Range Of Phenol Concentrations Research Articles

Bioremediation of phenolic compounds in coal‐contaminated environments: Bio‐kinetic studies using a mixed bacterial culture

AbstractTwo distinct bacterial strains were combined in a mixed culture to investigate the degradation of phenol. The mixed cultures consisting of species like Rhodococcus and Bacillus, were isolated from the waste effluent collected from Dankuni coal complex (DCC) in West Bengal. The experimental phenol biodegradation were performed batch wise at an optimized temperature and pH conditions of 37°C and 7.0 for a wide range of phenol concentrations initially, with saline solutions which is not supplemented with nutrients initially. Experimental results concluded a highest possible specific growth rate at 150 mg/L for phenol biodegradation of 2400 mg/L within a span of 72 h. Several significant physicochemical parameters were investigated in order to determine the ideal conditions for phenol breakdown. It was also observed that a spectroscopic study of the intermediate at 260 nm of the phenol biodegradation commenced through the formation of a cis, cis intermediate, indicating ortho‐cleavage pathway. A simulated substrate utilization and growth profiles was obtained by using substrate inhibition model equation using MATLAB R2017a were used to compare for the validation of the obtained experimental growth and substrate characterization data.

Reed Membrane as a Novel Immobilization Matrix for the Development of an Optical Phenol Biosensor

Background: Biocompatible and easily available immobilization matrix is vital for the construction of enzyme-based biosensor. Methods: Reed membrane was selected as a novel immobilization matrix to construct an optical phenol biosensor. Tyrosinase from mushroom was immobilized in a reed membrane using glutaraldehyde as a cross-linker. The detection scheme was based on the measurement of the color intensity of the adduct resulting from the reaction of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with the quinone produced from the oxidation of phenol by tyrosinase. The performance of such method including specificity, sensitivity, repeatability and practical use were validated. Results: The prepared biosensor demonstrated optimum performance at pH 6-7, temperature of 40°C and a linear response in the phenol concentration range of 5-100 μM. It also showed good operation stability for repeated measurements (over 200 times) and good storage stability after it had been kept at 4°C for 2 months. Conclusion: Reed membrane is a novel matrix for immobilization of enzyme. The prepared biosensor permits good sensitivity, reproducibility and stability. It is anticipated that reed membrane is a promising solid support for fabricating other enzyme-based biosensors.

IMMOBILIZATION OF TYROSINASE IN NANOCRYSTALLINE CELLULOSE/CHITOSAN COMPOSITE FILM FOR AMPEROMETRIC DETECTION OF PHENOL

Nanocrystalline cellulose (NCC)/chitosan composite for immobilization of tyrosinase enzyme for the determination of phenol have been developed. The NCC/Chitosan composite film on screen printed carbon electrode (SPCE) was prepared by using drop casting technique. Characterization of the modified SPCE surface was investigated by using Transmission Electron Microscopy (TEM) and Fourier Transform Infrared (FTIR), respectively. Chronoamperometric (CA) technique is used to perform the electrochemical measurements. The detection of phenols by the developed system is derived on the direct electrochemical reduction of quinones produced by enzymatic reaction. The results demonstrated that the maximum response was observed at ratio of NCC/chitosan of 1 to 1 (v/v), tyrosinase concentration of 10 mg/mL and pH buffer of 7, respectively. It was found that the developed system gave linear response in the phenol concentration range of 0.39 – 7.74 µM (slope = 28.316, R2 = 0.9808) with the detection limit of 0.38 µM. The reproducibility of the system was also estimated and the Relative Standard Deviation (RSD) was found to be at 4.27%.

