Degradation of trace contaminants using coupled sonochemistry and Fenton's reagent

2003 ◽  
Vol 47 (10) ◽  
pp. 85-92 ◽  
Author(s):  
Y. Jiang ◽  
T.D. Waite
Keyword(s):  
Reaction Temperature ◽  
Aqueous Media ◽  
Operating Conditions ◽  
Oh Radicals ◽  
Fenton’S Reagent ◽  
Pseudo First Order Reaction ◽  
Optimal Operating ◽  
Fenton's Reagent ◽  
First Order ◽  
Phenol Decomposition

The degradations of phenol in air-equilibrated aqueous media were investigated using coupled sonochemistry and Fenton's reagent for a variety of operating conditions. The decomposition yields of phenol (100-500 mM) were substantially enhanced due to the addition of Fenton's reagent (FeSO4) into the solutions irradiated at 608 kHz with 30 W and with reaction temperature 25 ± 1°C. The decomposition process follows a pseudo-first-order reaction kinetics with respect to phenol concentration, and the rate constant of phenol disappearance observed increases by approximately 2-3 fold when FeSO4 concentration was between 400 and 1000 M at pH = 3.5 ± 0.2 (controlled by phosphate buffer) as a result of Fe(II) reaction with H2O2 enabling further production of additional OH• radicals. The results obtained here also indicate that the decomposition rate of aqueous phenol using coupled ultrasound and Fenton's reagent was strongly dependant on the initial concentration of reactant, the amount of Fe(II) added as well as the pH of solution. The optimal operating conditions for 100-500 mM phenol decomposition in the air-equilibrated aqueous media were obtained when FeSO4 concentration was between 400 and 1,000 mM with pH in the range 3.5-4.2 under ultrasonic irradiation at 608 kHz, 30 W and reaction temperature 25 ± 1°C.

Electro-Fenton as a feasible advanced treatment process to produce reclaimed water

2004 ◽  
Vol 50 (2) ◽  
pp. 83-90 ◽  
Author(s):  
A. Durán Moreno ◽  
B.A. Frontana-Uribe ◽  
R.M. Ramírez Zamora
Keyword(s):  
Reclaimed Water ◽  
Electrical Current ◽  
Primary Treatment ◽  
Operating Conditions ◽  
Treatment System ◽  
Continuous Reactor ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Fenton’S Reaction ◽  
The Cost

The feasibility of the electro-Fenton process to generate simultaneously both of the Fenton's reagent species (Fe2+/H2O2), was assessed as a potentially more economical alternative to the classical Fenton's reaction to produce reclaimed water. An air-saturated combined wastewater (mixture of municipal and laboratory effluents) was treated in discontinuous and continuous reactors at pH = 3.5. The discontinuous reactor was a 2 L electrochemical laboratory cell fitted with concentric graphite and iron electrodes. The continuous reactor tests used a pilot treatment system comprising the aforementioned electrochemical cell, two clarifiers and one sand filter. Several tests were carried out at different conditions of reaction time (0-60 min) and electrical current values (0.2-1.0 A) in the discontinuous reactor. The best operating conditions were 60 min and 1 A without filtration of effluents. At these conditions, in discontinuous and continuous reactors with filtration, the COD, turbidity and color removal were 65-74.8%, 77-92.3% and 80-100%, respectively. Fecal and total coliforms, Escherichia coli, Shigella and Salmonella sp. were not detected at the end of the pilot treatment system. Electrogeneration of the Fenton's reagent is also economical; its cost is one-fifth the cost reported for Advanced Primary Treatment.

scholarly journals Biogas production in the methane fermentation of excess sludge oxidized with Fenton’s reagent

2019 ◽  
Vol 116 ◽  
pp. 00104
Author(s):  
Iwona Zawieja ◽  
Kinga Brzeska
Keyword(s):  
Fermentation Process ◽  
Biogas Production ◽  
Process Conditions ◽  
Oh Radicals ◽  
Fenton’S Reagent ◽  
Iron Ions ◽  
Fenton Reagent ◽  
Excess Sludge ◽  
Methane Fermentation ◽  
Fenton's Reagent

The advanced oxidation processes (AOPs) play an important role in the degradation of hardly decomposable organic pollutants. AOPs methods rely on the production of highly reactive hydroxyl OH• radicals. The aim of the conducted research was to intensify biogas production in the methane fermentation process of excess sludge subjected to the process of deep oxidation with Fenton's reagent. In the process of oxidation of sewage sludge with the Fenton reagent, doses of iron ions in the range 0.02–0.14 g Fe2+/g TS (total solids) were used Hydrogen peroxide was measured in the proportions 1: 1–1:10 in relation to the mass of iron ions. The basic substrate of the study was excess sludge. In the case of excess sludge oxidation with the use of Fenton's reagent, the most favorable process conditions were considered to be the dose of iron ions 0.08 g Fe2+/g d.m. and a Fe2+: H2O2 ratio of 1:5. As a result of subjecting the excess sludge to disintegration with the Fenton reagent in the above-mentioned dose, with respect to the fermentation process of unprocessed sludge, about two-fold increase in the digestion degree of excess sludge and about 35% increase of the biogas yield was obtained.

