کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4440041 1311043 2011 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Henry’s law constant measurements for formaldehyde and benzaldehyde as a function of temperature and water composition
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علم هواشناسی
پیش نمایش صفحه اول مقاله
Henry’s law constant measurements for formaldehyde and benzaldehyde as a function of temperature and water composition
چکیده انگلیسی

Henry’s law constants H of formaldehyde and benzaldehyde were determined using a dynamic system based on the water/air equilibrium at the interface within the length of a microporous tube. The measurements were conducted over the range 273–293 K in (i) deionized water, (ii) 35 g L−1 solution of NaCl simulating seawater and (iii) two nitric acid solutions, i.e. 0.63 and 6.3 wt%.In pure water, the obtained data were used to derive the following Arrhenius expressions: ln H = (6423 ± 542)/T − (13.4 ± 2.0) and ln H = (6258 ± 280)/T − (17.5 ± 1.0) for formaldehyde and benzaldehyde, respectively. The H values, calculated at 293 K from Arrhenius expressions cited above were the following (in units of M atm−1): H = 5020 ± 1170 (formaldehyde), H = 47 ± 5 (benzaldehyde). The temperature dependence of H permits then to derive the solvation enthalpies for both compounds: ΔHsolv = −(53.4 ± 4.5) kJ mol−1 and ΔHsolv = −(52.0 ± 2.3) kJ mol−1 for formaldehyde and benzaldehyde, respectively.In 35 g L−1 salt solution, the H values were 27–66% and 12–21% lower than their respective determinations in deionized water, for formaldehyde and benzaldehyde respectively. The observed salt effect was used to estimate the following Setschenow coefficients at 293 K for 0.6 M NaCl: formaldehyde (0.21) and benzaldehyde (0.09).In 6.3 wt% nitric acid solution, H values of benzaldehyde were approximately 30% higher than those found in pure water although no significant influence was observed for formaldehyde.Finally, our experimental data were then used to estimate the fractions of formaldehyde and benzaldehyde in atmospheric aqueous phase and their derived atmospheric lifetimes.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Atmospheric Environment - Volume 45, Issue 17, June 2011, Pages 2991–2998
نویسندگان
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