Oxidative Degradation Of Phenol Research Articles

Oxidative degradation of phenol in aqueous solution by using heat, ZVI, AC, heat/ZVI, or heat/AC activated persulfate

Oxidative degradation of phenol in aqueous solution by using heat, ZVI, AC, heat/ZVI, or heat/AC activated persulfate

Promotion of conductive carbon black loaded CuFe2O4 on the oxidative degradation of phenol by persulfate

Promotion of conductive carbon black loaded CuFe2O4 on the oxidative degradation of phenol by persulfate

The degradation of phenol via in situ H2O2 production over supported Pd-based catalysts

The oxidative degradation of phenol via in situ H2O2 production offers an attractive route to the destruction of organic contaminants in water streams, overcoming the significant concerns associated with traditional water remediation technologies.

Oxidative degradation of phenol by sulfidated zero valent iron under aerobic conditions: The effect of oxalate and tripolyphosphate ligands

After adding either organic or inorganic ligands, sulfidated nano-zero-valent iron (SnZVI) was used for aerobic degradation of phenol, and the effect of the ligand species on oxidation performance was investigated. We found that SnZVI hardly degraded phenol in the absence of ligand addition. Ligands initiated and promoted the degradation of pollutants by SnZVI. The data herein show that a characteristic inorganic ligand, tripolyphosphate (TPP), is more effective in enhancing oxidation than a characteristic organic ligand oxalate. In addition to the scavenging of reactive oxidants by the organic ligand, more ferrous ion (Fe(II)) dissolution from SnZVI in the TPP system is another cause for the superior enhancement by the inorganic ligand. In the oxalate system, as the sulfur content of SnZVI increased, the oxidation efficiency increased because FeS shell promoted the transfer of electrons to produce more reactive oxygen species (ROS). In TPP system, the effect of sulfur content on oxidation performance is more complex. The SnZVI with low sulfur content showed poor oxidation performance compared with that of nZVI. Further experiments proved that sulfidation might weaken the complexation of TPP with surface bound Fe, which would slow down the ionic Fe(II) dissolution rate. Therefore, sulfidation has the dual effects of enhancing electron transfer and inhibiting the complexation of inorganic ligands. In addition, the mechanisms of ROS generation in different ligand systems were investigated herein. Results showed that the critical ROS in both the oxalate and TPP systems are hydroxyl radicals, and that they are produced via one-electron activation of O2.

Oxidative Degradation of Phenol using in situ Generated Hydrogen Peroxide Combined with Fenton’s Process

Oxidative destruction of organic compounds in water streams could significantly reduce environmental effects associated with discharging waste. We report the development of a process to oxidise phenol in aqueous solutions, a model for waste stream contaminants, using Fenton’s reactions combined with in situ synthesised hydrogen peroxide (H2O2). Bifunctional palladium-iron supported catalysts, where Pd is responsible for H2O2 synthesis while Fe ensures the production of reactive oxygen species required for the degradation of phenol to less toxic species is reported. A comparison is made between in situ generated and commercial H2O2 and the effect of phenol degradation products on catalyst stability is explored.

Heterogeneous Fenton oxidation of phenol in fixed-bed reactor using Fe nanoparticles embedded within ordered mesoporous carbons

Iron nanoparticles embedded within ordered mesoporous carbon catalyst (Fe-OMC) was prepared using a facile “one-pot” synthesis method. The as-synthesized catalyst was characterized by using FTIR, XRD, SEM-EDS mapping, HRTEM and XPS. The results revealed that Fe oxide nanoparticles were highly dispersed in the OMC. The prepared Fe-OMC materials as heterogeneous Fenton catalysts were specifically applied in the fixed-bed reactor which operated under continuous-flow condition, showing a promising performance in the oxidative degradation of phenol with high catalytic activity (e.g. phenol conversion nearly 100%) and stability. The effects of feed flow rate and catalyst bed height on the conversions of phenol and H2O2, the iron leaching concentration as well as pH values of reaction solutions were also systematically investigated to determine the optimal operation conditions. The experimental results showed that the Fe-OMC catalyst achieved the highest activity (>99% phenol and H2O2 conversion) with remarkable low iron leaching concentration (10–20mg/L) under continuous-flow operations. The stability and reusability evaluations of Fe-OMC catalysts indicated the phenol conversion remains above 90% during a 39h long-term evaluation. It can be finally concluded that the prepared Fe-OMC catalyst in this work shows promising potential to be an efficient heterogeneous Fenton catalyst for the degradation of hazardous phenolic aqueous solutions.

