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Recovery of chromium from tannery effluents using a redox–adsorption approach

 

作者: Thomas F. O'Dwyer,   Benjamin K. Hodnett,  

 

期刊: Journal of Chemical Technology&Biotechnology  (WILEY Available online 1995)
卷期: Volume 62, issue 1  

页码: 30-37

 

ISSN:0268-2575

 

年代: 1995

 

DOI:10.1002/jctb.280620105

 

出版商: John Wiley&Sons, Ltd.

 

关键词: adsorption isotherm;chromium;redox;tannery effluent

 

数据来源: WILEY

 

摘要:

AbstractAdsorption isotherms for sodium and trivalent chromium uptake from aqueous solutions onto Amberlite resin were prepared at 18°C. Adsorption of each cation followed the Langmuir model. The rate of uptake of each cation was found to be film diffusion controlled with sodium showing the most rapid uptake. In aqueous solutions containing both chromium and sodium as the only cationic species, it was found that with increasing initial concentration of sodium, the trivalent chromium uptake on the resin decreased substantially. To overcome this difficulty a four step redox–adsorption system has been developed for the removal of Cr3+from tannery effluents. The first step comprises the oxidation of trivalent chromium to the hexavalent form using selected common oxidising agents. The liquid effluent is then passed through an Amberlite cation‐exchange resin in step 2 where the sodium in the waste stream is completely removed. The anionic hexavalent form of chromium (Cr2O 72−) passes unaltered through the resin along with the waste stream. In the third stage the dichromate is reduced back to the trivalent cationic form which is subsequently removed from the waste stream by a second Amberlite ion‐exchange bed in stage 4. Each step in this process is assessed in batch and flow mode using simulated and real tannery

 

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