Degradation Of Aniline Research Articles

Heterogeneously degradation of aniline in aqueous solution using persulfate catalyzed by magnetic BiFeO3 nanoparticles

In this study, magnetic BiFeO3 nanoparticles (BFO MNPs) were successfully synthesized by simple sole-gel method. The BFO MNPs catalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) techniques. The prepared catalyst was used to activate persulfate (PS) to generate sulfate radicals (SO4−) for the enhanced degradation of aniline from aqueous solution. It was found that BFO MNPs showed high catalytic activity toward PS decomposition for the degradation of aniline. The degradation efficiency of aniline (0.5 mM) was 100% within 120 min using initial dosage of 0.5 g/L BFO MNPs and concentration of 5 mM persulfate. Even at neutral pH (7.0), aniline was efficiently degraded in BFO MNPs /PS system. The effects of reaction parameters such as initial pH, PS concentration and dosage of BFO MNPs were investigated. The radical scavenging and electron paramagnetic resonance (EPR) results showed that sulfate radicals (SO4−) and hydroxyl radicals (OH) were generated by the activation of PS with BFO MNPs for the degradation of aniline. The stability of catalyst was tested by means of successive reuse cycles. The results revealed that BiFeO3 catalyst exhibited high reusability and stability in degrading aniline through PS activation.

Degradation and mineralization of aniline by O 3 /Fenton process enhanced using high-gravity technology

The degradation and mineralization of aniline (AN) using ozone combined with Fenton reagent (O3/Fenton) in a rotating packed bed (RPB) was proposed in this study, and the process (RPB-O3/Fenton) was compared with conventional O3/Fenton in a stirred tank reactor (STR-O3/Fenton) or single ozonation in an RPB (RPB-O3). Effects of high gravity factor, H2O2 dosage, H2O2 dosing method and initial pH on the AN mineralization efficiency were investigated in the RPB-O3/Fenton process. In addition, the behavior of Fe(II) was monitored at different H2O2 dosing methods and pH values. Finally, the optimal operation conditions were determined with high gravity factor of 100, initial pH of 5, Fe(II) concentration of 0.8 mmol·L− 1 and H2O2 dosage of 2.5 ml. Under these conditions, for aniline wastewater at the volume of 1 L and concentration of 200 mg·L− 1, a fast and thorough decay of AN was conducted in 10 min, and the TOC removal efficiency reached 89% in 60 min. The main intermediates of p-benzoquinone, nitrobenzene, maleic acid and oxalic acid were identified by liquid chromatography/mass spectroscopy (LC/MS), and the degradation pathways of AN in RPB-O3/Fenton system were proposed based on experimental evidence. It could be envisioned that high-gravity technology combined with O3/Fenton processes would be promising in the rapid and efficient mineralization of wastewater.

Fabrication and catalytic activities of anodes consisting of ZnO nanorods on boron-doped diamond film

Boron-doped diamond (BDD) and ZnO are widely used in the fields of electrocatalysis and photocatalysis, respectively. In general, BDDs are used directly as anodes or the bottom electrodes of multilayered films owing to processing difficulties, while ZnO is more often used to fabricate nanostructures because it provides a large specific surface area that is very helpful for enhancing catalytic performance. In this study, a nanoporous (NP) surface was constructed on a BDD film grown on Ta substrate, and ZnO nanorods were grown in situ on the NPBDD to enhance adhesion between the ZnO nanorod layer and the NPBDD surface. The effect of the BDD-surface-pore structure on the growth sizes and morphologies of the ZnO nanorods was studied by analyzing the microstructures, phases, and compositions of the samples. In addition, the photoelectrocatalytic performance of ZnO/NPBDD anodes in aniline degradation was analyzed and compared to that of conventional BDD and NPBDD anodes. The mechanism for the degradation of the ZnO/NPBDD film was analyzed by UV–vis spectroscopy and the ZnO/NPBDD anode was used to rapidly decompose aniline in a photoelectro-Fenton reaction following pH and current optimization. In short, ZnO/NPBDD films are potentially useful photoelectric anodes for the degradation of organic matter.

Controlled Synthesis of highly proficient and durable hollow hierarchical heterostructured (Ag-AgBr/HHST): A UV and Visible light active photocatalyst in degradation of organic pollutants

Progression in nano technology enormously influence on the synthesis of highly proficient photo materials and investigate their applications in diverse fields. A novel mesoporous heterostructure Ag-AgBr/HHST (hollow hierarchical silica-titania supported silver-silverbromide), synthesized by a facile one-pot micro emulsification method at controlled calcination temperature and investigated its photocatalytic performance for the degradation of methyl orange and aniline as ultra violet and visible light responsive material. Mesoporous Ag-AgBr/HHST was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), UV–vis. diffuse reflectance spectroscopy (UV–vis. DRS), Nitrogen adsorption-desorption analysis, photoelectron spectroscopic measurements (XPS) and photoluminescence spectral analysis (PL). The XRD, HRTEM and optical spectroscopic analysis justified the incredible effect of calcination temperature on the structure and morphology of nano composite. The results indicates, the photocatalyst synthesized at optimum calcinations temperature (550 °C) consist of small-hollow-spheres@big-hollow-spheres, leading the Ag and AgBr nano particles with an average particle size of 2–8 nm are homogeneously distributed on the surface of the hollow hierarchical silica-titania matrix, some particles are deeply embedded in HHST. Due to exceptional morphology, high surface area, small particles size and porous structure, the Ag-AgBr/HHST revealed elevated photocatalytic performance to degraded the 200 mL (200 ppm) of each methyl orange and aniline under simulated ultra violet as well as visible light irradiations in very short time intervals. Hollow hierarchical silica-titania offer high-quality conducting channel to pick up mass loading and enhance charge transfer. Whereas, strong connection of Ag and AgBr with silica-titania, feature highly active sites that causes synergetic effect capable for commendable photocatalytic performance compared with individual HHST, Ag-AgBr and (Degussa P25). While the photocatalyst obtained at 650 °C have some extant of phase conversion starting anatase to rutile phase of titania, and consist of big sized aggregated nano particles. The recycling runs experiments and reusability of the photocatalyst illustrate the venerable stability of the material that strengthens the synthesis of novel hollow hierarchical mesoporous compounds in this domains.

Photocatalytic degradation of aniline using an autonomous rotating drum reactor with both solar and UV-C artificial radiation

The aim of this work was to evaluate the performance of a novel self-autonomous reactor technology (capable of working with solar irradiation and artificial UV light) for water treatment using aniline as model compound. This new reactor design overcomes the problems of the external mass transfer effect and the accessibility to photons occurring in traditional reaction systems. The UV-light source is located inside the rotating quartz drums (where TiO2 is immobilized), allowing light to easily reach the water and the TiO2 surface. Several processes (UV, H2O2, Solar, TiO2, Solar/TiO2, Solar/TiO2/H2O2 and UV/Solar/H2O2/TiO2) were tested. The synergy between Solar/H2O2 and Solar/TiO2 processes was quantified to be 40.3% using the pseudo-first-order degradation rate.The apparent photonic efficiency, ζ, was also determined for evaluating light utilization. For the Solar/TiO2/H2O2 process, the efficiency was found to be practically constant (0.638–0.681%) when the film thickness is in the range of 1.67–3.87 μm. However, the efficiency increases up to 2.67% when artificial UV light was used in combination, confirming the efficient design of this installation. Thus, if needed, lamps can be switched on during cloudy days to improve the degradation rate of aniline and its mineralization. Under the optimal conditions selected for the Solar/TiO2/H2O2 process ([H2O2] = 250 mg/L; pH = 4, [TiO2] = 0.65–1.25 mg/cm2), 89.6% of aniline is degraded in 120 min. If the lamps are switched on, aniline is completely degraded in 10 min, reaching 85% of mineralization in 120 min. TiO2 was re-used during 5 reaction cycles without apparent loss in activity (<2%). Quantification of hydroxyl radicals and dissolved oxygen allows a chemical-based explanation of the process. Finally, the UV/Solar/TiO2/H2O2 process was found to have lower operation costs than other systems described in literature (0.67 €/m3).

