Quinoline Mineralization Research Articles

Microbial degradation of quinoline by immobilized bacillussubtilis

Quinoline containing effluent discharged from pharmaceuticals, dyes and pesticide industries pollute the environment affecting human health due to its toxicity and nauseating odor. Quinoline is carcinogenic, mutagenic and toxic to the environment. Biotreatment is a viable process as quinoline gets easily degraded by microbes. We isolated a bacterium from the soil suspension of paper mill effluent and it was analyzed by Institute of Microbial Technology, Chandigarh from biochemical, morphological and physiological tests. The test results match with Bacillus subtilis as per the Bergey's manual of systematic Bacteriology. Quinoline mineralization by free and immobilized cells was studied. Adsorption technique was used for immobilization. 100 ppm of quinoline was completely degraded in 45 h by the free cells whereas cells immobilized on coconut shell carbon takes only 30 h. Cells on coconut shell carbon are capable of degrading even 300 ppm quinoline completely in 70 h. It was also found that cells immobilized on activated coconut shell carbon were more effective than cells on foam pieces. The optimum pH for efficient quinoline degradation was 9. The stability and recyclability of immobilized cells for 3 months at different concentrations for quinoline degradation was tested by performing an experiment. The excellent storage stability and recyclability of immobilized Bacillus subtilis can be critically used for the mineralization of heterocyclic organics in wastewater.

Enhanced degradation of quinoline by coupling microbial electrolysis cell with anaerobic digestion simultaneous

In this study, the feasibility of quinoline-wastewater treatment was investigated in a coupled microbial electrolysis cell and anaerobic digestion system (MEC-AD). Improved degradation and enhanced mineralization of quinoline were obtained, and the optimal voltage was determined to be 1.0 V. Effective removal of quinoline at relative high concentration, and a 1.5-fold increase in methane production were achieved. The results indicated that the MEC-AD could simultaneously remove carbon and nitrogen from quinoline. Gas chromatography-mass spectrometry analysis identified 2-hydroxyquinoline and 8-hydroxycoumarin as the intermediates of quinoline. The formation and degradation of metabolites were rapid, and they did not accumulate in the MEC-AD. The results of microbial community structure analysis demonstrated that the functional species were enriched and coexisted, and that the dominant bacterial genera were SM1A02, Comamonas, Desulfovibrio, Geobacter, and Actinomarinales_norank; the dominant archaeal genera were Methanocorpusculum and Nitrosoarchaeum. Furthermore, the applied current played a selective role in the enrichment of microorganisms.

Enhancing photocatalytic degradation of quinoline by ZnO:TiO2 mixed oxide: Optimization of operating parameters and mechanistic study

This study focuses on the photocatalytic degradation of quinoline, a recalcitrant heterocyclic nitrogenous aromatic organic compound, using the mixed oxide ZnO–TiO2 photo-catalyst. Photo-catalysts were synthesized by the solid-state reaction method at different calcination temperatures of 400 °C, 600 °C, and 800 °C. Different analytical methods, including Field emission scanning electron microscope, Brunauer-Emmett-Teller surface area, X-ray diffraction, UV–vis diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy analysis were used for the catalyst characterization. The highest pore surface area of 57.9 m2g−1 was obtained for the photo-catalyst calcined at 400 °C. The effects of calcination temperature, solution pH, initial concentration, catalyst dose as well as irradiation time were studied. At the optimum condition, i.e., calcination temperature of 400 °C, pH ≈8 and catalyst dose of 2.5 gL−1, maximum quinoline degradation and total organic carbon (TOC) removal efficiency of ≈92% and ≈78% were obtained after 240 min for initial quinoline amount of 50 mgL−1. The 1st, 2nd, and nth-order kinetic models were applied to analyze the quinoline degradation rate. The photocatalytic mechanism was studied by drawing energy level diagram with the help of the band-gap structures of the ZnO and TiO2, potential of the free radicals like OH and O2 and HOMO-LUMO energy gap of the quinoline molecule. The proposed pathways of quinoline mineralization were suggested on the basis of the identified intermediates by the gas chromatograph-mass spectrometer analysis and scavenger study.