Rapid Disposal of Pentachlorophenol Contaminated Soils in a Soil Reactor

2012 ◽  
Vol 518-523 ◽  
pp. 2695-2703
Author(s):  
Yu Tao ◽  
Ai Jun Wang ◽  
Li Juan Wang ◽  
Guang Min Liu ◽  
Hong Qi
Keyword(s):  
Contaminated Soils ◽  
Operating Conditions ◽  
Toxic Chemicals ◽  
Molar Ratio ◽  
Optimum Operating ◽  
Fenton’S Reagent ◽  
Practical Application ◽  
Oxidative Potential ◽  
Fenton's Reagent ◽  
Rotating Speed

At present the point source soil contaminations by toxic chemicals are very serious, and many methods are used for the rapid disposal. In recent years, Fenton’s reagent has been paid more and more attention because of its high oxidative potential and simplicity. In this work, pentachlorophenol (PCP) was used to simulate contaminated soils, and a tilted soil reactor was designed to study its decomposition by Fenton’s reagent. The effects of six variables on PCP degradation were evaluated: (1) initial soil-water ratio; (2) reaction time; (3) H2O2-Fe2+ molar ratio; (4) dosing method; (5) reaction tank rotating speed and (6) initial H2O2 concentration, and the optimum operating conditions were identified. However, further research is required for practical application.

scholarly journals Metal adsorption in aqueous media using Moringa oleifera Lam. seeds produced in Ecuador as an alternative method for water treatment

2019 ◽  
Vol 11 (2) ◽  
Author(s):  
Andrea Carolina Landázuri ◽  
Jaime David Cahuasquí Segura ◽  
Andres Sebastián Lagos Estrella
Keyword(s):  
Moringa Oleifera ◽  
Metal Removal ◽  
Aqueous Media ◽  
Order Reaction ◽  
Batch Experiments ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Mechanical Stirring ◽  
Adsorption Capacities ◽  
Moringa Oleifera Lam

This work explores the technical viability in the use ofMoringa oleifera Lam. seeds produced in Ecuador as an adsorbent medium for copper (Cu), nickel (Ni) and chromium (Cr) present in water that could be implemented in future Water Resource Recovery Facilities in Ecuador. The seeds were prepared following a sequence of washing, drying, crushing, sieving, rewashing, and final drying. Two treatments were performed based on particle size.  Treatment 1 consisted on a mixture of 70% of particles larger than 2 mm and 30% of particles between 1 and 2 mm; while Treatment 2 consisted only on 1 - 2 mm particles. Batch experiments were performed with metal concentrations ranging from 10 to 150 ppm, a dose of 1.00 g of MO per liter, and mechanical stirring for 1 hour. Treatment 2 showed to be more favorable to metal removal and the Langmuir model better characterized adsorption of the three metals.The best kinetic description of the three metals is that of a pseudo first-order reaction where the adsorption capacities are 50.93 mg Cu/g MO, 30.14 mg Ni/g MO, and 40.98 mg Cr/g MO, with removal percentage of 37 - 53 %, 39 - 76%, and 11 - 33%, respectively. 

Reactions of Hydroxyl Radicals with Chlorobenzenes: Comparison of TiO2 Photocatalyst Reactions to Fenton’s Reagent

1989 ◽  
Vol 24 (4) ◽  
pp. 537-552 ◽  
Author(s):  
G. Lepore ◽  
C.H. Langford
Keyword(s):  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Aqueous Media ◽  
Surface Generation ◽  
Fenton’S Reagent ◽  
Adsorbed State ◽  
Fenton's Reagent ◽  
Photo Catalysis ◽  
Solution Generation ◽  
The Individual

Abstract A comparative study on reactions of solution and surface generated hydroxyl radicals with chlorobenzenes has been carried out, to determine the reaction path of reactive intermediates in photo-catalysis. Two separate approaches for generating hydroxyl radical oxidants in aqueous media were employed. Fenton’s reagent (solution generation) and TiO2 irradiation (surface generation) were exploited in the decomposition of dichlorobenzenes, 1,2,4-trichlorobenzene and a mixture (o-DCB, m-DCB, 1,2,4-TCB). Photocatalysis displayed a distinctive order for the individual chlorobenzenes with increasing ease of disappearance: p-DCB < 1,2,4-TCB < o-DCB < m-DCB. Reduced selectivity was observed for a mixture. Use of Fenton’s reagent resulted in the following pattern for both individual and the mixture of chlorobenzenes: 1,2,4-TCB < o-DCB ≈ p-DCB ≈ m-DCB. Added acetone, suppressed the disappearance of the parent chlorinated aromatics in both systems. However, in the reaction with Fenton’s reagent 1,2,4-TCB displayed considerable sensitivity in comparison to the DCB isomers. In contrast, the photocatalysis of three individual substrates evaluated in a mixture (1,2,4-TCB, m-DCB, o-DCB) did not manifest significant differences. Results indicate that reactions observed on the photocatalyst must occur in the adsorbed state, where the oxidant is an adsorbed hydroxyl radical or the surface trapped hole itself.

