第三章 水环境化学.pdf

《环境化学》第三章水环境化学
水环境化学
Aquatic Environmental
Chemistry
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《环境化学》第三章水环境化学
第一节第一节
水的基本特征及污染物存在水的基本特征及污染物存在
形态形态
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H
《环境化学》第三章水环境化学
OO
一、水的特征与分布一、水的特征与分布
HH
1、水分子特性 O
(1)高熔点(melting point)和高沸点(boiling point) H
H
、偶极偶极作用
A - 氢键
B、氢键 H
O
比较项目 CH4 NH3 H2O HF
MP(℃) -192 -78 0 -83
BP(℃) -164 -33 100 20
(2)特殊的密度
ρ气<ρ固<ρ液,4℃时ρH2O最大。
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《环境化学》第三章水环境化学
Property Effects and Significance
Excellent solvent Transport of nutrients and waste products,
making biological processes possible in an
aqueous medium
Highest dielectric constant of mon High solubility of ionic substances and their
liquid ionization in solution
Higher surface tension than any other liquid Controlling factor in physiology, governs drop
and surface phenomena
Transparent to visible and longer-wavelength Colorless, allowing light required for
fraction of ultraviolet light photosynthesis to reach considerable depths in
bodies of water
Maximum density as a liquid at 4 °C Ice floats, vertical circulation restricted in
stratified bodies of water
Higher heat of evaporation than any other Determines transfer of heat and water
material molecules between the atmosphere and bodies
of water
Higher latent heat of fusion than any other Temperature stabilized at the freezing point of
liquid except ammonia water
Higher heat capacity than any other liquid Stabilization of temperatures anisms and
except ammonia geographical region
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《环境化学》第三章水环境化学
2、天然水的分布
储存地存水量(kg) 水的停留时间(year)
海洋 ×1021 37600
冰 ×1019 15000
地下水 ×1018
湖泊 ×1017
大气 ×1016
江河 ×1015 (=12天)
天然水的储量约为1428 ×1018 千克,江河水约占千万分之九,储量
最小,%。%。
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《环境化学》第三章水环境化学
Movement of water vapor
to land, 110
Precipitation condensation
Evaporation
304
Snowpack, ice
Evaporation and 1164
transpiration, 195 Runoff,
110
Precipitation
Lake reservo