Electrocoagulation

Arteriovenous malformations are rare in the head and neck region and generally arise from intracranial vessels. We present two rare cases with spontaneous arteriovenous malformations related to the ear. The role of magnetic resonance imaging and colour Doppler sonography in the diagnosis and management of such cases is discussed along with a review of the literature.

Electro—coagulation is rapidly becoming a viable
environmental solution for industries. The novel
approach of this proposal is to design, build,
and operate an electro—coagulation reactor that
permits the continuous treatment of industrial
residual water with out the need of storing said
waste waters and to treat these as they are
produced. To evaluate and to optimize the
electrochemical process, a model system has been
executed, in order to study its composition and
its removal efficiency. It was observed that at
low voltages, the removal of metals and organic
material had increased. It has been demonstrated
that the electro—coagulation has been efficient
in both static and dynamic modes, although in the dynamic mode the percentages of removal
have been greater, and the volume of water
treated during the same time frame has also been
greater.

In the first journal in the desalination world, Desalination, during the last 20 years, there is the birth of a new seawater pretreatment process: electrocoagulation (EC). In order to note some facts of this birth, relate its context, and understand its circumstances, this review concerns a brief description of the application of EC as a new seawater pretreatment process throughout the work of Sanfan and Qinlai (1987) until the work of Yi et al. (2009) via the work of Sanfan (1991); all of them are published in Desalination. The first paper (1987) discusses the mechanism of removing some ions from the brackish water using EC method. Experiment results present some major parameters for the EC process. The most important one in operation is electric current density (CD). Moreover, the first paper suggests the method of selecting optimum density
and some ways could raise economic property of EC and could reduce handling costs. In the paper of Sanfan (1991) the further research results of improving economic property of EC
method are discussed. In order to reduce the cost and raise the handling efficiency, five different technological processes are set up and studied. The best one was the using Fe electrode
and aerating for raw water combine with reusing flocs. It can reduce 60% of handling cost in comparison withal electrode and remove 75% of hardness. Finally, Yi et al. (2009) use a simple and new effective electrochemical method (EM) prior to reverse osmosis for seawater desalination. The influences of three main factors in EMs—CD, operating time and sedimentation time on the efficiency of pretreatment—have been investigated. It is shown that the EM is very effective
for removal of turbidity. The qualities of the raw and the treated seawater have been measured using UV–Vis spectrometry. The morphologies and the particle size distribution of the resulted sludge have been characterised by scanning electron microscopy (SEM) and a particle size analyser, and the mechanism of the EM has been analysed theoretically. Raw seawater with a turbidity of 54.1 NTU, 94.48 mg L−1 SS after EM pretreatment at 26.30 mA cm−2 CD for 40 min reduces the turbidity to 1.00 NTU. The time taken for the same depletion of turbidity in case of 39.45 mA cm−2 CD is 35 min, and the absorbance of the curve decreases when EM treatment is applied. The experimental results reveal that particular size in seawater agglomerate and get bigger after EM treatment, and the turbidity removal is enhanced by charge neutralisation and sweep coagulation. The sludge generated from the process is found to have larger specific surface
areas at higher CD from SEM observation, leading to better treatment efficiency.

Electrocoagulation is an effective electrochemical approach for the treatment of different types of contaminated water and has received considerable attention in recent years due its high efficiency in dealing with numerous stubborn pollutants. It has been successful in dealing with organic and inorganic contaminants with negligible or almost no generation of by-product wastes. During the past decade, vast amount of research has been devoted to utilizing electrocoagulation for the treatment of several types of wastewater, ranging from polluted groundwater to highly contaminated refinery wastewater. This paper offers a comprehensive review of recent literature that has been dedicated to utilizing electrocoagulation for water treatment, focusing on current successes on specific applications in water and wastewater treatment, as well as potentials for future applications. The paper examines such aspects as theory, potential applications, current challenges, recent developments as well as economical concerns associated with the technology. Most of the recent EC research has been focusing on pollutant-specific evaluation without paying attention to cell design, process modeling or industrial applications. This review attempts to highlight the main achievements in the area and outlines the major shortcomings with recommendations for promising research options that can enhance the technology and broaden its range of applications.

