Degradation Rate Of Aniline Research Articles

Activation of peroxydisulfate via BiCoFe-layered double hydroxide for effective degradation of aniline.

The sulfate radical-based advanced oxidation processes (SR-AOPs) is a promising method for the degradation of pollutants, with the development of highly efficient catalysts for persulfate activation has been widely concerned. The novel BiCoFe-LDH (BCF-x) was synthesized successfully by coprecipitation method, which can activate peroxydisulfate (PDS) efficiently to degrade aniline. Comparative analysis with pure CoFe-LDH revealed a remarkable increase in reaction rate constant by approximately 14.66 times; the degradation rate of aniline (10mg/L) was 100% in 60min with the condition of 0.5g/L BCF-1.5 and 0.5g/L PDS, due to BCF-1.5 which was characterized as a complex of CoFe-LDH and Bi2O2CO3, promoting electron transport to improve the efficiency of activated PDS. In the reaction system, SO4•-, ·OH, and 1O2 were responsible for the aniline degradation and ·OH was the primary one. Furthermore, this work proposes a reaction electron transfer catalytic mechanism, which provided a new insight and good application prospect for efficient activation of PDS for pollutant degradation.

Remediation and resource utilization of petroleum-contaminated soil by pyrite-assisted pyrolysis as bifunctional materials to adsorb heavy metal and activate peroxymonosulfate oxidation

Petroleum-contaminated soil (PCS) requires not only efficient remediation technology but also economically viable reuse strategy of remediated soil with vast volume. This study developed a pyrite-assisted pyrolysis to convert PCS into a bifunctional material for the adsorption of heavy metal and the activation of peroxymonosulfate (PMS) oxidation. Adsorption isotherm and kinetic model fitting by Langmuir and pseudo-second-order well clarified the adsorption capacity and behavior of carbonized soil (CS) loaded with sulfur and iron (FeS@CS) for heavy metals. The theoretic maximum adsorption capacities of Pb2+, Cu2+, Cd2+, and Zn2+ by Langmuir model were 415.40, 80.25, 61.55, and 30.90 mg/g, respectively. The main adsorption mechanism includes sulfide precipitation, co-precipitation and surface complexation by iron oxides, and complexation by oxygen-containing functional groups. When the dosage of FeS@CS and PMS were both 3 g/L, the removal rate of aniline reached 99.64 % in 6 h. After five cycles of reuse, the aniline degradation rate was still as high as 93.14 %. The non-free radical pathway dominated in CS/PMS and FeS@CS/PMS systems. The electron hole was the primary active species in the CS/PMS system, which promoted aniline degradation by accelerating direct electron transfer. In comparison with CS, the surface of FeS@CS contained more iron oxides, oxygen-containing functional groups, and oxygen vacancies, making 1O2 the primary active species in the FeS@CS/PMS system. This study proposed a new integrated strategy for the efficient remediation of PCS and value-added reutilization of remediated soil.

Evaluating the influence of gradient applied voltages on electro-enhanced sequence batch reactor treating aniline wastewater: System performance, microbial community and functional genes

Aniline is an important industrial raw material. Its complex structure makes it difficult to be chemically oxidized and its intense biological toxicity also increases the difficulty of biodegradation. Therefore, electro-biological system based on biological processing have become a new direction in the field of environmental governance. Comparative evaluation of the performance differences of reactors at gradient external voltages (1.5, 3.0, 4.5 and 6.0 V) was investigated to seek the optimal applied voltage in the electro-enhanced sequence batch reactor treating aniline wastewater. Results showed that all reactors degraded aniline effectively, the aniline degradation rate of five reactors was about 100%. However, the highest removal efficiency of total nitrogen was obtained at 1.5 V, up to 88.89%. Compared with control, high applied voltage (>3.0 V) deteriorated the nitrification performance and the removal efficiency of TN was descended along with the increase of applied voltages. Besides, proper applied voltage promoted the secretion of extracellular polymeric substance. The sludge activity such as specific oxygen utilization rate (SOUR), dehydrogenase (DHA) was highly increased under the applied voltage of 1.5V, so did the Ammonia monooxygenase (AMO) and nitrate reductase (NAR). Based on the high-throughput sequencing analysis, introducing applied voltages altered the microbial diversity and community structure. Particularly, several functional genera such as autotrophic nitrifying bacteria and denitrifying bacteria were enriched in the system at 1.5V. Network analysis also found that the cooperative/competitive relationship between key functional genus became simpler under the higher voltage. Additionally, the contribution of the functional flora to key metabolic pathways (benzoate and nitrogen metabolism) and the expression of various functional genes was augmented at the 1.5V applied voltage.

