Membrane distillation of HI / H2 O and H2 SO4 / H2 O mixtures for the sulfur-iodine thermochemical process

Giampaolo Caputo, Claudio Felici, Pietro Tarquini, Alberto Giaconia, Salvatore Sau

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The concentration of hydriodic and sulfuric acid aqueous solutions by membrane distillation (MD) was experimentally investigated. Two commercial hydrophobic membranes, with two different recirculation batch configurations, were tested: direct contact membrane distillation (DCMD) with a polypropylene (PP) capillary membrane, and air-gap membrane distillation (AGMD) with polytetrafluoroethylene (PTFE) flat-sheet membrane. Feed temperatures were 58 °C for DCMD and 80 °C for AGMD, with cooling water at 15 °C and 1 atm operating pressure in both cases. H2SO4concentration in the feed solution increased from 1.1 up to 7.0 mol/L with the DCMD and from 0.9 up to 10.1 mol/L with the AGMD. HI concentration increased from 0.3 up to 7.0 mol/L with the DCMD and from 0.3 up to 8.0 mol/L with the AGMD. The latter value is higher than the azeotropic concentration of the HI / H2O (7.57 mol/L) mixture and, hence, HI further separation from water can be easily achieved with conventional distillation units. Durability of PTFE membrane in acid solutions was assessed too. © 2007 International Association for Hydrogen Energy.
Original languageEnglish
Pages (from-to)4736 - 4743
Number of pages8
JournalInternational Journal of Hydrogen Energy
Issue number18
Publication statusPublished - Dec 2007


All Science Journal Classification (ASJC) codes

  • Electrochemistry
  • Fuel Technology
  • Renewable Energy, Sustainability and the Environment

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