Adsorption of the Inhalation Anesthetic Isoflurane from Dry and Humid Atmosphere

Abstract

For environmental and occupational safety reasons, the inhalation anesthetic isoflurane must be removed from indoor air in hospitals. The present work investigated experimentally the coadsorption of isoflurane and water on four different commercial adsorbents: two activated carbons and two zeolites. Adsorption isotherms from dry and humid atmosphere are shown and discussed, i.e., mixture data are compared with those of the pure substances. For all four adsorbents the dominant parameter regarding structural properties is the pore size distribution. In the case of the zeolites, the surface chemistry, especially the aluminum content, plays a role, too.

Adsorption of Inhalation Anesthetics on Activated Carbon in Humid Atmosphere

“…Figure depicts the water vapor isotherm on the activated carbon D47/3. This isotherm was published previously by Bucher et al from our group. The amount of adsorbed water (μmol) relative to the BET surface area (m 2 ) is shown as a function of relative humidity.…”

“…Molecular structure of the investigated adsorptives , (carbon is gray, hydrogen light gray, oxygen red, fluorine yellow, and chlorine green).…”

“…In this work, a modified version of the experimental setup presented by Martens et al and Bucher et al , was used. A flow chart is shown in Figure .…”

“…Isotherms in this work are subject to the experimental error of measuring devices (MSB and FID) and control devices (MFCs and temperature controllers) used. Since the balances can be repeatedly tared during the measurement and inaccuracy of the mass flow controllers is also negligible, the error of gravimetric loading (0.1–2%) and calculated concentration (1%) can be neglected. ,, For the FID, a measurement time-dependent uncertainty of ±1% in 24 h is specified by the manufacturer. Before each measurement, the instrument was calibrated.…”

“…Regarding water adsorption onto MOFs, Mileo et al in a recent study showed that water cluster formation and hydrogen bonds can be observed for these adsorbents similarly to activated carbons. 22 Bucher et al 23 investigated the adsorption of isoflurane at relative humidities of 50 and 60% on a NaX and a MFI zeolite and two activated carbons. On a MFI zeolite with a module (silicon−aluminum ratio) of 500, no change in the adsorption capacity was observed regardless of relative humidity.…”