Degradation Of Aniline Research Articles

Fabrication of a stable Ti/TiOxHy/Sb−SnO2 anode for aniline degradation in different electrolytes

A novel anode Ti/TiOxHy/Sb−SnO2 with excellent oxidation ability and long lifetime was successfully fabricated by introducing a TiOxHy interlayer through a simple way. The Ti substrate was modified through thermal oxidation followed by an electrochemical reduction process. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), accelerated lifetime test, scanning electron microscope (SEM) and X-ray diffraction (XRD) were adopted to characterize its morphology, crystal structure and electrochemical properties. These studies indicated that TiOxHy interlayer played a critical role in improving electrode stability. Besides, the electrochemical oxidation of aniline in the NaCl and Na2SO4 were both investigated to test the application of this Ti/TiOxHy/Sb−SnO2 electrode. Results showed that nearly 70% of aniline could be degraded within 2h. After characterization of the intermediates and products, a possible electrochemical degradation mechanism of aniline was proposed. It was worth noting that due to electro-polymerization, some nonconductive oligo(aniline)s could accumulate on the anode surface and lower the oxidation ability of the anode. However, the anode could be recovered repeatedly (at least 5 times) by essential electrochemical activation process, which also relied on the high electrode stability.

Treatment of aniline-contaminated wastewater by sequencing biofilm batch reactor system under Micro-Aerobic condition

Sequencing biofilm batch reactor (SBBR) under micro-aerobic condition was applied to the treatment of aniline-contaminated wastewater in this study. Hydraulic retention time (HRT) of 12—36 h and dissolved oxygen (DO) concentration of 0.1—0.5 mg/L were selected as the operating variables to model, analyze and optimize the process. Five dependent parameters, aniline (AN), chemical oxygen demand (COD), ammonium, total nitrogen (TN) and total phosphorus (TP) removal efficiencies as the process responses, were studied. From the results, increase in DO concentration could promote the AN, COD and ammonium removal; increase in HRT could also lead to increase of the AN and ammonium removal, but might decrease COD removal due to endogenous respiration and soluble microbial products. In the SBBR system, 24 h for HRT and 0.5 mg/L for DO concentration were chosen as the optimum operating condition. The actual removal efficiencies of COD, AN and ammonium under the optimum operating condition were 98.37%, 100% and 89.29%, respectively. The experimental findings were in close agreement with the model prediction. The presence of glucose could promote bacterial growth and has positive influence on AN degradation and ammonium removal.

Ruthenium hydroxide supported on activated alumina for catalytic permanganate oxidation of aniline

Ruthenium loaded on CeO2 or TiO2 has been proved to be effective catalysts in permanganate oxidation, but the small size of supports led to a difficult separation of catalysts from the aqueous solution. Therefore, ruthenium hydroxide supported on activated alumina (diameter 3–4 mm), i.e. Ru-AA, was synthesized and employed as catalyst in permanganate oxidation of aniline at circumneutral pH for the first time. The characterization for Ru-AA by SEM-EDAX proved the existence of Ru on the surface of AA, but XRD patterns for AA were not affected by the impregnation of ruthenium hydroxide, due to its low concentration, low crystallinity, and good dispersion. Acting as an electron shuttle, Ru-AA significantly improved the apparent second-order rate constant (kapp) of aniline oxidation from 10.3 to 18.9 M−1 s−1 with its concentration increasing from 0.55 to 2.2 g L−1. Aniline degradation in catalytic oxidation was markedly influenced by pH, and the kapp decreased from 314.3 to 3.3 M−1 s−1 with increasing pH from 4.0 to 9.0. The intermediates of aniline in the catalytic permanganate oxidation were determined by LC–MS/MS analysis. Ru-AA displayed an excellent stability in first 10 consecutive runs, and the regenerated Ru-AA showed a better performance than the spent one after 15 runs, but less catalytic capability than the virgin one due to the leaching of Ru. The schematic mechanism for Ru-AA-catalyzed permanganate oxidation of aniline was proposed finally.