Physiological and functional diversity of phenol degraders isolated from phenol-grown aerobic granules: Phenol degradation kinetics and trichloroethylene co-metabolic activities

Aerobic granule is a novel form of microbial aggregate capable of degrading toxic and recalcitrant substances. Aerobic granules have been formed on phenol as the growth substrate, and used to co-metabolically degrade trichloroethylene (TCE), a synthetic solvent not supporting aerobic microbial growth. Granule formation process, rate limiting factors and the comprehensive toxic effects of phenol and TCE had been systematically studied. To further explore their potential at the level of microbial population and functions, phenol degraders were isolated and purified from mature granules in this study. Phenol and TCE degradation kinetics of 15 strains were determined, together with their TCE transformation capacities and other physiological characteristics. Isolation in the presence of phenol and TCE exerted stress on microbial populations, but the procedure was able to preserve their diversity. Wide variation was found with the isolates’ kinetic behaviors, with the parameters often spanning 3 orders of magnitude. Haldane kinetics described phenol degradation well, and the isolates exhibited actual maximum phenol-dependent oxygen utilization rates of 9–449 mg DO g DW−1 h−1, in phenol concentration range of 4.8–406 mg L−1. Both Michaelis–Menten and Haldane types were observed for TCE transformation, with the actual maximum rate of 1.04–21.1 mg TCE g DW−1 h−1 occurring between TCE concentrations of 0.42–4.90 mg L−1. The TCE transformation capacities and growth yields on phenol ranged from 20–115 mg TCE g DW−1 and 0.46–1.22 g DW g phenol−1, respectively, resulting in TCE transformation yields of 10–70 mg TCE g phenol−1. Contact angles of the isolates were between 34° and 82°, suggesting both hydrophobic and hydrophilic cell surface. The diversity in the isolates is a great advantage, as it enables granules to be versatile and adaptive under different operational conditions.

Regularity of Intermittent Bursts in BriggsRauscher Oscillating Systems with Phenol

AbstractThe intermittency or intermittent bursting as the type of dynamic state when two qualitatively different behaviors replace one another randomly during the course of the reaction, although all the control parameters remain constant, is found in the BriggsRauscher oscillating system moderated by a very small amount of phenol. Within a range of phenol concentrations, the oscillation amplitude is diminished considerably, and after oscillations cease, they repeat intermittently, giving several bursts of oscillations. For the concentrations used here, the range of phenol concentrations where intermittent bursting oscillations occur in a closed reactor is ca. 1.8×10−5 to 3.6×10−5 M. Bursting also occurs in an open reactor and can be sustained indefinitely at 5.53×10−5 M concentration. The intermittent bursting behavior is robust, and can be achieved at a variety of conditions.

Performance of Chloride Ions on Electrocatalytic Oxidation Process Using Ti-Nanotubes/PDDA-PbO2 Anode for Phenol Removal

AbstractThe performance of the electrocatalytic oxidation of phenol on poly(diallyldimethylammonium chloride) (PDDA)–modified PbO2 anodes in the presence of chloride ions was studied. The objective was to elucidate the influence of NaCl dosage, current density, initial phenol concentration, and initial pH on this catalysis process in the presence of Cl−. The results revealed that at low current densities, the presence of Cl− could greatly enhance the current efficiency by electrogenerating active chlorine, and the current density increased, but if competitive adsorption of ·OH radicals occurred, the removal efficiency did not improve significantly and the current efficiency decreased. This indicated that the pH value had a major impact on phenol, with optimal removal observed at approximately pH 6–7. In both acidic and alkaline solutions outside this optimal pH window, the removal efficiency deteriorated. The modified anode performs well for phenol degradation for a wide range of phenol concentrations und...

The degradation of phenol in water solution by TiO2 photocatalysis in a helical reactor

Heterogeneous photocatalysis is an advanced oxidation process (AOP) which has been
 widely studied by numerous researchers in the world and is used to degrade or remove a
 wide range of pollutants in water and air.
 The photocatalytic oxidation and mineralization of phenol in aqueous catalyst suspensions of
 titanium dioxide (TiO2) Degussa P25 (80% anatase, 20% rutile) has been carried out in a
 helical reactor. The photodegradation was investigated using two kinds of high pressure
 mercury irradiation lamps one emitting at 254 nm (15 Watts) and the other emitting at 365 nm
 (400 Watts). The effects of the recirculation flow, source of withdrawal, initial phenol
 concentration, amount of catalyst, suspension pH and light intensity on photodegradation of
 phenol were investigated. These parameters were studied to find the optimal conditions for a
 complete and fast oxidation of this organic compound.
 Kinetic experiments were performed at 32 oC over a range of phenol concentrations from 2.5
 to 25 mg l-1, a range of TiO2 concentrations from 0.1 to 1 g l1, a range of suspensions pH from
 3 to 9. The helical reactor was operated under a continuous flow-mode.
 Results showed that photodegradation is an effective method for the removal of phenol from
 wastewaters. The efficiency of the process depends strongly on the experimental conditions.
 The amount of catalyst, UV irradiation time, pH and light intensity were important parameters
 in the degradation process. The rate constants for the different parameters (TiO2, phenol
 concentration) were evaluated. Kinetic studies showed that titanium dioxide photocatalyst P25
 was very active in phenol degradation; we observed that 99% of pollutant was degraded after
 6 hours of UV irradiation; furthermore, we observed that phenol degradation was more
 effective under acidic conditions than alkaline. The kinetics were described by the Langmuir-
 Hinshelwood (L-H) kinetic model. An overall pseudo-first order kinetic constant has been
 calculated for phenol conversion and values obtained in acidic pH are higher than those
 calculated for basic pH media.