An attempt to stimulate aniline degrading bioreactor by exogenous auto-inducer: Decontamination performance, sludge characteristics, and microbial community structure response

To break the contradiction between aniline and nitrogen metabolism in activated sludge reactor by influencing microbial interspecific communication, Auto-inducer C6-HSL and 3-oxo-C8-HSL were selected in this study to interfere with aniline degradation system. The two Auto-inducers enhanced the aniline degradation rate and ammonia removal efficiency of the systems, especially C6-HSL. Meanwhile, the main ammonia removal way was assimilation. Exogenous Auto-inducer effectively stabilized the sludge structure and activity from the destruction of aniline, and promoted EPS secretion. Microbial diversity analysis showed that most of functional microflora of seed sludge gradually deactivated with the operation of the reactor, while Rhodococcus, Leucobacter, g_norank_f_Saprospiraceae proliferated wildly under the action of Auto-inducer. Additionally, the interspecific relationship also demonstrated a different trend. Exogenous Auto-inducer was proved to exert positive effects on aniline degradation system to a certain extent, providing new insights in the field of aniline wastewater bio-degradation.

Electrochemical oxidation of aniline using a high-flux CNT filter

Carbon nanotube (CNT) membrane electrochemical filtration has been found to provide effective solutions for water contaminant removal. However, bubble elimination, water flux increase, and CNT membrane robustness enhancement still remain great challenges for CNT electrochemical filtration technologies. To improve the performance of the electrochemical CNT filter, a ceramic flat membrane is used as the CNT electrode support. Aniline (AN) is chosen as the target pollutant to investigate the effects of water quality (initial pH, initial AN concentration, and support electrolyte concentration) and running conditions (anode potential and water flux). In addition, the current efficiencies (CE) of the two different modes (single-pass filtration and recirculated filtration) are also estimated. The results showed that the effects of various impact factors on the AN degradation were generally similar in both modes. Overall, the CEs of the sing-pass filtration mode with the stable influent conditions were higher than those of the recirculation filtration mode. Increasing the flux and applied anode potential did increase the AN degradation rate. The maximum water flux density of the high-flux CNT electrochemical filter reached 83.9 mL/(cm2·h), 4.0–16.1 fold of that of a typical CNT electrochemical filter, addressing the defects of bubble formation and CNT fragility of the free-standing BUCKYPAPER membrane in a conventional electrochemical filter. The configuration with a ceramic membrane support greatly improved the practicability of CNT-based electrochemical filtration technology for real wastewater treatment.

Study on the capability of a bacterial strain for aniline degradation under some specific circumstances

The purpose of the study is to explore the characteristics of a laboratory cultured bacterial strain Delftia sp. named AD1 for aniline degradation. Several degradation conditions were studied to provide information for biological treatment of aniline-containing wastewater. The bacterial strain AD1 is salt-tolerant, and the most suitable salt concentration for the growth of AD1 and the biodegradation of aniline is 5% (NaCl w/v), but when the salinity surpasses 5%, the growth of AD1 and the biodegradation of aniline could be restricted. The copper ion (Cu2+) had the most significant restriction impact on the growth of AD1, but up to 99.9% of aniline (initial concentration: 600mg/L) can be degraded under the effect of heavy metal ion. Both the single bacterial strain AD1 and mixed bacterial strains (AD1 and nitrifying bacteria) can efficiently degrade aniline, and the degradation rate of aniline for both groups reached 99.9%. However, the mixed bacterial strains did not show palpable advantage of the speed of aniline degradation over single bacterial strain AD1. Though nitrifying bacteria in the mixed bacterial strains was expected to degrade the ammonia nitrogen produced in aniline biodegradation process, there was no conspicuous difference in the concentration of ammonia nitrogen and total nitrogen between the samples of single bacterial strain AD1 and mixed bacterial strains.

