Removal of chromium(VI) from wastewater by combined electrocoagulation- electroflotation without a filter

Ping Gao; Xueming Chen; Feng Shen; Guohua Chen

doi:10.1016/j.seppur.2004.10.008

Removal of chromium(VI) from wastewater by combined electrocoagulation- electroflotation without a filter

Ping Gao, Xueming Chen, Feng Shen, Guohua Chen

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

256 Citations (Scopus)

Abstract

A combined electrocoagulation and electroflotation process was designed to reduce Cr⁶⁺ to Cr³⁺ first and then to remove the total Cr from wastewater to a value below 0.5 mg/L. Acidic condition was employed in the reduction of Cr⁶⁺ and neutral conditions were found to be beneficial for the coagulation of the precipitates of Cr(OH)₃ and Fe(OH) ₃. The formation of Fe(OH)₃ was ensured by sparging compressed air in the coagulation unit through a draft tube. The air not only oxidizes Fe²⁺ produced electrically, but also helps to mix the water for a better coagulation of the particles. The two-stage electroflotation arrangement can separate the solids from the wastewater to a value of less than 3 mg/L with total Cr less than 0.5 mg/L. The residence time required is about 1.2 h. The optimal conditions for the treatment are: charge loading about 2.5 Faradays/m³ water, pH value in the coagulation unit is 5-8. The power consumption is less than 1 kW h/m³ water at the conductivity of 1.5 mS/cm. When aluminum ions are either added or produced in situ in the coagulation unit, the treated wastewater can be discharged without any filtration. © 2004 Elsevier B.V. All rights reserved.

Original language	English
Pages (from-to)	117-123
Journal	Separation and Purification Technology
Volume	43
Issue number	2
DOIs	https://doi.org/10.1016/j.seppur.2004.10.008
Publication status	Published - 1 Jan 2005
Externally published	Yes

Bibliographical note

Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

Research Keywords

Electroplating
Filtration
Flotation
Precipitation
Reduction
Wastewater

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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title = "Removal of chromium(VI) from wastewater by combined electrocoagulation- electroflotation without a filter",

abstract = "A combined electrocoagulation and electroflotation process was designed to reduce Cr6+ to Cr3+ first and then to remove the total Cr from wastewater to a value below 0.5 mg/L. Acidic condition was employed in the reduction of Cr6+ and neutral conditions were found to be beneficial for the coagulation of the precipitates of Cr(OH)3 and Fe(OH) 3. The formation of Fe(OH)3 was ensured by sparging compressed air in the coagulation unit through a draft tube. The air not only oxidizes Fe2+ produced electrically, but also helps to mix the water for a better coagulation of the particles. The two-stage electroflotation arrangement can separate the solids from the wastewater to a value of less than 3 mg/L with total Cr less than 0.5 mg/L. The residence time required is about 1.2 h. The optimal conditions for the treatment are: charge loading about 2.5 Faradays/m3 water, pH value in the coagulation unit is 5-8. The power consumption is less than 1 kW h/m3 water at the conductivity of 1.5 mS/cm. When aluminum ions are either added or produced in situ in the coagulation unit, the treated wastewater can be discharged without any filtration. {\textcopyright} 2004 Elsevier B.V. All rights reserved.",

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author = "Ping Gao and Xueming Chen and Feng Shen and Guohua Chen",

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AU - Gao, Ping

AU - Chen, Xueming

AU - Shen, Feng

AU - Chen, Guohua

N1 - Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

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N2 - A combined electrocoagulation and electroflotation process was designed to reduce Cr6+ to Cr3+ first and then to remove the total Cr from wastewater to a value below 0.5 mg/L. Acidic condition was employed in the reduction of Cr6+ and neutral conditions were found to be beneficial for the coagulation of the precipitates of Cr(OH)3 and Fe(OH) 3. The formation of Fe(OH)3 was ensured by sparging compressed air in the coagulation unit through a draft tube. The air not only oxidizes Fe2+ produced electrically, but also helps to mix the water for a better coagulation of the particles. The two-stage electroflotation arrangement can separate the solids from the wastewater to a value of less than 3 mg/L with total Cr less than 0.5 mg/L. The residence time required is about 1.2 h. The optimal conditions for the treatment are: charge loading about 2.5 Faradays/m3 water, pH value in the coagulation unit is 5-8. The power consumption is less than 1 kW h/m3 water at the conductivity of 1.5 mS/cm. When aluminum ions are either added or produced in situ in the coagulation unit, the treated wastewater can be discharged without any filtration. © 2004 Elsevier B.V. All rights reserved.

AB - A combined electrocoagulation and electroflotation process was designed to reduce Cr6+ to Cr3+ first and then to remove the total Cr from wastewater to a value below 0.5 mg/L. Acidic condition was employed in the reduction of Cr6+ and neutral conditions were found to be beneficial for the coagulation of the precipitates of Cr(OH)3 and Fe(OH) 3. The formation of Fe(OH)3 was ensured by sparging compressed air in the coagulation unit through a draft tube. The air not only oxidizes Fe2+ produced electrically, but also helps to mix the water for a better coagulation of the particles. The two-stage electroflotation arrangement can separate the solids from the wastewater to a value of less than 3 mg/L with total Cr less than 0.5 mg/L. The residence time required is about 1.2 h. The optimal conditions for the treatment are: charge loading about 2.5 Faradays/m3 water, pH value in the coagulation unit is 5-8. The power consumption is less than 1 kW h/m3 water at the conductivity of 1.5 mS/cm. When aluminum ions are either added or produced in situ in the coagulation unit, the treated wastewater can be discharged without any filtration. © 2004 Elsevier B.V. All rights reserved.

KW - Electroplating

KW - Filtration

KW - Flotation

KW - Precipitation

KW - Reduction

KW - Wastewater

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EP - 123

JO - Separation and Purification Technology

JF - Separation and Purification Technology

IS - 2

ER -

Removal of chromium(VI) from wastewater by combined electrocoagulation- electroflotation without a filter

Abstract

Bibliographical note

Research Keywords

UN SDGs

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