酸雨的形成--水滴中的催化氧化SO / 2 反应

Roger J. CHENG 鄭均華

纽约州立大学，大气科学研究中心 郑均华研究员主持的科研项目

• ATMOSPHERIC SCIENCES RESEARCH CENTER
• STATE UNIVERSITY of NEW YORK

环境中的微观世界 工业污染、酸雨形成及生态环境影响 ● 通过开展显微镜测量，具体形象的揭示了工业污染排放的二氧化硫及其界面氧化反应 ● 在酸雨形成过程中的主要特征以及它们在建筑腐蚀、植被灼烧等方面的生态环境影响。 纽约州立大学，大气科学研究中心 郑均华研究员主持的科研项目 INDUSTRIAL EMISSION, ACID RAIN FORMATION and their EFFECT on OUR ENVIRONMENT ● Microscopically Examination, by Atmospheric Scientist- Roger J. CHENG of ASRC- (Atmospheric Sciences Research Center)- SUNYA,(State University of New York at Albany) illustrated   ● the characterization of industrial emission, catalytic oxidation of SO/2 in the formation of acid rain drop, and their ecological effects ----( building erosion & leaf damage) on our environment.

• ---- A LABORATORY OBSERVATION

• The INTERNATIONAL CONFERENCE on GLOBAL & REGIONAL
• ENVIRONMENTAL ATMOSPHERIC CHEMISTRY
• CHINA 1989

Industrial particulates and sub-microcrystals of sulfates have been positively identified from field samples of acid precipitations (cloud, fog and rain droplets). Laboratory experiments confirmed that gaseous SO/2 absorbed by water droplets when contaminated by a few fine particulates of flyash from coal combustion, could be converted to sulfuric acid. The oxidation rate of H/2SO/3 to H/2SO/4 in aqueous solutions was investigated under three different conditions via titrimetric and turbidimetric methods. The resulting turbidity was determined by a UV-spectrophotometer (420 nm) and compared to a curve prepared from standard sulfate solution. Without flyash present in a solution of H2/SO3 only 8% of [SO/4] is generated after 24 hours. In the presence of flyash obtained from a coal-fired power plant, the conversion Increases to 13%. However, a much large effect appears when flyash from oil-fired power plant exist. The conversion reaches 32% and is four times that of the system without flyash. The oxidation is a fast process and most [SO/3] changes to [SO/4] in 3-4 hours.

Formation of acid precipitations in the atmosphere has been suggested primarily as a result of the oxidation of SO/2 by photochemical processes in the gas phase and by homogeneous reaction in solution. But these mechanisms cannot explain the observed high concentration of sulfates in the atmosphere. It is hypothesized here that the formation of acid precipitation in the atmosphere is also due to heterogeneous reaction of catalytic SO/2 oxidation on the surface of industrial particulates inside cloud droplets. Heterogeneous catalysts, such as carbon, vanadium, manganese and iron associated with the surface of particulates generated by electric power plants burning fossil fuels (especially coal); contribute to the complex surface chemical interactions which result in the formation of acid droplets and sulfate crystals.

Characterization of industrial particulates and sulfate aerosols from field samples collected from ASRC Whiteface Mountain Research Station in the Adirondack region of New York State, the chemical processes of catalytic SO/2 oxidation inside microscopic droplets and the effect of acid precipitation on our environment are presented with illustrations.

• The INTERNATIONAL CONFERENCE on GLOBAL & REGIONAL
• ENVIRONMENTAL ATMOSPHERIC CHEMISTRY
• MAY 3-10, 1989, BEIJING, CHINA

• CATALYTIC REACTIVITY
  of AIRBORNE PARTICULATE MATERIAL
  CONF. on CARBONACEOUS PARTICLES in the ATMOSPNERE
• by NATIONAL SCIENCE FOUNDATION and LAWRENCE BERKELEY LAB.
• MARCH-1978-BERKELEY, CALIFORNIA

• 

• FORMATION of ACID DROPLETS: HETEROGENEOUS SO/2 OXIDATION Roger J. CHENG --鄭均華 ASRC UNIVERSITY at ALBANY SUNY 纽约州立大学，大气科学研究中心 郑均华研究员主持的科研项目 Atmospheric Sciences Research Center State University of New York

• ACID DROPLET PROJECT: PUBLICATIONS:
• Roger J. CHENG, ASRC UNIVERSITY at ALBANY SUNY
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