Enhanced aniline degradation by Desulfatiglans anilini in a synthetic microbial community with the phototrophic purple sulfur bacterium Thiocapsa roseopersicina

Desulfatiglans anilini is a sulfate-reducing bacterium (SRB) capable of oxidizing aniline, although growth and aniline turnover rates are slow, making it difficult to analyze the metabolism of the strain. Therefore, this study was designed to investigate the effect of sulfide on growth of D. anilini cultures, in order to improve its growth and aniline turnover rates, and study the biochemical mechanisms of sulfide inhibition. Hydrogen sulfide was found to inhibit growth of D. anilini, regardless of whether the strain was grown with aniline or phenol, and complete inhibition was observed at 20mM hydrogen sulfide. For improving the growth of D. anilini with aniline, the sulfide-consuming phototrophic bacterium Thiocapsa roseopersicina was co-cultured in a synthetic microbial community with D. anilini using a co-cultivation device that continuously removed hydrogen sulfide from the culture. The doubling time of D. anilini with aniline was 15 days in the co-cultivation device, compared to 26 days in the absence of a sulfide-oxidizing partner. Moreover, the aniline degradation rate was significantly increased by a factor of 2.66 during co-cultivation of D. anilini with T. roseopersicina. The initial carboxylation reaction during aniline degradation was measured in cell-free extracts of D. anilini with carbon dioxide (CO2) as a co-substrate in the presence of aniline and ATP. The effects of hydrogen sulfide on this aniline carboxylating system and on phenylphosphate synthase activity for phenol activation were studied, and it was concluded that hydrogen sulfide severely inhibited these enzyme activities.

Fabrication of hierarchical g-C3N4/MXene-AgNPs nanocomposites with enhanced photocatalytic performances

Ag-decorated g-C3N4/Ti3C2 ternary plasmonic photocatalysts with improved visible-light photocatalytic activity of aniline were investigated. The maximum degradation rate of aniline reached to 81.8%, which could be attributed to the enhanced visible light absorption efficiency caused by surface plasmon resonance (SPR) of AgNPs, as well as the effective separation of photogenerated charge carriers owing to MXenes. This work provides a new strategy for the construction of MXene-based photocatalysts.

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).

Biodegradation of aniline by Enterobacter ludwigii KH-5 isolated from the soil around Shiraz refinery, Iran

&lt;div&gt; &lt;p&gt;Aniline is a harmful substance that pollutes the environment and seriously endangers human health. In the present study five different bacteria were enriched and isolated from the soil around Shiraz refinery (Iran) as aniline degrading bacteria. They were identified as &lt;em&gt;Enterobacter ludwigii &lt;/em&gt;KH-5,&lt;em&gt; Raoultella planticola&lt;/em&gt; KH-A2&lt;em&gt;, Alcaligenes faecalis&lt;/em&gt; KH-A3&lt;em&gt;, Serratia marcescens&lt;/em&gt; KH-A4 and&lt;em&gt; Microbacterium barkeri&lt;/em&gt; KH-A1 based on 16S rDNA gene sequencing. The highest aniline degradation rate (96%) was observed by &lt;em&gt;E. ludwigii&lt;/em&gt; KH-A5. This strain with the greatest amount of minimum inhibitory concentration (MIC) was the most aniline resistant bacterium. The optimum pH and temperature that supported biodegradation of aniline by strain KH-A5 were 7.0 and 28-35 &amp;deg;C, respectively. The maximum growth and biodegradation of aniline by KH-A5 were observed at the initial aniline concentration of 100 mg l&lt;sup&gt;-1&lt;/sup&gt;. The strain could growth on aniline up to concentration of 700 mg l&lt;sup&gt;-1&lt;/sup&gt; with the degradation rate of 11%. Further studies demonstrated that the addition of 0.5 g l&lt;sup&gt;-1&lt;/sup&gt; glucose or potassium nitrate as a second carbon or nitrogen source could slightly enhance the biodegradation efficiency from 96.0% to 99.0%. However, even more addition of glucose or potassium nitrate could not further enhance the biodegradation process but delayed the biodegradation of aniline by the strain KH-A5. It could be concluded that these new strains, particularly&lt;em&gt; E. ludwigii&lt;/em&gt; KH-A5, have a potential use for bioremediation of the site contaminated with aniline.&lt;/p&gt; &lt;/div&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Bioaugmentation with GFP-Tagged Pseudomonas migulae AN-1 in Aniline-Contaminated Aquifer Microcosms: Cellular Responses, Survival and Effect on Indigenous Bacterial Community.