Demonstrating the In Situ Biodegradation Potential of Phenol Using Bio‐Sep® Bio‐Traps® and Stable Isotope Probing

AbstractThe effect of phenol concentration on phenol biodegradation at an industrial site in the south of Wales, United Kingdom, was investigated using standard Bio‐Sep® Bio‐Traps® and Bio‐Traps® coupled with stable isotope probing (SIP). Unlike many 13C‐amendments used in SIP studies (such as hydrocarbons) that physically and reversibly adsorb to the activated carbon component of the Bio‐Sep® beads, phenol is known to irreversibly chemisorb to activated carbon. Bio‐Traps® were deployed for 32 days in nine site groundwater monitoring wells representing a wide range of phenol concentrations. Bio‐Traps® amended with 13C‐phenol were deployed together with non‐amended Bio‐Traps® in three wells.Quantitative polymerase chain reaction (qPCR) analysis of Bio‐Traps® post‐deployment indicated an inhibitory effect of increasing phenol concentration on both total eubacteria and aerobic phenol‐utilizing bacteria as represented by the concentration of phenol hydroxylase gene. Despite the chemisorption of phenol to the Bio‐Sep® beads, activated carbon stable isotope analysis showed incorporation of 13C into biomass and dissolved inorganic carbon (DIC) in each SIP Bio‐Trap® indicating that chemisorbed amendments are bioavailable. However, there was a clear effect of phenol concentration on 13C incorporation in both biomass and DIC confirming phenol inhibition. These results suggest that physical reductions of the phenol concentrations in some areas of the plume will be required before biodegradation of phenol can proceed at a reasonable rate. © 2013 Wiley Periodicals, Inc.

Development of an amperometric biosensor for phenol detection

With the aim of searching for an in situ method for monitoring phenol, Agaricus bisporus tissue with tyrosine activity was used as a biocomponent and an oxygen electrode used as a transducer to develop a biosensor. The experimental methodology investigated the relation between dissolved oxygen and phenol concentration using a standard solution. Biosensor calibration was evaluated by studying reaction time and tissue amount necessary to promote a reliable response and to minimize errors. The influence of air saturation of the sample and washing of the electrode was also investigated. Results showed that 5 g of mushroom tissue with a 1 min reaction time promoted the best biosensor response within a phenol concentration range of 5–10 ppm. Washing of the electrode did not change the performance of the analysis; however, initial air saturation caused less variation amongst the samples.

Inhibition and gene expression of Nitrosomonas europaea biofilms exposed to phenol and toluene

