Laboratory studies of the influence of thin organic films on the neutralization reaction of H2SO4 aerosol with ammonia

Abstract The neutralization reaction of micro-encapsulated sulfuric acid aerosol with gaseous ammonia has been investigated. Experimental parameters were: influence of different coating substances, coating thickness, relative humidity and reaction time. The reaction of H 2 SO 4 aerosol with NH 3 was measured as a function of time by chemical characterization of the particulate and gaseous phase before and after mixing of the reactants in a flow reactor. A remarkable decrease in the reaction rate was observed, depending on molecular structure of the organic coating substance and the thickness of coating. Straight chain molecules like n -hexadecane and n -hexadecanol strongly retard the reaction. Branched chain molecules as coating showed no significant effect, probably because of their inability to form tight films. Naturally occurring organic coating substances affect the neutralization, too. The mass transport resistance of the films investigated are interpreted in terms of the accommodation and reaction coefficient.

[1]  W. Garrett.  Retardation of Water Drop Evaporation with Monomolecular Surface Films , 1971 .

[2]  Kinetics of the Reaction between Gaseous Ammonia and Sulfuric Acid Droplets in an Aerosol , 1958 .

[3]  D. Klockow,et al.  Preparation of refillable permeation tubes , 1978 .

[4]  J. Gentry,et al.  MEASUREMENT OF THE KINETICS OF SOLUTION DROPLETS IN A CONTINUOUSLY MIXED CHAMBER , 1985 .

[5]  C. Junge,et al.  Studien zur bestimmung des Säuregehaltes von aerosolteilchen , 1969 .

[6]  Martin Ferm,et al.  Method for determination of atmospheric ammonia , 1979 .

[7]  David Y. H. Pui,et al.  Electrical neutralization of aerosols , 1974 .

[8]  E. J. Mack,et al.  Modification of laboratory fog with organic surface films , 1972 .

[9]  J. Gentry,et al.  Investigation of the reaction between single aerosol acid droplets and ammonia gas , 1984 .

[10]  Peter H. McMurry,et al.  Study of the ammonia (gas)-sulfuric acid (aerosol) reaction rate , 1983 .

[11]  Benjamin Y. H. Liu,et al.  A submicron aerosol standard and the primary, absolute calibration of the condensation nuclei counter , 1974 .

[12]  T. Novakov,et al.  The lifetime of aerosols in ambient air: Consideration of the effects of surfactants and chemical reactions , 1985 .

[13]  R. Niessner.  Coated particles: Preliminary results of laboratory studies on interaction of ammonia with coated sulfurid acid droplets or hydrogensulfate particles , 1984 .

[14]  Benjamin Y. H. Liu,et al.  On the performance of the electrical aerosol analyzer , 1975 .

[15]  G. T. Barnes.  The effects of monolayers on the evaporation of liquids , 1986 .

[16]  H. Burtscher,et al.  In situ measurement of adsorption and condensation of a polyaromatic hydrocarbon on ultrafine C particles by means of photoemission , 1986 .

[17]  E. V. Sydow,et al.  The crystal structure of the monoclinic form of n‐hexadecanol , 1960 .

[18]  T. Graedel,et al.  Chemistry within aqueous atmospheric aerosols and raindrops , 1981 .

[19]  R. Niessner,et al.  Modified La Mer-generator for the production of small amounts of sulfuric acid aerosol , 1980 .

[20]  R. Niessner,et al.  A Thermoanalytical Approach to Speciation of Atmospheric Strong Acids , 1980 .

[21]  R. Niessner.  The chemical response of the photo-electric aerosol sensor (PAS) to different aerosol systems , 1986 .

[22]  J. Gentry,et al.  Measurement of the kinetics of solution droplets in the presence of adsorbed monolayers: determination of water accommodation coefficients , 1984 .

[23]  Charles J. Weschler,et al.  Organic films on atmospheric aerosol particles, fog droplets, cloud droplets, raindrops, and snowflakes , 1983 .

[24]  R. Cary,et al.  Neutralization of sulfuric acid aerosol by ammonia , 1980 .

[25]  D. Chang,et al.  Retardation of aqueous droplet evaporation by air pollutants , 1980 .

[26]  Reinhard Niessner,et al.  Investigation of surface properties of ultrafine particles by application of a multistep condensation nucleus counter , 1990 .

[27]  Victor K. La Mer,et al.  The Rate of Evaporation of Water through Fatty Acid Monolayers , 1955 .

[28]  J. Gentry,et al.  Measurement of water and ammonia accommodation coefficients at surfaces with adsorbed monolayers of hexadecanol , 1985 .