Ionic Liquid Assisted Synthesis of Hierarchical BiOBr Crystals and Its Application in Visible Photocatalytic Degradation of Aniline

Ionic Liquid Assisted Synthesis of Hierarchical BiOBr Crystals and Its Application in Visible Photocatalytic Degradation of Aniline

Rapid degradation of aniline in aqueous solution by ozone in the presence of zero-valent zinc

The effects of Zn(0) dosage from 0.1 to 1.3gL−1, pH from 2 to 12 and temperature from 288 to 318K on the degradation of aniline in aqueous solution by ozone in the presence of Zn(0) were investigated through batch experiments. The results demonstrated that Zn(0) had a significantly synergistic role in the degradation of aniline by ozone. A complete decomposition of the initial aniline (10mgL−1) was achieved by ozone together with Zn(0) within 25min, and meanwhile nearly 70% of the total organic carbon in the solution was removed. The decomposition efficiency of aniline markedly increased with an increase of Zn(0) dosage. However, temperature exerted a slight impact on the degradation of aniline and the optimum removal efficiency of aniline was realized at 298K. Aniline was efficiently degraded at all the tested pHs except for 12. Free radicals were investigated by electron paramagnetic resonance technique and free radical scavengers. H2O2 concentration generated during the reactions was analyzed using a photometric method. Based on the results obtained in this study, it is proposed that O2− instead of OH is the dominant active species responsible for the degradation of aniline. It is concluded that ozone combined with Zn(0) is an effective and promising approach to the degradation of organic pollutants.

Identification of Anaerobic Aniline-Degrading Bacteria at a Contaminated Industrial Site.

Anaerobic aniline biodegradation was investigated under different electron-accepting conditions using contaminated canal and groundwater aquifer sediments from an industrial site. Aniline loss was observed in nitrate- and sulfate-amended microcosms and in microcosms established to promote methanogenic conditions. Lag times of 37 days (sulfate amended) to more than 100 days (methanogenic) were observed prior to activity. Time-series DNA-stable isotope probing (SIP) was used to identify bacteria that incorporated (13)C-labeled aniline in the microcosms established to promote methanogenic conditions. In microcosms from heavily contaminated aquifer sediments, a phylotype with 92.7% sequence similarity to Ignavibacterium album was identified as a dominant aniline degrader as indicated by incorporation of (13)C-aniline into its DNA. In microcosms from contaminated canal sediments, a bacterial phylotype within the family Anaerolineaceae, but without a match to any known genus, demonstrated the assimilation of (13)C-aniline. Acidovorax spp. were also identified as putative aniline degraders in both of these two treatments, indicating that these species were present and active in both the canal and aquifer sediments. There were multiple bacterial phylotypes associated with anaerobic degradation of aniline at this complex industrial site, which suggests that anaerobic transformation of aniline is an important process at the site. Furthermore, the aniline degrading phylotypes identified in the current study are not related to any known aniline-degrading bacteria. The identification of novel putative aniline degraders expands current knowledge regarding the potential fate of aniline under anaerobic conditions.

Comparative genome analysis reveals genetic adaptation to versatile environmental conditions and importance of biofilm lifestyle in Comamonas testosteroni.

Comamonas testosteroni is an important environmental bacterium capable of degrading a variety of toxic aromatic pollutants and has been demonstrated to be a promising biocatalyst for environmental decontamination. This organism is often found to be among the primary surface colonizers in various natural and engineered ecosystems, suggesting an extraordinary capability of this organism in environmental adaptation and biofilm formation. The goal of this study was to gain genetic insights into the adaption of C. testosteroni to versatile environments and the importance of a biofilm lifestyle. Specifically, a draft genome of C. testosteroni I2 was obtained. The draft genome is 5,778,710 bp in length and comprises 110 contigs. The average G+C content was 61.88 %. A total of 5365 genes with 5263 protein-coding genes were predicted, whereas 4324 (80.60 % of total genes) protein-encoding genes were associated with predicted functions. The catabolic genes responsible for biodegradation of steroid and other aromatic compounds on draft genome were identified. Plasmid pI2 was found to encode a complete pathway for aniline degradation and a partial catabolic pathway for chloroaniline. This organism was found to be equipped with a sophisticated signaling system which helps it find ideal niches and switch between planktonic and biofilm lifestyles. A large number of putative multi-drug-resistant genes coding for abundant outer membrane transporters, chaperones, and heat shock proteins for the protection of cellular function were identified in the genome of strain I2. In addition, the genome of strain I2 was predicted to encode several proteins involved in producing, secreting, and uptaking siderophores under iron-limiting conditions. The genome of strain I2 contains a number of genes responsible for the synthesis and secretion of exopolysaccharides, an extracellular component essential for biofilm formation. Overall, our results reveal the genomic features underlying the adaption of C. testosteroni to versatile environments and highlighting the importance of its biofilm lifestyle.

