Fenton Reagent Concentrations Research Articles

Homogeneous Photo-Fenton Degradation and Mineralization of Model and Simulated Pesticide Wastewaters in Lab- and Pilot-Scale Reactors

The homogeneous photocatalytic degradation of model pesticide clopyralid (CLPR) has been investigated under various experimental setups. Lab-scale experiments under UV-A radiation in an acidic environment showed that the degradation rate generally increased when increasing either Fe3+ or H2O2 concentration up to a point beyond which (i.e., 100 mg L−1 for peroxide or 7 mg L−1 for ferric ions) Fenton reagents had little or even detrimental effect on degradation. Thus, there is an optimum concentration of Fenton reagents for maximizing treatment performance, beyond which degradation rates are not enhanced. Excessive concentrations of peroxide and/or catalyst may (i) introduce unnecessary treatment costs, (ii) reduce performance due to scavenging effects, and (iii) raise environmental concerns associated with the disposal of, e.g., high concentrations of iron in the receiving water courses. Switching from UV-A to visible light led to similar rates of degradation, i.e., 86% and 82.2%, respectively, after 90 min of reaction, highlighting the potential of using renewable energy, i.e., natural sunlight, to drive the process. Treatment for 120 min also led to 90% mineralization and quantitative release of nitrogen originally present in the pesticide; this was also accompanied by complete elimination of eco-toxicity to Vibrio fischeri. Pilot-scale experiments were performed in a fountain-type reactor using a commercial pesticide formulation containing CLPR. Both the degradation and mineralization rates increased with increasing the intensity of the incident UV-A radiation from 1.88 to 4.03 mW cm−2. Experiments were also conducted with different liquid volumes, i.e., from 3 to 8 L. Illumination of 5 L wastewater resulted in 80% mineralization after 60 min and this only slightly decreased to 73% at 8 L. Overall, the findings underline the promising perspectives of the application of the treatment method in upgrading the quality of water and liquid waste containing pesticides.

Kinetic modelling of total organic carbon degradation in dairy wastewater

ABSTRACT Several treatment strategies have been proposed to minimize the environmental impact of dairy wastewaters. However, their complex and variable composition makes it difficult to predict the degradation kinetics of organic compounds. In this study, we used a mathematical approach to describe the kinetics of total organic carbon degradation in real dairy wastewater by photo-Fenton oxidation. The reactions were conducted under different ultraviolet light intensities, pH, temperature and Fenton reagent concentrations, obtaining a maximum TOC removal of 90.84%. The kinetic model was developed based on well-established photo-Fenton reactions. The present approach considers that account that small and large molecules of unknown contaminants are present in the effluent, and the smaller molecules are consumed first. The specific degradation rate (kd ) was considered as an exponential function of total organic carbon conversion, comprising this effect of molecular size distribution on the treatment process. Fitting of experimental data to model predictions provided mean R 2 values of 0.843–0.953.

Optimasi Pengolahan Limbah Cair Textile Menggunakan Metode Sono-Fenton

The textile and textile product (TPT) industry is one of the mainstay commodities that drive the economy in Indonesia. Export market opportunities are very open for this commodity, but the current problem is the waste generated from this industry. PT.Vonex is a textile industry with spinning and dyeing products. Textile liquid waste produced has a very concentrated color characteristic and when the dye enters the waters it can cover the surface of the water body so as to block sunlight from entering the waters. Textile wastewater treatment with the sono-Fenton method as DCA (Decolorizing Agent) can be used as an alternative choice in overcoming these problems. In this study, an analysis of the reduction of the dye was carried out by using variations in the concentration of Fenton's reagent and the length of sonication time. The variations in the concentration of Fenton's reagent used were 1:1, 2:1, 4:1, and 6:1 while the sonication time used variations of 10, 30, 60 and 90 minutes. The test results show that the use of Fenton's reagent assisted by ultrasonic waves (sonication) in textile wastewater treatment can reduce the levels of color values, pH, COD, BOD, and TSS. The results showed that the variation of Fenton reagent concentration 1:1 with a sonication time of 30 minutes was the optimum condition with a percentage decrease in color value of 99.61%, a decrease in pH value of 68.94%, a decrease in COD value of 90.64%, a decrease in BOD levels by 97.48%, and a decrease in TSS levels by 91.28%.

