Soluble acid aerosols

ReVAP [Reduced Volatility Alkylation Process] A process for improving the safety of alkylation processes catalyzed by hydrofluoric acid. A proprietary additive curtails the emission of the acid aerosol, which forms in the event of a leak. The additive has a high boiling point and is miscible with acid but is sparingly soluble in hydrocarbons. Developed by Phillips Petroleum Corporation and ExxonMobil and first installed at Woods Cross, UT, in 1996. See also Alkad. 

One-step clean-and-shine products have become popular in the household market. These products are appHed to the floor with a sponge mop and their detergent action removes and suspends soil, which coUects on the mop and is removed when the mop is rinsed with water. The formulation, which remains on the floor, dries to a poHsh film. An earlier product of this type was dispensed from an aerosol as a foam. Formulas as of this writing (ca 1995) are appHed as Hquids (29,30). In one product, the dried film obtained from the formulation is soluble in the formulation, which includes low molecular weight, high acid polymers and a fairly large amount of ammonia (31). Repeated use does not contribute to a buildup of poHsh. 

R23 is the only significant removal process for N02 and serves as well as a radical sink reaction for HO. Sulfur dioxide (with higher water solubility than NO2.) is also oxidized to sulfuric acid in aerosols and fog droplets (71,72,73,74) its gas-phase oxidation via R24 does not constitute a radical sink, since H02 is regenerated. 

Condensed phase interactions can be divided roughly into two further categories chemical and physical. The latter involves all purely physical processes such as condensation of species of low volatility onto the surfaces of aerosol particles, adsorption, and absorption into liquid cloud and rainwater. Here, the interactions may be quite complex. For example, cloud droplets require a CCN, which in many instances is a particle of sulfate produced from SO2 and gas-particle conversion. If this particle is strongly acidic (as is often the case) HNO3 will not deposit on the aerosol particle rather, it will be dissolved in liquid water in clouds and rain. Thus, even though HNO3 is not very soluble in... 

All of these species are very soluble in a rain or cloud drop and are an important source of atmospheric aerosols. For ammonia and ammonium, the condensed phases (I and s) represent approximately two-thirds of the total atmospheric burden, whereas for nitric acid and nitrates, about two-thirds is in the gas phase (Soderlund and Svensson, 1976). 

Denmark 1.5 days after the explosion. Air samples collected at Roskilde, Denmark on April 27-28, contained a mean air concentration of 241Am of 5.2 pBq/m3 (0.14 fCi/m3). In May 1986, the mean concentration was 11 pBq/m3 (0.30 fCi/m3) (Aarkrog 1988). Whereas debris from nuclear weapons testing is injected into the stratosphere, debris from Chernobyl was injected into the troposphere. As the mean residence time in the troposphere is 20-40 days, it would appear that the fallout would have decreased to very low levels by the end of 1986. However, from the levels of other radioactive elements, this was not the case. Sequential extraction studies were performed on aerosols collected in Lithuania after dust storms in September 1992 carried radioactive aerosols to the region from contaminated areas of the Ukraine and Belarus. The fraction distribution of241 Am in the aerosol samples was approximately (fraction, percent) organically-bound, 18% oxide-bound, 10% acid-soluble, 36% and residual, 32% (Lujaniene et al. 1999). Very little americium was found in the more readily extractable exchangeable and water soluble and specifically adsorbed fractions. 

Clearance to pulmonary lymph nodes will occur at a fractional rate of 0.0001 per day. Dissolution of the deposited particles and absorption of cerium into the systemic circulation will occur at rates that are between the extremes represented by CeCh in CsCl particles and Ce oxide or Ce in fused aluminosilicate particles as given by the functions included in Figure 9. These rates should not be expected to be constant over the entire clearance period and will depend upon the overall composition of the bulk aerosol particles, which indude particle size, amount of stable lanthanide present, acidity, and the solubility of other components of the particles. The accuracy of predicting respiratory tract clearance and internal organ uptake of radiocerium will depend heavily upon adequate determination of the particle solubility characteristics. 

Fiber-bed scrubbers are used to collect fine or soluble particulate matter or as mist eliminators to collect liquid aerosols, including inorganic (e.g., sulfuric acid mist) and volatile organic compounds. Insoluble or coarse PM will clog the fiber bed with time, and VOCs that are difficult to condense will not be collected efficiently. 

This system was studied by Schwartz. Toluene at 10 ppm, nitric oxide at 1 ppm, and nitrogen dioxide at 1.2 ppm were irradiated with ultraviolet lamps in a 17-m batch reactor for 270 min. Collected aerosols were successively extracted with methylene chloride and then methanol. The methylene chloride extract was fractionated into water-soluble and water-insoluble material, and the latter fraction was further divided into acidic, neutral, and basic fractions. The acidic and neutral fractions were analyzed by gas chromatography and chemical-ionization mass spectrometry the compounds identified are shown in Figure 3-7. The two analyzed fractions represented only about 5.5% of the total aerosol mass. It is noteworthy that classical nitration of an aromatic ring appears to... 

Kawamura, K., R. Semere, Y. Imai, Y. Fujii, and M. Hayashi, Water Soluble Dicarboxylic Acids and Related Compounds in Antarctic Aerosols, J. Geophys. Res., 101, 18721-18728 (1996b). 

Measurements of the solubility of HBr in sulfuric acid at 220 K gave Henry s law constants from 8.5 X 103 M atm-1 for 72 wt% H2S04 to 1.5 X 107 M atm-1 for 54 wt% H2S04 (Williams et al., 1995 Abbatt, 1995). Application of these values to stratospheric aerosol particles typical of midlatitude conditions gives very small equilibrium concentrations of dissolved HBr i.e., most of the HBr will remain in the gas phase. 

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