Degradation of aniline in aqueous solution using non-thermal plasma generated in microbubbles

Aniline is carcinogenic and toxic to human and aquatic life. A long treatment time and the addition of chemicals are usually necessary to remove aniline from water. In this study a novel approach, dielectric barrier discharge (DBD) combined with microbubbles (MBs), was employed to degrade aniline in aqueous solution. The aniline removal rates with DBD/MB were influenced by input power, bubble sizes, initial pH, the existence of a buffer solution, and initial conductivity. Compared to counterpart that did not use MBs, the DBD/MB process significantly enhanced aniline degradation and mineralization. Hydroxyl radicals were identified as the primary active species responsible for aniline degradation used electron spin resonance and the free-radicals inhibitor tertiary-butyl alcohol. This study revealed that the DBD/MB combination could enhance the dissolution and mass transfer of plasma-generated active species from the gas to liquid phase, and furthermore, that MBs collapsed under water surface increased production of hydroxyl radicals and promoted aniline degradation. Thus, employing MBs to enhance the reactive capacity of a DBD reactor may contribute to the development of an alternative method to degrade recalcitrant chemicals since it does not need any dosing with chemicals.

Degradation of aniline by liquid ferrate(VI)

Degradation of aniline by liquid ferrate(VI)

Degradation of aniline from aqueous solution by Fenton process: modeling and optimization

Degradation of aniline from aqueous solution by Fenton process: modeling and optimization

Synthesis, characterization and photocatalytic activity of TiO2/ZnO-supported phosphomolybdic acid nanocomposites

Three nanocomposites of phosphomolybdic acid supported on TiO2and ZnO nanoparticles were synthesized and characterized by means of FESEM, FTIR and XRD analysis. Photocatalytic activity of the synthesized nanocomposite was investigated for aniline as an organic pollutant model. Relatively, good degradation efficiency above 70% was achieved for all nanocomposites in presence of hydrogen peroxide as electron scavenger. The kinetic study showed that photocatalytic degradation of aniline followed the Langmuir-Hinshelwood model. Results showed that hydroxyl radicals and holes play an important role in photocatalytic degradation of aniline using synthesized nanocomposites. These results suggested that synthesized nanocomposites could be promising photocatalysts in the removal of aniline from aqueous solutions.

Efficient activation of ozone by zero-valent copper for the degradation of aniline in aqueous solution

Abstract A series batch experiments were performed to explore the catalytic role of zero-valent metals, including Fe(0), Co(0), Al(0) and Cu(0), in ozonation degradation of aniline in aqueous solution. It was found that Cu(0) exhibited the best catalytic activity of ozonation. Approximately 98% of the initial aniline (10 mg/L) was destructed by ozone assisted with Cu(0) within 24 min. The dosage of Cu(0) and solution pH were two critical factors affecting aniline degradation. The increase of Cu(0) dosage promoted aniline degradation. And aniline could be effectively removed in an initial pH range of 4–10, whereas a lower or higher solution pH was not favorable for the degradation of aniline. Free radicals were investigated by electron paramagnetic resonance technique, which confirmed that ·OH was the primary active oxidant responsible for the degradation of aniline. The further mechanism investigation revealed that the generation of ·OH is ascribed to Fenton-like reaction between Cu(I) and H 2 O 2 , both of which are in situ yielded through a series subsequent of reactions starting with oxidation–reduction reaction between ozone and Cu(0). Based on the results obtained in this study, it can be inferred that ozone activated with Cu(0) is a promising approach to degrade organic pollutants.

