Ion Fractionation in Drops from Breaking Bubbles
Abstract
Available data for ion ratios in precipitation are analyzed and shown to be consistent with the hypothesis of a distinctive marine aerosol in which all reported ions are enriched with respect to Na, compared with sea water values. Experiments with bubble-produced aerosols from a Na(22)P(32)04 solution show that the fractionation ratio (P04(3-)/Na(+))aerosol/ (P04(3-)/Na(+)solution is greater than 1 for all drop sizes from 0.5 to 50 microns, and may be as high as 700 for 15micron drops. Drops formed by the central jets of small bubbles show enrichment ratios E (=F-1) below 10 which are independent of drop size, while drops from the film caps of large bubbles frequently show an additional high peak, log-normal and centered on micron drops, with a standard deviation (about the geometric mean) of log 1.75. It is suggested that small bubbles form an efficient surface microtome which selectively ejects only the uppermost 1-micron layer of the solution into the aerosol phase, and that this selectivity is responsible for the anomalous ion ratios reported in marine precipitation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1965
- Accession Number
- AD0625179
Entities
People
- Ferren Macintyre
Organizations
- Massachusetts Institute of Technology