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Application of Hollow Fiber Membrane Contactors for Catalyst Recovery in the WPO Process
Author(s) -
ORTIZ INMACULADA,
URTIAGA ANE,
ABELLÁN M. JOSÉ,
SAN ROMÁN FRESNEDO
Publication year - 2003
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2003.tb05989.x
Subject(s) - chemistry , catalysis , extraction (chemistry) , hydrogen peroxide , aqueous solution , hollow fiber membrane , stripping (fiber) , sulfuric acid , membrane , solvent , chromatography , chemical engineering , inorganic chemistry , materials science , organic chemistry , biochemistry , engineering , composite material
A bstract : In this work the use of a membrane based liquid extraction process for recovery of the homogeneous catalyst employed in the wet peroxide oxidation process (WPO) is studied. In the WPO process the oxidation agent is the hydroxyl radical that is obtained by using a combination of hydrogen peroxide and a mixture of Fe(II), Cu(II), and Mn(II) in aqueous solution. The mixture of metallic cations permits the almost total degradation of the refractory organic compounds, but the use of metallic salts as catalysts induces additional pollution. To recover the homogeneous catalyst of the WPO process by means of non‐dispersive solvent extraction (NDSX) two hollow fiber membrane contactors are employed, one for the extraction step and the second for the backextraction step. From the initial assays, the extractant LIX 622N was selected for Cu(II) recovery and Cyanex 272 for Fe(II) and Mn(II) recovery. Selective separation of Fe(II) and Mn(II) can be obtained by adjusting the pH of the feed aqueous phase. The three metals are stripped using sulfuric acid to give concentrated solutions of CuSO 4 , FeSO 4 , and MnSO 4 that can be recycled to the formulation of the catalyst solution of the WPO process. A mathematical model has been proposed to describe the recovery of Cu. Two design parameters are required: the membrane mass transport coefficient of the extraction and stripping modules ( k m = 3.07 × 10 −7 m/sec ) and the equilibrium parameter of the extraction reaction ( K Ex = 0.0832 ).