Biodegradation of aniline by freely suspended and immobilized Pseudomonas moraviensis AN-5

Pseudomonas moraviensis AN-5 isolated from contaminated sludge could utilize aniline as a sole carbon and nitrogen source. The aniline degradation by cells immobilized in alginate, polyvinyl alcohol (PVA) and polyurethane foam (PUF) was significantly better than freely suspended cells. The immobilized AN-5 degraded aniline nearly completely at the initial concentration of 22 mM by 48 hr of incubation. Compared to other binding materials, PUF-immobilized cells were more stable in aniline biodegradation in reused cycles. Moreover, immobilized cells could be stored for three months at 4oC with little reduction of the aniline degradation capacity. These results revealed that PUF-immobilized P. moraviensis AN-5cells has enhanced aniline biodegradation activity. Citation: Ha Danh Duc, Bui Minh Triet, 2017. Biodegradation of aniline by freely suspended and immobilized Pseudomonas moraviensis AN-5. Tap chi Sinh hoc, 39(3): 303-308. DOI: 10.15625/0866-7160/v39n3.9630. *Corresponding author: hadanhduc@gmail.com Received 11 April 2017, accepted 20 August 2017

Synthesis of barbituric acid doped carbon nitride for efficient solar-driven photocatalytic degradation of aniline

Abstract A series of barbituric acid doped carbon nitride (CN-BA) photocatalysts were successfully prepared by copolymerizing dicyandiamide with barbituric acid (BA). Under AM1.5 simulated sunlight, CN-BA photocatalysts exhibit enhanced photocatalytic activity compared to pure carbon nitride for the degradation of aniline. The highest activity is obtained with 2% doped CN-BA photocatalyst. Results on the photodegradation of aniline indicate that for the optimized CN-BA photocatalyst, the concentration of aniline solution was reduced gradually from 16 mg/L to 1.354 mg/L in 2 h. This corresponds to a 6 times higher photodegradation efficiency than pure carbon nitride samples. The enhanced photocatalytic activity of CN-BA relies on the enhanced surface area, the higher light absorption and the reduced recombination of the photo-generated electron-hole pairs. This interpretation results from multiple characterizations with EPR, BET, N2 adsorption, Solid-state 13C NMR, UV–vis DRS, FESEM, and TEM. Under simulated sunlight irradiation, CN-BA is excited and generates electron-hole pairs. The photo-generated electrons in the CN-BA conduction band react with the molecular oxygen to form O2−. Part of the O2− transforms into OH, which further oxides aniline. Meanwhile, photo-generated holes in the valence band of CN-BA can benefit to the formation of OH or directly oxide aniline.

Biodegradation of aniline by a novel bacterial mixed culture AC

In this study, a novel bacterial mixed culture AC, capable of degrading aniline, was developed by us. The mixed culture presented better aniline degradation abilities comparing with different pure strains. Aniline at high concentrations could be tolerated and degraded by the mixed culture. An almost complete degradation of aniline at the concentration of 1500 mg L−1 was observed within 60 h. To provide further insight into the microbial diversity of the bacterial mixed culture, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and high-throughput sequencing analyses were performed. PCR-DGGE profiles revealed that the microbial community had changed with varying initial concentrations of aniline. The taxonomic classification of the bacterial communities showed that the acclimated mixed culture was mainly composed of Serratia, Escherichia/Shigella, Bacillus and Acinetobacter. The mixed culture was immobilized by entrapment in different polumeric matrices. The immobilized bead exhibited good activity for aniline degradation and kept stable during successive repeated experiments. The effects of physico-chemical parameters on the aniline degradation were determined. Comparing with the free cells, the immobilized bead exhibited better degradation ability in wide range of pH, temperature and salinity. HPLC analysis showed that the mixed culture could convert aniline to catechol, and then catechol was further biodegraded to cis, cis-muconic acid. Ames test showed that the metabolic transformation products of aniline had no inherent toxicity. All these results showed that the mixed culture had a great potential to be used in the treatment of wastewater containing aniline.

