| Removal of fluoride from semiconductor wastewater by electrocoagulation-flotation. | |
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MedLine Citation:
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PMID: 15743636 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This work employs an anodic surfactant, sodium dodecyl sulfate (SDS), to improve the flotation performance of the electrocoagulation-flotation (ECF) process to treated fluoride containing semiconductor wastewater following calcium precipitation. The dissolved fluoride ions and CaF(2) particles in the wastewater after calcium precipitation were effectively removed in the ECF process simultaneously. The dosage of SDS required for ECF was much less than those for dispersed air flotation (DiAF) or dissolved air flotation (DAF) processes because the CaF(2) particles can be collected by hydro-fluoro-aluminum flocs in ECF. Thus, SDS only served as a frother to make the bubbles tiny and stable in the ECF defluoridation process. The interference of co-existing anions can be overcome by increasing the dosage of calcium ions and SDS. The optimum initial acidity for ECF is close to the initial fluoride concentration after calcium precipitation; the amount of SS removed dropped rapidly if the initial acidity exceeded the optimal value because the surface charge of the hydro-fluoro-aluminum particles increased. The initial acidity of the wastewater after calcium precipitation can be modified by changing the [Ca(OH)(2)]/[Ca(2+)](T) ratio and the appropriate ratio is approximately given by the acid dissociation constant of hydrofluoric acid and the initial pH of the wastewater before calcium precipitation. |
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Authors:
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C Y Hu; S L Lo; W H Kuan; Y D Lee |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Water research Volume: 39 ISSN: 0043-1354 ISO Abbreviation: Water Res. Publication Date: 2005 Mar |
Date Detail:
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Created Date: 2005-03-03 Completed Date: 2005-07-15 Revised Date: 2009-11-19 |
Medline Journal Info:
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Nlm Unique ID: 0105072 Medline TA: Water Res Country: England |
Other Details:
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Languages: eng Pagination: 895-901 Citation Subset: IM |
Affiliation:
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Research Center for Environmental Pollution Prevention and Control Technology, Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Calcium
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chemistry Chemical Precipitation Electrochemistry / methods* Electrodes Fluorides / chemistry, isolation & purification* Hydrogen-Ion Concentration Semiconductors Sodium Dodecyl Sulfate / chemistry Surface-Active Agents / chemistry Waste Disposal, Fluid / methods* Water Pollutants, Chemical / isolation & purification Water Purification / methods* |
| Chemical | |
Reg. No./Substance:
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0/Fluorides; 0/Surface-Active Agents; 0/Water Pollutants, Chemical; 151-21-3/Sodium Dodecyl Sulfate; 7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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