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No.80 (2005/9) >

 
Title :How does pH affect extraction behavior of Cr(III) and Cr(VI)? -True effect of pH on chromium dithiocarbamate extraction systems-
Authors :Honma, Yoshiro
Murakami, Masahiko
Takada, Takeo
Kuniyoshi, Masayuki
Authors alternative :国吉, 正之
Issue Date :Sep-2005
Abstract :The effect of pH of aqueous phase on the extraction of Cr(III) and Cr(VI) in ammonium 1-pyrrolidinecarbodithioate/diisobutyl ketone (APCD/DIBK) extraction system was studied. In order to avoid side effects such as masking, all of the experiments were carried out in the absence of buffer agent. As first step, manners of pH change that caused from addition of the chelating agent was examined in detail. Then, based on the results of the examination, effect of pH on the chromium extraction was discussed extensively. Both pH conditions before and after APCD addition affected the extraction behavior of chromium. By considering the change of pH in aqueous solution, it was clear that a root of the effect of pH on the extraction of both Cr(III) and Cr(VI) consists in the change of the species of chromium in aqueous phase. In APCD/DIBK extraction system, species that extracted effectively were Cr(H_2O)_5(OH)^<2+> and HCrO^<2->_4. The results of the examination of the pH change caused by chelating agent also clarified a cause of difference in the extractability of two carbodithioate chelating agents; APCD and sodium diethylcarbodithioate (NaDDTC).
Type Local :紀要論文
ISSN :0286-9640
Publisher :琉球大学理学部
URI :http://hdl.handle.net/20.500.12000/5377
Citation :琉球大学理学部紀要 = Bulletin of the College of Science. University of the Ryukyus no.80 p.63 -79
Appears in Collections:No.80 (2005/9)

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