Degradation of ibuprofen by photo-based advanced oxidation processes: exploring methods of activation and related reaction routes

Several homogeneous photo-based advanced oxidation processes-namely photolysis, photo-oxidation, and photo-Fenton oxidation—were investigated for the elimination of ibuprofen in water. The effects of several operating parameters, such as the lamp type (low or medium pressure mercury, xenon-arc), the concentration of hydrogen peroxide (0.5 to 7 times the stoichiometric amount required for mineralization), and the concentration of Fenton reagent, were quantified. Photo-Fenton oxidation was also combined with low-frequency sonication to investigate possible synergistic interactions. Ibuprofen degradation under ultraviolet photolysis and ultraviolet/hydrogen peroxide oxidation followed pseudo-first-order kinetics with respect to the pollutant concentration and the apparent rate constant increased with lamp power (6–10 W) and oxidant concentration. Photo-Fenton oxidation under ultraviolet light (L1 lamp, 254 nm, 6 W) and visible light (L2 lamp, 360–740 nm, 150 W) led to complete ibuprofen removal after 3 h, but the mineralization yield of the L1/Fenton process (82%) was higher than that of the L2/Fenton process (59%) because of the effects of ultraviolet/hydrogen peroxide oxidation in the former. Coupling L2/Fenton with sonication improved the degradation rate of the molecule at low Fenton reagent concentration, but the beneficial effect of ultrasound on ferrous iron regeneration vanished when the iron to ibuprofen molar ratio was close to 1. An overall reaction scheme for ibuprofen degradation is proposed based on the transformation products detected during these processes.

Effect of power ultrasound and Fenton reagents on the biomethane potential from steam-exploded birchwood.

The global demand for non-fossil energy sources is increasing rapidly. As a result, biogas presents a suitable alternative; however, first generation biofuels (e.g., sugar cane) potentially impact food crops globally. Second generation biofuels based on lignocellulose-based biomass are being used more frequently as they do not impact food crops. Furthermore, in Northern Europe, there is a significant interest in utilizing birchwood and paper mill waste for biogas production due to its high availability. The utilization of birchwood for biogas has significantly improved in recent years with the improvement of required pretreatment processes. To date, the most effective and economically feasible pretreatment in an industrial context is the steam explosion of lignocellulose-based biomass. Despite this, there is potential for releasing more digestible components from this biomass by efficiently degrading the lignocellulose components. This research presents another pretreatment that can be applied to steam-exploded wood based on ultrasonication and Fenton reagents. It was observed that by treating the steam exploded birchwood with ultrasonication and mild concentrations of Fenton reagents, an increase in the rate of biogas production was achievable. This would allow the increase in biogas yield of a continuously feed industrial anaerobic digester without increasing the size of the reactor.

Removal of Paracetamol Using Effective Advanced Oxidation Processes.

Fenton, photo-Fenton, and photo-induced oxidation, were investigated and compared for the treatment of 0.26 mmol L−1 of paracetamol (PCT) in a deionised water matrix, during a reaction span of 120.0 min. Low and high Fenton reagent loads were studied. Particularly, the initial concentration of Fe2+ was varied between 0.09 and 0.18 mmol L−1 while the initial concentration of H2O2 was varied between 2.78 and 11.12 mmol L−1. The quantitative performance of these treatments was evaluated by: (i) measuring PCT concentration; (ii) measuring and modelling TOC conversion, as a means characterizing sample mineralization; and (iii) measuring cytotoxicity to assess the safe application of each treatment. In all cases, organic matter mineralization was always partial, but PCT concentration fell below the detection limit within 2.5 and 20.0 min. The adopted semi-empirical model revealed that photo induced oxidation is the only treatment attaining total organic matter mineralization ( 100% in 200.0 min) at the expense of the lowest kinetic constant (k = 0.007 min−1). Conversely, photo-Fenton treatment using high Fenton reagent loads gave a compromise solution ( 73% and k = 0.032 min−1). Finally, cytotoxicity assays proved the safe application of photo-induced oxidation and of photo-Fenton treatments using high concentrations of Fenton reagents.