Investigation of the Activity of TiO2 Nanotubes towards the Photocatalytic Degradation of Aniline

The high density and well ordered TiO2nanotube array material was successfully application in photocatalytic degradation aniline organic wastewater analog under 254 nm, 300 nm and 365 nm UV irradiation. The results exhibited that the rate of degradation of aniline reached 99% under the concentration of aniline was 0.33 mmol•L-1, PH=7, intensity of UV irradiation was 254 nm and reaction time was 120 min. The factors that influence the rate of degradation were also investigated.

Degradation of Aniline Wastewater Using Dielectric Barrier Discharges at Atmospheric Pressure**supported by National Natural Science Foundation of China (No. 51377075), the Natural Science Foundation of Jiangsu Province of China (No. BK20131412), the Environmental Protection Scientific Foundation of Jiangsu Province of China (No. 201004)

Aniline is a toxic water pollutant detected in drinking water and surface water, and this chemical is harmful to both human and aquatic life. A dielectric barrier discharge (DBD) reactor was designed in this study to investigate the treatment of aniline in aqueous solution. Discharge characteristics were assessed by measuring voltage and current waveforms, capturing light emission images, and obtaining optical emission spectra. The effects of several parameters were analyzed, including treatment distance, discharge power, DBD treatment time, initial pH of aniline solutions, and addition of sodium carbonate and hydrogen peroxide to the treatment. Aniline degradation increased with increasing discharge power. Under the same conditions, higher degradation was obtained at a treatment distance of 0 mm than at other treatment distances. At a discharge power of 21.5 W, 84.32% of aniline was removed after 10 min of DBD treatment. Initial pH significantly influenced aniline degradation. Adding a certain dosage of sodium carbonate and hydrogen peroxide to the wastewater can accelerate the degradation rate of aniline. Possible degradation pathways of aniline by DBD plasmas were proposed based on the analytical data of GC/MS and TOC.

Low-temperature biodegradation of aniline by freely suspended and magnetic modified Pseudomonas migulae AN-1

Aniline is of great environmental concern with regards to widespread occurrence in water and soil and increasing threat into the life forms. Bioremediation involving the use of degrading bacterium in the removal of aniline is the most promising process, yet inhibited under low temperature usually. In the present study, a new psychrotrophic bacterial strain isolated from groundwater, designated AN-1, was shown to be capable of aniline degradation in a concentration range of 135-2202 mg L(-1) within 72 h at 10 °C. Strain AN-1 was proposed to be a Pseudomonas migulae group of bacteria based on the evolutionary relationship and the morphological and biochemical characteristics. The pH, NaH2PO4, and aniline concentration were used as independent variables to optimize the aniline removal by AN-1 at 10 °C, and a statistically significant (R (2) = 0.9230, p < 0.005) quadratic polynomial mathematical model was suggested. Moreover, an efficient biocomposite by assembling Fe3O4 nanoparticles onto the surface of AN-1 cells was constructed. Compared with free cells, the microbial cell/Fe3O4 biocomposite had the same biodegradation activity but exhibited remarkable reusability. This study highlights AN-1 might be a promising candidate for aniline removal from wastewater at low temperatures.

Mineralization of aniline in aqueous solution by electrochemical activation of persulfate

Oxidative degradation of aniline in aqueous solution was carried out by coupling electrolysis with persulfate oxidation, in which a synergistic effect occurred. Experiments were performed under a batch-wise mode to evaluate the influence of various operation parameters on the electrolytic behavior, such as acidity of aqueous solution, temperature, electrode potential, persulfate anion concentration and nitrogen/oxygen gas dosage. The aniline pollutants could be almost entirely mineralized by means of electro-activated persulfate oxidation, wherein sulfate radicals were presumed to be principal oxidizing agents. Besides, electrogenerated hydrogen peroxide originated from cathodic reduction of oxygen, supplied chiefly by anodic oxidation of water, would contribute partially for decomposition of aniline. On the whole, the electro-activated persulfate process is a very promising method for treatment of aniline in wastewater.

