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Environmental Chemistry
Glossary
of Important Terms
Chapters 1 & 2
Ecology
The study of environmental factors that affect
organisms and how organisms interact with these factors and with each other.
Atmosphere
The thin layer of gases that cover Earth’s
surface. Reservoir of gases, moderates Earth’s temperature, absorbs energy and
damaging ultraviolet radiation from the sun, transports energy away from equatorial
regions and serves as a pathway for vapor-phase movement of water in the hydrolic cycle.
Biosphere
Composed of all living entities on Earth.
Geosphere
Consists of the solid earth, including soil, which supports most
plant life.
Lithosphere
The part of the geosphere that is directly involved with
environmental processes through contact with the atmosphere, the hydrosphere, and living
things. Varies from 50 to 100 km in thickness. Consists of outer mantle and crust.
Hydrosphere
Contains the Earth’s water.
Environmental Chemistry
The study of the sources, reactions, transport, effects, and fates
of chemical species in water, soil, and air environments and the effects of technology
thereon.
Ecosystem
Consists of an assembly of mutually interacting organisms and their
environment in which materials are interchanged in a largely cyclical manner.
Pollutant
A substance present in greater than natural concentration as a
result of human n activity that has a net detrimental effect upon its environment or upon
something of value in that environment.
Contaminant
Cause deviations from the normal composition of an environment. Are
not classified as pollutants unless they have some detrimental effect.
Hazardous waste
A potentially dangerous substance that has been discarded,
abandoned, neglected, released or designated as a waste material, or one that may interact
with other substances to pose a threat.
Aquatic Chemistry
The branch of environmental chemistry that deals with chemical
phenomena in water.
Hydrology
The study of water
Limnology
The branch of science dealing with characteristics of freshwater,
including biological properties as well as chemical and physical properties.
Oceanography
The science of the ocean and its physical and chemical
characteristics.
Eutrophication
Relatively high productivity is required for the support of fish.
Excessive productivity can result in choking by weeds and can cause odor problems. The
growth of algae may become quite high in very productive water, with the result that the
concurrent decomposition of dead algae reduces oxygen levels in the water to very low
values.
Dissolved Oxygen (DO)
Frequently the key substance in determining the extent and kinds of
life in a body of water.
Biochemical Oxygen Demand (BOD)
Another important water-quality parameter. It refers to the amount
of oxygen utilized when the organic matter in a given volume of water is degraded
biologically. (Chapter 7)
Dispersion Aerosols
Colloidal-sized particles in the atmosphere formed by grinding up
bulk matter .
Condensation Aerosols
Particles formed from chemical reactions of gases.
Chapter 3
Strong Acid
(release H+ ions) Give up protons easily. ex HCl and H2SO4
Strong Base
Accept and hold proton tightly. ex Hydroxide ion
Weak Acid
Don’t give up protons easily. ex CH3COOH
Weak Base
Have little affinity for a proton. ex Chloride ion
pH
A number between 0 and 14 that describes the acidity of an
aqueous solution. Mathematically, pH is equal to the negative logarithm of a
solution’s H3O+ concentration.
Alkalinity
The capacity of water to accept H+ ions (protons).
Acidity
The capacity of the water to neutralize OH?.
Chapter 4
Nernst Equation
Used to account for the effect of different activities upon
electrode potential.
Chapter 5
Colloidial particles
Particles which have some characteristics of both species in
solution and larger particles in suspension, which range in diameter form about 0.001
micrometer (m m) to about 1m m, and which scatter white light as a light blue hue observed
at right angles to the incident light.
Tyndall effect
The characteristic light scattering phenomenon of colloids results
from their being the same order of size as the wavelength of light.
Hydrophilic colloids
Generally consist of macromolecules, such as proteins and synthetic
polymers, that are characterized by strong interaction with water resulting in spontaneous
formation of colloids when they are placed in water.
Hydrophobic colloids
Interact to a lesser extent with water and are stable because of
their positive or negative electrical charges.
Association colloids
Consist of special aggregates of ions and molecules called micells.
Micells
A spherical cluster formed by the aggregation of soap molecules in
water.
Chapter 6
Bacteria
Single-celled prokaryotic microorganisms that may be shaped as rods
(bacillus), spheres (coccus), or spirals (vibrios, spirilla, spirochetes).
Fungi
Nonphotosynthetic organisms, larger than bacteria, aerobic and can
thrive in more acidic media than bacteria. Important function is the break down of
cellulose in wood and other plant materials.
Protozoa
Microscopic animals consisting of single eukaryotic cells.
Algae
Microscopic organisms that subsist on inorganic nutrients and
produce organic matter from carbon dioxide by photosynthesis.
Virus
Microorganism...
Prokaryotes
Microorganisms that lack a nuclear membrane so that their nuclear
genetic material is more diffuse in the cell.
Eurkaryotes
Have well defined cell nuclei enclosed by a nuclear membrane.
Producers
Utilize light energy and store it as chemical energy.
Reducers
Break down chemical compounds to more simple species and thereby
extract the energy needed for their growth and metabolism
Chemotrophs
Use chemical energy derived from oxidation-reduction reactions for
their energy needs.
Phototrophs
Utilized light energy from photosynthesis.
Autotrophs
Use carbon dioxide and ionic carbonates for the C that they
require.
Heterotrophs
Obtain their carbon from other organisms.
Chapter 7
Classes of Water Pollutants
| Class of Pollutant |
Significance |
Trace elements
Heavy metals
Organically-bound metals |
Health, aquatic biota
Health, aquatic biota
Metal transport |
| Radionuclides |
Toxicity |
Inorganic pollutants
Asbestos
Algal nutrients
Acidity, alkalinity, salinity
(in excess) |
Toxicity, aquatic biota
Human health
Eutrophication
Water quality, aquatic life |
Trace organic pollutants
Polychlorinated biphenyls
Pesticides
Petroleum wastes |
Toxicity
Possible biological effects
Toxicity, aquatic biota, wildlife
Effect on wildlife, esthetics |
Sewage, human, animals’ wastes
Biochemical oxygen demand
Pathogens
Detergents |
Water quality, oxygen levels
Water quality, oxygen levels
Health effects
Eutrophication, wildlife, esthetics |
| Chemical carcinogens |
Incidence of cancer |
| Sediments |
Water quality, aquatic biota, wildlife |
| Taste, odor, and color |
Esthetics |
Chapter 8
Methods to treat waste water
Municipal water treatment
Treatment of water for industrial use
Sewage Treatment
Primary treatment
Consists of the removal of insoluble matter such
as grit, grease, and scum from water. Process involves screening and
solids are scraped off and disposed of.
Grit Removal
Practiced to prevent grit accumulation in other
parts of the treatment system, to reduce clogging of pipes and other
parts, and to protect moving parts from abrasion and wear. Process involves
allowing the grit to settle in a tank under conditions of low velocity
and then it is scraped mechanically from the bottom of the tank.
Primary sedimentation
Removes both settleable and floatable solids. Tendency
for particles to aggregate, sometimes aided by the addition of chemicals.
Secondary treatment
Designed to remove BOD, usually by taking advantage
of the same kind of biological processes that would other wise consume
oxygen in water receiving the wastewater. Microorganisms provided with
added oxygen are allowed to degrade organic material in solution or
in suspension until the BOD of the waste has been reduced to acceptable
levels.
Trickling filter
One of the simplest biological waste treatment
processes. Wastewater is sprayed over rocks or other solid support material
covered with microorganisms. The structure of the trickling filter is
such that contact of the wastewater with air is allowed and degradation
of organic matter occurs by the action of the microorganisms.
Activated Sludge Process
Probably the most versatile and effective of all
waste treatment processes.
Chapter 9
Atmosphere
Two major components
Nitrogen 78.08%
Oxygen 20.955
Two minor components
Argon 0.934%
Carbon dioxide 0.035%
Four more noble gases
Neon 1.818 x 10-3%
Krypton 1.14 x 10-4%
Helium 5.24 x 10-4%
Xenon 8.7 x 10-6%
Atmospheric air may contain 0.1 to 5% water by
volume, with a normal range of 1 to 3%.