Removal of microcystin-LR using UV-assisted advanced oxidation processes and optimization of photo-Fenton-like process for treating Nak-Dong River water, South Korea

UV-assisted advanced oxidation processes (AOPs) are promising for the removal of microcystin-LR (MC-LR), one of cyanotoxins released during harmful algal blooms. Nevertheless, the efficiency and potential of the photo-Fenton-like process (UV-C/Fe(III)/H2O2) in treating MC-LR have not been explored in much detail. In this study, MC-LR degradation efficiencies of various UV-assisted AOPs were compared that they were higher in the order: UV-C/Fe(III)/H2O2 > UV-C/Fe(II)/H2O2 > UV-A/TiO2 > UV-C/H2O2 > UV-C > UV-A/Fe(II)/H2O2 > UV-A/H2O2 > UV-A. The concentrations of Fe(III) and H2O2 used in the photo-Fenton-like process were varied to evaluate their influences on MC-LR degradation in both deionized water and a water sample from Nak-Dong River, Daegu (South Korea). The highest removal efficiency (>80%) for MC-LR was achieved after 15 min by the photo-Fenton process at a low optimum Fenton reagent concentration (Fe = 0.5 mg L−1 and H2O2 = 1 mg L−1) in the river water. Twelve transformation products of MC-LR were identified with 1029.5, 1012.5, 1015.5, 1011.5, 965.6, 835.5, 815.4 and 783.4 m/z (two products) with the presence of four reaction sites: the conjugated diene bond of Adda, the methoxy group of Adda, the CC bond of Mdha, and the acid group of MeAsP. Theses alleviated the hepatotoxicity of MC-LR, as indicated by a protein phosphatase (PP) 2A assay. Considering the impacts of the chemistry for the treatment of river water, natural organic matter has a slightly higher impact on MC-LR degradation than the initial pH and alkalinity. The kMC-LR were maintained at 0.167–0.187 min−1 and t1/2 (min), obtained from the different river water samples, were all within 5 min in spite of the relatively high dissolved organic carbon concentrations.

Electrochemical degradation of scarlet red dye from aqueous environment by titanium-based dimensionally stable anodes with SS electrodes

Textile effluents are toxic and carcinogenic materials that exist in the aquatic environment. In this study, the degradation efficiency of commercially available scarlet red dye investigated on TSA-SS Electro Fenton process (EFP) was reported. It is of great interest in the field of environmental engineering to remove dyes from aquatic environment. The influence of operating parameters such as pH (2–9), current density (0.1–0.5 mA/cm2), concentration of dye (0.1–0.5 g/L), H2O2 (0.1–0.5 g/L) concentration and Fe2+ concentration (0.01–0.03 g/L) were analyzed by batch system. The optimum degradation conditions were determined as pH—3, current density—0.4 mA/cm2, concentration of dye—0.4 g/L, H2O2 concentration—0.5 g/L and Fe2+ concentration—0.025 g/L. These results indicated that the degradation efficiency of scarlet red dye by EFP depends on solution pH and Fenton reagent concentration and a low pH value was favorable for the dye degradation. It has been demonstrated that more than 94% dye removal was obtained at 50 min. Electro Fenton process was also investigated by cyclic voltammetry technologies.

Parametric Study for the Treatment of Simulated Cetirizine Wastewater Using Electrochemical Methods: Optimization and Cost Analysis

Cetrizine is a very stable antihistamine drug widely used for treating allergic problems. The present study involves treatment of simulated cetirizine wastewater by electro-oxidation (EO) and electro-fenton (EF) processes using RuO2 coated Ti electrodes (Ti/RuO2).The experiments were designed using Box Behnken Design (BBD) under response surface methodology (RSM). The effect of pH, current, dose of fenton reagent and electrolysis time was determined on the degradation efficiencies and specific energy consumption of treatment processes. The degradation efficiency of EO treatment for simulated cetirizine wastewater was obtained 57.61% at optimum operational parameters pH 7, current 0.54 A and electrolysis time of 89 min. The specific energy consumption of 3.20 kWh/m3 was evaluated in EO process at optimized conditions. Whereas, in case of EF treatment 78.37% degradation was obtained at optimum conditions (elapsed time = 52.86 min, dose of Fe2+ = 1 mmol at constant supply of 0.84 A current) of EF treatment process. The specific energy consumption of 3.71 kWh/m3 was evaluated in EF process at optimized conditions. Current and time were observed as highly significant operational parameters for the EO treatment whereas current, time and fenton reagent concentration were strongly affecting the degradation using EF treatment of simulated cetirizine.

