title: Supported liquid membrane system for Cr(III) separation from Cr(III)/Cr(VI) mixtures.
abstract: This paper presents the results of analyses of the chromium(III) transport process from mixtures of Cr(III)/Cr(VI) ions using supported liquid membranes (SLM), in which dinonylnaphthalene sulfonic acid (DNNSA) and di(2-ethylhexyl) phosphoric acid (D2EHPA) were used as carriers. In both cases the membrane worked as a selective barrier for Cr(VI) ions. The increase in both the time of Cr(VI) ions-carrier interaction and the Cr(VI) concentration in the feed phase negatively influenced the Cr(III) separation. The polarizing layer consisting of Cr(VI) ions prevents the access of Cr(III) ions to the inter phase surface and leads to the deactivation of the carrier, which is the result of the strong oxidation properties of Cr(VI) ions. These factors meant that, in the case of the membrane with DNNSA, the membrane could not be used for the effective separation of Cr(III) from the Cr(III)/Cr(VI) mixture. On the other hand, the membrane with D2EHPA can be used for fast and efficient transport of Cr(III) ions, but only for strictly defined process parameters, i.e. where the level of chromium(VI) concentration is below 10(-3)M and with intensive feed phase mixing.
authors: Department of Environmental Protection, Kazimierz Pułaski University of Technology and Humanities in Radom, Chrobrego 27, Radom, Poland.
authors: P
authors: P
authors: Religa
authors: Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warynskiego 1, 00-645 Warsaw, Poland E-mail: j.rajewski@ichip.pw.edu.pl.
authors: J
authors: J
authors: Rajewski
authors: Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warynskiego 1, 00-645 Warsaw, Poland E-mail: j.rajewski@ichip.pw.edu.pl.
authors: P
authors: P
authors: Gierycz
authors: Department of Environmental Protection, Kazimierz Pułaski University of Technology and Humanities in Radom, Chrobrego 27, Radom, Poland.
authors: R
authors: R
authors: Swietlik
mesh_terms: D002857:Chromium / Q000737:chemistry*; D007477:Ions; D007700:Kinetics; D008567:Membranes, Artificial; D014874:Water Pollutants, Chemical
chemical_list: D007477:Ions; D008567:Membranes, Artificial; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion