Acid Orange II Research Articles

The application of chromium substituted magnetite as heterogeneous Fenton catalyst for the degradation of aqueous cationic and anionic dyes

In this study, the heterogeneous Fenton degradation of cationic and anionic dyes catalyzed by a series of Cr-containing magnetites (Fe3−xCrxO4, x=0.00, 0.18, 0.33, 0.47 and 0.67) has been investigated under neutral pH conditions. Methylene blue (MB) and acid orange II (AOII) were chosen as models of cationic and anionic contaminants. Emphases were laid on the comparison of degradation characteristic between MB and AOII and the effect of Cr substitution on the degradation efficiency of both dyes. The octahedral occupancy of Cr3+ increased the BET surface area and superficial hydroxyl amount of magnetite, resulting in an improvement of adsorption ability of MB. However, these Cr-containing magnetites showed no adsorption to AOII. The MB degradation, following the Langmuir–Hinshelwood model, was well fitted by zero-order equation while AOII degradation following the Eley–Rideal model, was well fitted with two-stage pseudo-first-order kinetics. The Cr incorporation significantly improved the catalytic activity of magnetite in heterogeneous Fenton reaction, but the extent of improvement varied with the substitution level. These new insights are of high importance for the environmental application of metal substituted magnetites in the purification of textile wastewater.

Mesoporous zinc ferrite: Synthesis, characterization, and photocatalytic activity with H2O2/visible light

Mesoporous ZnFe2O4 (meso-ZnFe2O4) was synthesized by a hydrothermal process in which cetyltrimethylammonium bromide (CTAB) participates in the reaction to produce nanocrystals. Synthesized ZnFe2O4 was characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area, scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance spectra (DRS). The meso-ZnFe2O4 was resulted from the agglomeration of nanoparticles with size of 5–10nm. The photocatalytic activity of ZnFe2O4 under visible light (λ>400nm) was evaluated by the degradation of Acid Orange II (AOII) at different sintering temperatures, the amount of ZnFe2O4, and the concentration of H2O2. The photocatalytic degradation of AOII was almost complete within 2h in H2O2/visible light system. The high efficiency for AOII degradation was attributed to the strong absorption of ZnFe2O4 in visible-light region and the generation of reactive OH by H2O2 in the system. The involvement of OH in oxidizing AOII was examined by determining the photocurrent of ZnFe2O4, [OH], and degradation rates using different scavengers. Organic compounds as intermediates of the degradation process were identified by LC/MS. Moreover, ZnFe2O4 retained their degradation efficiencies for a series of repetitive batch runs, indicating the true photocatalytic process.

Study on Dyeing Properties of Acid Dyes for Different Tree Species

Use acid scarlet3R ,acid orangeⅡ,acid black ATT and black powder as pigment,prepare for Acid Color, choose four fast growing woods-Chinese fir, poplar, eucalyptus and rubber wood as research objects, study on dyeing properties and dyeing effects of acid dyes for different tree species. It is found, there are differences in staining effects for four fast growing woods. Attachment properties of dyestuff solution on Chinese fir is good, but dyes proportion is very poor; Attachment properties of dyestuff solution on poplar is good, but dyes proportion is very poor; Both attachment property of dyestuff solution and dyes proportion of eucalyptus are not good; Both attachment property of dyestuff solution and dyes proportion of rubber wood are good.

Electrodeposition of polyhedral Cu 2O on TiO 2 nanotube arrays for enhancing visible light photocatalytic performance

Nano-sized polyhedral crystalline Cu 2O was evenly loaded throughout the structure of TiO 2 nanotube arrays (TNTs) using an electrodeposition method, which resulted in a nanocomposite namely Cu 2O/TNTs. The content of Cu 2O loaded on the arrays was controlled by varying the electrodeposition charges. Under visible light, the photocurrent for water splitting and photocatalytic decolorization efficiency of dye Acid orange II (AO-II) of the Cu 2O/TNTs obtained with the deposition charges of 500 mC were about 35 and 18 times that of TNTs, respectively. The polyhedral Cu 2O/TNTs would be a promising material for solar energy conversion and organic pollutant degradation.

Degradation of Acid Orange II at neutral pH using Fe 2(MoO 4) 3 as a heterogeneous Fenton-like catalyst

Iron molybdate, Fe 2(MoO 4) 3, has been successfully prepared by a simple wet chemical process. Degradation of Acid Orange II (AOII) was studied in detail using Fe 2(MoO 4) 3 as a heterogeneous Fenton-like catalyst. The results show that this new catalyst is highly effective for the degradation of AOII at neutral pH. For 100 mg l −1 of the initial concentration with an initial pH of 6.7, the degradation efficiency of AOII reaches 94.1% within 60 min. Moreover, the catalytic activity is slightly affected by the solution pH in a wide range of 3.0–9.0. This indicates that the use of Fe 2(MoO 4) 3 overcomes the low efficiency of Fenton-like reaction at neutral and even alkaline pH. Fe 2(MoO 4) 3 exhibits low iron leaching, good structural stability and no loss of performance after five recycle times. A mechanism proposed herein suggests that the high catalytic activity can be attributed to the formation of an acidic microenvironment near the surface of the solid acid Fe 2(MoO 4) 3 particles where catalysis occurs, as well as the synergistic effect of Fe 3+ and MoO 4 2−.