Degradation of Total organic carbon (TOC) and Chemical oxygen demand (COD) in Petroleum wastewater by solar Photo-Fenton process.

The aim of this study is to investigate the performance of solar photo-Fenton process (H2O2/Fe2+/Solar) to treat petroleum wastewater from Sohar oil Refinery, Oman. The effect of operating conditions such as pH, reaction time, Fenton ratio, and Fenton reagent concentrations are investigated. The obtained optimum conditions include H2O2 dosage (1 g L-1), Fe+2 dosage (0.08 g L-1), pH (3) and reaction time (180 min). TOC and COD removal rates are 64 % and 78 %, respectively. However, the photolytic process was less efficient in the petroleum wastewater treatment, achieving an 11.5% and 9% of COD and TOC removals, respectively. The solar photo-Fenton process has well efficient for petroleum wastewater treatment in the acidic conditions and more economic by free energy.

Fenton Degradation of Fast Green Dye

The degradation of commercial textile dye named fast green (FG) was investigated by Fenton reagent under different operating conditions in an aqueous solution. The operating conditions were amount of hydrogen peroxide (0.05, 0.1 and 0.15 mL), pH (2-12) and concentration of ferrous ion (10, 20 and 30 mg). The initial rate of degradation was affected by the concentration of Fenton reagents [Fe(II) and H2O2 solution]. The rate of degradation enhanced as the concentration of ferrous ion increased. As the ferrous ion concentration increased from 10 to 30 mg, the removal percent was increased from 73% to 89%, respectively, at 25 min of reaction time. Also, the removal percent of FG increased from 74 % to 81 % as the amount of H2O2 increased from 0.05 to 0.15 mL, respectively, at 25 min of reaction time. It was also found that at pH 3 removal percent reach maximum value with 91.8%. The kinetic study of FG degradation was also studied in this work and the results indicated that the degradation kinetics of FG followed the first-order kinetic.

Treatment of Simulated Waste Water Containing Methyl Red by Advanced Oxidation Process

Advanced oxidation process is one of the promising technologies to eliminate the toxic pollutants, total organic contents etc. from waste water. Attempts are being made from previous few years on treatment of waste water using various advanced oxidation treatment methods like Fenton process. In Fenton process the reaction of FeSO4 and Fenton reagent H2O2 at low pH, involves the decomposition of Fenton reagent and results in Fe2+ generation, produce hydroxyl radicals which oxidize tough to decompose organics compounds due to its high oxidizing ability, in very short time. In this study, the application of Fenton process for the degradation of organic component from the water contaminated with methyl red an azo dye, has been inspected to present the assessment of Fenton process in waste water treatment. Concentration of Fenton reagent, ferrous sulphate and other process parameters like contact time and PH has been studied. H2SO4 and NaOH solution is used for pH adjustments. Different combination of experiments to check the COD removal, respect to the doses of H2O2 and FeSO4 has been performed. The optimum doses of which are 3.5 ml and 0.50 gm respectively, the best result (81.1% reduction) is obtained at pH of 3.0 ± 0.2, and reaction time of 30 min, and it is also proved that Fenton process is inefficient in alkaline and neutral medium.

