HR: 1340h
AN: V43B-1585    [Abstracts]
TI: Elements in Nucleating Crystals (Mineraloids?) on Fibers: Are Fumaroles Unknown Resources for a Future Hydrogen Economy?
AU: * OBENHOLZNER, J H
EM: obenholzner@a1.net
AF: NHM/MINERALOGY, POSTFACH 417, Vienna, A-1014 Austria
AB: Crabtree et al. (2004) summarized some key aspects of H₂ production and H storage. Elements in compounds necessary for natural H₂ production are Mn in MnO (photosynthesis) and Fe in Fe clusters (bacteria). Relevant elements for H₂ production and H storage in compounds known from fumarole emissions and/or volcanic ash leachates are: Mn, Fe, Ti, Mg, B, N, Al, Ni, La, K, Na. H₂ and H_ {2}S are common species of many fumaroles. If H₂S is pumped through steel tubes Fe sulfides are forming and H₂ is released. In the past several estimations of global volcanic metal fluxes to the atmosphere had been published. No attempt had been made to mine volcanic gases for certain elements. Filter experiments performed at a fumarole at La Fossa volcano, Vulcano Island, Italy and subsequent FESEM/EDS analysis document some phenomena difficult to explain. 1. On an Al-P-O ceramic filter applied for 5 mins. at a filter-2-bubblers system (0.8 - 1 l/min) once Hg-S-rich particles got collected, at another time Ce-La-carbonate particles. Other filters (borosilicate glass fiber and/or Nuclepore or Millipore (0.2 micrometers) applied for 1 h before or after the ceramic filters did not collect these particles. It remains unanswered if problems related to adhesion caused these results, or the ceramic filter had been in place at times of particle ``bursts", or classical physics cannot explain such phenomena. 2. Particles are nucleating on glass and organic fibers. One set of experiments followed a traditional aerosol particle collection approach utilizing a filter-2-bubblers system (AC). Another experiment had been the clogging of a fumarole vent by various glass fiber materials (CE). FESEM/EDS data from AC and CE show both nucleating particles on fibers. One data set of the AC and CE documents that one type of particle (CE: mostly metal chlorides, to a minor amount metal sulfides and AC: barberiite) nucleates on one fiber, whereas other fibers are empty. This single fiber anomaly had been detected up-to-now in the T range of 25 - ca. 300°C and at pH: 0-2. CE at higher T (> 400 °C) did not show the single fiber anomaly. 3. One of the observed metal chlorides is Bi-Cl. Bi chlorides are not known in nature. BiCl₃ melts at 230-232°C, BiCl₄ melts at 226°C. The T of the environment of nucleation had been ca. 300°C. Bismucolite (BiOCl) is a mineral, but can be excluded as an interpretation of the Bi-Cl data. A summary is given below according to elements important for H storage and detection on fibers by FESEM/EDS: Ti: Ti enrichment on organic coalescer at AC, Traces of Ti on GW at CE, Traces of Ti, [Cr or Mn(?)], Ni, Pb!, [Fe! - Cl, - S or Mo(?)] on GW at CE - fibers attached to corroded stainless steel (grade 316; no Ti, no Pb); N + B: Barberiite (?) NH_ {4}BF₄ on GW at AC; Al: i.e. in cancrinite on GW at CE; Ni + Fe : Fe-Ni-(Cr)-Cl on RW & GW at CE; Mg: Mg-Fe & Bi-Cl on GW at CE; La: REE-phosphate in rock coatings (Fulignati et al., 2002); Ce, La carbonate particles on AN; Na: NaCl on various fibers at AC; K: KCl on various fibers at AC. Abbrevations: GW is a high-Si glass fiber; RW is a low-Si glass fiber; AN is Anodisc (Al-P-O); (!) = abundant; (or) = peak overlap in EDS. An approach to mine elements of fumarole gases needs intensified research on how filters work in such environments and which elements can pass the filters and might be collected in the bubbler systems. Such research could provide more information on volcanic systems. If such data also support economic arguments needs detailed quantification and hazard evaluation. References: Crabtree et al., 2004. Physics Today, 39-44, Dec. 2004. Fulignati et al., 2002. JVGR, 115, 397-410.
DE: 1622 Earth system modeling (1225)
DE: 1749 Volcanology, geochemistry, and petrology
DE: 2129 Interplanetary dust
DE: 4801 Aerosols (0305, 4906)
DE: 8409 Atmospheric effects (0370)
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005