Effective mineralization of quinoline and bio-treated coking wastewater by catalytic ozonation using CuFe2O4/Sepiolite catalyst: Efficiency and mechanism

In this study, CuFe2O4 nanocomposite loaded on natural sepiolite (CuFe2O4/SEP) was prepared by the citrate sol-gel method. CuFe2O4/SEP was characterized by X-ray diffraction, Brunauer-Emmett-Teller adsorption analysis, scanning electron microscopy, and energy dispersive spectroscopy. The CuFe2O4/SEP composite was stable and showed an excellent catalytic activity for ozonation. The efficiency of quinoline mineralization in the catalytic ozonation with CuFe2O4/SEP was 90.3%, and this value was 5.4 times higher than that of the uncatalyzed ozonation (16.8%). The quinoline mineralization followed a pseudo first-order kinetics with all the catalysts. The rate constant for the mineralization of quinoline by ozonation in the presence of CuFe2O4/SEP was 0.0885 min−1, which was 16.7 times higher than that in ozone alone (0.0053 min−1). Radical scavenging tests revealed that hydroxyl radical (OH) and superoxide radical (O2−) were the reactive oxygen species (ROS) in the quinoline degradation. In the presence of CuFe2O4/SEP, ozone and hydrogen peroxide were rapidly converted into the ROS. Although neutral and alkaline pH were more beneficial for the quinoline mineralization, CuFe2O4/SEP exhibited significant catalytic activity even under acidic conditions. Meanwhile, five-cycle successive tests suggested that CuFe2O4/SEP was recyclable and hence, stable. Furthermore, the feasibility of the catalytic ozonation for the treatment of biologically treated coking wastewater was evaluated. The catalytic ozonation resulted in 57.81% total organic carbon removal efficiency at 60 min, which was 2.9 times higher than that in the uncatalyzed ozonation (19.99%).

Mineralization of quinoline in aqueous solution by microwave-assisted catalytic wet peroxide oxidation system: process optimization, products analysis and degradation route research.

The experimental design methodology was used to optimize the experimental parameters of quinoline mineralization by microwave-enhanced catalytic wet peroxide oxidation (CWPO). Initial pH value, temperature, H2O2 dosage, and microwave power were selected as independent variables. The mineralization efficiency approached 83.82% under the optimized conditions: initial pH 6.00, temperature 60 °C, H2O2 dosage 0.09 mol/L, and microwave power 565.10 W. Regression analysis with an R2 value of 0.9867 showed a good agreement between the experimental results and the predicted values. Furthermore, based on the detection and identification of products by gas chromatography mass spectrometry, the oxidation degradation pathways of quinoline were proposed. The energy balance and costs analysis indicated that the total cost of the microwave-enhanced CWPO process for wastewater treatment was 40.60 yuan/m3.

Catalytic ozonation of quinoline using nano-MgO: Efficacy, pathways, mechanisms and its application to real biologically pretreated coal gasification wastewater

Nano-MgO was prepared by homogeneous precipitation method and applied for the degradation of quinoline. The characterization of the catalyst was determined by X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), Transmission Electron Microscope (TEM) and Energy Dispersive Spectrometer (EDS). The results showed that the presence of nano-MgO significantly improved the degradation and mineralization of quinoline. Nine intermediates were identified by liquid chromatograph–tandem mass spectrometer (LC–MS/MS), gas chromatograph and mass spectrometry (GC–MS) and ion chromatograph (IC) analysis. And a possible degradation pathway of quinoline in catalytic ozonation was proposed. The change of dissolved ozone concentration and the effect of tert butyl alcohol (TBA) and phosphate indicated that the prepared catalyst could enhance ozone decomposition into hydroxyl radicals, which was considered to be mainly responsible for the pollutants removal. In addition, catalytic ozonation pretreatment was applied for the treatment of biologically pretreated coal gasification wastewater. The results demonstrated that catalytic ozonation pre-treatment improved the biodegradability of wastewater containing quinoline in terms of BOD5/COD (B/C), toxicity and resazurin dehydrogenase activity (DHA), indicating the potential of catalytic ozonation integrated with biosystem for this type of wastewater. This study would assist in obtaining a better understanding of the application of catalytic ozonation pre-treatment in biologically pretreated coal gasification wastewater.

