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Environmental Chemistry Complete Notes..

Environmental Chemistry Environmental chemistry: It is the branch of chemistry that deals with the study of various chemical processes taking place in the various segments of the environment. Broadly speaking, it is the study of the sources, transportation, reactions, effects and the ultimate of the chemical species occurring in one or more segments of the environment. Components of Environment : Atmosphere:   This comprises a blanket of gaseous layer around earth. Hydrosphere :  This comprises about 96% of earth’s surface & includes all   sources of water like oceans rivers lakes, glaciers, ground water etc. Lithosphere :  It refers to earth’s solid crust containing the outer mineral cover. It comprises soil, minerals, organic matter etc.  Biosphere:   It refers to the domain of living organism in covalent with atmosphere hydrosphere as well as lithosphere.    Environmental pollution...
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Degradable Plastics


All plastics are polymers, long molecules made of repeating units. Because polymers are extremely stable, they resist reaction. Most conventional plastics require hundreds or even thousands of years to break down.

 Degradable plastics are an important step forward in technology. These new plastics can break down in a relatively short time—within six months to a year. 

 There are two main kinds of degradable plastics:
(1) biodegradable plastics and (2) photodegradable plastics. 

 (1.) Biodegradable plastics:-
These plastics are susceptible to decay processes that are similar to the decay processes of natural objects, such as plants. 

 (2.) Photodegradable plastics:-
These plastics are disintegrate when they are exposed to certain wavelengths of light. The ability of a degradable plastic to decay depends on the structure of its polymer chain.
Biodegradable plastics are often manufactured from natural polymers, such as cornstarch and wheat gluten. Micro-organisms in the soil can break down these natural polymers. Ideally, a biodegradable plastic would break down completely into carbon dioxide, water, and biomass within six months, just like a natural material.
Photodegradable plastic is a Canadian contribution to the environmental health of the planet. It was developed in Canada more than 25 years ago by Dr. James Guillet, of the University of Toronto. 
This plastic incorporates light-absorbing, or chromomorphic, molecular groups as part of its
backbone chain. The chromomorphic groups change their structure when they are exposed to
particular frequencies of light (usually ultraviolet).
The structural changes in these groups cause the backbone to break apart. Although the
photodegradable process is not very effective at the bottom of a landfill, it is ideally suited to
the marine environment. Plastics that are discarded in oceans and lakes usually float at the surface,
and thus are exposed to light. The rings that are used to package canned drinks can strangle marine wildlife. These rings are now made with photodegradable technology in many countries.
Several nations are conducting further research into other marine uses for this technology...

 Thank You..
Anjani kumar Singh.

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