Catalytic performance of cerium-modified ZSM-5 zeolite as a catalyst for the esterification of glycerol with acetic acid

2020 ◽  
Vol 18 (9) ◽  
Author(s):  
Priyanka Gautam ◽  
Sanghamitra Barman ◽  
Amjad Ali
Keyword(s):  
Activation Energy ◽  
Acetic Acid ◽  
Process Parameters ◽  
Reaction Temperature ◽  
Zeolite Catalyst ◽  
Catalytic Performance ◽  
Order Reaction ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order

AbstractEsterification of glycerol with acetic acid was carried out over cerium-modified ZSM-5 zeolites to synthesize monoacetin (MA) and diacetin (DA). The modified zeolite catalyst was characterized. The effect of reaction process parameters such as acetic acid to glycerol mole ratio (1–11), reaction temperature (30–120 °C), and catalyst weight (2–8 wt %) on the selectivity of the product was investigated. At 120 °C reaction temperature, 8 wt % catalyst, and 9:1 acetic acid to glycerol mole ratio, about 98.32% conversion of glycerol were obtained. This reaction follows pseudo-first-order reaction kinetics and the activation energy was found to be 63.72 kJ mol−1.

scholarly journals Highly efficient TiO2-supported Co–Cu catalysts for conversion of glycerol to 1,2-propanediol

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wongsaphat Mondach ◽  
Sarun Chanklang ◽  
Pooripong Somchuea ◽  
Thongthai Witoon ◽  
Metta Chareonpanich ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Low Cost ◽  
Aqueous Media ◽  
Value Added ◽  
Initial Pressure ◽  
Operating Conditions ◽  
Impregnation Method ◽  
Glycerol Conversion ◽  
Cu Catalysts

AbstractGlycerol is a low-cost byproduct of the biodiesel manufacturing process, which can be used to synthesize various value-added chemicals. Among them, 1,2-propanediol (1,2-PDO) is of great interest because it can be used as an intermediate and additive in many applications. This work investigated the hydrogenolysis of glycerol to 1,2-PDO over Co–Cu bimetallic catalysts supported on TiO2 (denoted as CoCu/TiO2) in aqueous media. The catalysts were prepared using the co-impregnation method and their physicochemical properties were characterized using several techniques. The addition of appropriate Cu increased the glycerol conversion and the 1,2-PDO yield. The highest 1,2-PDO yield was achieved over a 15Co0.5Cu/TiO2 catalyst at 69.5% (glycerol conversion of 95.2% and 1,2-PDO selectivity of 73.0%). In the study on the effects of operating conditions, increasing the reaction temperature, initial pressure, and reaction time increased the glycerol conversion but decreased the selectivity to 1,2-PDO due to the degradation of formed 1,2-PDO to lower alcohols (1-propanol and 2-propanol). The reaction conditions to obtain the maximum 1,2-PDO yield were a catalyst-to-glycerol ratio of 0.028, a reaction temperature of 250 °C, an initial H2 pressure of 4 MPa, and a reaction time of 4 h.

Disappearance Time of a Few Polycyclic Aromatic Hydrocarbons in Soil

2021 ◽  
Vol 18 (1) ◽  
pp. 67-75
Author(s):  
Mizanur Rahman ◽  
Suprava Ghosh ◽  
Prahash Chandra Sarma
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Half Life ◽  
Zero Order ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
First Order ◽  
Increasing Trend ◽  
Polycyclic Aromatic ◽  
Horizontal Spread

The present study attempts to determine the order of reactions for degradation of four polycyclic aromatic hydrocarbons viz., anthracene, fluorene, naphthalene and phenanthrene in six selected soil samples by method of trials. The half-life period or the disappearance times in days for 50% (DT 50) of the hydrocarbons initially applied to the soil were determined after finding out the probable order of the reactions using the half-life equations. A few of the extracts are subjected to GC analysis. Nine of 21 samples studied in the experiment are degraded and zero-order while the remaining samples are of the first order. The increasing trend in electrical conductivity and decreasing trend of pH support the formation of polar substances from non-polar hydrocarbons. Average DT 50 values for a mixture of the cited PAHs are 6 and 16 days, respectively, in presence of Fenton’s Reagent and without it in the samples having 200 ppm concentration. In a semi-closed system, where there is no horizontal spread of solids and liquids, the DT 50 depends on initial pollutant concentration. Fenton’s Reagent has been found to enhance the rate of degradation by the rapid conversion of the hydrocarbons into derivatives or fragments.

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