The recently isolated aniline-degrading bacterium Pseudomonas migulae AN-1 was tagged with green fluorescent protein (GFP) to investigate its bioaugmentation potential against anilinecontaminated groundwater through microcosm experiments. The survival and cellular response of GFP-tagged AN-1 introduced in a lab-scale aquifer corresponded directly with aniline consumption. During the process, the GFP-tagged AN-1 biomass increased from 7.52 × 10⁵ cells/ml to 128 × 10⁵ cells/ml and the degradation rate of aniline was 6.04 mg/l/h. GFP-tagged AN-1 was moderately hydrophobic (41.74%-47.69%) when treated with 20- 100 mg/l aniline and exhibited relatively strong hydrophobicity (55.25%-65.78%) when the concentration of aniline was ≥100 mg/l. The membrane permeability of AN-1 increased followed by a rise in aniline below 100 mg/l and was invariable with aniline above 100 mg/l. Pyrosequencing analysis showed that the relative abundance of Proteobacteria (accounted for 99.22% in the non-bioaugmentation samples) changed to 89.23% after bioaugmentation with GFP-tagged AN-1. Actinobacteria increased from 0.29% to 2.01%, whereas the abundance of Firmicutes barely changed. These combined findings demonstrate the feasibility of removing aniline in aquifers by introducing the strain AN-1 and provide valuable information on the changes in the diversity of dominant populations during bioaugmentation.

Efficacy of forming biofilms by Pseudomonas migulae AN-1 toward in situ bioremediation of aniline-contaminated aquifer by groundwater circulation wells.

The formation and activity of aniline-degrading biofilms developed by the psychrotrophic Pseudomonas migulae AN-1 were studied for the in situ remediation of contaminated aquifer using in-well bioreactor of groundwater circulating wells (GCWs). Biofilms grown in mineral salt medium with aniline exhibited tolerance to high concentrations of aniline. In aniline degradation rate, AN-1 biofilms exhibited slight differences compared with planktonic cells. The effectiveness and bio-implication of AN-1 biofilms in GCWs were investigated to treat aniline-contaminated aquifer. The results demonstrate that AN-1 biofilms survived the GCWs treatment process with high aniline-degrading efficiency. This system provides a novel environmentally friendly technology for the in situ bioremediation of low-volatile contaminants.

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.

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.

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.

Orthogonal Study on the Degradation of Aniline Process Parameters by Ultrasonic

Objective: To optimize the ultrasonic degradation of aniline wastewater process parameters. Methods: ultrasonic power, ultrasonic time, ultrasonic temperature, pH value, etc. 4 orthogonal factors and determine the optimum process conditions. Results: In the ultrasonic power 320W, ultrasonic time was 60min, ultrasonic temperature is 30 °C, pH value of 4 under the action of ultrasound sonication best, under optimum conditions, aniline degradation rate of 90.08%, and the various factors the impact of the size order of ultrasonic temperature&gt; ultrasonic time&gt; ultrasonic power&gt; solution pH. Conclusion: Ultrasonic degradation of organic matter, is easy to operate, efficient, non-polluting or less polluting characteristics, is a better degradation of aniline wastewater new technology.

