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Abstract

This paper demonstrates the performance characteristics of Photovoltaic Cell Electro-Fenton oxidation for treatment of refinery wastewater. The photovoltaic electro-oxidation was constructed and deliberates the extent of its custom in purifying this wastewater, which is a photovoltaic cell, DC to AC convertor, a battery and an electric – oxidation reactor. Throughout electrochemical treatment, many operating limits were examined, such as hydrogen peroxide, electrolysis time, current density and total organic carbon in addition to energy consumption and cost. The effects of the operational variables counting the current (0.5-2 mA), H2O2 concentration (10-50 ppm) and the electrolysis time (10-30 min) and were deliberate by using reply surface methodology (RSM) and Minitab-17. The agitation speed, pH and NaCL of the solution had remained occupied as 250 rpm, 3, 0.25 g correspondingly. Fast recovery and mineralization of organics and their middle reaction crops were stated. Underneath the best standards of the working variables more than 98% elimination competence of organic content and 39.67 kWh/m3for the consumption of energy was got.

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... These processes can completely injury the contaminants into innocuous inorganic substances. In original year's maintenance have been intent on advanced oxidation developments remains nameless by way of electro-oxidation [20]. Though the first investigation on the request of electrochemical procedures aimed at the action of wastewater in the oil manufacturing was available in the late 1990s, there are still numerous chances to implement these skills at full scale [21]. ...
... This might remain credited toward the existence of a substantial activity of the adsorption through the EC procedure as the electrolysis time has been lengthy. Also, long oxidation times led toward step through step detoxification beforehand inorganic tin, water, and CO2 remained formed [20]. ...
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This paper proves the presentation features of chemical and mechanical aimed at action of heavy metal in produced water (PW). The Electro-catalytic (EC) is one of chemical-mechanical remained made and reflects the extent of its custom in purifying this wastewater. Throughout EC behavior, numerous operating limits were inspected, for instance titanium dioxide, rpm electrolysis time, and copper metal in produced water. The belongings of the working variables including the rpm (100-300), TiO2 concentration (10-30 mg/L), and the electrolysis time (5-15 min) by using Response surface methodology (RSM) and Minitab 17. The current and pH of the solution had remained occupied by way of 1 Amps, 3 respectively. Underneath the finest standards of the employed variables more than 98% removal of copper was found. The elective catalytic method is appropriate aimed at water contaminated by heavy metal, especially aimed at low concentrations of heavy metal in produced water.
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The increasing of global energy demand leads to the huge amount of wastewaterassociated with refinery processes. Refinery wastewater (RWW) contains significant levels ofcontaminants and are characterized by enormous amounts of refinery effluent. Since the wastes ofrefinery processing is a reason to ecological contaminations, treatment is a vital step for eliminationof these pollutants. This study was designed to determine effect of pH, process time and nano hematitedose in order to eliminate the organics pollutants from the refinery wastewater using adsorptionprocess and MINITAB software. The nano hematite was characterized by Fourier transform infraredspectroscopy and scanning electron microscopy (SEM). The effect of adsorption time, nano adsorbentdose, and pH on the elimination of organic pollutants in the RWW was also investigated. The removalefficiency of organic content was 85.1% at pH 6.5, within time of 150 min, and adsorbent dose was0.9 g. The isotherms data of the adsorption process were determined by the Langmuir, Freundlich,and Brunauer-Emmett-Teller (BET) models. The latter demonstrated the highest adsorption kinetics,which ended up with a constant rate and higher adsorption capacity. These results indicated thatthe use of nano hematite was highly efficient in the removal of RWW organic pollutants withhigh adsorption capacity as determined by BET model
Conference Paper
Potassium ferrate remains a multi-functional green substance aimed at refinery wastewater action by substantial combined effectiveness in oxidization, disinfection, and coagulation, creating environment approachable Ferric end-products throughout the reactions. This scheme is required toward the kinetics of the potassium ferrate (K2FeO4) oxidation of organic content in oily wastewater and to investigate the effects of Potassium ferrate concentration, pH, and temperature on the reaction. The reaction remained active at squat temperature, higher pH, and larger concentration of ferrate in a basic condition. Central Composite Design and Response Surface Methodology were useful aimed at modeling and optimizing the decontamination process. The conventionality of untried and predicted data (R² = 0.9165, Radj² = 0.8498) were verified using Variance Analysis. potassium ferrate by CCD/RSM allowable to reduce COD by 88.5, through using 80 ppm potassium ferrate, 4 min oxidation time, 200 rpm oxidation, 50 rpm coagulation, at pH=9.5 within 30 min coagulation time.Efficient removal of organic by potassium ferrate preoxidation is believed to be a consequence of several process mechanisms. The coagulation was also improved by increasing particle concentration in water, because of the formation of the intermediate forms of precipitant iron species during preoxidation. In addition, it was also observed that ferrate preoxidation caused algae agglomerate formation before the addition of coagulant, the subsequent application of alum resulted in further coagulation.