This review discusses the advanced oxidation process (AOP) phenomena in electrocoagulation
(EC) process. AOPs have been broadly defined as near ambient temperature treatment
processes based on highly reactive radicals, especially the hydroxyl radical ð
OHÞ as the
primary oxidant. In principle, as water-containing colloidal particulates, oils, or other contaminants
move through the applied electric field, there may be ionisation, electrolysis, hydrolysis,
and free-radical formation which may alter the physical and chemical properties of water and
contaminants. Further, when the electrochemical reactors operate at a high cell potential and
an anodic process occurs in the potential region of water discharge, hydroxyl radicals ð
OHÞ
are generated. In order to get more probabilities to have free radicals formation in EC, ultrasound
during EC may be very useful as discussed by some authors. Further, EC process at pH
less than 3 has more chance to produce hydroxyl radicals formation. Finally, this review
concludes that there is no proof of the presence of AOP phenomena in EC process and more
research is needed here focusing on free radicals formation.

During the two last decades, electrocoagulation method (EC) was the focus of many industrial applications and remains a fascinating domain of research. Most published researches concern uses in treating potable water and wastewaters to increase both the removal of dissolved and undissolved contamination. Significant achievements have been realized comprising participations to fundamental comprehension, electrode metals, working parameters, device conception, and economic aspects determinations. Despite the fact that there are several benefits mentioned through the specialized references, the EC large-scale use is not until now viewed as a recognized wastewater technique due to the absence of viable models used in designing device. The present review discusses the mechanisms involved in the EC process and opens a broad perspective on its modeling. The scientific community is near to suggest empirical/theoretical models to present the EC technology as a viable green process. However, more great efforts remain to be accomplished. Technological software developers such as COMSOL™ Multiphysics are invited to insert the EC process in their electrochemistry module to better commercialize this intensified technique and encourage its massive use through the world.

Electrochemical technology may present an option of treating water since they have proved some benefits over conventional techniques, like decreased handling and storage of chemicals and cost-effectiveness. Consecutive electrochemical techniques have yet to be tried for removing Escherichia coli in potable waters. In this review, a brief discussion of the work of Lynn [1] is presented. Lynn [1] studied electrocoagulation (EC) and electrooxidation (EO) employing two model surface waters and two model groundwaters to define the performance of consecutive EC-EO for removing E. coli. At a current density of 1.67 mA/cm 2 for 1 min, bench-scale EO alone attained 4-logs reduction of E. coli in the model shallow aquifer. Elevating the EO current density to 6.67 mA/cm 2 for 1 min presented similar levels of E. coli reduction in the model deep aquifer. Employing a current density of 10 mA/cm 2 for 5 min EC attained 1-log or bigger E. coli removal in all model waters. No supplementary reduction beyond EC alone was reached employing consecutive EC-EO. Diminutions in the initial pH of the surface waters in order to reach bigger natural organic matter elimination did not improve E. coli cells killing with EC-EO comparatively with EC alone. De facto, around 64% of NOM was eliminated regardless of the variation in pH, which possibly restricted E. coli removal. More causes for the shortage of enhancement in E. coli disinfection may have comprised the existence of iron after EC or deficient EO current density. Diminishing the initial water pH did enhance E. coli reduction employing EO when pretreated via EC compared to the baseline water matrix pH. Despite the breakthroughs obtained throughout the Lynn [1] research in both EC and EO processes for disinfecting water in terms of mechanisms and optimization, great research remains to be accomplished with a view to largely accept these electrochemical techniques in the water treatment industry. Finding the correct hybridization and appropriate combination of such methods, and probably introduce other physical techniques like adsorption and magnetic treatment, would open large perspectives in implementing electrochemical engineering in water treatment.