Pure culture biofilms of the ammonia-oxidizing bacterium Nitrosomonas europaea were grown in a Drip Flow Biofilm Reactor and exposed to the aromatic hydrocarbons phenol and toluene. Ammonia oxidation rates, as measured by nitrite production in the biofilms, were inhibited 50% when exposed to 56 µM phenol or 100 µM toluene, while 50% inhibition of suspended cells occurred at 8 µM phenol or 20 µM toluene. Biofilm-grown cells dispersed into liquid medium and immediately exposed to phenol or toluene experienced similar inhibition levels as batch grown cells, indicating that mass transfer may be a factor in N. europaea biofilm resistance. Whole genome microarray analysis of gene expression was used to detect genes up-regulated in biofilms during toluene and phenol exposure. Two genes, a putative pirin protein (NE1545) and a putative inner membrane protein (NE1546) were up-regulated during phenol exposure, but no genes were up-regulated during toluene exposure. Using qRT-PCR, up-regulation of NE1545 was detected in biofilms and suspended cells exposed to a range of phenol concentrations and levels of inhibition. In the biofilms, NE1545 expression was up-regulated an average of 13-fold over the range of phenol concentrations tested, and was essentially independent of phenol concentration. However, the expression of NE1545 in suspended cells increased from 20-fold at 7 µM phenol up to 80-fold at 30 µM phenol. This study demonstrates that biofilms of N. europaea are more resistant than suspended cells to inhibition of ammonia oxidation by phenol and toluene, even though the global transcriptional responses to the inhibitors do not differ in N. europaea between the suspended and attached growth states.

Palygorskite–expanded graphite electrodes for catalytic electro-oxidation of phenol

A palygorskite–expanded graphite (EG) electrode was developed for degradation of phenol. Phenol was determined by differential pulse voltammetry (DPV) with this electrode. Compared to carbon paste electrodes and unmodified EG electrodes, the novel electrode appeared to induce catalytic electro-oxidation of phenol. The dependence of signals on operating conditions was studied. The modified electrode exhibited a linear response over a wide range of phenol concentrations from 50 to 500 µM, with a detection limit of 4.5 µM (s/n = 3). Low cost and very simple manufacturing procedure allow for the novel electrodes to be applied as disposable devices for catalytic electro-oxidation of phenol.

Investigation of interaction between phenol and cetylpyridinium chloride micelle in the absence and in the presence of electrolyte by 1H NMR spectroscopy

In recent years, the micellar enhanced ultrafiltration (MEUF) of phenol in wastewater using cetylpyridinium chloride (CPC) as surfactant has gained many attentions. However, so far no research has focused on the interaction between phenol and CPC micelle. In this study, the interaction between phenol and CPC micelle with and without electrolyte was investigated by using 1H NMR spectroscopy. In the absence of electrolyte, at low phenol concentrations (0.5 mM and 1 mM) phenol was solubilized at the micelle–water interface by the ion interaction between C 6H 6O − and C 5H 5N +, and in the hydrophilic head group region of CPC micelle by the polar interaction between phenol and CPC micelle. When phenol concentration range was from 1 mM to 8 mM, the micelle–water interface and the hydrophilic head group region of CPC micelle saturated with C 6H 5O − and phenol, then phenol penetrated into the palisade layer deeper but was still close to the hydrophilic head group of CPC micelle. The presence of NaCl and Na 2SO 4 had almost no influence on the solubilization of phenol in CPC micelle, however, the presence of Na 2CO 3 promoted the solubilization of phenol in CPC micelle significantly. In the presence of Na 2CO 3, more C 6H 5O − ions were solubilized at the water–micelle interface by the ion interaction between C 6H 6O − and C 5H 5N +. At low Na 2CO 3 concentration the micelle–water interface of CPC micelle saturated with C 6H 5O −, and benzene ring penetrated into the palisade layer of CPC micelle, but deeper penetration was not observed with the increase of Na 2CO 3 concentration. Excessive CO 3 2− could make some C 6H 5O − transfer from CPC micelle to water, resulting in the decrease of the solubilization extent of phenol in CPC micelle.

Variable Stoichiometry during the Laccase‐Catalyzed Oxidation of Aqueous Phenol

The oxidation of aqueous phenol through the catalytic action of laccase from Trametes versicolor was studied over a wide range of phenol concentrations and enzyme activities. The stoichiometric ratio, which is defined as the molar ratio of phenol transformed to oxygen consumed in the catalytic reaction, was found to increase with phenol concentration in the reaction mixture from a theoretical lower limit of 1 and to approach a theoretical upper limit of 4. A logistic equation was proposed to relate reaction stoichiometry to substrate concentration and was successfully used to relate these parameters over a range of phenol concentrations extending from approximately 0.15 to 8 mM. This expression was incorporated into two kinetic models in order to account for variations in reaction stoichiometry during the reaction and to extend the range over which the models may be accurately applied. The new models demonstrated an improved ability to predict concentrations of phenol and oxygen over time in a closed batch reaction system.

