کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8911025 | 1637937 | 2018 | 46 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Experimental estimation of the bisulfite isomer quotient as a function of temperature: Implications for sulfur isotope fractionations in aqueous sulfite solutions
ترجمه فارسی عنوان
برآورد تجربی فسیل کننده ایزومر بیسولفیت به عنوان تابعی از درجه حرارت: نتایج برای تجزیه ایزوتوپ های گوگرد در محلول های سولفیت آبی
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کلمات کلیدی
سولفیت، بیسولفیت، طیف سنجی رامان، اثرات ایزوتوپ، کاهش سولفات تخلیه،
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
چکیده انگلیسی
Bisulfite (HSO3â) and sulfite (SO32â) compounds play key roles in numerous geochemical and biochemical processes extending from the atmosphere to the subseafloor biosphere. Despite decades of spectroscopic investigations, the molecular composition of HSO3â in solution remains uncertain and, thus, the role of bisulfite in (bio)chemical and isotope fractionation processes is unclear. We report new experimental estimates for the bisulfite isomer quotient (Qiâ¯=â¯[(HO)SO2â]/[(HS)O3â]; []â¯=â¯concentration) as a function of temperature from the interpretation of Raman spectra collected from aqueous NaHSO3 solutions contained in fused silica capsules. In pure NaHSO3 solutions (1Na+:1HSO3â, stoichiometric) over [NaHSO3]â¯=â¯0.2-0.4â¯m (moles/kg H2O), the following relationship is obtained: ln(Qi)=878.59(±32.98)T-1.9642(±0.1081),where T = 278-358â¯K (5-85â¯Â°C) (based on 50 determinations; additional significant figures are provided to avoid rounding errors). This relationship suggests that the minor isomer, (HS)O3â, may comprise 23-38% (±3%) of the mole fraction of HSO3â over 5-85â¯Â°C, respectively, which is higher in relative abundance than has generally been understood previously. We additionally provide estimates for Qi in NaHSO3 solutions containing a total ionic strength of µâ¯=â¯1.0â¯m (0.2â¯m NaHSO3â¯+â¯0.8â¯m NaCl) and different pH (3.3-4.5), but do not appear to resolve any significant differences in Qi as a function of these additional variables. These new values of Qi are employed to re-assess the bulk sulfur isotope fractionations among bisulfite and other S(IV) compounds as a function of temperature, which appear to be highly dependent on the amount of (HS)O3â present. Our new constraints on the bisulfite isomer quotient may allow for a detailed assessment of the molecular composition and isotope mass balance of S(IV) solutions containing HSO3â, and may be useful in the further investigation of the mechanisms and isotope fractionations associated with a number of processes that involve bisulfite compounds. These may include the intracellular enzymatic transformations of sulfite and bisulfite compounds that occur as part of dissimilatory sulfate reduction, which is a major and geologically important form of anaerobic respiration.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geochimica et Cosmochimica Acta - Volume 220, 1 January 2018, Pages 309-328
Journal: Geochimica et Cosmochimica Acta - Volume 220, 1 January 2018, Pages 309-328
نویسندگان
Daniel L. Eldridge, Bjorn O. Mysen, George D. Cody,