Analysis Degradation Effect of Aniline Wastewater by Ultrasound

aniline solution for the study, the effects of ultrasonic time, reaction factors such as temperature, ultrasonic power, and the pH of its ultrasonic degradation rate. Experimental results show that: as time increases, the ultrasonic degradation rate of aniline also rise, When the ultrasound the irradiation time 80min, aniline degradation rate reached 89.3%, 90min when the degradation rate of 92.1%, the degradation rate of aniline with decreases with the rise of the temperature of the solution, more than 40°C the degradation rate decreased significantly. Aniline degradation rate increased with the initial solution pH value increases, indicating that the alkaline conditions are favorable for degradation of aniline solution. Relative to the traditional method, the method is fast, simple, degradation rate, etc..

Degradation of aniline by Fe2+-activated persulfate oxidation at ambient temperature

The aniline degradation by persulfate activated with ferrous ion (Fe2+) was investigated in batch reactor at ambient temperature. The experimental factors in aqueous solutions including persulfate concentration, Fe2+ concentration, pH and ionic strength level were discussed. It is demonstrated that, aniline degradation rate increases with increasing persulfate concentration, but much more ferrous ion inhibits the aniline degradation. When the aniline concentration is 0.10 mmol/L, the maximum aniline degradation occurs at the S2O8 2− to Fe2+ molar ratio of 250/5 at pH 7.0. In the pH range of 5.0–8.5, increasing pH causes higher aniline degradation. What’s more, the increase of ionic strength in solution causes inhibiting in the reaction. Produced intermediates during the oxidation process were identified using gas chromatography-mass spectrometry (GC-MS) technology. And degradation pathways of aniline were also tentatively proposed.

Comparison of Aniline Degradation by Fenton and Electro‐Fenton Reactors Using Plate and Rod Electrodes

Aniline degradation was investigated using the conventional Fenton process and an electro‐Fenton (EF) process with plate and rod electrode EF reactors. The performance of the two EF reactors was evaluated by determining the effect of important parameters (Fe2+, H2O2, and aniline concentrations) on the aniline removal efficiency and the initial aniline degradation rate. The change in the biochemical oxygen demand (BOD5) and ratio BOD5/COD of a high concentration of aniline were also studied.Experimental results reveal that compared with conventional Fenton process, aniline degradation and chemical oxygen demand (COD) removal in the EF process increased 43% and 10%, respectively. In the two EF reactors, the aniline was completely degraded (100%) when the ratio of [H2O2]:[Fe2+]:[aniline] was 5.8:0.1:1. Within the range of Fenton's reagent used in the two reactors, controlling the H2O2 concentration was the key point of promoting the aniline oxidation. The plate electrode system had a higher efficiency than rod electrode system in terms of H2O2 efficiency, due to the reactor design of decreasing the electrical resistance. Treatment with a high concentration aniline increased biodegradability (BOD5 and ratio BOD5/COD) of pollutant when plate and rod electrode EF reactors were used. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1111–1117, 2013

Degradation kinetics and mechanism of aniline by heat-assisted persulfate oxidation

Oxidation of aniline by persulfate in aqueous solutions was investigated and the reaction kinetic rates under different temperature, persulfate concentration and pH conditions were examined in batch experiments. The results showed that, the aniline degradation followed pseudo first-order reaction model. Aniline degradation rate increased with increasing temperature or persulfate concentration. In the pH range of 3 to 11, a low aniline degradation rate was obtained at strong acid system (pH 3), while a high degradation rate was achieved at strong alkalinity (pH 11). Maximum aniline degradation occurred at pH 7 when the solution was in a weak level of acid and alkalinity (pH 5, 7 and 9). Produced intermediates during the oxidation process were identified using liquid chromatography-mass spectrometry technology. And nitrobenzene, 4-4′-diaminodiphenyl and 1-hydroxy-1,2-diphenylhydrazine have been identified as the major intermediates of aniline oxidation by persulfate and the degradation mechanism of aniline was also tentatively proposed.