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This study aims to examine the ability of Photo Fenton oxidation processes when they have been used to treat simulated wastewater (SWW). A batch photo-Fenton oxidation process had been achieved to eliminate lead ions from SWW. The experimentations were intended by a Response surface method experimental design comprising the consequence of the irradiation time (30-120 min.), hydrogen peroxide (25– 100 ppm), Ferrous sulfate (5-20 ppm), lead concentration (2-10 ppm), UV Lamp (7w) and pH (3–9) then examining the results by statistical programs. Then and at the best values of these conditions (120 min., 65 ppm of H2O2, 12.5 ppm of ferrous sulfate, 2 ppm of lead concentration, UV lamp 3 and, pH 9) at room temperature. The elimination efficiency of the Photo Fenton oxidation (78 %) under optimal conditions. The result showed that the Photo Fenton process is suitable for heavy metal removal from wastewater.
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In this study, refinery wastewater treatment scheme, the electro-Fenton oxidation process is obtainable. Through Fenton oxidation treatment, numerous working limits remained examined, for instance hydrogen peroxide, electrolysis time and pH. The effects of the working variables including the pH (2-9), hydrogen peroxide concentration (20-60 mg/L) and the reaction time (10-30 minutes) and remained thoughtful through means of answer surface methodology and Minitab-17. The current, agitation speed and sodium chloride of the aqueous solution consumed remained engaged as 1 Amps, 200 rpm and 0.2 g congruently. Beneath the finest standards of the employed variables extra than 98% oil removal in refinery wastewater.
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With the development of industrial society, organic wastewater produced by industrial manufacturing has caused many environmental problems. The vast majority of organic pollutants in water bodies are persistent in the environment, posing a threat to human and animal health. Therefore, efficient treatment methods for highly concentrated organic wastewater are urgently needed. Advanced oxidation processes (AOPs) are widely noticed in the area of treating organic wastewater. Compared with other chemical methods, AOPs have the characteristics of high oxidation efficiency and no secondary pollution. In this paper, the mechanisms, advantages, and limitations of AOPs are comprehensively reviewed. Besides, the basic principles of combining different AOPs to enhance the treatment efficiency are described. Furthermore, the applications of AOPs in various wastewater treatments, such as oily wastewater, dyeing wastewater, pharmaceutical wastewater, and landfill leachate, are also presented. Finally, we conclude that the main direction in the future of AOPs are the modification of catalysts and the optimization of operating parameters, with the challenges focusing on industrial applications.
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This research describes the photocatalytic design for oil removal from produced water. It involves batch and continuous processes. The photocatalytic degradation of oil has been conducted in glass reactors. The effects of nano-TiO 2 concentration, the number of lamps, and the time of radiation were studied in the batch system, while in the continuous treatment, the number of lamps, the direction of light radiation, and the time of processes were studied. The results showed that all the oil was removed in the batch system and the maximum percentage of oil removal was 71% in the continuous system.
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During extractions industries, particularly oil companies in Iraq such Ahdab oil field that consuming a huge amount of water which led to producing oil-contaminated water thus it made dangerous on natural life (agricultural lands and rivers) and infrastructural through cause complex corrosion for pipelines and equipment's. Coagulation and flocculation processes are efficient to separate oil content and the suspended solids portion from the waste water. During the study have been used additives of the ferrous sulphate, aluminum sulphate and calcium sulphate in the range (10-40) ppm, for the processes of coagulant, and polyelectrolyte-(polyacrylamide) additional to the flocculent has used. Additives materials within the coagulant and flocculant treatments have been led to obtaining of the optimal eliminations amount total suspended solids, oil contents and others. It has been noted that the percentage of oil removing about 86.67%, 85.5% and 79.6 via using 30 ppm coagulant dose of ferric sulphate, aluminum sulphate and calcium sulphate with 2.5 mg/L of polyacrylamide at pH = 6.86 and room temperature (25 o C). Generally, ferrous sulphate has highly ability to adsorbing the oil particulates and suspended solids of the refinery wastewater, as well the reducing economic cost of water treatments.
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Oily waste water treatment beforehand injection into reservoirs of oil is required to diminish creation damage. This can be done using solar-catalytic procedure to lessen the oil droplets in oily waste water. In order to optimize the purification of waste water and, a new technique of degradation (the heterogeneous solar-catalysis) of the oil content was underlined. As catalysts we chose a semiconductor which are ZnO, TiO2 and AL2O3 in the presence of solar as source of energy. The results show that the adsorption of the oil content on catalyst agent supported in absence of radiation solar is negligible. It was found that the removal of oil content by zinc oxide touched 95.2 % and 92.11%, 80.7% for titanium dioxide and aluminum oxide respectively in pH=7.42 and 120 min irradiation time. The capability of catalyst agent to eliminate organic was augmented after addition different catalyst agent. Generally, zinc oxide meaningfully by its high ability to adsorb suspended solids and organic compound from oily waste water, in addition, decreases the economic cost of waste water treatment. The kinetics of organic degradation follows pseudo-first order.
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The present research based its strategy in general on evaluating the feasibility of using the process of Fenton oxidation (solar-oxidation) as a technique to remove the residual organic pollutants that are available in direct red wastewater. The following values highlight the optimized Fenton parametric concentrations so as to maximize the removing of Direct Red wastewater: [DR] = 20 mg/L M, Fe²⁺= 7.5 mg/L, H2O2= 75mg/L, pH = 3 at room temperature. According to the above-mentioned conditions and during 30 minutes of reaction, the procedure managed to achieve degradation efficiency in excess of 75%. For the same time duration of 30 minutes, the DR degradation efficiency had been drastically surging from 59% up to 90.5% as a response to lowering the initial pH value from 7 to 3. As for the DR wastewater, the solar Fenton technique managed to carry out an approximate percentage of DR removal of 90.5% in contrast with a percentage of 38.5% in the case of Fenton oxidation technique.
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The aim of the present work is to investigate the effect of the electrodes design in an electrocoagulation reactor as well as specific operational parameters on the value of total dissolved solids (TDS) presented in the simulated wastewater that polluted by lead ions. Triple concentric aluminum tubes electrodes were used in the electrochemical cell. The operating variables were the electrolysis time (5–60 min.), initial lead concentration (10–300 ppm), pH (2–12), electric current (0.5–2.5 Amps.), and mixing speed (0–300 rpm). Response surface methodology method and statistical programs were employed to design experiments and to establish the mathematical correlations. The results show the significant effect of the electrodes design as well as the operational variables on the behavior of TDS response and its maximum limit was found in the range 550–600 ppm.
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A novel method is applied to produce amorphous carbon thin film (ACTF) from oil palm leaves. The novel prepared ACTF is in the form of thin films like graphene sheets having winding surface. ACTF was characterized by different methods of characterization: FTIR, BET, SEM, EDX, TEM, and Raman. ACTF employed as an adsorbent to separate emulsified condensate oil from synthetic produced water as a treatment process before reinjection in oil reservoirs. The adsorption performance of batch and fixed bed adsorption systems were investigated. Contact time, initial concentration of condensate oil (Co=100–2500mg/l) and temperature were studied by batch experiments. The obtained results indicated that the adsorption capacity and the removal efficiency increased with time up to 132.77mg condensate/g adsorbent and 66.38% respectively, within 6h equilibrium time at 308K. The thermodynamic adsorption experiments conducted at 288, 308 and 318K, referring exothermic nature of the adsorption process.
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The cleanup of oil spill using natural adsorbents is considered as an eco-friendly and cost-effective way, emphasizing the importance of such natural and effective promising technique. Palm fibers, PFs, were used as natural sorbent material for oil spill removal. The present study examines the sorption efficiency and capacity of raw and modified fibers for three types of oil: diesel oil, crude oil and vegetable oil. The results revealed that the efficiency of fibers to remove different types of oil from artificial saline water was related to sorption time and the system conditions such as oil film thickness, particle size, sorbent dosage and temperature. The results showed high sorption efficiency and capacity of palm fibers for different kinds of oil. PFs were very proved to be promising fibers because of all advantages of agricultural wastes plus the high resistance of that fibers which appeared obviously in the present study.
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This study compares the anodic oxidation of three classes of produced water (PW) (fresh, brine and saline) generated by petrochemical industry using Ti/IrO2–Ta2O5 and BDD electrodes in a flow reactor. During electrochemical treatment, various operating parameters were investigated, such as temperature, pH, conductivity, current density, total organic carbon (TOC), chemical oxygen demand (COD) as well as energy consumption and cost. When both electrodes materials are compared under the same operating conditions, higher TOC and COD removal efficiencies were achieved for BDD anode, nevertheless, the energy consumption and cost were higher when compared with the values estimated for Ti/IrO2–Ta2O5. Different Cl– concentrations in the effluents promoted the electrogeneration of strong oxidant species, such as chlorine and hypochlorite, increasing the efficiency of treatment. These results encourage the applicability of this method as a pre-treatment process for the petrochemical industry, reducing depuration time.
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Three modified electrodes (C/PbO2, Pb + Sn/PbO2 + SnO2, and Pb/PbO2) were prepared by electrodeposition and used as anodes for electrochemical degradation of Reactive Yellow 160 (RY160) dye in aqueous solution. Different operating conditions and factors affecting the treatment process including current density, temperature, initial concentration of (RY160), pH, conductive electrolyte and time of electrolysis were studied and optimized. The best degradation occurred in the presence of NaCl (4 g L−1) as a conductive electrolyte. After 15 min, nearly complete degradation of RY160 was achieved (97.9%, 96.65 and 95.35% using C/PbO2, Pb+Sn/PbO2+SnO2, and Pb/PbO2 electrodes, resp.) at pH 7.13. Higher degradation efficiency was obtained at 25°C. The optimum current density for the degradation of RY160 on all electrodes was 50 mA cm−2. The prepared C/PbO2, Pb+Sn/PbO2+SnO2 and Pb/PbO2 electrodes were found to be highly efficient in the treatment of effluents obtained from dyeing factory which contain RY160 dye with very slight matrix effect.