Photo‐activated periodate in homogeneous degradation and mineralization of quinoline: Optimization, kinetic, and energy consumption

Aqueous solutions of quinoline (Qu) were treated with photo‐activated potassium periodate (UV/KPI) process. A low consumption, cylindrical photo‐reactor was employed for this purpose. Either KPI oxidant or UV irradiation alone had little effect in Qu degradation; however, the combined UV/KPI process leads to significant degradation and mineralization. Experiments were conducted based on central composite design (CCD) methodology. The established optimized conditions for treatment of 40 mg L−1 of the substrate were [KPI] = 695.5 mg L−1, pH = 4.3 and T = 35.6 °C. Under these conditions, 96.5% degradation and 71.5% mineralization were obtained after 70 min operations. A quadratic equation predicts the variation of degradation efficiency as a function of the influencing parameters. To investigate about the involved species, tert‐butyl alcohol was used as radical scavenger and it was found that the contribution of hydroxyl radical was about 73.1%. Kinetic study revealed that Qu degradation was a pseudo first‐order reaction and the corresponding activation energy was determined. Meanwhile, the required irradiation energy for one order of magnitude degradation was estimated as 3.13 kWh m−3. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1621–1627, 2017

Microwave-enhanced catalytic wet peroxide oxidation of quinoline: the influence of pH and H2O2dosage and identification of reactive oxygen species

This article presents a study about the initial pH and H2O2dosage influence on TOC abatement by MW-CWPO with Cu/Ni-catalyst and reactive oxygen identification based on quinoline mineralization inhibition using the specific radical scavengers.

Electrochemical mineralization pathway of quinoline by boron-doped diamond anodes

Boron-doped diamond anodes were selected for quinoline mineralization, and the resulting intermediates, phenylpropyl aldehyde, phenylpropionic acid, and nonanal were identified and followed during quinoline oxidation by gas chromatography-mass spectrometry and high-performance liquid chromatography. The evolutions of formic acid, acetic acid, oxalic acid, NO2−, NO3−, and NH4+ were quantified. A new reaction pathway for quinoline mineralization by boron-doped diamond anodes has been proposed, where the pyridine ring in quinoline is cleaved by a hydroxyl radical giving phenylpropyl aldehyde and NH4+. Phenylpropyl aldehyde is quickly oxidized into phenylpropionic acid, and the benzene ring is cleaved giving nonanal. This is further oxidized to formic acid, acetic acid, and oxalic acid. Finally, these organic intermediates are mineralized to CO2 and H2O. NH4+ is also oxidized to NO2− and on to NO3−. The results will help to gain basic reference for clearing intermediates and their toxicity.

Oxidative Degradation of Quinoline Using Nanoscale Zero-Valent Iron Supported by Granular Activated Carbon

The nano zero-valent iron supported granular activated carbon (nFe0/GAC or 2.5%-nFe0/GAC) was synthesized by the liquid chemical reduction method and further used for the oxidative degradation of quinoline. The 2.5%-nFe0/GAC was characterized by various techniques such as Brunauer-Emmett-Teller (BET) surface area, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). It was ascertained that iron is of zero state and well dispersed on GAC. The 2.5%-nFe0/GAC exhibited an H4 type hysteresis loop with a surface area of ∼240 m2/g. The kinetic study reveals that quinoline degradation follows the pseudo–first order. At optimum conditions of pH=4, m=7.5 g/L, Co=100 mg/L, and T=303 K, it was observed that (1) ∼93% of quinoline and ∼63% of total organic carbon (TOC) removal is obtained, (2) iron leaching is within the permissible limit, and (3) it requires ∼63±5 min for completion of the half-life of quinoline. The activation energy is ∼22.4 kJ/mole, which indicates that quinoline removal is controlled by a chemical surface reaction. The degradation by-products of quinoline were analyzed. The mass fragments (of m/z=146 and 178) due to hydroxylation were obtained, which were further reduced into low m/z fragments, which may lead to mineralization of quinoline.