For treating wastewater, electrochemical engineering has been rediscovered during the last four decades through the world for its inherent advantages comparatively with traditional technologies especially chemical and biological techniques. However, the expansion of this technology founded on electric current applying has been retarded by several technical-economic factors especially the detection of disinfection by-products (DBPs) formation. This work focuses on the challenges and future tendencies for this highly-efficient technology to reach full-scale implementations particularly in disinfecting water. Lately, new versions of electrochemical techniques have been suggested such as employing sulfate radical anion (4 SO •−) and sunlight to generate • OH radicals in TiO 2 photocatalysis and photo-Fenton water treatment. These improvements elevated electrochemical engineering efficiency and acceptation. However, more efforts remain to be accomplished for water reuse vision. Future researches would focus on integrating membranes processes such as nano filtration and reverse osmosis for safe removal of DBPs.

One of the important factors for electrocoagulation (EC) process is the conductivity of the solution to be treated. Essential mechanisms in EC are charge neutralisation by metal (Fe/Al) hydroxocations and aggregation by van der Waals forces since fl occulation of pollutants with metal is caused by their adsorption on metal hydroxide aggregates. In order to enhance the EC process efficiency in organic wastewater effluents, sodium sulphate (Na2 SO4) has been used as a supporting electrolyte (SE) to increase the electric current diffusion in the EC cell. However, literature has reported controversial effect of sodium sulphate on EC process. This review tries to understand the sulphate effect on the EC reactions. Na2SO4 has been found less efficient than NaCl as SE in EC process for the removal of humic substances, oil-in-water emulsions, and fluoride. However, for unskimmed milk sample and cutting oil emulsion sulphate anions were found to be quite harmful both for electrical consumption and EC efficiency. These results may be related to the facts that in the sulphate media the 70% of the aluminium is in the form of Al(OH)3(am) and in the chloride media this percentage is around 40% and the adsorption of chloride or sulphate ions onto the surface of the Al(OH)3(am) can reduce the adsorption efficiency. Consequently, metal cations must be well distributed in the wastewater before the metal hydroxide formation to decrease the negative effect of SE in EC process.

Electrocoagulation (EC) is an electrochemical method of applying an electric current on wastewater and producing and injecting metallic coagulant in situ and eliminating colloids and metals, as well as other dissolved solids from wastewater. EC technology has been successfully used in eliminating pollutants, pesticides, and radionuclides. This method as well kills pathogenic microbes. This review focuses on implied mechanisms of killing microorganisms' during EC application. The electrical current contribution in EC efficiency through the destruction of microbes via building pores in the cytoplasmic membrane, which augments the cell permeabil-ity, is well established. Physical elimination and chemical deactivation mechanisms are described for microbes' removal procedure through the EC technique: (i) enmeshment of microbial pollutants upon EC flocs, (ii) sweep flocculation is preferentially for the destabilization of negatively charged microorganisms, and (iii) deactivation of bacteria membranes via electrochemically formed reactive oxygen species or direct interaction of the electric field.

Electrocoagulation (EC) process has been largely found efficient in terms of pathogens removal. This literature
review focuses on describing the key killing microorganisms' pathway followed throughout the EC technique. The pathogens
removal route using EC is deeply assessed following the practical experimentation realized during these last years. Physical
elimination and chemical deactivation pathways are suggested for bacteria reduction procedure throughout the EC method
employing Fe/Al anodes: (1) entrapping pathogens in flocs, (2) destabilizing negatively charged microbes through sweep
flocculation, and (3) demobilizing bacteria cell envelopes upon electrochemically formed reactive oxygen species or direct
impact of the electric field. Finally, deepest investigation works on microbes’ removal through EC are more called to promote the
industrial applications of this performant technology.

Transurethral electrovaporization of the prostate is a new, minimally invasive technique being used by urologists for surgical ablation of prostatic tissue. There are insufficient data concerning factors affecting the vaporization and coagulation lesions produced by this technique. The aim of this study was to determine the role of various parameters for adequate tissue evaporation. This study compared bovine liver and human prostatic lesions made by the Vaportrode instrument with those produced by standard electrocautery loops, roller balls, and laser fibers. Additionally, two electrosurgical instruments with differing technical capabilities were compared for their ability to cause vaporization of tissue. Results revealed that the Vaportrode lesions were maximal with a new electrode when used with a Force 40S electrosurgical generator set at 300 W and a drag speed of 25 to 30 seconds per 10 mm of tissue. The lesions produced by this technique had a 74% greater coagulation volume compared to a standard cautery loop. The evaporation defect was comparable to a laser lesion produced in contact at 60 W. We conclude that electrovaporization under optimal conditions causes a vaporization lesion comparable to that produced by high power density laser prostatectomy. Additionally, the coagulation volume of a vaportrode lesion is considerably greater than that produced by standard electrocautery resection.