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Emulsified oil in waste water constitutes is a severe problem in the different treatment stages before disposed off in a manner that does not violate environmental criteria. One commonly used technique for remediation of petroleum contaminated water is adsorption. The main objective of this study is to examine the removal of oil from oil–water emulsions by adsorption on bentonite, powdered activated carbon (PAC) and deposited carbon (DC). The results gave evidence of the ability of the adsorbents to adsorb oil and that the adsorptive property of the three adsorbents (bentonite, PAC, and DC) has been influenced by different factors. The effects of contact time, the weight of adsorbents and the concentration of adsorbate on the oil adsorption have been studied. Oil removal percentages increase with increasing contact time and the weight of adsorbents, and decrease with increasing the concentration of adsorbate. Equilibrium studies show that the Freunlich isotherm was the best fit isotherm for oil removal by bentonite, PAC, and DC. The data show higher adsorptive capacities by DC and bentonite compared to the PAC.
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Contaminated soil and groundwater have been the subject of study and research, so that the field of remediation has grown and evolved, continually developing and adopting new technologies in attempts to improve the decontamination. The cleanup of environmental pollution involves a variety of techniques, ranging from simple biological processes to advanced engineering technologies. Cleanup activities may also address a wide range of contaminants. This article is a short analysis of the technologies for cleaning up groundwater and soil, highlighting knowledge and information gaps. Challenges and strategies for cleaning up different types of contaminants, mainly heavy metals and persistent organic compounds are described. Included are technologies that treat ground water contaminants in place in the subsurface and soil technologies that treat the soil either in place or on site in a treatment unit. Emerging technologies such as those based on oxidation-reduction, bioremediation, and nanotechnologies are covered. It is evident that for a good efficiency of remediation, techniques or even whole new technologies may be incorporated into an existing technology as a treatment train, improving its performance or overcome limitations. Several economic and decision-making elements are developed in the final part, based on the analysis carried out throughout the article. The work highlights the fact that excellence in research and technology progress could be attained by the development of technologies to deal more effectively and economically with certain toxic contaminants such as heavy metals, volatile organic compounds, and persistent organic pollutants, associated with optimization of technologies under field remediation conditions and requirements, improving capacity and yields, and reducing costs. Moreover, increasing knowledge of the scope and problem of equipment development could improve the benefits.
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The purpose of this education is to explore uses of moringa seeds (M. oleifera) in the adsorption of organic contents from wastewater of oilfield refinery, Iraq. Adsorption treatment conditions were optimized to assess the relations between working condition, such by means of moringa amount, contact time and pH, to classify the best working circumstances. Organic removal rates were 89.65% under the optimum conditions comprise a contact time of 1.5 h, 1.5 g moringa dose and pH 3. The aptitude of moringa seeds to eliminate organic contents was augmented subsequently addition of different dosage at regular mixing time between 0.5 and 1 h. The equilibrium data of adsorption were investigated by Freundlich and Langmuir isotherm replicas. We noted that supreme adsorption capacity of organic intended from Langmuir isotherm stood about 23.97 mg/g. The devised adsorption can be explored as a well-organized green treatment for removal of organic matter from refinery waste water in acidic conditions pH < 7.
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An efficient method was developed to prepare oxidized potato starch under the pasting point by Electro-Fenton system, in which a complex of sodium citrate and Fe2+ (SC-Fe2+) was used as catalyst, and H2O2 was used as oxidant. In the preparation process the oxidation degree of starch was controlled by the molar ratios of SC-Fe2+ and hydrogen peroxide. The structures and thermal properties of the prepared oxidized starch were characterized by FT-IR, XRD, SEM, DSC and DTG. The characterization results indicated that the obtained oxidized potato starch owned one grainy molecule structure, and displayed a high viscosity (not less than 63 Pa·s) by comparing to the raw starch. The carbonyl and carboxyl contents of oxidized potato starch achieved 0.81 per 100 AGU and 0.79 per 100 AGU, respectively after the raw starch was oxidized. And the oxidized starch showed good thermal stability, which can dramatically improve the application performance of starch-based biomaterials.
