2004 Fiscal Year Final Research Report Summary
Selective, Rapid and Perfect Removals of Diluted Heavy Metal Ions in Waste Waters.
| Project/Area Number |
15560704
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Earth system and resources enginnering
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| Research Institution | Waseda University |
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Principal Investigator |
SASAKI Hiroshi Waseda University, Faculty of Science and Engineering, Professor, 理工学術院・理工学部, 教授 (50006037)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Cadmium, Arsenaite, Selenite / Nano Size Particle / Ultrafine Particle / Suspended Solid / Fiberlike Slag / Zeta Potential / Rapid Solid / Liquid Separation / Waste Water Treatment |
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| Research Abstract |
Treatment of wastewater from mining operations and refineries by precipitation which generates large volume of hydroxide sludge can coprecipitate toxic substances such as Cd, As, Pb, Se, etc. Results in our laboratory works showed that Ferro-Nickel Slag fibers(FS) in column bed served as excellent media in the rapid separation (2 mm/s linear velocity) of suspended low concentrated ultra fine sludge particles (SS) from precipitation. This can be explained by the DLVO theory based on the heterocoagulation phenomena between the FS fibers in column bed and the ultra fine particles.
In the separation of low concentrated toxic substances such as Cd, Se and Pb in the wastewater, the above mechanisms were also applied but with FS fiber surface modifications. This was carried-out to low concentrated Cd solution (1 mg/L), which was rapidly separated by precipitation of Cd to ultra fine CdS particles by the addition of sulfide ions in the presence of 10^0-10^2 mg/L Fe or Zn. Rapid separation of 1 mg/L Cd^<2+> was also carried-out by application of ferrous sulfide surface modification to FS fibers. Other precipitation method was also applied to Pb solution (1mg/L) using bioreactor with Sulfate Reducing Bacteria (SRB) on FS bed. In the rapid separation of SeO_4^<2->, the basic ferrous and ferric hydroxide surface modification on the surface of FS fibers was conducted. Favorable rapid separation results were obtained and as a conclusion, low concentrated toxic substances can be selectively removed suggesting that potential drastic change in wastewater treatment processes in the future.
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