Textile industry, is a major consumer of water for different wet processes of operations. It is concern owing to significant organic matter and dyeing agents which produce color, inturn contributes high Chemical Oxygen Demand (COD). The Electrocoagulation (EC) process is considered as an effective treatment in the removal of dye and COD from textile mill wastewater. This paper focuses on, the performance of an EC process by incorporating titanium plates (Electro-oxidation) for the treatment of textile mill wastewater. The wastewater was characterized for COD, Biochemical Oxygen Demand (BOD), pH, conductivity, chlorides, turbidity and color. The effect of operating parameters such as current density, electrolysis time, and initial COD concentration was studied. Furthermore, energy and electrode consumption was also examined. The optimum electrolysis time and voltage for Stainless Steel–Titanium (SS-Ti) and Aluminium–Titanium (Al-Ti) was found to be 60 min at 14 V and 45 min at 16 V respectively. The COD removal efficiency of SS coated with sodium alginate hydrogel in combination with Ti was found to be 90% and Al coated with sodium alginate hydrogel in combination with Ti was observed 87%. The electrode dissolution of SS was 0.62 mg/L and Al was 0.125 mg/L at 16 V at 60 mins and 14 V at 45 mins respectively. The power consumption of SS and Al was found to be 9.6 kWh/m 3 and 5.25 kWh/m 3 , respectively. The most suitable EC–EO performance was achieved using Al–Ti electrode in economical terms when compared to SS–Ti electrode.

The optimisation of the electrocoagulation-electroflotation (EC-EF) process assisted by the mucilage of the Opuntia ficus indica (OFI), on the turbidity removal was performed through the response surface methodology (RSM). For a solution of 300 mg/L of silica gel, high turbidity removal (93.14% 6 1.31) was obtained under the optimal conditions of 2.5 mg/L, 21.2 V, 9.65 and 2.61 mS/cm for the mucilage concentration, voltage, pH and conductivity, respectively, this experimental value was close to the predicted value of 92.96% 6 0.3. OFI mucilage increases turbidity removal efficiency and reduces specific energy consumption at a fixed current density. The turbidity removal of the EC-EF process was improved by 30.94% compared with the conventional EC-EF (EC-EF without OFI mucilage) which shows 62.02% 6 1.45 of turbidity removal.