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Cotinine, the majormetabolite of nicotine, has been recently detected in the environment and considered as emerging contaminant in waters. Its chemical treatment has scarcely been investigated in the literature. Here, we show for the first time that double perovskite oxide can be used as heterogeneous catalyst for electrochemical advanced oxidation application and cotinine was selected as the target pollutant. Highly stable magnetic double perovskite Sr2FeCuO6 was synthetized for this purpose. The cotinine mineralization in a synthetic sulfate solution of pH 3.0 has been comparatively assessed by anodic oxidation with (AO-H2O2-BDD) and without electro-generated hydrogen peroxide (AO-BDD) and by the heterogeneous electro-Fenton (EF) processes using the magnetic double perovskite Sr2FeCuO6 as the heterogeneous catalyst. The comparative electrolysis experiments were carried out with 500 mL stirred reactor equipped with a boron-doped diamond (BDD) and a carbon felt cathode. Faster mineralization decay was observed with the electro Fenton process due to the additional oxidation by hydroxyl radicals produced from Fenton´s reaction between the iron sites and the electro-generated hydrogen peroxide at the cathode. Moreover, the synergistic effect of the cuprous sites was pointed out. The leaching test confirms the high stability of the catalyst and its heterogeneous action. The influence of current intensity and cotinine concentration was examined. Seven stable organics intermediates were detected and four of them were identified as N-Hydroxymethyl norcotinine, norcotinine, 4-oxo-4-(3-pyridyl) butanoic acid and 4-(3-Pyridyl)-3-butenoic Acid. The initial N was released as nitrate and, in smaller proportion, as ammonium ion. Short chain aliphatic acids, mainly oxalic and formic acids were detected. EPR analyses revealed that cotinine was mainly decomposed by the attack of [rad]OH. A reaction sequence for cotinine mineralization involving all the detected products is finally proposed. The reusability of the magnetic catalyst for at least 3 times highlights the practical applicability of the envisaged heterogeneous process.
Article
Adsorption of methyl orange (MO) from the aqueous solution on a low-cost adsorbent made of sawdust wood (SW) is studied experimentally. In the current research, a comparative study has been conducted between the natural sawdust wood (SW) and the activated sawdust wood (ASW). Conditions of experimental study were included the followings: 10 ppm of methyl-orang, pH=6 and a dosage in the range of 0.5-2 gm for different sizes of sawdust. During the study, Fourier-transform infrared spectroscopy-(FTIR) as well as (UV/V) is spectroscopy techniques were used. Results obtained indicate that the removal efficiency of methyl orange at 25 ± 3 C exceeded 38.7%. A good fit for equilibrium data was obtained as per Langmuir model (R 2 > 0.99). Maximum adsorption capacity of MO on ASW is 1.8 mg g-1. Results analysis of the activated sawdust waste show more a potential effectiveness as cheap adsorbent for the dyes removal from industrial wastewater.
Article
Fenton based reactions are effective for pharmaceutical removals, but traditional Fenton processes have drawbacks of pH adjustment and large amount of produced iron sludge. To overcome these challenges, a heterogeneous electro-Fenton process was proposed for effective contaminant degradation at circumneutral pH without iron sludge production. The anti-inflammatory drug ibuprofen (a common pharmaceutical in natural waters) was used as a representative contaminant. Activated carbon fibers (ACFs) supported ferric citrate (Cit-Fe/ACFs) was synthesized and used as the cathode, and RuO2/Ti was used as the anode. H2O2 was electro-generated in situ from O2 reduction and the production rate of OH per unit area was 6.8 μM W-1 cm-2 using Cit-Fe/ACFs cathode. A maximal ibuprofen degradation of 97% was obtained after 120 min at the current density of 7 mA cm-2. The electrical energy per order (EEO) varied from 0.24±0.03 to 2.65±0.04 kWh log-1 m-3 when the current density ranged from 1 to 7 mA cm-2. The Cit-Fe/ACFs cathode showed relatively good reusability and ∼85% IBP removal was achieved after 6 cycles of degradation. Our results showed that the prepared Cit-Fe/ACFs cathode was promising for the treatment of pharmaceutical contaminants.
Article
This exhaustive review focuses on the fundamental principles and applications of heterogeneous electrochemical wastewater treatment based on Fenton’s chemistry reaction. The elementary equations involved in formation of hydroxyl radical in homogeneous electro-Fenton (EF) and photo electro-Fenton (PEF) processes was presented and the advantages of using insoluble solids as heterogeneous catalyst rather than soluble iron salts (heterogeneous electro-Fenton process) (Hetero-EF) was enumerated. Some of the required features of good heterogeneous catalysts were discussed, followed by the mechanisms of catalytic activation of H2O2 to reactive oxygen species (ROS) especially hydroxyl radical (●OH) by heterogeneous catalyst in Hetero-EF system. Extensive discussion on the two configuration of Hetero-EF system vis-à-vis added solid catalysts and functionalized cathodic materials were provided along with summaries of some relevant studies that are available in literature. The solid catalysts and the functionalized cathodic materials that have been utilized in Hetero-EF wastewater treatment were grouped into different classes and brief discussions on their synthesis route were given. Besides, the use of solid catalysts and iron-functionalized cathodic materials in bioelectrochemical system (BES) especially bioelectro-Fenton technology (BEF) using microbial fuel cells (MFCs) with concurrent electricity generation for Hetero-EF treatment of biorefractory organic pollutants was discussed. In the final part, emphasis was made on the challenges and future prospects of the Hetero-EF for wastewater treatment.
