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  • From: "Lawrence F. London, Jr." <venaurafarm@bellsouth.net>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: [permaculture] Ions & agriculture and permaculture. Fwd: Re: [soilandhealth] Re: Cuba.... was potting soil/organic fertilizers
  • Date: Wed, 17 Aug 2011 23:24:51 -0400


http://en.wikipedia.org/wiki/Ion
Ion
From Wikipedia, the free encyclopedia
"Cation" and "Anion" redirect here."
"An ion is an atom or molecule in which the total number of electrons is
not equal to the total number of protons, giving it a net positive or
negative electrical charge. The name was given by physicist Michael
Faraday for the substances that allow a current to pass ("go") between
electrodes in a solution, when an electric field is applied. It is from
Greek ιον, meaning "going."

"An ion consisting of a single atom is an atomic or monatomic ion; if it
consists of two or more atoms, it is a molecular or polyatomic ion."

"Anions and Cations"

"An anion (-) (pronounced /ˈæn.aɪ.ən/ an-eye-ən), from the Greek word
ἄνω (ánō), meaning "up", is an ion with more electrons than protons,
giving it a net negative charge (since electrons are negatively charged
and protons are positively charged).

Conversely, a cation (+) (pronounced /ˈkæt.aɪ.ən/ kat-eye-ən), from the
Greek word κατά (katá), meaning "down", is an ion with fewer electrons
than protons, giving it a positive charge. Since the charge on a proton
is equal in magnitude to the charge on an electron, the net charge on an
ion is equal to the number of protons in the ion minus the number of
electrons."

"Characteristics

Ions in their gas-like state are highly reactive, and do not occur in
large amounts on Earth, except in flames, lightning, electrical sparks,
and other plasmas. These gas-like ions rapidly interact with ions of
opposite charge to give neutral molecules or ionic salts. Ions are also
produced in the liquid or solid state when salts interact with solvents
(for example, water) to produce "solvated ions," which are more stable,
for reasons involving a combination of energy and entropy changes as the
ions move away from each other to interact with the liquid. These
stabilized species are more commonly found in the environment at low
temperatures. A common example is the ions present in seawater, which
are derived from the dissolved salts there.

All ions are charged, which means that like all charged objects they are:

* attracted to opposite electric charges (positive to negative, and
vice versa),
* repelled by like charges, and
* when moving, travel in trajectories that are deflected by a magnetic
field.

Electrons, due to their smaller mass and thus larger space-filling
properties as matter waves, determine the size of atoms and molecules
that possess any electrons at all. Thus, anions (negatively charged
ions) are larger than the parent molecule or atom, as the excess
electron(s) repel each other, and add to the physical size of the ion,
because its size is determined by its electron cloud. Conversely,
cations are generally smaller than the corresponding parent atom or
molecule, for the same reason. One particular cation (that of hydrogen)
contains no electrons, and thus is very much smaller than the parent
hydrogen atom.
[edit] Natural Occurrences

Ions are ubiquitous in nature and are responsible for diverse phenomena
from the luminescence of the Sun, and the existence of ionosphere on
Earth. Atoms in their ionic state may have a different color from
neutral atoms, and thus light absorption by metal ions gives the color
of gemstones. In both inorganic and organic chemistry (including
biochemistry), the interaction of water and ions is extremely important
(an example is the energy that drives breakdown of ATP. The following
sections describe contexts in which ions feature prominently and are
arranged in decreasing physical length-scale, from the astronomical to
the microscopic."

<>
ABSORPTION
http://en.wikipedia.org/wiki/Absorption
Absorption (chemistry), absorption of particles of gas or liquid in
liquid or solid material

http://en.wikipedia.org/wiki/Absorption_%28chemistry%29
Sorption
From Wikipedia, the free encyclopedia
(Redirected from Absorption (chemistry))
Look up sorption in Wiktionary, the free dictionary.

Sorption refers to the action of absorption or adsorption:

Absorption is the incorporation of a substance in one state into
another of a different state (e.g., liquids being absorbed by a solid or
gases being absorbed by a liquid).
Adsorption is the physical adherence or bonding of ions and
molecules onto the surface of another phase (e.g., reagents adsorbed to
solid catalyst surface).

