Chuong gioi thieu (phan 1) ppt

Back to the Sun for Energy, Fuel, and Raw Materials • Direct use for solar heating and solar voltaic power generation • Indirect use for wind, biomass, hydroelectric solar-powered hydr

THE ENVIRONMENT AND SUSTAINABILITY SCIENCE

Environmental Chemistry, 9th Edition

Stanley E Manahan Taylor and Francis/CRC Press

2010

1.1 From the Sun to Fossil Fuels and

Back Again

Early 2000s have shown evidence of strain on

Earth's support systems

Shortages and high prices for fuel and

materials in early 2008

• Leading to economic collapse

Evidence of global warming

• Glaciers melting

• Loss of Arctic ice cap

Stress and depletion of Earth's natural capital

• Agricultural land depleted

• Water sources limited

• Wildlife habitat lost

2

The Brief But Spectacular Era of Fossil

Fuels

• Began with coal in latter 1700s

• Coal-fired steam engine as a source of power

• Progressed to petroleum and natural gas

• Petroleum supplies will become exhausted within

decades

• New supplies of natural gas are being found

• Natural gas is an ideal fossil fuel for many applications

• Not all coal can be used because of global warming

potential

Relative to the time of human life on Earth, the

era of fossil fuels must soon end

• How it ends and what replaces it will largely determine the welfare of humankind for centuries to come

Back to the Sun for Energy, Fuel, and

Raw Materials

• Direct use for solar heating and solar voltaic power

generation

• Indirect use for wind, biomass, hydroelectric

(solar-powered hydrologic cycle)

Photosynthetically-Produced Biomass

for Synthetic fuels

• Fermentation of sugars to ethanol

• Chemical conversion of lipids to synthetic diesel fuel

• Chemical conversion of biomass to CO and H 2 followed

by chemical synthesis of hydrocarbons and alcohols

Several abundant sources of biomass

• Crop byproducts such as corn stover

• Dedicated crops such as hybrid poplar or corn stover

• Highly productive algae, which may even be grown in

brackish water

1.2 The Science of Sustainability

Sustainability or sustainable development is an economic and industrial system that meets the needs of the present without compromising the

ability of future generations to meet their own needs (Bruntland

Commission 1987)

• Maintenance of Earth’s ability to maintain an acceptable level of

human activity and consumption over a sustained period of time.

Nobel-level breakthroughs required to achieve sustainability (Chu,

2009)

1 Solar energy capture and conversion to electricity to improve

several-fold

2 Improved electric batteries

• Capture and store electricity from intermittent renewable sources

• Practical driving range in electric vehicles

3 Improved crops to convert more solar energy to biomass chemical

energy

• Now less than 1%

• Genetic engineering should improve several-fold

Environmental Science

The science of the complex interactions that occur

among the terrestrial, atmospheric, aquatic, living, and

anthropological systems that compose Earth and the

surroundings that may affect living things

Green Science and Technology

The practice of sustainable science and technology

Green Chemistry

The practice of inherently safer and more

environmentally friendly chemical science

Green Engineering

Engineering practiced in a sustainable and

environmentally friendly manner

Environmental chemistry has developed as

a positive force for a clean environment

• Revealing problems such as by pollutant

analysis

• Measures to control pollution

• Foreseeing problems before they develop

• Appropriate action to forestall environmental problems

•Support of other disciplines such as industrial ecology and green chemistry employed in

environmental improvement

chemical nature of substances to their adverse

effects on organisms

1.4 WATER, AIR, EARTH, LIFE, AND

TECHNOLOGY

Much of environmental chemistry deals with

the interchange of materials among water, air,

earth, and biological systems and the effects of technology thereon

See Figure 1.2 (next slide)

interchange of matter and energy among the

various environmental spheres

• Effects of organisms

• Effects of humans (technology)

Water and the Hydrosphere

•Covers 70% of Earth’s surface

•97% in oceans

•Most remaining fresh water in ice

Water plays essential roles in all

environmental spheres

•Essential to life

•Transfers plant nutrients from soil to roots

•Dissolves minerals and forms deposits in the

geosphere

•Transfer of water and energy in the

atmosphere

•Many industrial uses and transfer of energy

(latent heat in steam) in the anthrosphere

Air and the Atmosphere

•Source of essential gases

• Oxygen for animals and other organisms

• Carbon dioxide for plant photosynthesis

• Nitrogen converted to chemically

combined form as a plant nutrient

• Oxygen, nitrogen and argon for industrial

uses

•Protective functions

• Filters out damaging ultraviolet radiation

• Regulates Earth’s surface temperature

within a range compatible with life

Aspects of Atmospheric Science

•Movement of air masses

•Heat balance

•Chemical properties and reactions

Earth: The Geosphere

Solid iron-rich inner core/molten outer

core/mantle/crust

Crust is Earth’s thin outer skin (5-40 km thick)

•Interacts with other spheres

•Provides life support, food, minerals, fuels

Geology is the science of the geosphere

•Considers mineral solids

•Interaction with water

•Interaction with atmosphere

•Effects upon and by living organisms

•Engineering geology considers human

interactions with and modifications of the

geosphere

The Biosphere: Living Organisms

Biology is the science of life

•Deals largely with macromolecules

synthesized by organisms

•Ultimate environmental concern is interaction with life

•Toxic substances in the environment affect

organisms including humans

•Environmental biodegradation of toxic

substances

Technology and the Environment

•Ways in which humans do and make things

with materials and energy

•How humans construct and operate the

anthrosphere

•Product of engineering based on science

Challenge is to integrate technology with

considerations of the environment and ecology

•Properly applied technology can benefit the

environment

•Pollution control technology

•Constructed environmental features such as

artificial wetlands

•Efficient energy conversion processes

•Renewable energy resource utilization

•Production of goods with minimum waste

•High-speed, minimally polluting

transportation systems

1.5ECOLOGY, ECOTOXICOLOGY, AND THE BIOSPHERE

The biosphere is in a thin layer at the interface of the

atmosphere with the geosphere and hydrosphere

Strong mutual interactions between organisms and the

other environmental spheres

• Earth’s oxygen produced by organisms

• Atmospheric CO 2 removed by photosynthesis

• Biological processes largely determine aquatic

chemistry

• Geospheric rocks weathered by organisms

Sequestering solar energy and carbon as biomass,

represented {CH 2 O}, by photosynthesis:

• CO 2 + H 2O + hn ® {CH 2 O} + O 2

Biodegradation of biomass by organisms:

• CO 2 + H 2O + hn ® {CH 2 O} + O 2

Deals with the relationships between living

organisms with their physical environment and with each other

Ecosystem

Group of organisms interacting to mutual

advantage and with their environment

• Cycles of material in ecosystems

• An organism lives in its habitat in the

environment

• The role it plays is its niche

A population consists of the numbers of a

particular species in a habitat

Toxicology refers to the detrimental effects of

poisonous chemical species (toxicants) on

organisms

Ecotoxicology refers to the detrimental effects

of toxicants on ecosystems

•At several levels ranging from biological

effects to effects upon whole populations

1.6 ENERGY AND CYCLES OF ENERGY

Earth receives solar energy at 1,340

watts/meter 2 at the top of the atmosphere

• Enormous amount of incoming energy largely

in visible region of the electromagnetic

spectrum

•Must re-radiate this energy to outer space as

longer-wavelength infrared radiation

Light and Electromagnetic Radiation

Electromagnetic radiation carries energy

through space at 3.00 x 10 8 meters/second (c,

speed of light)

In order of shortest wavelength (more

energetic) to longer wavelength (less

energetic):

• gamma>X-rays>ultraviolet>visible>infrared

Characteristics of wavelength (l, , meters),

amplitude, and frequency (n, s -1 or Hertz)

• nl, = c

Energy: E = hn where h is Planck’s constant

Dual wave/particle nature of electromagnetic

radiation

Energy Flow and Photosynthesis in

Living Systems

Figure 1.3 Energy conversion and transfer by

photosynthesis

1.7 HUMAN IMPACT AND POLLUTION

Pollutant: Substance in greater than natural

concentration that is detrimental

Contaminants cause deviations from normal

concentration but are not pollutants unless

they have adverse effects

Interchanges of contaminants released from the anthrosphere among

various segments of the other environmental spheres and illustrations of

pathways involved in chemical fate and transport

Fate and transport of contaminants

controlled largely by

•Physical transport: Movement without reacting

or interacting with other phases

•Reactivity: Including chemical or biochemical

reactions or physical interactions with other

phases

Three Major Environmental

Compartments Considered in Chemical

Fate and Transport

Physical Transport

(1) Advection: Movement of masses of fluid

that simply carry pollutants with them

• Vertical advection of air or water is called

convection

the natural tendency of molecules to move

from regions of higher to lower

concentrations

• Also called Fickian transport

• Approximated by turbulent mixing such as

in flowing water

• Chemical reactions

• Biological uptake

• Binding to and release from surfaces

Two broad categories of reactivity

Relationship for a Pollutant with Respect

to a Specified Compartment of the

Environment

Steady state applies when there is not net

change of mass of pollutant within the control

volume

Distribution Among Phases

• Partitioning between major compartments

• Partitioning between phases within a

compartment

•Partitioning between water and a solid

depends upon a substances solubility or

hydrophilicity

•Partitioning between water and air depends

upon vapor pressure

Sorption

•Adsorption onto material surface

•Absorption within body of material

1.9 CHEMICAL FATE AND TRANSPORT IN

THE ATMOSPHERE, HYDROSPHERE, AND

GEOSPHERE

Pollutants in the Atmosphere

• Volatile organic compounds transported in

atmosphere

• Partitioning between air and atmospheric

particles

Pollutants in the Hydrosphere

• More hydrophilic compounds tend to stay in

water

•Soil water partition coefficient, K d ,

where C s and C w are concentrations

on solids and in water, respectively

•Partitioning of organics onto solids depends

upon organic fraction of solids

Pollutants in the Geosphere

•Transport of contaminants depends upon

porosity, nature of geospheric solids, nature of contaminants

1.10 ENVIRONMENTAL MISCHIEF AND

TERRORISM

Chemistry can be used for harmful acts

• Explosives, corrosives, and otherwise

damaging substances

• Toxic substances

Chemistry can be used to combat terrorism

• Instruments to detect harmful substances

• Protective materials

Some environmental incidents have resembled

terrorist attacks

•1984 Bhopal, India, release of methyl

isocyanate that killed 3,500

•2003 release of toxic hydrogen sulfide with

natural gas that killed over 200 in China

Measures that are good practice of

environmental chemistry tend to reduce

terrorist threats

Protection Through Green Chemistry and Engineering

Green chemistry is safe and sustainable

chemistry

• Avoids hazards that can be used to do harm

• Reduces vulnerability such as interruption of

materials supplies

• Avoids use, generation, or storage of hazardous substances

• Avoids severe conditions that may pose hazards

• Carefully monitor conditions for trouble

1.11 ENVIRONMENTAL FORENSICS

Environmental forensics deals with the legal and

medical aspects of pollution

Important in several areas

• Health effects

• Legal liabilities

• Determining responsibilities for terrorist

attacks

• Assessment of hazardous waste sites

• Suitability of sites for brownfields restoration

Important aspects regarding environmental

incidents

• Source • Timing • Extent