Self-Driven Bioelectrochemical Mineralization of Azobenzene by Coupling Cathodic Reduction with Anodic Intermediate Oxidation

Bioelectrochemical systems have been intensively studied as a promising technology for wastewater treatment and environment remediation. Coupling of the anodic and cathodic electrochemical reactions allows an enhanced degradation of recalcitrant organics, but external power supply is usually needed to overcome the thermodynamic barrier. In this work, we report a self-driven degradation of azobenzene in a microbial fuel cell (MFC), where the cathodic reduction of azobenzene was effectively coupled with the anodic oxidation of its reduction degradation intermediate (i.e., aniline). The anodic degradation rate of aniline, as the sole carbon source, was significantly higher than that under open-circuit conditions, suggesting a considerable bioelectrochemical oxidation of aniline. Output voltages up to 8mV were obtained in the MFC. However, a shift of cathodic electron acceptor from oxygen to azobenzene resulted in a decreased aniline degradation rate and output voltage. The present work may provide valuable implications for development of sustainable bioelectrochemical technologies for environmental remediation.

Kinetics and mechanism of chlorinated aniline degradation by TiO2 photocatalysis

Abstract Photooxidation of 4-chloroanaline (4-CLA) in UV/TiO2/H2O2 system was investigated in the following working conditions: pH 4; [TiO2] = 50–500 mg/L; [H2O2] = (0.1–10) × 10−3 M; τirr = 5–180 min A pollutant degradation pathway by four possible routes was proposed, according to organic intermediates identified by gas-chromatography coupled with mass spectrometry-screening method. Based on experimental results can be concluded that after 90 min of irradiation, 4-CLA was completely degraded in the presence of H2O2 (1 × 10−3 M). Mineralization yields of organic chlorine and nitrogen were ≥88% for prolonged irradiation time (180 min). These results are consistent with the proposed degradation pathway that presents as intermediates, aromatic compounds like 4-chlorophenol, 4-aminophenol, 4-chloronitrobenzene, and aniline. The presence of these intermediates in irradiated samples is also supported by 82.4% TOC removal yield obtained at prolonged irradiation time.

Interplay of Photoabsorption, Electronic Structure, and Recombination Rate of Charge Carriers on Visible Light Driven Photocatalytic Activity of Cu‐ and N‐Doped Ba3V2O8

AbstractPalmierite Ba3V2O8 and related Cu‐ and N‐doped congeners were prepared by sol‐gel, ion‐exchange, and solid‐state reactions, respectively, with the aim of tailoring their optical, electronic, and photocatalytic properties. The catalysts were characterized by XRD analyis, UV/Vis diffuse reflectance spectroscopy, SEM with energy‐dispersive X‐ray spectroscopy, photoluminence spectroscopy, BET measurements, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and TEM analysis. The electronic structures of Cu‐ and N‐doped optimal compositions were calculated theoretically on the basis of density functional theory. A series of photocatalytic degradation experiments of methylene blue under visible light irradiation disclosed the optimal dopant concentrations of Cu and N into Ba3V2O8, and the photocatalytic ability of the optimal compositions was also tested by the degradation of aniline. The differences in the degradation performance of Cu‐ and N‐doped samples are discussed on the basis of inextricably linked parameters such as photoabsorption, electronic structure, and mobility of the photoinduced charge carriers.

Biodegradation of Aniline by Alkaliphilic Strain &lt;i&gt;Bacillus&lt;/i&gt; s&lt;i&gt;p.&lt;/i&gt; Strain AN2 under High Salinity Condition

Aniline is considered as an environment hazard. Aniline-containing wastewater frequently has elevated salinity and high pH, which is generally not degraded by neutrophilic bacteria. The research explored the degradation ability of aniline by the novel isolated bacterial strain under alkaline and hyperhaline conditions. The strain was designated Bacillus sp. AN2 based on 16S rDNA sequence and Biolog Microstation Identification System. This strain had an unusually high salinity tolerance in minimal medium (0-6% NaCl, w/v). The optimal pH for microbial growth and aniline biodegradation was pH 9.0. For the initial concentrations of 200, 500, and 800 mgL-1, 95%, 74% and 62% of the aniline was degraded, respectively. The results suggest that the strain has potential for aniline degradation under alkaline and elevated salinity environmental conditions.

