Uptake Measurements of Acetic Acid on Ice and Nitric Acid-Doped Thin Ice Films over Upper Troposphere/Lower Stratosphere Temperatures

Abstract

The adsorption of gaseous acetic acid (CH(3)C(O)OH) on thin ice films and on ice doped with nitric acid (1.96 and 7.69 wt %) was investigated over upper troposphere and lower stratosphere (UT/LS) temperatures (198-208 K), and at low gas concentrations. Experiments were performed in a Knudsen flow reactor coupled to a quadrupole mass spectrometer. The initial uptake coefficients, γ(0), on thin ice films or HNO(3)-doped ice films were measured at low surface coverage. In all cases, γ(0) showed an inverse temperature dependence, and for pure thin ice films, it was given by the expression γ(0)(T) = (4.73 ± 1.13) × 10(-17) exp[(6496 ± 1798)/T]; the quoted errors are the 2σ precision of the linear fit, and the estimated systematic uncertainties are included in the pre-exponential factor. The inverse temperature dependence suggests that the adsorption process occurs via the formation of an intermediate precursor state. Uptakes were well represented by the Langmuir adsorption model, and the saturation surface coverage, N(max), on pure thin ice films was (2.11 ± 0.16) × 10(14) molecules cm(-2), independent of temperature in the range 198-206 K. Light nitration (1.96 and 7.69 wt %) of ice films resulted in more efficient CH(3)C(O)OH uptakes and larger N(max) values that may be attributed to in-bulk diffusion or change in nature of the gas-ice surface interaction. Finally, it was estimated that the rate of adsorption of acetic acid on high-density cirrus clouds in the UT/LS is fast, and this is reflected in the short atmospheric lifetimes (2-8 min) of acetic acid; however, the extent of this uptake is minor resulting in at most a 5% removal of acetic acid in UT/LS cirrus clouds.

Crystal Hydrates of Organic Compounds

“…Ƚɟɨɦɟɬɪɢɸ ɩɨɥɢɷɞɪɢɱɟɫɤɢɯ ɩɨɥɨɫɬɟɣ ɤɥɚɬɪɚɬɚ ɨɛɨɡɧɚɱɚɸɬ, ɭɤɚɡɵɜɚɹ ɱɢɫɥɨ ɜɟɪɲɢɧ ɭ ɪɚɡɥɢɱɧɵɯ ɝɪɚɧɟɣ ɬɚɤɨɝɨ ɩɨɥɢɷɞɪɚ (ɰɢɮɪɚɦɢ) ɢ ɤɨɥɢɱɟɫɬɜɨ ɝɪɚɧɟɣ ɤɚɠɞɨɝɨ ɬɢɩɚ (ɧɚɞɫɬɪɨɱɧɵɦ ɢɧɞɟɤɫɨɦ), ɤɪɨɦɟ ɬɨɝɨ, ɢɫɩɨɥɶɡɭɸɬɫɹ ɛɭɤɜɟɧɧɵɟ ɨɛɨɡɧɚɱɟɧɢɹ. Ɍɚɤ, ɩɪɚɜɢɥɶɧɭɸ ɞɨɞɟɤɚɷɞɪɢɱɟɫɤɭɸ ɩɨɥɨɫɬɶ ɨɛɨɡɧɚɱɚɸɬ ɫɢɦɜɨɥɚɦɢ 5 12 ɢɥɢ D. ȼ ɫɬɪɭɤɬɭɪɧɨ ɢɫɫɥɟɞɨɜɚɧɧɵɯ ɤɥɚɬɪɚɬɚɯ ɧɚɛɥɸɞɚɸɬɫɹ ɬɚɤɠɟ ɩɨɥɢɷɞɪɵ 4 2 5 8 (d, ɞɟɤɚɷɞɪɢɱɟɫɤɚɹ ɩɨɥɨɫɬɶ), 4 3 5 6 6 3 (Dc, ɩɨɥɨɫɬɶ-ɞɨɞɟɤɚɷɞɪ ɫ ɤɜɚɞɪɚɬɧɵɦɢ, ɩɹɬɢɭɝɨɥɶɧɵɦɢ ɢ ɲɟɫɬɢɭɝɨɥɶɧɵɦɢ ɝɪɚɧɹɦɢ), 5 12 6 2 (T, ɬɟɬɪɚɞɟɤɚɷɞɪ), 5 12 6 3 (P, ɩɟɧɬɚɞɟɤɚɷɞɪ), 5 12 Ɇɚɥɵɟ ɩɨɥɨɫɬɢ ɤɥɚɬɪɚɬɧɵɯ ɤɚɪɤɚɫɨɜ ɦɨɝɭɬ ɡɚɩɨɥɧɹɬɶɫɹ ɦɨɥɟɤɭɥɚɦɢ ɧɟɛɨɥɶɲɨɝɨ ɪɚɡɦɟɪɚɬɚɤɢɦɢ ɤɚɤ ɜɨɞɨɪɨɞ, ɷɧɟɪɝɨɧɨɫɢɬɟɥɶ ɜ ɬɨɩɥɢɜɧɵɯ ɷɥɟɦɟɧɬɚɯ, ɞɥɹ ɤɨɬɨɪɨɝɨ ɭɫɬɨɣɱɢɜɵɟ ɤɥɚɬɪɚɬɵ ɜɵɫɬɭɩɚɸɬ ɩɟɪɫɩɟɤɬɢɜɧɵɦ ɟɦɤɢɦ ɯɪɚɧɢɥɢɳɟɦ. Ɍɚɤ, ɜ ɫɦɟɲɚɧɧɨɦ ɩɨɥɭɤɥɚɬɪɚɬɟ ɬɪɢɦɟɬɢɥɚɦɢɧɚ ɦɨɥɟɤɭɥɚɦɢ H 2 ɩɪɢ 80 Ɇɉɚ ɡɚɩɨɥɧɟɧɵ ɩɨɱɬɢ ɜɫɟ ɦɚɥɵɟ ɩɨɥɨɫɬɢ [ 46 ].…”

“…Ʉɚɪɤɚɫ ɯɨɡɹɢɧɚ ɫɩɨɫɨɛɟɧ ɨɛɪɚɡɨɜɵɜɚɬɶɫɹ ɧɟ ɬɨɥɶɤɨ ɧɚ ɇ-ɫɜɹɡɹɯ ɢ ɢɧɵɯ ɜɬɨɪɢɱɧɵɯ ɜɡɚɢɦɨɞɟɣɫɬɜɢɹɯ (ɧɚɩɪɢɦɟɪ, ɤɥɚɬɪɚɬɵ ɦɨɱɟɜɢɧɵ, ɬɢɨɦɨɱɟɜɢɧɵ ɢɥɢ ɝɢɞɪɨɯɢɧɨɧɚ), ɧɨ ɢ ɧɚ ɤɨɜɚɥɟɧɬɧɵɯ ɫɜɹɡɹɯ. Ɍɚɤ, ɭɫɟɱɟɧɧɨ-ɨɤɬɚɷɞɪɢɱɟɫɤɨɣ ɩɨɥɨɫɬɢ 4 6 3) ɨɛɨɡɧɚɱɚɸɬɫɹ Tm 1 (n 1 )m 2 (n 2 )…, ɝɞɟ m 1 , m 2 , … -ɱɢɫɥɨ ɦɨɥɟɤɭɥ ɜɨɞɵ ɜ ɰɢɤɥɚɯ; n 1 , n 2 , … -ɱɢɫɥɨ ɨɛɳɢɯ ɦɨɥɟɤɭɥ ɜɨɞɵ ɞɥɹ ɞɜɭɯ ɫɦɟɠɧɵɯ ɰɢɤɥɨɜ. ɉɪɢ ɱɟɪɟɞɨɜɚɧɢɢ ɜ ɥɟɧɬɟ ɤɨɥɟɰ ɢ ɚɰɢɤɥɢɱɟɫɤɢɯ ɡɜɟɧɶɟɜ ɩɨɫɥɟɞɧɢɟ ɨɛɨɡɧɚɱɚɸɬɫɹ Ak, ɝɞɟ k -ɱɢɫɥɨ ɦɨɥɟɤɭɥ ɜ ɬɚɤɨɦ ɡɜɟɧɟ.…”

“…Ɋɚɫɩɪɟɞɟɥɟɧɢɟ ɦɨɥɟɤɭɥ ɜɨɞɵ ɜ ɤɪɢɫɬɚɥɥɨɝɢɞɪɚɬɚɯ (ɜ %) ɜ ɡɚɜɢɫɢɦɨɫɬɢ ɨɬ ɬɢɩɚ ɤɨɨɪɞɢɧɚɰɢɢ H-ɫɜɹɡɹɦɢ (D -ɩɪɨɬɨɧɨɞɨɧɨɪɧɚɹ, A -ɩɪɨɬɨɧɨɚɤɰɟɩɬɨɪɧɚɹ H-ɫɜɹɡɶ) [ 34 ] Ɋɢɫ. 6. Ɇɨɥɟɤɭɥɚ E-ɰɢɤɥɨɞɟɤɫɬɪɢɧɚ ɧɨɣ ɩɥɨɬɧɨɫɬɢ ɭɩɚɤɨɜɤɢ), ɤɨɧɤɭɪɢɪɭɸɳɟɟ ɫ ɬɟɧɞɟɧɰɢɟɣ ɤ ɨɛɪɚɡɨɜɚɧɢɸ ɪɟɝɭɥɹɪɧɵɯ ɦɨɬɢɜɨɜ ɢɡ ɧɚɫɵɳɟɧɧɵɯ H-ɫɜɹɡɟɣ.…”