Mineralization of Quinoline by BDD Anodes: Variable Effects and Its Effluent Characteristics

BDD anodes were selected for quinoline mineralization and influence of operating parameters, such as current density, initial quinoline concentration, supporting electrolyte, and initial pH was investigated. Based on the consideration of quinoline removal efficiency and average current efficiency, at initial quinoline concentration of 50 mg L−1and pH of 7, the optimal condition was confirmed as current density of 75 mA cm−2, electrolysis time of 1.5 h, and Na2SO4concentration of 0.05 mol L−1by orthogonal test. At different electrolysis time, its effluent characteristics were focused on. The biodegradability (the ratio between BOD5and COD) was enhanced from initial 0.02 to 0.57 at 90 min. The specific oxygen uptake rate was used to assess effluent toxicity, and the value gradually reduced with decreasing effluent organic concentration with mean value of 5.51, 4.19, and 2.20 mgO2 g−1MLSS at electrolysis time of 15, 30, and 45 min, respectively. Compared with control sample (prepared with glucose), the effluent of quinoline mineralization showed obvious inhibition effect on microorganisms at electrolysis time of 15 min, and then it was significantly faded at 30 min and 45 min.

Internal loop photo-biodegradation reactor used for accelerated quinoline degradation and mineralization

Biofilm biodegradation was coupled with ultra-violet photolysis using the internal loop photobiodegradation reactor for degradation of quinoline. Three protocols-photolysis alone (P), biodegradation alone (B), and intimately coupled photolysis and biodegradation (P&B)-were used for degradation of quinoline in batch and continuous-flow experiments. For a 1,000 mg/L initial quinoline concentration, the volumetric removal rate for quinoline was 38 % higher with P&B than with B in batch experiments, and the P&B kinetics were the sum of kinetics from the P and B experiments. Continuous-flow experiments with an influent quinoline concentration of 1,000 mg/L also gave significantly greater quinoline removal in P&B, and the quinoline-removal kinetics for P&B were approximately equal to the sum of the removal kinetics for P and B. P&B similarly increased the rate and extent of quinoline mineralization, for which the kinetics for P&B were nearly equal to the sum of kinetics for P and B. These findings support that the rate-limiting step for mineralization was transformation of quinoline, which was accelerated by the simultaneous action of photolysis and biodegradation.

Photoelectrocatalytic degradation of quinoline with a novel three-dimensional electrode-packed bed photocatalytic reactor

Photoelectrocatalytic degradation performance of quinoline in saline water was assessed with a newly designed continuous flow three-dimensional electrode-packed bed photocatalytic reactor. The efficiency of the three-dimensional electrode electrochemically assisted photocatalytic process was measured in terms of degradation and mineralization of quinoline. It was found that quinoline could be degraded more efficiently by photoelectrochemical process than by photocatalytic or electrochemical oxidation in saline water. The experimental results showed that oxidation of quinoline by photoelectrochemical process were well described with a pseudo first-order kinetics. The dependence of the rate constants on various parameters in the photoelectrocatalytic reactor, such as initial concentration of chloride ion, applied cell voltage, airflow and pH value were investigated in detail. Photoelectrocatalytic degradation of quinoline was more favorable in alkali solution than in acidic solution. It is also interesting to note that chloride ion had an obvious enhancement effect rather than a scavenging effect on the photoelectrocatalytic degradation of quinoline in saline water. A kinetic synergetic effect was observed with an enhancement of the rate constant by a factor of 3.7 compared to photoelectrocatalytic degradation of quinoline without addition of Cl − ion.