Bu çalışmada, Taguchi deneysel tasarım metodu kullanılarak tekstil atıksuyunun arıtımında alüminyum elektrotların kullanıldığı Elektrokoagülasyon prosesinde optimum deney şartları; başlangıç pH, akım yoğunluğu, elektriksel iletkenlik, elektroliz süresi ve elektrotlar arası mesafe belirlenmiştir. Deneysel çalışmada performans kriteri olarak KOİ parametresi incelenmiştir. Optimizasyon çalışması için belirlenen parametre sayısı 5 ve her bir parametre için 4 farklı seviye incelenmesi düşünülerek L16 (4 5) Taguchi faktöriyel deney tasarımı yapılmıştır. Elde edilen sonuçlar neticesinde, KOİ giderme verimine göre optimum koşullar sırasıyla, başlangıç pH 6, akım yoğunluğu 100 A/m 2 , iletkenlik 7,5 ms/cm, elektroliz süresi 15 dakika ve elektrotlar arası mesafe 2,5 cm olarak bulunmuştur. Bu şartlarda tahmin edilen KOİ giderme verimi %76,8 iken deneysel olarak bulunan değer %75,1'dir. Sonuç olarak tekstil atıksuyunun arıtımında EC prosesi Taguchi deneysel tasarım metodu kullanılarak bu prosese etki eden parametreler optimize edilmiştir. Anahtar Kelime: Elektrokoagülasyon, Taguchi metodu, KOİ giderimi, Tekstil atıksuyu 1. Giriş Türkiye'de nüfusun artışı ve teknolojinin gelişmesiyle birlikte diğer endüstrilerde olduğunu gibi tekstil endüstrisi de gelişmekte ve mevcut olanlarda kapasitelerini arttırmaktadır. Bu durum mevcut doğal kaynaklardan biri ve en önemlisi olan suyun tüketimini ve deşarjını arttırmaktadır. Tekstile endüstrisinde çeşitli proseslerde kullanılan ve atıksu olarak nitelenen sular alıcı ortamlara deşarj edildiklerinde alıcı ortamdaki ekolojik dengeyi bozmakta ya da büyük tahribatlara neden olmaktadır. Bu nedenle bu atıksuların alıcı su ortamlarına verilmeden önce mutlaka arıtılması ve tekrar proseste kullanılması gerekmektedir. Özellikle tekstil endüstrisinde yüksek su tüketimi nedeniyle atıksu oluşumu oldukça fazladır. Tekstil endüstrisinde ortaya çıkan atıksuların çoğunluğu yıkama ve boyama prosesleri sonucu oluşmaktadır. Bu atıksular miktar ve karakteristik yönden değişiklik göstermektedir. Atıksuların karakteristiği elyaf cinsi, uygulanan işlemler ve kullanılan kimyasal maddelere bağlı olarak değişiklik gösterir. Bu nedenle tekstil endüstrisi atıksuları özellikle boyama prosesinde fazla miktarda kullanılan azoboyalar suda aromatik aminlerin oluşumunu sağlar buda suda kansorojenik ürünlerin oluşumuna neden olur. Ayrıca proses sonucu oluşan atıksular; yüksek renk ve pH değerlerine sahip (pH: 2-12), yüksek KOI konsantrasyonu ve süspanse katı madde içeren, düşük biyolojik parçalanmaya sahiptir [1, 2, 3, 4]. Tekstil endüstrisi atıksuların arıtılabilirliliği ile ilgili birçok çalışma yapılmıştır. Genellikle bu atıksular şu arıtma yöntemleri ile arıtılabilirliği incelenmiştir; kimyasal koagulasyon, biyolojik oksidasyon, kimyasal çöktürme, klorlama, ozan, adsorbsiyon, kimyasal oksidasyon ve membran proseslerdir [5, 6, 7] .Çoğu tekstil atıksuyunun mikroorganizmalarda toksik etki yapmasından dolayı bu atıksuların arıtımı biyolojik (aerobik-anaerobik) proseslerle gerçekleştirilemesi oldukça güç ve maliyetlidir [8, 9]. Kimyasal artımda kullanılan en yaygın yöntemlerden biri kimyasal koagülasyondur. Ancak tekstil endüstrisinde çözünmüş boyar maddelerin gideriminde bu yöntem pek etkili değildir [10]. Aktif karbon adsorsiyonu, polimer ve mineral sorbentler ve biyosorbentler kullanılarak tekstil

Oily wastewaters are the most important discharges of gas refineries from an environmental point-of-view. In the present study, treatment of gas refinery oily wastewater by electrocoagulation using aluminum electrodes was investigated. The effects of electrode distance, initial pH, sodium sulfate (Na2SO4) as a supporting electrolyte, polyaluminum chloride dosage as a coagulant aid, and current density on the efficiency of chemical oxygen demand (COD) removal were examined. The results revealed that the COD removal rate increases by applying more current density and polyaluminum chloride and, to a lesser extent, Na2SO4 dosage. The results also showed that 97% COD can be removed at optimum operational conditions. Specific electrical energy consumption could be reduced from 19.48 kWh (kg COD removal)(-1) to 11.057 kWh (kg COD removal)(-1) using Na2SO4 as a supporting electrolyte. Gas chromatographic analysis of raw and treated wastewater also revealed that most normal hydrocarbons (nea...