Facilitated ultrasonic irradiation in the degradation of diazinon insecticide

Abstract In this study, the degradation of diazinon insecticide was investigated using ultrasound facilitated by Fenton's and Fenton-like reagents under various experimental conditions. The effects of oxidant (persulphate ions, S2 O 8 2 − and hydrogen peroxide (H2O2)), transition metal (including Co2+, Ag+ and Fe2+), Fenton's reagent concentration and temperature on diazinon degradation were examined. A solution with an initial diazinon concentration of 50 mg L−1 was used in this study. Ultrasonic irradiation in combination with Fenton's and Fenton-like reagents not only effectively degraded diazinon but also rapidly reduced its toxicity. The optimal experimental conditions were determined as follows: 20 mg L−1 Fe2+, 150 mg L−1 H2O2, 25 °C and pH 3. After reacting for 60 min, the diazinon removal efficiency reached 98%, with a mineralization efficiency of 30%. Degradation occurred primarily via oxidation and resulted in the substitution of sulphur with oxygen in the diazinon P S bond.

Effect of different carriers and operating parameters on degradation of flax wastewater by fluidized-bed Fenton process.

This investigation evaluates the effectiveness of a fluidized-bed Fenton process in treating flax wastewater. Flax wastewater was taken from a paper-making factory in a secondary sedimentation tank effluent of a paper-making factory in Hebei. The performance of three carriers (SiO2, Al2O3, Fe2O3) used in the reactor was compared, and the effects of different operational conditions, and Fenton reagent concentrations were studied. Experimental results indicated that SiO2 was the most appropriate carrier in the system. The dose of Fe2+ and H2O2 was a significant operating factor in the degradation progress. The bed expansion was considered to be another factor influencing the treatment effect. Under the appropriate conditions (300 mg/L Fe2+, 600 mg/L H2O2, and 74.07 g/L SiO2 as the carrier, at pH=3, 50% bed expansion), the highest removal rate of total organic carbon (TOC) and color was 89% and 94%, respectively. The article also discussed the process of the colority removal of flax wastewater and the kinetics of TOC removal.

The Use of Advanced Oxidation Processes (AOPs) in Dairy Effluent Treatment

There are several studies in this same sense aiming to develop new processes and new technologies to minimize the volume and toxicity of effluents generated by chemical industries. Currently, technology advances in effluent and residues treatment is based on environmental sustainability (residual reuse) and in the degradation of pollutant substances with easier natural degradation. Technology has improved, Advanced Oxidation Processes (AOPs) for instance, being based on the generation of hydroxyl radicals as oxidant agent, seems to have great efficiency in the treatment of industrial detriments promoting the reduction of coloration in effluents and environmental decontamination. This project represents the efforts in making the effluent treatment of dairy industries using AOPs (Fenton Reagent, UV), produced by YAKULT, unit of Lorena, State of Sao Paulo viable. There have been evaluated, in the bench level, in batch process, different parameters such as time of exposition to UV radiation, pH range, temperature and different Fenton Reagent concentration. Due to these procedures, the reduction of COD was the main control variable in the results provided by the experiments, with 94.17% of organic matter degradation in the effluent.

Azo Dye DB71 Degradation Using Ultrasonic-Assisted Fenton Process: Modeling and Process Optimization

In the present study, ultrasonic-assisted Fenton process called sono-Fenton (SF) with low concentration of Fenton reagents was studied via degradation of Direct Blue 71. Influences of seven operational parameters including initial pH (pH0), initial concentration of pollutant (C 0), dose of Fenton reagents (C Fe and C H2O2), ultrasound irradiation frequency (FrS), ultrasound irradiation power (P S), and treatment time (t SF) were investigated on the dye removal efficiency (DR). A combined design of experiments consists of full factorial for t SF, and Taguchi for other six parameters was designed, and experiments were conducted in accordance with the design. The experimental data were collected using a batch reactor equipped with controllable ultrasonic bath. The DR of 0–33.5 mg/l was achieved under experimental conditions. These results approved that the SF process can be a promising approach in terms of colored wastewater treatment. The data were used for model building by Taguchi and artificial neural network. Further statistical tests were applied to exhibit models goodness and to compare models. Finally, optimization process was carried out using Taguchi and genetic algorithm. The optimization procedure causes optimal point which gives an insight of optimal operating condition.