Immobilization of tyrosinase in chitosan film for an optical detection of phenol

An optical biosensor based on the immobilized tyrosinase enzyme in a chitosan film is described for the detection of phenol. The film was prepared by depositing a chitosan solution containing tyrosinase onto a microscope glass slide via spin coating technique. The quinone produced from the enzymatic oxidation of phenol was reacted with 3-methyl-2-benzothiazolinone hydrazone (MBTH) to produce a maroon color adduct. The color intensity of the adduct was found to increase proportionally with the increase of the substrate concentrations after 15 min exposure to the substrate. The optimum enzyme loading and chitosan concentrations were found to be 0.9 mg and 2% (w/v), respectively. The biosensor also demonstrated optimum activity at pH 6–7, optimum temperature of 45 °C and a linear response in the phenol concentration range of 2.5–70.0 μM. The response characteristics of the biosensor towards different phenolic compounds were determined. It was found that the biosensor gave a linear response in the concentration range of 2.5–50.0 μM for 4-chlorophenol, 2.5–100.0 μM for m-cresol and 12.5–400.0 μM for p-cresol. The limit of detection and the apparent Michaels–Menten constant ( K m) of the biosensor were 0.9, 1.0, 1.0, 3.0 μM and 0.038, 0.037, 0.056, 0.201 mM for 4-chlorophenol, phenol, m-cresol and p-cresol, respectively. It showed good stability for at least 2 months.

Determination of Phenol by Preconcentration‐Direct Chemiluminescence in a FIA Assembly

The determination of phenol in water samples is proposed with the aid of a flow‐injection system. The analytical procedure is based on the direct chemiluminometric emission by oxidation of the analyte with potassium permanganate in acidic medium. The flow assembly is provided with a solid‐phase reactor filled with a resin type XAD‐4 for analyte preconcentration. A large study of potential interferences, namely, amino acids reaching water through degradation of organic matter; metals and inorganic metal ions typically present in water interfering with the CL emission of the parent compound, was performed. The calibration graph was linear over the phenol concentration range 1.0–20.0 ng mL−1; the LOD was 5.0 ng mL−1. Finally, the method was applied to the determination of phenol in waste‐ and groundwater.

Rate and capacity of hepatic microsomal ring-hydroxylation of phenol to hydroquinone and catechol in rainbow trout ( Oncorhynchus mykiss)

Rainbow trout ( Oncorhynchus mykiss) liver microsomes were used to study the rate of ring-hydroxylation of phenol at 11 and 25 °C by directly measuring the production of two potentially toxic metabolites, hydroquinone (HQ) and catechol (CAT). An HPLC method with integrated ultraviolet and electrochemical detection was used for metabolite identification and quantification at low (pmol) formation rates found in fish. The Michaelis–Menten saturation kinetics for the production of HQ and CAT over a range of phenol concentrations were determined at trout physiological pH. The apparent Km's for the production of HQ and CAT at 11 °C were 14±1 and 10±1 mM, respectively, with Vmax's of 552±71 and 161±15 pmol/min per mg protein. The kinetic parameters for HQ and CAT at 25 °C were 22±1 and 32±3 mM (Km) and 1752±175 and 940±73 pmol/min per mg protein (Vmax), respectively. The calculated increase in metabolic rate per 10 °C temperature rise ( Q 10) was 2.28 for HQ and 3.53 for CAT production. These experiments assess the potential for metabolic bioactivation in fish through direct quantification of putative reactive metabolites at the low, but toxicologically significant, chemical concentrations found in aquatic organisms. This work initiates a series of studies to compare activation pathway, rate, and capacity across fish species, providing a basis for development of biologically-based dose response models in diverse species.