Electrodeposition preparation of Ag loaded N-doped TiO2 nanotube arrays with enhanced visible light photocatalytic performance

Abstract Ag nanoparticles loaded N-doped TiO2 nanotube arrays (Ag/N-TNTs) were successfully fabricated by an electrodeposition method. The Ag/N-TNTs were characterized using field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffusion reflection spectroscopy (UV–vis DRS). The average photocurrent density and the photocatalytic degradation efficiency of the Ag/N-TNTs obtained for the degradation of Acid Orange II（AO-II）are 6 times and 6.8 times higher than those of annealed TiO2 nanotube arrays (A-TNTs), respectively. This bestows the Ag/N-TNTs as a promising photocatalytic material for organic pollutant degradation under visible light.

Heterogeneous Fenton Catalyst Supports Screening for Mono Azo Dye Degradation in Contaminated Wastewaters

Degradation of acid orange II (AOII), a dye present in textile industry wastewater, by the heterogeneous Fenton process (HFP) was performed. In order to select an adequate support, heterogeneous Fenton catalysts were prepared using several materials such as carbon nanotubes, carbon nanofibers, activated carbon, hydrotalcite-like materials, mesoporous silica (MCM41), silica, silica xerogel, sepiolite, and zeolite USY, that were tested in the degradation of AOII as the model compound. Color, total organic carbon, chemical oxygen demand removal, and toxicity were studied in the process. The best catalyst was iron supported on sepiolite. The best performing catalytic material was used to investigate the influence of the presence of carbonate ions, pH, and reuse of catalyst. Also, a real textile wastewater was successfully treated with this catalyst.

Photo-Fenton-like catalytic activity of nano-lamellar Fe2V4O13 in the degradation of organic pollutants

A new photo-Fenton-like catalyst with high activity, Fe2V4O13, has been found. It can be obtained by a simple wet chemical process. The catalyst has a nano-lamellar structure with a thinness of less than 100 nm, a BET surface of 52.26 m2 g−1, and a band-gap of 1.59 eV favorable to absorption of visible light. Experiments demonstrated that Fe2V4O13 could effectively catalyze degradation of Acid Orange II (AOII) by H2O2 in visible light. The degradation was well fitted by a simple pseudo-first-order reaction with a rate constant of 0.0965 min−1. Moreover, the photo-Fenton-like catalytic activity of Fe2V4O13 was much higher than that of not only α-Fe2O3 and V2O5 but also their mixture (Fe2O3 + 2V2O5) with an identical atomic ratio of Fe and V, and that of both Fe3O4 and γ-FeOOH. The high catalytic activity of Fe2V4O13 possibly involves a special two-way Fenton-like, semiconductor photo-catalytic mechanism and the synergistic activation of Fe(III) and V(V) in Fe2V4O13 towards H2O2.

Electro-photocatalytic degradation of acid orange II using a novel TiO 2/ACF photoanode

A novel photoanode was prepared by immobilizing TiO 2 film onto activated carbon fibers (TiO 2/ACF) using liquid phase deposition (LPD) to study the electro-photocatalytic (EPC) degradation of organic compounds exemplified by an azo-dye, namely, Acid Orange II (AOII). Results demonstrated that by applying a 0.5 V bias (vs. SCE) across the TiO 2/ACF electrode, the AOII degradation rate was increased significantly compared to that of photocatalytic (PC) oxidation. The application of an electric field promotes the separation of photogenerated electrons and holes as confirmed by electrochemical impedance spectroscopy (EIS) measurements. The structural and surface morphology of the TiO 2/ACF electrode was characterized by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). SEM images showed that TiO 2 was deposited on almost every carbon fiber with an average thickness of about 200 nm with the inner space between neighboring fibers being maintained unfilled. The morphological features of the photo-anode facilitated the passage of solution as well as UV light through the felt-form electrode and created a three-dimensional environment favorable to EPC oxidation. Both the large outer surface area of the 3D electrode and the good organic adsorption capacity of the ACF support promoted high contact efficiency between AOII and TiO 2 surface. Anatase was the major crystalline TiO 2 deposited. UV–vis spectrophotometry, TOC (total organic carbon) analysis, and HPLC technique were used to monitor the concentration change of AOII and intermediates as to gain insight into the EPC degradation of AOII using the TiO 2/ACF electrode.

Design of BDD-TiO2 Hybrid Electrode with P−N Function for Photoelectrocatalytic Degradation of Organic Contaminants

P-N hybrid electrode of boron-doped diamond (BDD) and TiO2 were designed and fabricated via selective deposition of TiO2 onto BDD electrode. This hybrid electrode exhibit high photoelectrocatalytic activities toward degradation of acid orange II (AOII) and 2, 4-dichloropheonl (2,4-DCP) due to the P-N effect and high electrocatalytic and photocatalytic activities of BDD electrode and TiO2 particles. The structures of TiO2 and BDD were confirmed by Raman spectra analysis. Atom force microscopy and scanning electron microscopy showed that the TiO2 deposits consist of adherent nanomicro-sized particles, scattered on the BDD substrate. AOII and 2,4-DCP in a solution can be efficiently degraded at the hybrid electrode in the photoelectrocatalysis (PEC) process. Effect of applied bias potentials and solution pH values on AOII and 2,4-DCP degradation were investigated. In the electro-oxidation process, some intermediates such as phenols were detected and they accumulated with the reaction evolution based on the analysis of UV-vis and GC-MS variation. By contrast, phenols intermediates will be degraded with the reaction evolution in the photoelectrocatalysis process. And, organic aromatic and aliphatic carboxylic acids were detected. Furthermore, different degradation mechanism of AOII and 2,4-DCP in the electro-oxidation, photocatalysis, and photoelectrocatalysis is proposed.