The future for electrocoagulation as a localised water treatment technology

Holt, P.K.; Barton, G.W.; Mitchell, Cynthia

doi:10.1016/j.chemosphere.2004.10.023

Cited by 632 publications

(419 citation statements)

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“…On the whole, in electrocoagulation processes, gravity and buoyancy forces are the two main factors determining the pollutants separation mechanism and a combination of physico-chemical parameters within an electrocoagulation reactor shifts the dominant separation mechanism. Moreover, the pollutant's physicochemical properties influence its interactions within the system and eventual removal path (Holt et al 2005;Chen 2004). In this way, various results have been reported throughout the literatures, especially about application of different anode materials.…”

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confidence: 94%

“…According to Faraday's law, dissolution of electrode is related to the total charge passed which implies that the amount of adsorbent produced in the electrochemical reactor would be proportional to the electrical current (Ratna Kumar et al 2004). In addition, electrical current is the prime factor determining the separation mechanism (Holt et al 2005). Thus, a range of electrical current varying within 100-400 mA was investigated and the results are depicted in Fig.…”

Section: Effect Of Electrical Currentmentioning

confidence: 99%

“…Aluminum and iron are usually used as anode materials, the dissolution of which produces hydroxides, oxyhydroxides and polymeric hydroxides (Kobya et al 2010;Holt et al 2005;Ghanbari et al 2014). In an ECF process, coagulants which are formed through electrolytic oxidation of the sacrificial electrode, destabilize the contaminants followed by agglomeration of the destabilized phases to form flocs (Mollah et al 2004).…”

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Electrocoagulation/Flotation of Textile Wastewater with Simultaneous Application of Aluminum and Iron as Anode

et al. 2014

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Wastewater discharged from textile industry contains a variety of polluting substances including dyes. Amongst treatment processes, electrocoagulation/flotation is a promising method for color removal from textile wastewater. In this study, the performance of a new electrocoagulation/flotation with combined Fe-Al anodes and a copper made cell as cathode was investigated for the treatment of real textile wastewater. The optimal operational condition for decolorization was pH=7, 300 mA electrical current, 3 cm distance between the two anodes and 40 min reaction time using iron and aluminum as anode materials simultaneously. Under this condition, 98 % color (ADMI) removal was achieved. Furthermore, 87 % COD removal was obtained in similar optimal condition except in 400 mA. To investigate electrical current dependency on the COD removal rate, a kinetic study was carried out and data were in good agreement with the first order kinetic model. The rate constants (k) of COD removal were 0.0234, 0.0291, 0.0393 and 0.0519 min −1 for 100, 200, 300 and 400 mA, respectively.

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confidence: 94%

Section: Effect Of Electrical Currentmentioning

confidence: 99%

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Electrocoagulation/Flotation of Textile Wastewater with Simultaneous Application of Aluminum and Iron as Anode

et al. 2014

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“…As limitações no uso da CC podem ser minimizadas pela adição de eletrodos de sacrifício em paralelo na configuração da célula eletrolítica. 31 Além disso, para se reduzir o efeito de passivação do catodo e aumentar a vida útil do eletrodo, pode-se inverter, manualmente, o sentido da corrente em intervalos regulares de tempo. Assim, o catodo torna-se anodo e vice-versa.…”

Section: Introductionunclassified

Avaliação do processo eletrolítico em corrente alternada no tratamento de água de produção