Reaction engineering studies on biodegradation of phenol by Pseudomonas putida MTCC 1194 immobilized on calcium alginate

Phenol in industrial wastewater has been biologically degraded by Pseudomonas putida immobilized in calcium alginate matrix. Effect of different process variables like, initial phenol concentration, temperature, cell loading, bead size, etc. has been studied previously. An attempt has been made to explain the kinetics of this immobilized whole cell catalytic process on the basis of Michaelis–Menten (M–M) model within the phenol concentration range 100–1000 ppm. It has been observed that at phenol concentration above 750 ppm, the reaction behavior deviate from Michaelian kinetics possibly due to the effect of intraparticle diffusion. The batch experimental data have been obtained in shake flask experiments in aerobic conditions. The kinetic parameters of M–M model, v max and K m, and the effective diffusion coefficient ( D es) for large immobilized beads have been evaluated from Lineweaver–Burk plots and the Eadie–Hofstee plots, respectively. The simulated data satisfactorily correspond to those of the experimental values in the phenol concentration range up to 500 ppm.

Solar‐assisted photochemical and photocatalytic degradation of phenol

AbstractPhotocatalytic (TiO2, air and solar radiation) and photochemical (H2O2 and solar radiation) mineralizations of phenol solutions (up to 500 mg dm−3) in a batch reactor using concentric solar radiation were studied. A compound parabolic reflector as a concentrating reflector was used to obtain concentrated solar radiation in both cases. Considerable enhancement (Five‐fold) in the rate of degradation was obtained when concentrated solar radiation was used instead of plain solar radiation in photocatalytic degradation. The effect of initial phenol concentration, intensity and presence of anions has been studied in both the cases. Low concentrations of intermediates were observed, during the reaction, over the entire range of phenol concentrations studied in the case of photocatalytic degradation using Degussa‐P25 TiO2 as photocatalyst and in the absence of anions; whereas significant quantities of intermediates were observed in the case of the photochemical degradation. The presence of anions generally had a detrimental effect on the mineralization process in both cases. Different anions showed different effects. Total organic carbon (TOC) variations with time were also studied. A rational explanation has been given for the decrease in the rate in the presence of anions.© 2001 Society of Chemical Industry

Studies on composition and stability of a large membered bacterial consortium degrading phenol

A ten member microbial consortium (AS) consisting of eight phenol-degrading and two non-phenol-degrading strains of bacteria was developed and maintained in a fed-batch reactor by feeding 500 mg l(-1) phenol for four years at 28 +/- 3 degrees C. The consortium could degrade 99% of 500 mg l(-1) phenol after 24 hours incubation with a biomass increase of 2.6 x 10(7) to 4 x 10(12) CFU ml(-1). Characterization of the members revealed that it consisted of 4 principal genera, Bacillus, Pseudomonas, Rhodococcus, Streptomyces and an unidentified bacterium. Phenol degradation by the mixed culture and Bacillus subtilis, an isolate from the consortium was compared using a range of phenol concentrations (400 to 700 mg l(-1)) and by mixing with either 160 mg l(-1) glucose or 50 mg l(-1) of 2,4-dichlorophenol in the medium. Simultaneous utilization of unrelated mixed substrates (glucose/2,4-dichlorophenol) by the consortium and Bacillus subtilis, indicated the diauxic growth pattern of the organisms. A unique characteristic of the members of the consortia was their ability to oxidize chloro aromatic compounds via meta pathway and methyl aromatic compounds via ortho cleavage pathway. The ability of a large membered microbial consortia to maintain its stability with respect to its composition and effectiveness in phenol degradation indicated its suitability for bioremediation applications.

Effects of electrochemical treatment of granular activated carbon on surface acid groups and the adsorptive capacity for phenol

An electric current was passed through a granular activated carbon (GAC) column to investigate changes in the surface characteristics of the GAC and the adsorptive capacity for phenol. Using potentiometric titration, it was observed that the GAC was less acidic after cathodic treatment and more acidic after anodic treatment. Oxic and anoxic isotherms were compared using statistical methods to evaluate changes in the adsorptive capacity of GAC for phenol. Under oxic conditions, the adsorptive capacity of GAC decreased after anodic and cathodic treatment. Under anoxic conditions, a decrease in adsorptive capacity in the lower range of phenol concentrations investigated was observed after anodic treatment, while cathodic treatment may not have significantly altered the adsorptive capacity. The observed changes in adsorptive capacity could not be definitely correlated with the observed changes in the measured surface acid group concentrations in this study.