Article
In this work, an eco-friendly solution for the remediation of wastewater generated in the lignin recovery process from eco-industrial paper mill has been proposed in their way towards a more circular economy strategy. Thus, the application of the electro-Fenton process for the degradation of the non-recovered lignin and other organic compounds form a scarcely studied acid black liquor waste (ABLW) was successfully performed. This treatment was able to operate in a range of COD loads (0.5-19.5mgO2·L-1) showing high degradation values of the ABLW determined by the abatement of color, total phenolic content and COD. Then, the optimization of the working conditions for the design of a sustainable treatment system with optimum efficiency was carried out using a response surface methodology. The experiment carried out in the calculated optimal conditions for the electro-Fenton degradation process (current intensity 132.5mA, catalyst dosage of 0.10mM, and temperature 40°C) showed a COD removal of 74.82% and current efficiency 77.79%, close to the theoretical value predicted by the model 73.12% and 77.06%, respectively. In addition, the identification of the final products permitted to confirm the mineralization efficiency.
Article
The application of ceramic microfiltration membranes to the tertiary treatment of produced water from an Arabian Gulf oilfield has been studied using a dedicated pilot plant. Studies were based on a previously published protocol in which the retentate stream was recycled so as to successively increase the feed concentration throughout the experimental run. Chemical cleaning in place (CIP) was applied between each run and the flux and permeability recovery recorded for various cleaning protocols studied, the CIP being based on the combination of caustic soda (NaOH) and citric acid. Surface analysis of the membrane, and specifically its hydrophilicity, was also conducted. Results indicated the main influencing factor on permeability recovery from the CIP to be the employment of backflushing during the CIP itself. A final flux of 700 L m⁻² h⁻¹ was sustained through the application of 6 wt% NaOH with 6 wt% citric acid combined with backflushing at approximately twice the rate of the filtration cycle flux. A consideration of the impact of this flux value on the viability of two commercially-available ceramic membrane technologies indicated the footprint incurred to be slightly lower than that of the upstream induced gas flotation technology and corroborated a previously published estimate. The flux was sustained despite surface analysis indicating a loss of the innate hydrophilicity of the ceramic membrane.
Article
Treatment of stabilized landfill leachate is a great challenge due to its poor biodegradability. Present study made an attempt to treat this wastewater by combining electro-Fenton (E-Fenton) and biological process. E-Fenton treatment was applied prior to biological process to enhance the biodegradability of leachate, which will be beneficial for the subsequent biological process. This study also investigates the efficiency of iron molybdophosphate (FeMoPO) nanoparticles as a heterogeneous catalyst in E-Fenton process. The effects of initial pH, catalyst dosage, applied voltage and electrode spacing on Chemical Oxygen Demand (COD) removal efficiency were analyzed to determine the optimum conditions. Heterogeneous E-Fenton process gave 82% COD removal at pH 2, catalyst dosage of 50 mg/L, voltage 5 V, electrode spacing 3 cm and electrode area 25 cm2. Combined E-Fenton and biological treatment resulted an overall COD removal of 97%, bringing down the final COD to 192 mg/L.
Article
The use of membrane technology for produced oily water treatment has become an active area of research for both academia and industry. The search for membranes with enhanced efficiency and prolonged life time during oily water treatment has been a rallying point for many scientists. The focus of this review is on the advancement of polymeric and ceramic membrane technologies, membrane modification strategies used to mitigate membrane fouling and optimization of permeate flux, particularly for oily water systems. In addition, recent methodologies used for modeling the permeate flux decline are also highlighted.
Article
Development of sustanaible technologies for treatment of azo dyes containing wastewaters has long been of great interest. In this study, we proposed an innovative concept of using microbial reverse-electrodialysis electrolysis cell (MREC) based Fenton process to treat azo dye wastewater. In such MREC-Fenton integrated process, the production of H2O2 which is the key reactant of fenton-reaction was driven by the electrons harvested from the exoelectrogens and salinity-gradient between sea water and fresh water in MREC. Complete decolorization and mineralization of 400 mg L⁻¹ Orange G was achieved with apparent first order rate constants of 1.15 ± 0.06 and 0.26 ± 0.03 h⁻¹, respectively. Furthermore, the initial concentration of orange G, initial solution pH, catholyte concentration, high and low concentration salt water flow rate and air flow rate were all found to significantly affect the dye degradation. This study provides an efficient and cost-effective system for the degradation of non-biodegradable pollutants.