Oxidative degradation of phenols in sono-Fenton-like systems upon high-frequency ultrasound irradiation

The kinetics of oxidative degradation of phenol and chlorophenols upon acoustic cavitation in the megahertz range (1.7 MHz) is studied experimentally in model systems, and the involvement of in situ generated reactive oxygen species (ROSs) is demonstrated. The phenols subjected to high frequency ultrasound (HFUS) are ranked in terms of their rate of conversion: 2,4,6-trichlorophenol > 2,4-dichlorophenol ~ 2-chlorophenol > 4-chlorophenol ~ phenol. Oxidative degradation upon HFUS irradiation is most efficient at low concentrations of pollutants, due to the low steady-state concentrations of the in situ generated ROSs. A dramatic increase is observed in the efficiency of oxidation in several sonochemical oxidative systems (HFUS in combination with other chemical oxidative factors). The system with added Fe2+ (a sono-Fenton system) derives its efficiency from hydrogen peroxide generated in situ as a result of the recombination of OH radicals. The S2O82-/Fe2+/HFUS system has a synergetic effect on substrate oxidation that is attributed to a radical chain mechanism. In terms of the oxidation rates, degrees of conversion, and specific energy efficiencies of 4-chlorophenol oxidation based on the amount of oxidized substance per unit of expended energy the considered sonochemical oxidative systems form the series HFUS < S2O82-/HFUS < S2O82-/Fe2+/HFUS.

The generation of hydroxyl radicals by hydrogen peroxide decomposition on FeOCl/SBA‐15 catalysts for phenol degradation

Iron oxychloride (FeOCl) supported on mesoporous silica (SBA‐15), as a Fenton‐like solid catalyst for phenol degradation, showed supreme activity for production of hydroxyl radical (HO·) by H2O2 decomposition, and the generation capacity was comparable to the conventional Fenton reagent (Fe2++H2O2). The structure of FeOCl was characterized with spectroscopies. The generation of HO· species during the reaction was detected using 5,5‐dimethyl‐1‐pyrroline N‐oxide trapped electron paramagnetic resonance. Furthermore, the kinetics in detail was driven for the creation and diffusion of HO· by H2O2 decomposition over FeOCl, which follows a first‐order rate through a two‐step reaction. With the combination of the catalyst structure and kinetic parameters, the plausible mechanism for H2O2 decomposition during the oxidative degradation of phenol was rationalized. As a Fenton‐like solid catalyst, FeOCl/SBA‐15 is a promising alternative for the removal of low‐level organic contaminates from water. © 2014 American Institute of Chemical Engineers AIChE J, 61: 166–176, 2015

Oxidative Degradation of Phenol by Corona Dielectric Barrier Discharge at Gas-Liquid Interphase

Oxidative Degradation of Phenol by Corona Dielectric Barrier Discharge at Gas-Liquid Interphase

영가철 기반 펜톤 시스템을 활용한 페놀의 산화분해

ABSTRACT For the last couple of decades, the Fenton (-like) systems have been extensively studied for oxidation of organiccontaminants in water. Recently, zero-valent iron (ZVI) has received attention as a Fenton catalyst as well as a reducingagent capable of producing reactive oxidants from oxygen. In this study, the ZVI-based Fenton reaction was assessed forthe oxidative degradation of phenol using ZVI/O 2 , ZVI/H 2 O 2 , ZVI/Oxalate/O 2 and hv/ZVI/Oxalate/O 2 systems. Reactionparameters such as pH and reagent dose (e.g., ZVI, H 2 O 2 , and oxalate) were examined. In the presence of oxalate (ZVI/Oxalate/O 2 and hv/ZVI/Oxalate/O 2 systems), the degradation of phenol was greatly enhanced at neutral pH values. It wasfound that ZVI accelerates the Fenton reaction by reducing Fe(III) into Fe(II). The conversion of Fe(III) into Fe(II) by ZVIwas more stimulated at acidic pH than at near-neutral pH values.Key words :Advanced oxidation process, Fenton reaction, Zero-valent iron, Hydroxyl radical, Phenol oxidation

Nanosized Pt-, Ru-, and Pd-containing catalysts for organic synthesis and solution of environmental issues

Synthesis of Pt-, Ru-, and Pd-containing nanoparticles in the pores of polymeric matrix of hypercrosslinked polystyrene, their structure and catalytic properties are under consideration. Physicochemical studies have shown that metal nanoparticle formation depends on the properties of the polymeric matrix porous structure, the nature of metal precursors and the synthesis conditions. The study of catalytic properties of metal nanoparticles stabilized in mesoporous matrices showed promising applications of these systems in the reactions of selective oxidation and hydrogenation, which are intermediate stages in the synthesis of precursors of vitamins and medicines. In order to solve environmental problems, nanocatalysts were investigated in the processes of oxidative degradation of phenol and reductive denitrification of nitrates for purification of sewage and natural water.