Synthesis and characterization of nanometal-ordered mesoporous carbon composites as heterogeneous catalysts for electrooxidation of aniline

The Cu, Co and Ni nanometal embedded ordered mesoporous carbons (NM-OMCs) were fabricated by a soft-template method using phenol/formaldehyde as carbon source and triblock copolymer F127 as template agent. The morphology, structure, surface physicochemical properties and pore structure of the NM-OMCs were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption isotherms. Their potential application to the electrocatalytic degradation of aniline was investigated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and OH radicals generation test. Furthermore, the electrochemical oxidation process of aniline was also investigated in the presence of the OMC-based catalyst particles suspended in a Na2SO4 solution using a PbO2 anode. Results revealed that the NM-OMCs inherited the ordered mesostructure of pristine OMC and the metal nanoparticles (Cu, Co or Ni) were embedded in the carbon framework. The Cu-OMC exhibited significantly higher catalytic activity than OMC and other NM-OMCs for the electrooxidation of aniline. In electrochemical oxidation process of aniline, nearly all of aniline could be degraded after 120min of electrolysis with Cu-OMC particles as catalyst, while 89%, 92%, and 97% with OMC, Co-OMC and Ni-OMC catalysts, respectively, obviously higher than 76% of electrochemical oxidation without assistance of catalysts. After characterization of intermediates, a possible electrochemical degradation pathway of aniline was proposed.

Efect of Ti F surface interaction on the photocatalytic degradation of phenol, aniline and formic acid

Abstract A study is undertaken of the effect of fluorinating two TiO2 catalysts, both with the same surface area but one composed only of pure anatase phase (SA) and the other of mixed anatase and rutile phases (P25), on the degradation of phenol, formic acid and aniline. The catalysts were characterised by FTIR, BET, EDAXs, SEM, XRD and DRS-UV–vis studies. The method used for synthesis of the F-P25 and F-SA resulted in fluorinated catalysts with properties different to those of other fluorinated catalysts reported in the bibliography. The results obtained show that, unlike other studies in which the formation of free hydroxyl radicals ( OHfree) was enhanced with the fluorinated catalysts, in the F-P25 and F-SA catalysts it was the formation of surface hydroxyl radicals ( OHsurf) which was significantly enhanced. In this way, the F-P25 and F-SA catalysts gave rise to higher degradation rate constants of phenol (kphenol), aniline (kaniline) and formic acid (kformic) than the P25 and SA catalysts.

Mineralization of aniline using hydroxyl/sulfate radical-based technology in a waterfall reactor

The aim of this work is to study the applicability of a UV/H2O2 process intensified with persulfate (PS) as a source of SO4− radicals to efficiently mineralize a synthetic effluent containing aniline in a glass reactor arranged in a cascade configuration. pH conditions were studied and the concentration of PS was optimized. The synergism for aniline mineralization between the UV/H2O2 process and the combined UV/H2O2/PS process was quantified in 10.1%.Aniline degradation reached 100% under the UV/H2O2/PS process after 20 min. Its mineralization is favored under acidic conditions and with the presence of persulfate (optimal conditions: 49% in 90 min; pH = 4; [PS] = 250 ppm). On the contrary, the worst conditions were found at pH = 11, since hydrogen peroxide decomposes and carbonates were formed increasing the scavenging effect.The different mechanisms involved (formulated from intermediates identified by mass spectrometry) confirm these results. Aniline was found to follow a degradation pathway where phenol is the main intermediate. The presence of sulfate radicals increases phenol degradation rate leading to a higher mineralization extent. Benzoquinone was identified as the main aromatic oxidation product of phenol, whereas succinic, 4-oxo-pentanoic, fumaric and oxalic acids were detected as aliphatic oxidation products for both UV/H2O2 and UV/H2O2/PS oxidation processes.

Degradation of Aniline by Bismuth Oxyiodide (BiOI) under Visible Light Irradiation

Visible-light-driven porous spherical photocatalyst bismuth oxyiodide (BiOI) was successfully prepared by facial hydrothermal synthesis. The obtained catalyst was characterized using x-ray diffraction (XRD), ultraviolet-visible diffuse reflection (UV-Vis DRS) and scanning electron microscope (SEM). The experiment which used the visible-driven catalyst to degrade aniline wastewater investigated the effects of initial concentration of aniline and reaction time on the removal efficiency of aniline. The highest photodegradation efficiency of aniline was 97.3% with a BiOI dosage of 1 g L-1and initial aniline concentration of 50 mg L-1 after 2 h of visible light irradiation. The chemical oxygen demand (COD) of the solution decreased substantially and the high chemical oxygen demand removal efficiency achieved 71%. In addition, the investigation of different scavengers demonstrated that h+ and •O2− are the main reactive species in the photodegradation of aniline. The fate of nitrogen was investigated by ion chromatography. The high photodegradation and mineralization capability efficiency suggest BiOI is a promising photocatalyst for the degradation of organic pollution in the practical application.