<>
ADSORPTION
http://en.wikipedia.org/wiki/Adsorption
Adsorption
From Wikipedia, the free encyclopedia
Not to be confused with Absorption.
Adsorption is the adhesion of atoms, ions, biomolecules or molecules of
gas, liquid, or dissolved solids to a surface.[1] This process creates a
film of the adsorbate (the molecules or atoms being accumulated) on the
surface of the adsorbent. It differs from absorption, in which a fluid
permeates or is dissolved by a liquid or solid.[2] The term sorption
encompasses both processes, while desorption is the reverse of
adsorption. It is a surface phenomenon.

Similar to surface tension, adsorption is a consequence of surface
energy. In a bulk material, all the bonding requirements (be they ionic,
covalent, or metallic) of the constituent atoms of the material are
filled by other atoms in the material. However, atoms on the surface of
the adsorbent are not wholly surrounded by other adsorbent atoms and
therefore can attract adsorbates. The exact nature of the bonding
depends on the details of the species involved, but the adsorption
process is generally classified as physisorption (characteristic of weak
van der Waals forces) or chemisorption (characteristic of covalent
bonding). It may also occur due to electrostatic attraction.[3]

Adsorption is present in many natural physical, biological, and chemical
systems, and is widely used in industrial applications such as activated
charcoal, capturing and using waste heat to provide cold water for air
conditioning and other process requirements (adsorption chillers),
synthetic resins, increase storage capacity of carbide-derived carbons
for tunable nanoporous carbon, and water purification. Adsorption, ion
exchange, and chromatography are sorption processes in which certain
adsorbates are selectively transferred from the fluid phase to the
surface of insoluble, rigid particles suspended in a vessel or packed in
a column.

+

Isotherms

Adsorption is usually described through isotherms, that is, the amount
of adsorbate on the adsorbent as a function of its pressure (if gas) or
concentration (if liquid) at constant temperature. The quantity adsorbed
is nearly always normalized by the mass of the adsorbent to allow
comparison of different materials.

+

Adsorbents
Characteristics and general requirements
Activated carbon is used as an adsorbent

Adsorbents are used usually in the form of spherical pellets, rods,
moldings, or monoliths with hydrodynamic diameters between 0.5 and 10
mm. They must have high abrasion resistance, high thermal stability and
small pore diameters, which results in higher exposed surface area and
hence high surface capacity for adsorption. The adsorbents must also
have a distinct pore structure which enables fast transport of the
gaseous vapors.

Most industrial adsorbents fall into one of three classes:

Oxygen-containing compounds – Are typically hydrophilic and polar,
including materials such as silica gel and zeolites.
Carbon-based compounds – Are typically hydrophobic and non-polar,
including materials such as activated carbon and graphite.
Polymer-based compounds - Are polar or non-polar functional groups
in a porous polymer matrix.

+

Activated carbon

Activated carbon is a highly porous, amorphous solid consisting of
microcrystallites with a graphite lattice, usually prepared in small
pellets or a powder. It is non-polar and cheap. One of its main
drawbacks is that it is reacts with oxygen at moderate temperatures
(over 300 °C).
Activated carbon nitrogen isotherm showing a marked microporous type I
behavior

Activated carbon can be manufactured from carbonaceous material,
including coal (bituminous, subbituminous, and lignite), peat, wood, or
nutshells (e.g., coconut). The manufacturing process consists of two
phases, carbonization and activation. The carbonization process includes
drying and then heating to separate by-products, including tars and
other hydrocarbons from the raw material, as well as to drive off any
gases generated. The process is completed by heating the material over
400 °C (750 °F) in an oxygen-free atmosphere that cannot support
combustion. The carbonized particles are then "activated" by exposing
them to an oxidizing agent, usually steam or carbon dioxide at high
temperature. This agent burns off the pore blocking structures created
during the carbonization phase and so, they develop a porous,
three-dimensional graphite lattice structure. The size of the pores
developed during activation is a function of the time that they spend in
this stage. Longer exposure times result in larger pore sizes. The most
popular aqueous phase carbons are bituminous based because of their
hardness, abrasion resistance, pore size distribution, and low cost, but
their effectiveness needs to be tested in each application to determine
the optimal product.

Activated carbon is used for adsorption of organic substances and
non-polar adsorbates and it is also usually used for waste gas (and
waste water) treatment. It is the most widely used adsorbent since most
of its chemical (e.g. surface groups) and physical properties (e.g. pore
size distribution and surface area) can be tuned according to what is
needed. Its usefulness also derives from its large micropore (and
sometimes mesopore) volume and the resulting high surface area.



  • [permaculture] Ions & agriculture and permaculture. Fwd: Re: [soilandhealth] Re: Cuba.... was potting soil/organic fertilizers, Lawrence F. London, Jr., 08/17/2011

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