Effects of Single Metal-Ion Doping on the Visible-Light Photoreactivity of TiO2

Titanium dioxide (M-TiO2), which was doped with 13 different metal ions (i.e., silver (Ag+), rubidium (Rb+), nickel (Ni2+), cobalt (Co2+), copper (Cu2+), vanadium (V3+), ruthenium (Ru3+), iron (Fe3+), osmium (Os3+), yttrium (Y3+), lanthanum (La3+), platinum (Pt4+, Pt2+), and chromium (Cr3+, Cr6+)) at doping levels ranging from 0.1 to 1.0 at. %, was synthesized by standard sol−gel methods and characterized by X-ray diffraction, BET surface area measurement, SEM, and UV−vis diffuse reflectance spectroscopy. Doping with Pt(IV/II), Cr(III), V(III), and Fe(III) resulted in a lower anatase to rutile phase transformation (A−R phase transformation) temperature for the resultant TiO2 particles, while doping with Ru(III) inhibited the A−R phase transformation. Metal-ion doping also resulted in a red shift of the photophysical response of TiO2 that was reflected in an extended absorption in the visible region between 400 and 700 nm. In contrast, doping with Ag(I), Rb(I), Y(III), and La(III) did not result in a red shift of the absorption spectrum of TiO2. As confirmed by elemental composition analysis by energy dispersive X-ray spectroscopy, the latter group of ions was unable to be substituted for Ti(IV) in the crystalline matrix due to their incompatible ionic radii. The photocatalytic activities of doped TiO2 samples were quantified in terms of the photobleaching of methylene blue, the oxidation of iodide (I−), and the oxidative degradation of phenol in aqueous solution both under visible-light irradiation (λ > 400 nm) and under broader-band UV−vis irradiation (λ > 320 nm). Pt- and Cr-doped TiO2, which had relatively high percentages of rutile in the particle phase, showed significantly enhanced visible-light photocatalytic activity for all three reaction classes.

A Novel Adsorption/Saturation Approach to Ultrasonic Degradation of Phenol

AbstractThe study describes development and application of a kinetic model based on the local concentration of solutes and hydroxyl radicals to predict the rate of ultrasonically induced oxidative degradation of phenol at 300 kHz. The results reveal that the degradation follows saturation kinetics. The rate is slow at low concentrations of the solute, increases with concentration and reaches a maximum at what we defined as “the critical concentration”. At higher concentrations (than the “critical”) the rate slows down and stabilizes at a plateau as it becomes concentration-independent. Owing to the similarity of sonochemical reactions in water to chemical reactions in heterogeneous systems, a kinetic model based on Langmuir adsorption isotherm is developed to predict the rate of reaction in terms of the initial concentration of the solute. The similarity of the model to models describing catalytic and adsorptive reaction kinetics is explained by reduced mass transfer limitations under ultrasonic irradiation, and localization of the solute at the bubble-liquid interface as a function of concentration.

Oxidative degradation of phenol in aqueous electrolyte induced by plasma from a direct glow discharge

The liquid-phase oxidation of phenol induced by plasma that was generated from direct glow discharges at the tip of a platinum anode in aqueous electrolyte was investigated. Various influencing factors such as the initial pH, the concentration of reactants and the catalytic action of Fe2+ were examined. The results suggest that the reaction is a pseudo-first-order kinetic reaction; the initial pH significantly affects the degradation velocity and ferrous ions displayed a remarkable catalytic effect on the oxidation. The major oxidation intermediates were identified with high-performance liquid chromatograph and ion chromatograph analysis. It was found that the degradation proceeded differently in the presence and absence of catalysts and consequently two degradation pathways were proposed.