Magnetic M x O y @N-C as heterogeneous catalysts for the catalytic oxidation of aniline solution with sulfate radicals

Metal nanoparticles have been combined with magnet metal–organic frameworks (MOFs) to afford new materials that demonstrate an efficient catalytic degradation, high stability, and excellent reusability in areas of catalysis because of their exceptionally high surface areas and structural diversity. Magnetic M x O y @N-C (M = Fe, Co, Mn) nanocrystals were formed on nitrogen-doped carbon surface by using 8-hydroxyquinoline as a C/N precursor. The Co@N-C, MnO@N-C, and Fe/Fe2O3@N-C catalysts were characterized by X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), N2 adsorption/desorption, and X-ray photoelectron spectroscopy (XPS). The catalytic performances of catalysts were thoroughly investigated in the oxidation of aniline solution based on sulfate radicals (SO4 −.) toward Fenton-like reaction. Magnetic M x O y @N-C exhibits an unexpectedly high catalytic activity in the degradation of aniline in water. A high magnetic M x O y @N-C catalytic activity was observed after the evaluation by aniline degradation in water. Aniline degradation was found to follow the first-order kinetics, and as a result, various metals significantly affected the structures and performances of the catalysts, and their catalytic activity followed the order of Co > Mn > Fe. The nanoparticles displayed good magnetic separation under the magnetic field.

Cobalt super-microparticles anchored on nitrogen-doped graphene for aniline oxidation based on sulfate radicals

Cobalt super-microparticles anchored on nitrogen-doped graphene (Co–NG) were prepared using an inexpensive method and were tested for heterogeneous oxidation of aniline with peroxymonosulfate (PMS) in aqueous solutions. The crystal structure, morphology, and textural properties of Co–NG hybrids were investigated by various characterization techniques, such as X-ray diffraction, Raman spectroscopy, dark-field scanning transmission electron microscopy and X-ray photoelectron spectroscopy. Electron paramagnetic resonance and classical quenching tests were conducted to investigate the mechanism of PMS activation and aniline oxidation. The catalyst Co–NG exhibits an unexpectedly high catalytic activity in the degradation of aniline in water by advanced oxidation technology based on sulfate radicals (SO4−), and 100% decomposition can be achieved in 10min. This paper offers new insights on heterogeneous catalysis.

Photocatalytic degradation of Aniline from aqueous solutions under sunlight illumination using immobilized Cr:ZnO nanoparticles

The present study aimed at synthesizing chromium doped zinc oxide nanoparticles (Cr:ZnO NPs) under mild hydrothermal conditions (temperature ~100 °C, p = autogenous and time ~12 hr). Chromium oxide and n-butylamine were used as dopant and surface modifier, respectively. The characteristics of the synthesized nanoparticles were determined through conducting specialized experiments including powder XRD, FTIR, SEM, EDX, and UV-VIS spectroscopy. Then, the Cr:ZnO NPs were immobilized on a sandblasted glass through thermal method. The photocatalytic degradation of aniline was conducted in a continuous reactor with a volume of 1.5 liters. Before and after photocatalytic degradation, the immobilized Cr:ZnO NPs were characterized for SEM and EDX to determine the degree of stability of immobilized nanoparticles as well as the influence of the current applied on them. The photodegradation operational parameters investigated were aniline initial concentration (150, 200, and 250 mg/L), pH (5, 7, 6, and 12), and reaction time (2, 4, and 6 hours) under sunlight illumination. The characterization results indicated high purity of the Cr:ZnO NPs and no change in morphology or composition even after the immobilization and photo-oxidation process. Finally, it was found that the optimum conditions for 93% removal of aniline under sunlight illumination was about 6 hours retention time at pH 9.