Cerqueira

Marques

2011

Quím. Nova

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objective was to study the treatment of wastewater generated by the oil industry. This work consisted of tests of electroflocculation with alternate current (AC), and chemical coagulation. The removal efficiencies of organic load were evaluated by the removal of oils and greases, color and turbidity. The parameters investigated were the change in alternate current frequency, the initial pH, the distance between electrodes, the applied potential and time lapse. From the results, one may conclude that the electroflocculation process is potential applicability to the effluent studied, while chemical coagulation was not successful.Keywords: electroflocculation; offshore platforms; water production. INTRODUÇÃOAs atividades de exploração de petróleo, devido à crescente preocupação com o meio ambiente e ao surgimento de novas leis e resoluções ambientais mais restritivas, precisam se enquadrar dentro das novas exigências. Uma das questões mais preocupantes envolve a água de produção gerada nessa atividade, a qual aumenta gradativamente em volume à medida que os poços vão envelhecendo e que novos poços são perfurados. 1 Normalmente, essa água corresponde a mais de 90% de todos os efluentes gerados na indústria do petróleo: em média, para cada m³/dia de petróleo produzido são gerados de 3 a 4 m³/dia de água, podendo chegar a 7 ou mais, nas atividades de exploração, perfuração e produção. Para que a água produzida possa ser descartada em corpos receptores ou utilizada na reinjeção em poços de petróleo, é necessário o seu tratamento prévio para enquadrá-la na legislação vigente. A Resolução CONAMA 357/2005, 4 estabelece que para o descarte em corpos receptores, o limite de óleos e graxas na água produzida é de até 20 mg/dm 3 . Especificamente, para descarte em plataformas off-shore, aplica-se a Resolução CONAMA 393/2007, 5 que estabelece a média aritmética simples mensal do teor de óleos e graxas de até 29 mg/dm 3 , com valor máximo diário de 42 mg/dm 3 . Para reinjeção em poços de petróleo, a água deverá ter no máximo 5 mg/dm 3 de óleos e graxas.Uma parte do óleo presente na água de produção está na forma de emulsão devido às partículas sólidas finamente divididas oriundas da perfuração, assim como os produtos químicos residuais utilizados na desestabilização de emulsões óleo/água (O/A) e as moléculas surfactantes naturais do petróleo. 6 Neste caso, o diâmetro das gotas situa-se abaixo de 50 μm, o que dificulta a sua separação por meios gravitacionais. A separação do óleo emulsificado requer a desestabilização da emulsão O/A, a qual é governada por quatro diferentes fenômenos: coagulação, floculação, sedimentação (creaming) e coalescência. 7 O creaming é o deslocamento gravitacional das gotas para a superfí-cie da fase contínua em função da diferença de densidade entre as duas fases, não necessariamente após a coagulação e/ou floculação das gotas.A colisão entre as gotas pode levar à coalescência com a formação de grandes agregados até se tornar novamente uma fase contínua separada do meio dispersante por uma simples inte...

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“…Electrocoagulation (EC) is gaining recognition as an alternative process to conventional chemical coagulation (CC) of EC include a compact treatment facility, relatively low cost, less sludge production, minimum requirement of chemicals, and the possibility of complete automation [1][2][3][4]. During the last few decades, EC technology has undergone a rapid development, and has been proved to be competitive and effective in the treatment of drinking water and wastewater to remove heavy metals [5][6][7], anions [8,9], organic compounds [10][11][12][13], oil [14,15], and particulates [16,17].…”

Section: Introductionmentioning

confidence: 99%

An effective method for improving electrocoagulation process: Optimization of Al 13 polymer formation

Wang

Sun

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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h i g h l i g h t s• Al 13 polymer formation in EC process are investigated.• Al 13 species fraction positively correlated with removal of turbidity and organic.• pH 5-7 and lowering j favored the formation of Al 13 polymer.• Al 13 fraction can reach more than 60% under optimal EC conditions. Keywords: Electrocoagulation Aluminum species Electrochemical parameter a b s t r a c t Al 13 polymer has been believed to be the most active species responsible for coagulation. The character of Al species distribution and the formation of Al 13 polymer in electrocoagulation (EC) process were investigated in order to provide insight into optimizing EC operation and design. The results indicated that predominant Al species shifted from monomer toward medium polymer then to larger polymer or Al(OH) (s) with increasing EC time. The in-situ Al 13 polymer could be generated in EC process, and became the dominant species during 5-15 min. In EC process, Al 13 species fraction positively correlated with the removal of turbidity and organic. The increase of pH and current density could accelerate the hydrolysis-polymerization process of Al 3+ . pH 5-7 and lowering current density favored the formation of Al 13 polymer during EC process, EC process with bipolar electrodes had a higher yield of monomeric and Al 13 species, while EC process with monopolar electrodes facilitated the formation of larger polymer or Al(OH) (s) . The content of Al 13 polymer can reach more than 60% under optimal conditions.

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The future for electrocoagulation as a localised water treatment technology

Cited by 632 publications

References 18 publications

Electrocoagulation/Flotation of Textile Wastewater with Simultaneous Application of Aluminum and Iron as Anode

Electrocoagulation/Flotation of Textile Wastewater with Simultaneous Application of Aluminum and Iron as Anode

Avaliação do processo eletrolítico em corrente alternada no tratamento de água de produção

An effective method for improving electrocoagulation process: Optimization of Al 13 polymer formation

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