Article
The intensive use of triphenyltin chloride (TPTC) has caused serious environmental pollution, whereas, reports regarding its degradation are limited until now. In this study, an effective method for TPTC degradation was proposed based on the Bio-Electron-Fenton process in microbial fuel cells (MFCs). The maximum voltage of the MFC with graphite felt as electrode was 278.47% higher than that of carbon cloth. The electricity generated by MFC can be used for in situ generation of H2O2 to a maximum of 135.96 μmol·L−1 at the Fe@Fe2O3(*)/graphite felt composite cathode, which further reacted with leached Fe2+ to produce hydroxyl radicals. While 100 μmol·L−1 TPTC was added to the cathodic chamber, the degradation efficiency of TPTC reached 78.32 ± 2.07%, with a rate of 0.775 ± 0.021 μmol L−1 h−1. This Bio-Electron-Fenton driving TPTC degradation might involve in Sn-C bonds breaking and the main process is probably a stepwise dephenylation until the formation of inorganic tin and CO2. This study provides a promising approach for continuous power output and recalcitrant contaminants degradation simultaneously.
Article
The extent and kinetics of degradation of 1,4 dioxane, n-nitrosodimethylamine (NDMA), tris-2-chloroethyl phosphate (TCEP), gemfibrozil, and 17β estradiol in a prepared aqueous matrix by means of UV/TiO2 (ultraviolet light/titanium dioxide) oxidation was evaluated. Degussa P25 TiO2 was employed as a photocatalyst excited by UV light in a 1 L water-jacketed batch photoreactor. The rate of degradation was modeled using a pseudo-first order rate model and the Langmuir-Hinshelwood rate model with a high correlation. Degradation rate constants were found to be maximum at pH 5.0 and 1.5 g L(-)(1) TiO2 dose. For these conditions first order rate constants, values were as follows: 0.29 min(-1) for 1,4 dioxane, 0.50 min(-1) for NDMA, 0.12 min(-1) for TCEP, 0.61 min(-1) for gemfibrozil, and 0.53 min(-1) for 17β estradiol. While for the Langmuir-Hinshelwood rate model, the following constants were found: 0.11 Lmg(-1) and 2.81 mgL(-1) min(-1) for 1,4 dioxane, 0.12 Lmg(-1) and 4.35 mgL(-1) min(-1) for NDMA, 0.06 Lmg(-1) and 1.79 mgL(-1) min(-1) for TCEP, 0.21 Lmg(-1) and 3.27 mgL(-1) min(-1) for gemfibrozil, and 0.15 Lmg(-1) and 3.43 mgL(-1) min(-1) for 17β estradiol. In addition, specific byproducts of degradation were identified using GC/MS analysis. The results obtained from the kinetics analysis showed that UV/TiO2 oxidation is a promising process for treating trace organic contaminants in water, but further research is needed to better understand how to incorporate these findings into pilot and full-scale designs. The toxicity of oxidation byproducts, and their potential for interacting with other compounds should be considered in the treatment of contaminated waters using the UV/TiO2 oxidation process.
Conference Paper
Advanced oxidation processes (AOPs) have led the way in the treatment of aqueous waste and are rapidly becoming the chosen technology for many applications. In this paper, COD reduction of textile industry wastewater by electro-Fenton (EF) oxidation, was studied at batch experimental conditions. The wastewater samples with a COD of 590 mg l(-1) in average were taken from the outlet of an equalization tank of a textile industry in the Marmara Region in Turkey. The wastewater samples were treated in a batch reactor equipped with two iron electrodes. The EF tests were conducted at different H2O2 doses such as 313, 626, 940, and 1253 mg l(-1) and constant electrical power of 24 W and pH of 3. For each EF test electricity consumption was determined based on per unit of COD mass removed (kW kg(-1)). The COD removal increased with decreasing H2O2 dose. The highest treatment efficiency was attained at 313 mg l(-1) of H2O2, by which more than 85% of COD was removed within 10 min of reaction time. These results indicate that the EF process can be considered as an alternative method for textile wastewater treatment.
Article
This paper presents a brief account of different technologies used for the treatment of petroleum refinery effluents (PRE). Broadly, PRE treatment is accomplished in two stages, namely, a series of pre-treatment steps, in which suspended matter, oil and grease are reduced, and an advanced stage, in which wastewater contaminants are decreased to certain acceptable discharge limits. Photocatalytic degradation techniques have been widely used in water and wastewater treatment. However, the literature regarding PRE treatment is scarce, and the technique is still not being utilised on an industrial scale in refineries. This is largely due to limited research findings discussing PRE treatments. Most researches are focused on treating singular contaminants found in PRE, e.g., phenols, sulphides, oil, grease and other organic components. This review focused on works that investigated PRE treatment by monitoring general refinery wastewater parameters, namely, chemical oxygen demand (COD), biological oxygen demand (BOD), total petroleum hydrocarbon (TPH), oil and grease (O&G), sulphate and phenols at the advanced treatment steps. This paper presents an overview of photocatalytic degradation and discusses published works with the goal of presenting the technique as an attractive and viable process unit. If optimised, this process has great potential for replacing other separation and degradation treatment approaches employed at the advanced treatment stage for PRE.