Performance of three phase fluidized bed reactor for quinoline degradation on various supports at steady state and dynamic conditions

Quinoline degradation by Comamonas acidovorans was investigated in a three phase fluidized bed reactor at dilution rates below and above the critical value (micro(max) = 0.42 h(-1)). Quinoline was used as the sole source of carbon, nitrogen, and energy. Two attachment carriers, polyurethane foam (Bayvitec) and modified cellulose (Aquacel), and a gel entrapment carrier (polyvinyl alcohol) were studied and compared with regard to their effectiveness to immobilize cells. Attachment and biofilm formation was best at higher dilution rates, regardless of carrier type used. Except for the maximum biomass concentration on the carrier, Y(V) (biomass per volume of solid particles), there was no significant difference in reactor performance between the investigated carriers under stationary conditions. The highest value for Y(V) was found for the gel entrapment carrier (Y(V) = 35 g L(-1)). In a long-term run (66 days), the gel entrapment carrier established a permanent biofilm on the surface of the gel beads after 900 h of cultivation time. Complete quinoline mineralization was achieved at a dilution rate of 2.0 h(-1), which is 4.7 times higher than the critical dilution rate. Identical substrate overloads were applied to the gel entrapment and the cellulose carrier by a step increase of the quinoline feed concentration at a dilution rate of 0.8 h(-1) (D approximately 2micro(max)). The cells survived the overload, but the accumulation of quinoline and quinoline degradation products and the degradation efficiency were different for the two systems during the overload, showing the influence of the carrier type on the dynamic performance and stability of the process.

Parameters affecting the homogeneous and heterogeneous degradation of quinoline solutions in light-activated processes

The light-activated degradation kinetics of quinoline were studied in detail on Hg lamp and Suntest solar-simulated irradiation. Fenton-photoassisted mineralization in homogeneous solution with a peroxide to quinoline ratio of approximately 50 (quinoline, approximately 1 mM) was complete in about 30 min on Hg lamp irradiation. Reactions activated by a solar simulator led to 80% mineralization of the same quinoline solutions within the same time period due to a lack of a strong UV component. Heterogeneous photocatalytic TiO 2-mediated degradation proceeded at a slower rate than the homogeneous reaction. The influence of a number of factors, such as the substrate concentration, solution pH, gas atmosphere and dynamics of H 2O 2 addition, was investigated. The stoichiometry of the mineralization reaction was analysed as a function of the gas atmosphere used. Quinoline degradation was possible via dark and light-activated reactions. Quinoline did not affect the H 2O 2 consumption rate in the presence of Fe 3+ ions. This suggests that, during degradation, the reaction of Fe 3+ ions with H 2O 2 is the rate-determining step. Quinoline did not complex with Fe 3+ ions in the dark. However, complex formation occurred during photodegradation with Fenton-like reagents, such as Cr 6+ or Cu 2+ ions and combinations of Cu 2+ +Fe 3+ ions, in the presence of H 2O 2. The latter systems were compared with the classical Fenton reagent leading to quinoline mineralization.

Estimation of the energetic parameters associated with the aerobic degradation of quinoline by Comamonas acidovorans in continuous culture

AbstractAn estimation of the true growth yields and maintenance coefficients for Comamonas acidovorans DSM 6426 under continuous cultivation on quinoline has been performed. The data were checked for consistency using available electron, carbon and nitrogen balances. The true biomass energetic yields, ηmax, and energetic maintenance coefficients, me, were estimated using two models based on control of growth rate and control of substrate uptake rate, respectively. The estimations were converted to the various familiar true growth yield and maintenance units such as substrate‐based (Y, mS/X), oxygen‐based (Y, m) and carbon dioxide‐based (Y, m) units. For the complete mineralization of quinoline by C. acidovorans, values of ηmax = 0.371 and me = 0·0426 h−1 were obtained.

Isolation and characterization of quinoline-degrading bacteria from subsurface sediments.

Two gram-negative, motile bacteria isolated from deep subsurface sediments mineralized the nitrogen-containing polyaromatic hydrocarbon quinoline under aerobic conditions and transformed quinoline to soluble intermediates under anaerobic conditions. Many aromatic compounds were also able to serve as the sole source of carbon and energy under aerobic conditions. Rapid aerobic mineralization of quinoline at concentrations as low as 0.002 microgram ml-1 indicates that these organisms possess a high-affinity uptake and utilization system, which may reflect the oligotrophic nature of deep subsurface environments. Both bacteria harbored four plasmids of identical size, ranging from 50 to 440 kilobases.