Protective, from atmosphere
Source of Carbon Dioxide for plant photosynthesis
and oxygen for respiration
It absorbs most of the cosmic rays from outer
space
It absorbs most electromagnetic radiation from
the sun, filtering out damaging ultraviolet radiation
Reabsorbs infrared radiation
Stabilizes Earth’s temperature
Scale height equation
Ph = POe-Mgh/RT
Solar flux
Energy received at the surface of the outer atmosphere,
(also called insolation) = 1.34 x 103
w/m2
Inversions
Conditions characterized by high atmospheric stability.
They limit the vertical circulation of air, resulting in air stagnation
and the trapping of air pollutants in localized areas.
Microclimates
Highly localized climatic conditions. The climate
that organisms and objects on the surface are exposed to close to ground,
under rocks, and surrounded by vegetation and it often quite different
form the surrounding macroclimate.
Atmosphere
The thin layer of mixed gases covering the earth's surface.
Stratosphere
The portion of the earth's atmosphere between approximately
15 km and 50 km in altitude where ozone is formed by the reaction of ultraviolet
light on dioxygen molecules.
Troposphere
The portion of the earth's atmosphere that is closest
to the earth's surface (from 0 to 15 km in altitude).
Mesosphere
The portion of the earth's
atmosphere between approximately 50 and 85 km, where molecules exist
as charged ions caused by interaction of gas molecules with intense
UV light.
Chapter 10
Atmospheric particles (Table
10.1)
Aerosol
Colloidal-sized atmospheric particle.
Condensation aerosol
Formed by condensation of vapors or reactions of
gases.
Dispersion aerosol
Formed by grinding of solids, atomization of liquids,
or dispersion of dusts.
Fog
Term denoting high level of water droplets.
Haze
Denotes decreased visibility due to the presence
of particles
Mists
Liquid particles
Smoke
Particles formed by incomplete combustion of fuel
Stoke’s Law
Chapter 11
Sulfur Cycle (Figure 11.1)
Fate of CO in the Atmosphere
Rxs of sulfur dioxide conversion
Major
Stack Gas Scrubbing Systems*
| Process |
Chemical
Reactions |
Major
Advantages or Disadvantages |
Lime
slurry
scrubbing** |
 |
Up
to 200 kg of lime are needed per metric ton of coal, producing huge
quantities of waste product. |
Limestone
slurry
scrubbing** |
 |
Lower
pH than lime slurry, not so efficient. |
Magnesium
oxide scrubbing |
 |
The
sorbent can be regenerated, off site, if desired. |
Sodium-
base
scrubbing |
 |
No
major technological limitations. Relatively high annual costs. |
| Double
alkali** |
 |
Allows
for regeneration of expensive sodium alkali solution with inexpensive
lime. |
*For details regarding these and more advanced processes,
see (1) Satriana, M., New
Developments in Flue Gas Desulfurization Technology, Noyes Data Corp.,
Park Ridge, NJ, 1982, and (2) Takeshita, M. and H. Soud, FGD Performance
and Experience on Coal-Fired Plants, Gemini House, London, 1993.
**These processes have also been adapted to produce a gypsum product by
oxidation of CaSO3 in the spent scrubber medium:
CaSO3 + ½O2 + 2 H2O ? CaSO4 · 2 H2O(s)
Gypsum has some commercial value, such as in the manufacture
of plasterboard, and makes a relatively settleable waste product.
Removal Technologies (Table 11.1)
Three Oxides of Nitrogen
Chapter 12
Know structures
CFC-11
CFC-12
TCE
hexachlorobenxene
Halon-1211
Halon-1301
polychlorinated dibenzo-p-dioxins
polychlorinated dibenzofurans
Chapter 13
Generalized Reaction Scheme for
Photochemical Smog Formation
Chapter 14
Global warming
Acid Rain
Precipitation made acidic by the presence of acids
stronger than CO2(aq).
Ozone Layer destruction
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