Treatment of industrial waste pharmochemical by fenton’s reagent

This study aims to determine the optimal concentration of Fenton reagent for pharmaceutical chemistry industry, varying the concentration of ferrous sulfate and hydrogen peroxide subsequently monitor the treatment in pilot scale and wastewater treatment (WWTP) station of the main parameters: color, odor, pH and COD. Pilot tests to obtain the guidelines used in formulating the Fenton reagent to be used in large scale in the effluent tank were performed, the pilot test of experiment T12 showed the best result (Color and COD) for the composition of the treatment with: 3.2 mL of H2O2 and 160 mg Ferrous Sulfate. From this parameter the treatment was carried out daily monitoring in the laboratory and pilot scale, and the values were similar for both treatments, with the percentage reduction of COD of 93.57% in the lab test and 94.00% in the ETE test. The process of wastewater treatment using Fenton reagent showed excellent results, with better values than the limits established by law. But the treatment time of 16 days is not feasible for some industries, but is smoothly carried out in the study industry.

Fuzzy logic sensing of G-quadruplex DNA and its cleavage reagents based on reduced graphene oxide

Herein, by combining the merits of nanotechnology and fuzzy logic theory, we develop a simple, label-free, and general strategy based on an organic dye-graphene hybrid system for fluorescence intelligent sensing of G-quadruplexes (G4) formation, hydroxyl radical (HO∙), and Fe2+ in vitro. By exploiting acridine orange (AO) dyes-graphene as a nanofilter and nanoswitch and the ability of graphene to interact with DNA with different structures, our approach can efficiently distinguish, quantitatively detect target analytes. In vitro assays with G4DNA demonstrated increases in fluorescence intensity of the AO–rGO system with a linear range of 16–338nM and a detection limit as low as 2.0nM. The requenched fluorescence of the G4TBA–AO–rGO system has a non-linear response to Fenton reagent. But this requenching reduces the fluorescence intensity in a manner proportional to the logarithm to the base 10 of the concentration of Fenton reagent in the range of 0.1–100μM and 100–2000μM, respectively. Furthermore, we develop a novel and intelligent sensing method based on fuzzy logic which mimics human reasoning, solves complex and non-linear problems, and transforms the numerical output into the language description output for potential application in biochemical systems, environmental monitoring systems, and molecular-level fuzzy logic computing system.

An electrochemical biosensor for rapid detection of bovine serum albumin damage induced by hydroxyl radicals in room temperature ionic liquid

Oxidative protein damage has been widely implicated in carcinogenesis and other disorders. Sensitive and reliable detection of protein oxidative damage remains a significant challenge. Reported herein is a novel electrochemical biosensor for direct detection of bovine serum albumin (BSA) oxidative damage in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]). Oxidation of BSA immobilized on the electrode was induced by hydroxyl radical produced from Fenton reaction. An electroactive indicator, Tris(2,2′-bipyridyl)cobalt(III)perchlorate, was employed in the detection. The oxidative peak current of Co(bpy)33+ decreased with the incubation time of BSA film in Fenton reagents. Electrochemical impedance spectroscopy was used to study the interface properties of the protein modified electrode surface. More dramatic damage in [BMIM][PF6] compared with that in an aqueous solvent media confirmed that [BMIM][PF6] was suitable medium for the electrochemical detection of BSA damage. The influences of the incubation time, the concentrations of Fenton reagents and antioxidants on BSA damage were obtained. The method is promising for a rapid and sensitive detection of protein damage.

Performance Evaluation of Photo-Fenton and Fenton Processses for Dairy Effluent Treatment

This study aimed to evaluate the efficiency of Photo-Fenton and Fenton processes in reducing organic matter of dairy effluent. An Orthogonal Array L9 Taguchi was used to determine optimal conditions of acidity media, temperature, Fenton concentration and UV radiation intensity. Reaction time was set up to 60 min. Optimized parameters were: pH 3.0, temperature, Fenton reagent concentration and UV radiation at the highest level. The Dissolved Organic Carbon percentage reduction (DOC) was 91 %. An effective degradation study was carried out, in which, the reduction percentage was found to be less than the most efficient DOC removal. A cost/benefit evaluation of the AOP process employed on the in natura dairy effluent treatment showed that the reagent consumption the main cost of the process. The highest efficiency experiment for the dairy effluent of this study had operational costs lower than US$ 0.50 to Photo-Fenton and Fenton processes, respectively.