化条件为：微波辐照时间8.02分钟、木屑细度40~60目、固液比1:1.5、活化剂浓度21.5%，该条件下废木屑活性炭的产率达到54.9%，对甲基橙的脱色率达到89.56%。微波辐照法制备活性炭，加热时间短，能耗低，是活性炭制备的绿色化学工艺，且实现变废为宝，可为废木屑的资源化处置提供一条合理的途径。 Waste wood chips were prepared by microwave irradiation with Na2CO3 as activator. Based on the level design and response surface analysis method in Design expert software, the activated charcoal was prepared under microwave condition. The yield of activated carbon was determined by step-wise regression analysis. Through stepwise regression analysis, the two regression models were es-tablished for the effects of microwave time, sawdust fineness, solid-liquid ratio and activator con-centration on the yield of activated carbon and the decolorization capacity of methyl orange. The de-cisive coefficients of the regression equation were 0.9866 and 0.9978, respectively. The optimum conditions of carbonization were as follows: microwave irradiation time—8.02 min, sawdust fine-ness—40~60 mesh, solid-liquid ratio—1:1.5, activator concentration—21.5%, under which the yield of activated wood was 54.9%, the decolorization rate of methyl orange reached 89.56%. The preparation of activated carbon by microwave irradiation, with short heating time and low energy consumption, is a green chemical process made by activated carbon. It can also be used to save waste materials and provide a reasonable way for the waste wood sawdust to be disposed.

A microbial fuel cell-coupled constructed wetland promotes degradation of azo dye decolorization products

Microbial fuel cell coupled constructed wetland (CW-MFC) was constructed for azo dye decolorization and further degradation. Methyl Orange (MO) was chosen as the model azo dye due to the simple decolorization products. The decolorization products were analyzed qualitatively via GC–MS and the N,N-Dimethyl-p-phenylenediamine (DMPD) was chosen as one of the MO decolorization products to study the further degradation performance of decolorization products in the CW-MFC. 1,4-Benzenediamine, N-methyl- and p-Phenylenediamine (PPD) was another intermediate product of MO decolorization. Electrical characteristics of CW-MFC were studied to evaluate the interplay between the azo dye degradation and the electricity generation. The MO decolorization rate of open and closed-circuit CW-MFC were 75.59% and 87.60%, respectively, while the DMPD degradation rate in the anode layer of open and closed-circuit CW-MFC were 84.96% and 96.33%, respectively. In the anode layer, suitable anode materials can promote the further degradation of azo dye degradation products, while in the cathode layer, close current promoted the further degradation of the decolorization products.

Goethite as an efficient heterogeneous Fenton catalyst for the degradation of methyl orange

The heterogeneous Fenton process was employed to degrade methyl orange (MO) using goethite as the catalyst. The catalyst stability was evaluated by measuring color removal in three successive cycles. The goethite samples before and after the reaction were characterized by XRD, SEM and FTIR techniques. The effect of major parameters, including pH, H2O2 concentration, catalyst addition and initial dye concentration on the decolorization of MO was investigated. The results indicated that the MO decolorization rate increased with the increase of H2O2 concentration and catalyst addition, but decreased with the increase of initial MO concentration. The optimal initial pH for the decolorization was found as 3. The acute toxicity experiments illustrated that the Daphnia magna mortality declined with the progress of the oxidation.

Enhanced decolorization of methyl orange using zero-valent copper nanoparticles under assistance of hydrodynamic cavitation

The rate of reduction reactions of zero-valent metal nanoparticles is restricted by their agglomeration. Hydrodynamic cavitation was used to overcome the disadvantage in this study. Experiments for decolorization of methyl orange azo dye by zero-valent copper nanoparticles were carried out in aqueous solution with and without hydrodynamic cavitation. The results showed that hydrodynamic cavitation greatly accelerated the decolorization rate of methyl orange. The size of nanoparticles was decreased after hydrodynamic cavitation treatment. The effects of important operating parameters such as discharge pressure, initial solution pH, and copper nanoparticle concentration on the degradation rates were studied. It was observed that there was an optimum discharge pressure to get best decolorization performance. Lower solution pH were favorable for the decolorization. The pseudo-first-order kinetic constant for the degradation of methyl orange increased linearly with the copper dose. UV–vis spectroscopic and Fourier transform infrared (FT-IR) analyses confirmed that many degradation intermediates were formed. The results indicated hydroxyl radicals played a key role in the decolorization process. Therefore, the enhancement of decolorization by hydrodynamic cavitation could due to the deagglomeration of nanoparticles as well as the oxidation by the in situ generated hydroxyl radicals. These findings greatly increase the potential of the Cu0/hydrodynamic cavitation technique for use in the field of treatment of wastewater containing hazardous materials.