Ru(III) catalyzed permanganate oxidation of aniline at environmentally relevant pH

Ru(III) was employed as catalyst for aniline oxidation by permanganate at environmentally relevant pH for the first time. Ru(III) could significantly improve the oxidation rate of aniline by 5–24 times with its concentration increasing from 2.5 to 15μmol/L. The reaction of Ru(III) catalyzed permanganate oxidation of aniline was first-order with respect to aniline, permanganate and Ru(III), respectively. Thus the oxidation kinetics can be described by a third-order rate law. Aniline degradation by Ru(III) catalyzed permanganate oxidation was markedly influenced by pH, and the second-order rate constant (ktapp) decreased from 643.20 to 2.67 (mol/L)−1sec−1 with increasing pH from 4.0 to 9.0, which was possibly due to the decrease of permanganate oxidation potential with increasing pH. In both the uncatalytic and catalytic permanganate oxidation, six byproducts of aniline were identified in UPLC–MS/MS analysis. Ru(III), as an electron shuttle, was oxidized by permanganate to Ru(VI) and Ru(VII), which acted the co-oxidants for decomposition of aniline. Although Ru(III) could catalyze permanganate oxidation of aniline effectively, dosing homogeneous Ru(III) into water would lead to a second pollution. Therefore, efforts would be made to investigate the catalytic performance of supported Ru(III) toward permanganate oxidation in our future study.

Effect of chelating agent on oxidation rate of aniline in ferrous ion activated persulfate system at neutral pH

In the interest of accelerating aniline degradation, Fe2+ and chelated Fe2+ activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric acid, oxalic acid and ethylenediamine tetraaceatate (EDTA) to maintain available Fe2+. The results indicate that the concentration of chelating agent and ferrous ion didn’t follow a linear relationship with the degradation rate of aniline. A 1/1 ratio of chelating agent/Fe2+ results in a higher degradation rate compared to the results by other ratios. The oxidation enhancement factor using oxalic acid was found to be relatively low. In contrast, citric acid is more suitable chelating agent in the ferrous iron activated persulfate system and aniline exhibits a highest degradation with a persulfate/Fe2+/citric acid/aniline molar ratio of 50/25/25/1 compared to other molar ratios.

Magnetic Titanium Dioxide Nanocomposites for Surface‐Enhanced Resonance Raman Spectroscopic Determination and Degradation of Toxic Anilines and Phenols

Mesoporous M-TiO2 NCs, functionalized by PATP, can capture toxic anilines and phenols by azo coupling. Loading these nanodevices with Ag NPs offers the possibility for a sensitive quantitative determination of target compounds by SERRS spectroscopy, which allows multiplex detection because of the specific vibrational fingerprints. Sensitivity and selectivity can be further enhanced by concentrating the hybrid particles by an external magnet and compound-specific binding (anilines versus phenols). The bound toxic compounds can be degraded by TiO2-assisted photocatalysis after removal of the loaded hybrid particles from the sample solution with an external magnet. The degradation process can be enhanced in the presence of plasmonic Ag nanostructures.

Degradation of aniline with zero-valent iron as an activator of persulfate in aqueous solution

Zero valent iron (ZVI) can activate persulfate to generate sulfate free radicals which are a strong oxidant to degrade organic pollutants. The oxidative degradation of aniline in aqueous solution by persulfate activated with zero valent iron was studied under laboratory conditions. Batch experiments were conducted to investigate the effects of different parameters such as pH, ZVI concentration, aniline concentration, persulfate concentration and reaction temperature on aniline degradation. The results showed that aniline degradation increased with increasing temperature. The optimum dosage of ZVI was 0.4 g L−1 and 85% aniline degradation was observed. Maximum aniline degradation was observed at pH 4.0, whereas at pH above or below 4.0, aniline degradation efficiency was decreased. In the persulfate-ZVI system, the apparent energy of activation for aniline degradation was 14.85 kJ mol−1. The existence of persulfate radicals and hydroxyl radicals produced during the degradation of aniline were identified with scavenger ethanol and tert-butyl alcohol. The reaction intermediates nitrobenzene, nitroso-benzene and p-benzoquinone were detected by gas chromatography-mass spectrometry and based on these intermediates obtained a probable pathway for aniline degradation has been proposed.

Photocatalytic Degradation of Aniline Using Supported TiO2/Charcoal Composite

Photocatalytic Degradation of Aniline Using Supported TiO2/Charcoal Composite