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Granular ferric hydroxide (GFH) as an adsorbent for removal of arsenate and arsenite from drinking water
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Alireza Asgari1   , Amir Hosein Mahvi , Foroogh Vaezi , Azar Ghasri |
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Abstract: (18286 Views) |
| ABSTRACT
Background and Aim: The pollution of water resources with arsenic (As) is considered as a serious problem and there are several reports about pollution of superficial and underground water with arsenic, in particular arsenate and arsenite in our country specially in some areas of Kurdistan province. There are various methods for removal of arsenic from drinking water which are generally costly.
Material and Methods: In this study, granular ferric hydroxide (GFH) was used as a synthetic adsorbent for removal of arsenate and arsenite with concentrations of 0.5, 1.0 and 2.0 mg/L. The effects of changing contact time, pH and concentrations of competitive anions, concentration of iron added to water during removal of arsenic and the effect of sulfate and chloride ions on removal of arsenic and compatibility of adsorption with Ferundlinch and Langmuir equations were evaluated. Excel soft ware was used for data analysis.
Results: According to this study, GFH showed removal efficiencies of 95, 86.5 and 83.75 for arsenate and 91, 83.5 and 80 percent for arsenite (in initial concentrations of 0.5, 1 and 2 mg/L and at a PH of 7.5). The dosage of adsorbent for this treatment was 0.5 g/L and 30 minutes was required for contact time. SO42- and Cl- revealed no significant effect on removal of arsenic. Adsorbability of both arsenate and arsenite by GFH followed Ferundlich isotherm with R2=0.96, whereas arsenate adsorption (with R2 value of more than 0.94) complied more with Langmuir isotherm in comparison to arsenite adsorption (with R2 value of more than 0.92). Results of our study also indicated that the amount of iron added to water was much more than the standard value of 0.3mg/L used for dinking water.
Conclusion: The results of our study showed GFH is highly efficient in removal of arsenate and arsenite after modification of water PH, but it has disadvantages of addition of iron to water, need of import of GFH and high cost. The problem of addition of iron to water can be managed by traditional methods.
Key words: Drinking water, Arsenate, Arsenite, Granular Ferric Hydroxide, Adsorption.
Conflict of Interest: Nill
Received: March 27, 2008 Accepted: July 24, 2008 |
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| Keywords: Drinking water, Arsenate, Arsenite, Granular Ferric Hydroxide, Adsorption |
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Full-Text [PDF 274 kb]
(3313 Downloads)
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Type of Study: Original Research |
Subject:
General
Received: 2009/04/11 | Published: 2008/09/15
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