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Petroleum refinery effluents (PREs) are wastewaters characterised by high values of chemical oxygen demand (COD) and total organic carbon (TOC). Mineralisation of PRE is not commonly reported. For Fenton oxidation, in particular, reported PRE mineralisation is low. In this paper, treatability of a petroleum refinery effluent using a Fenton-like oxidative reaction is described. A statistically designed experimental matrix was used to evaluate the individual and combined effects of process variables based on a five-level central composite design (CCD). Response surface methodology (RSM) was employed to optimise the parameters of interest (COD and TOC), and response surface equations were subsequently developed. These parameters were optimised from studies of the independent variables, for reaction time [tr] = 30–240 min, molar ratio of hydrogen peroxide to the organic wastewater [H2O2]:[PRE] = 2–12 and mass ratio of hydrogen peroxide to catalyst [H2O2]:[Fe3+] = 5–20. The COD and TOC of the PRE at an initial pH of 7 were 1343 mg O2/L and 398 mg C/L, respectively. Under optimal conditions, maximal TOC and COD reduction achieved within 30 min of oxidation reaction were 70% and 98.1%, respectively. The obtained models had correlation coefficients (R2 and View the MathML source) of 0.9984 and 0.9916 for TOC and 0.9636 and 0.8835 for COD. At a pH of 3, corresponding optimal oxidation conditions were found to be [H2O2] = 1008.0 mM and [Fe3+] = 686.0 mg, that is, a molar ratio of [H2O2]:[PRE] = 12 and mass ratio of [H2O2]:[Fe3+] = 5.
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Bacillus sp. (M-12) was able to decrease the chemical oxygen demand (COD) of the waste water significantly. Polyvinyl Alcohol (PVA) was chosen to immobilize the bacterial cells and the immobilized cells could be used for waste water treatment for many cycles with high COD removal efficiency. The efficiency of decreasing COD could be improved when a nitrogen source such as (NH4)2SO4 was added into the waste water. A continuous waste water treatment system with immobilized cells and a cinder column was developed and this continuous system had a significant effect on decreasing the COD of the waste water, which could be reduced from 2600 to 240mg/L.
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Organic compound, especially aromatic compound is the main pollutant in industrial effluent. Conventional wastewater treatment processes are inefficient for the removal of these types of toxic and hazardous pollutants from wastewater. Electro Fenton is one of the powerful and environmentally friendly emerging technologies for the remediation of wastewaters containing organic, especially aromatic compounds. This paper reviews the fundamentals and recent developments in electro Fenton process. Electro Fenton process utilizes different electrolytic reactors such as bubble reactor, filter press reactor, divided double-electrode electrochemical cell, divided three-electrode electrochemical cell and double compartment cell. Different cathodes as working electrode and anodes as counter electrode used in this process are analyzed. The effects of various operating parameters and their optimum ranges for maximum pollutant removal and mineralization are reviewed. Also various pollutants removed by this process are evaluated. Quick removal and mineralization of pollutants and their intermediate reaction products were reported.
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Produced water is the largest waste stream generated in oil and gas industries. It is a mixture of different organic and inorganic compounds. Due to the increasing volume of waste all over the world in the current decade, the outcome and effect of discharging produced water on the environment has lately become a significant issue of environmental concern. Produced water is conventionally treated through different physical, chemical, and biological methods. In offshore platforms because of space constraints, compact physical and chemical systems are used. However, current technologies cannot remove small-suspended oil particles and dissolved elements. Besides, many chemical treatments, whose initial and/or running cost are high and produce hazardous sludge. In onshore facilities, biological pretreatment of oily wastewater can be a cost-effective and environmental friendly method. As high salt concentration and variations of influent characteristics have direct influence on the turbidity of the effluent, it is appropriate to incorporate a physical treatment, e.g., membrane to refine the final effluent. For these reasons, major research efforts in the future could focus on the optimization of current technologies and use of combined physico-chemical and/or biological treatment of produced water in order to comply with reuse and discharge limits.
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The application of the photo-Fenton process for the treatment of wastewaters contaminated with diesel oil was investigated. This particular process has been widely studied for the photochemical degradation of highly toxic organic pollutants. Experiments were performed according to a factorial experimental design at two levels and two variables: H(2)O(2) concentration (5-200 mM) and Fe(2+) concentration (0.01-1 mM). Experimental results demonstrated that the photo-Fenton process is technically feasible for the treatment of wastewaters containing diesel oil constituents, with total mineralization. A combination of factorial experimental design and gradient descent techniques was employed to optimize the amount of the Fenton reagents, resulting in Fe(2+) (0.1 mM) and H(2)O(2) (50 mM). These optimized levels did not exceed the limit for disposal of ferrous ions (0.27 mM) proposed at the local environmental legislation.