“…ɋɱɢɬɚɟɬɫɹ [ 5 ], ɱɬɨ ɱɚɫɬɢɰɚɦɢ ɥɶɞɚ ɩɟɪɢɫɬɵɯ ɨɛɥɚɤɨɜ ɜ ɜɟɪɯɧɟɦ ɫɥɨɟ ɬɪɨɩɨɫɮɟɪɵ ɡɚɯɜɚɬɵɜɚɸɬɫɹ ɦɨɥɟɤɭɥɵ ɥɟɬɭɱɢɯ ɨɪɝɚɧɢɱɟɫɤɢɯ ɫɨɟɞɢɧɟɧɢɣ ɫ ɨɛɪɚɡɨɜɚɧɢɟɦ ɤɪɢɫɬɚɥɥɨɝɢɞɪɚɬɨɜ. Ʉɢɧɟɬɢɱɟɫɤɢɟ ɤɪɢɜɵɟ ɚɞɫɨɪɛɰɢɢ, ɩɨɫɬɪɨɟɧɧɵɟ ɩɨ ɞɚɧɧɵɦ ɦɚɫɫ-ɫɩɟɤɬɪɨɦɟɬɪɢɢ ɜ ɩɪɨ-ɬɨɱɧɨɦ ɪɟɚɤɬɨɪɟ, ɩɨɞɬɜɟɪɞɢɥɢ ɩɨɝɥɨɳɟɧɢɟ ɥɶɞɨɦ ɭɤɫɭɫɧɨɣ ɤɢɫɥɨɬɵ (ɤɨɬɨɪɚɹ ɩɪɟɨɛɥɚɞɚɟɬ ɜ ɚɬɦɨɫɮɟɪɟ ɫɪɟɞɢ ɥɟɬɭɱɢɯ ɨɪɝɚɧɢɱɟɫɤɢɯ ɫɨɟɞɢɧɟɧɢɣ ɢ ɭɱɚɫɬɜɭɟɬ ɜ ɮɨɬɨɯɢɦɢɱɟɫɤɨɦ ɰɢɤɥɟ ɨɡɨɧɚ) [ 6 ], ɚ ɬɚɤɠɟ ɫɩɢɪɬɨɜ ɢ ɤɚɪɛɨɧɢɥɶɧɵɯ ɫɨɟɞɢɧɟɧɢɣ (ɷɬɚɧɨɥ, ɚɰɟɬɨɧ, ɯɥɨɪɚɥɶ) [ 7 ]. ɉɨɷɬɨɦɭ ɬɚɤ ɧɚɡɵɜɚɟɦɵɟ ɦɚɥɵɟ ɝɚɡɨɜɵɟ ɩɪɢɦɟɫɢ ɜ ɚɬɦɨɫɮɟɪɟ ɦɨɝɭɬ ɨɤɚɡɵɜɚɬɶ ɫɭɳɟɫɬɜɟɧɧɨɟ ɜɥɢɹɧɢɟ ɧɚ ɩɚɪɧɢɤɨɜɵɣ ɷɮɮɟɤɬ ɢ ɷɤɨɥɨɝɢɱɟɫɤɭɸ ɨɛɫɬɚɧɨɜɤɭ ɧɚ Ɂɟɦɥɟ ɜ ɰɟɥɨɦ [ 8 ].…”

Producing desired ice faces

“…However, ice on a substrate often has distinctly different properties from those of neat ice; indeed, such ice can even be hydrophobic (4, 5)! (ii) Uptake measurements often use a Knudsen cell with vapordeposited ice on a substrate (6) or compacted, finely divided, artificial snow (7) to arrive at a molecular-level picture for gasparticle interaction despite the irregular, highly variable surfaces used. (iii) Small crystallites can be well characterized but, as highlighted by Libbrecht and Rickerby (8), results can be clouded by competition from nearby crystallites; small faces compete with adjacent faces.…”