A kinetic study of the oxidation of phenol,o-chlorophenol and catechol by hydrogen peroxide between 298 K and 333 K: the effect of pH, temperature and ratio of oxidant to substrate

Kinetic studies on the oxidative degradation of phenol, o-chlorophenol and catechol present in dilute aqueous solutions in the concentration range between 50 ppm and 1000 ppm by hydrogen peroxide were conducted in a batch reactor. The temperature was varied between 298 K and 333 K. Initial rates of conversion for phenolic compounds were extremely high compared with the later part of the reaction. The pH of the reaction medium also decreased substantially during the reaction and reached a plateau in the range of 6.4 for phenol and 4.5 for catechol and chlorophenol. Conversions of phenolic substrates were found to increase with an increase in initial substrate concentration and hydrogen peroxide/substrate ratio. For a fixed initial concentration and hydrogen peroxide/substrate ratio, the conversion was found to be in the order catechol>chlorophenol>phenol. The temperature of the reaction medium was found to have a minimal effect on the degradation kinetics, probably due to simultaneous thermal decomposition of hydrogen peroxide at elevated temperature. A probable mechanistic explanation of the experimental data based on reactivity of the phenolic compounds and their stable oxygenated intermediates is discussed. © 1999 Society of Chemical Industry.

Electrochemical degradation of phenol in aqueous solution on bismuth doped lead dioxide : a comparison of the activities of various electrode formulations

This paper describes the development of electrochemical processes for the oxidative degradation of toxic organic chemicals in waste waters. Doped bismuth lead dioxide anodes have been tested by the kinetic study of phenol anodic oxidation in aqueous solution. The main products during oxidative degradation of phenol are 1,4- benzoquinone, maleic acid and carbon dioxide. Several deposits of Bi2O5–PbO2 on Ti/(IrO2–Ta2O5) substrates have been prepared by anodic oxidation of Pb2+ and Bi3+ in aqueous solutions containing perchloric acid to increase the solubility of bismuth. To study the effect of perchlorate ions, the efficiency of the PbO2 deposit prepared from lead nitrate in an aqueous solution (pure PbO2) was compared with that of a deposit prepared from perchloric acid solution (perchlorate doped PbO2). Although the phenol is oxidized at the same rate on the two deposits, the charge corresponding to the total elimination of 1,4-benzoquinone is three times higher for perchlorate doped PbO2 than for pure PbO2. Phenol degradation is more efficiently carried out on a PbO2 anode doped with perchlorate and with bismuth than on the same electrode doped only with perchlorate. Among the electrodes tested in this work, the pure PbO2 anode is the most efficient for phenol degradation. It is assumed that certain active sites on the anode occupied by perchlorate ions do not participate in the transfer of oxygen atoms and that for the PbO2 electrode doped with bismuth, oxygen evolution is favoured to the detriment of oxygen atom transfer.

Kinetics of Phenol Photooxidation by Hydrogen Peroxide and Ultraviolet Radiation

Oxidative degradation of phenol by H2O2 and ultraviolet radiation is carried out, and a kinetic model is derived in order to represent the photooxidation reaction. The model equations are fitted by the experimental data collected for two distinct phases of reaction, marked as phase I and phase II. In the first phase H2O2 concentration is the controlling factor in the degradation process, whereas in the second phase concentration of phenol is the controlling species. A mechanistic explanation of the behavior has been presented.

Paired electrooxidative degradation of phenol with in situ electrogenerated hydrogen peroxide and hypochlorite

The oxidants, hydrogen peroxide and hypochlorite, were generated by the cathodic reduction of oxygen and anodic oxidation of chloride ion in a paired electrolysis process and used for phenol degradation. The degradation of phenol with electrogenerated hydrogen peroxide was slightly affected by pH and ferrous ion concentration. The oxidative degradation of phenol with paired electrogenerated hydrogen peroxide and hypochlorite was significantly affected by phenol concentration. In comparison with the cathodic and anodic degradation of phenol, the removal of phenol increased by 56.1 and 178.1%, respectively, in the case of paired electrooxidative phenol degradation. The COD decreased from 3222 and 3222 ppm to 2253 and 2746 ppm in the anodic and cathodic compartments when the charge passed increased from 0 to 2500C.

Oxidative degradation of phenol in aqueous media using ultrasound

The degradation of phenol with ultrasound and the influence of several parameters - hydrostatic pressure, nature of the dissolved gas, frequency of the ultrasound - have been studied. Primary degradation products are dihydroxy benzenes and quinones. These products are further degraded upon time into low molecular carboxylic acids. COD reduction can be increased by the addition of Raney nickel. Based on the determination of the degradation products by HPLC and HPICE, a reaction scheme can be suggested.

Effects of anodic and cathodic reactions on oxidative degradation of phenol in an undivided bipolar electrolyzer.

Effects of anodic and cathodic reactions on oxidative degradation of phenol in an undivided bipolar electrolyzer.