In the present study, the technique of electrocoagulation (EC) followed by filtration was explored at the laboratory scale for the removal of organic compounds from olive debittering wastewater (ODW). Different parameters such as electrode type and distance as well as sample pH, current density, and electrolysis time were investigated in batch experiments with identical electrode geometries. Our results showed that highest pollutant removal efficiency and lowest operational cost were achieved using two Al electrodes at a distance of 1 cm apart with a sample pH of 4.0. Moreover, rises in the electrolysis time and current density (up to 60 min and 15 mA cm −2 , respectively) led to improvements in the removal of chemical oxygen demand (COD), total polyphenolic compounds (TPC), and turbidity. Under optimized conditions, the removal of COD, TPC and tur-bidity reached 78.51, 90.44 and 97.92%, respectively; the values of 1.01 g m −3 , 12.0 kWh cm −3 and 0.12 USD m −3 were calculated as the electrode consumption, electrical energy consumption and operating cost, respectively. Chromatography results revealed tyrosol and catechin as the main phenolic compounds present in both the initial effluent and the generated sludge.

In the field of disinfecting water, if there is a process that has attracted huge attention from water treatment specialists it is the electrocoagulation (EC) process. Indeed, during the last two decades and thanks to its techno-economic benefits, this electrochemical technology has been the subject of many hundreds of researches and patents published throughout the entire world. The generally accepted tendency concerning the usage of the EC technique is to employ it as an integrated step with additional processes. In the field of killing pathogens, EC process is frequently inserted as a pre-stage before electrooxidation (EO) method in the treatment train. For such a combination, more important virus reduction is possibly reached via the collective actions of physical removal by coagulation/filtration, ferrous iron-based disinfection, and EO disinfection. In this context, much more research needs to be realized to distinguish among the electric field and cohesion contributions. Furthermore, more investigation has to be pointed on evaluating the more and more probable production of the hydroxyl radical (OH) during the EC technology. On the other hand, like in the chemical water disinfection, identical problems such as disinfection by-products generation have also appeared in the EC applications. More research needs to be pointed into such directions.

As an electrotechnology, electrocoagulation (EC) is founded on the uninterrupted exercise of an external electric field across specified semi-conductive electrodes. This technique may be viewed as a side of a large domain of biotechnological methods and perceived cost-effective and environmentally-friendly in terms of the less intensive application of non-renewable resources and elevated degrees of energetic performance. From this point of view, EC is an encouraging treating system to control several of microalgae's utilization restrictions. Using electric field-founded technologies may include upstream (i.e. electroporation for genetic transformation, inactivation of culture contaminants, and improvement of growth kinetics) and downstream processes (e.g. harvesting and extraction methods). This review gives a thorough information of the present situation of the explicit usage of such methods on microalgal biotechnology, also following tendencies and defies concerning expansions in EC to be used to microalgae manufacturing utilization. Like other electrotechnolgies, EC remains a viable process usable in microalgal biotechnology even if it is based on the destruction of the cells. However, more researches should be planned in the perspective of a large industrial usage of this electrochemical technique.

Over the past decade, there has been a surge of minimally invasive techniques aimed at treating both discogenic low back pain (LBP) and radicular pain. This article assesses the current evidence for three such treatments: intradiscal electrothermal therapy (IDET), percutaneous discectomy, and nucleoplasty. An electronic search of the literature carried out using the Cochrane Library database (2007) and Medline (1966–2007) identified 77 references relating to IDET, 363 to percutaneous discectomy, and 36 to nucleoplasty. Two randomized controlled trials (RCTs) assessed the effectiveness of IDET; one demonstrated a positive effect on pain severity only, whereas the other demonstrated no substantial benefit. Other RCTs show that percutaneous intradiscal radiofrequency thermocoagulation is ineffective for the treatment of discogenic LBP. Trials of automated percutaneous discectomy suggest that clinical outcomes after treatment are at best fair and often worse when compared with microdiscectomy. There are no published RCTs assessing Coblation (ArthroCare Spine, Stockholm, Sweden) technology.