Decolorization of methyl orange by green rusts with hydrogen peroxide at neutral pH

Heterogeneous Fenton-like processes using green rusts (GRs) with hydrogen peroxide (H2O2) were studied to decolorize methyl orange (MO) in aqueous solution at an initial pH of 7.0. In this study, two types of crystal structure for GRs, the hydroxycarbonate GR(CO3(2-)) (GR1) and the hydroxysulphate GR(SO4(2-)) (GR2), were synthesized by partial oxidation of Fe(OH)2 suspension under light irradiation and distinguished by X-ray diffraction (XRD) due to different characteristic peaks. In oxidation reactions, decolorization rate of MO, bubbling air through the solution, was about 65% (experiment B), whereas, it was up to 95% in the presence of H2O2 (experiment C) within 60 min. The comparative tests of GR1 and GR2 show that the reduction capability of GR2 is stronger than GR1, which may be due to Fe(II) content and interlayer anions. XRD analysis and Fourier transform infrared spectroscopy revealed that the oxidation end products of GR2 were mainly a poorly crystallized mixture of magnetite (Fe3O4) and hydroxy ferric oxide (FeOOH). However, when GR was immediately oxidized, the weakly crystallized goethite (α-FeOOH) and lepidocrocite (γ-FeOOH) were formed for O2 and H2O2, respectively. Based on the intermediates obtained, a probable decolorization mechanism has been proposed.

Research of composition and photocatalytic property of carbon-doped Ti-O films prepared by R-MS using CO2 gas resource

In this paper, carbon-doped Ti-O films were prepared on silicon wafer and stainless steel by reaction magnetron sputtering using CO2 as carbon and oxygen source. By changing the ratio of CO2/O2, a series of films with different composition can be obtained. X-ray photoelectron spectroscopy (XPS) was employed to analyze composition of as-prepared films. The result proved that carbon was doped into titanium successfully. Ultraviolet–visible (UV–Vis) spectrophotometer in the wavelength range of 250–900nm was used to record the absorbance of as-prepared film samples. The photocatalytic activities of as-prepared films were evaluated by measuring the decolorization rate of methyl orange under UV light irradiation. The results showed that as-prepared carbon-doped Ti-O films have fairly photocatalysis activity, which to be hoped to become candidate materials for photocatalyst.

Hydrothermal preparation, characterization and photocatalytic activity of TiO2/Fe–TiO2 composite catalysts

Abstract Highly active TiO 2 /Fe–TiO 2 composite photocatalysts with a p–n heterojunction structure have been prepared by mixing hydrothermal-derived TiO 2 and Fe–TiO 2 nano-powders followed by grinding and drying. These photocatalysts were characterized by XPS, XRD, TEM, BET, UV–vis and Fluorescence spectroscopy, and their photocatalytic activities were evaluated by the decolorization rate of methyl orange under UV irradiation. TiO 2 /Fe–TiO 2 composite photocatalysts were generally shown to have a much higher photocatalytic destruction rate than pure TiO 2 , mainly due to electrostatic-field-driven electron–hole separation in TiO 2 /Fe–TiO 2 composites. The best TiO 2 /Fe–TiO 2 composite photocatalyst with mass ratio TiO 2 :0.5 at%Fe–TiO 2 of 12:1 showed approximately 3.8 times higher photocatalytic activity than undoped TiO 2 .

Photocatalytic Degradation and Kinetics of Methyl Orange with Bi-Doped TiO&lt;sub&gt;2&lt;/sub&gt; under Simulated Sunlight

Bi-doped TiO2 was prepared with sol-gel method and was characterized by X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation and kinetics of Methyl orange with Bi-doped TiO2 under xenon lamp irradiation were investigated. The optimum conditions were as follows: the initial concentration of Methyl orange was 20 mg/L, the value of pH was 3.0 and the dosage of Bi-doped TiO2 was 1.0 g/L. Under the optimal conditions, the decolorization rate of Methyl orange was 75.1 % and the kinetic constant was 0.0113 min-1.

Synthesis and Photocatalytic Property of BiVO&lt;sub&gt;4&lt;/sub&gt; Photocatalyst by Cotton Fiber Template Method

BiVO4 hollow nano-fiber photocatalytic material was prepared via two steps method of soaking and thermal transition using the cotton fiber as the template. The as-prepared samples were characterized by XRD, SEM and BET. The photocatalytic activity under visible light was evaluated by photocatalytic degradation of methyl orange(MO) in the solution. It was found that the samples calcinated at 400°C for 3.5 h had the hollow tube structure which is the copy of the cotton fibre structure and had the best photocatalytic activity. The decolorization rate of methyl orange can reach to be 97 % or so, increased 16 % than that of sample that prepared with no cotton fiber template. It indicated that the sample’s morphology and the specific surface area was the main reason of higher photocatalytic activity.

Decolorization of Methyl Orange Simulated Wastewater by Chlorine Dioxide with Ultrasound

Experiments were conducted to investigate the decolorization of methyl orange simulated wastewater in order to assess the effectiveness and feasibility of ultrasound(US) enhanced high-purity chlorine dioxide(ClO2) oxidation process. The results showed that in ClO2/US system the decolorization rate of methyl orange was up to 96%, which was increased by 8% as compared to ClO2treatment alone. The decolorization of methyl orange with/without ultrasonic irradiation follows apparent pseudo-first-order reaction kinetics. The apparent pseudo-first-order rate constant kappwas 0.19min-1in the ClO2/US system, which was a little higher than 0.13min-1of rate constant achieved in ClO2treatment alone. It shows that ClO2/US system can be an effective technology for the decolorization of azo dyes in wastewater.