4. INTERAKSI SEDIMEN-KOLOM...
Transcript of 4. INTERAKSI SEDIMEN-KOLOM...
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Have you ever heard HUMUS??
A brown to black complex variable of carbon
containing compounds as possessing cellular
organization in the form of plant and animal
bodies
Derived from plant and animal detritus changes
through biochemical processes
Diagram of the many possible environmental
flowpaths of humic substances
Sedimentary evolution
Diagenesis
Catagenesis
Metagenesisthe most advanced stage, where organic matter is almost
reduced to a carbonaceous residue
thermal degradation of the organic matter in sediment
generates hydrocarbons
organic matter loses mainly nitrogen, organic matter loses
mainly oxygen
The major organic elements in sedimentary humic
substances are carbon, hydrogen, oxygen, nitrogen, and
sulfur
Terestrial Humus
• Low alifatic structure
• High lignin
Marine Humus
• High alifatic structure
• Low lignin
carbohydrates
lipids
amino acids
humic acids (HA)
fulvic acids (FA)
humins
Organic matter which change :
lignin, sulfonat, tannin, pectin, polisakarida
Create humus substances with large molecul weight
Humus is the major soil organic matter component, making up
65% to 75% of the total
Humus assumes an important role as a fertility component of
all soils, far in excess of the percentage contribution it makes
to the total soil mass.
the fraction of
humic substances
that is soluble in
water under all pH
conditions
remains in solution
after removal of
humic acid by
acidification
light yellow to
yellow-brown in
color
the fraction of humic
substances that is not
soluble in water under
acidic conditions (pH <
2) but is soluble at higher
pH values
can be extracted from
soil by various reagents
and which is insoluble in
dilute acid
the major extractable
component of soil humic
substances
dark brown to black in
color
the fraction
of humic
substances
that is not
soluble in
water at
any pH
value and
in alkali
black in
color
Comprise a mixture of weak aliphatic and aromatic
organic acids
Not soluble in water under acid conditions but are
soluble in water under alkaline conditions
Consist of that fraction of humic substances that are
precipitated from aqueous solution when the pH is
decreased below 2
Readily form salts with inorganic trace mineral elements
Typical soil inputs
A mixture of weak aliphatic and aromatic organic acids
which are soluble in water at all pH conditions (acidic,
neutral and alkaline)
Smaller than humic acids (HAs), with molecular weights
which range from approximately 1,000 to 10,000
Have an oxygen content twice that of humic acids (HAs),
many carboxyl (-COOH) and hydroxyl (-COH) groups
Much more chemically reactive : the exchange capacity
is more than double that of humic acids (HAs)
The ratio of fulvic acid to humic acid
decreases with the burial depth of a sediment
Fulvic acid seems to result principally from the
oxidation of organic matter
The formation of fulvic acid decreases with
burial depth, because there is no more
oxygen in the sediment
The fraction already present in the sediment is
eliminated from the sediment by solubilization
in the pore water or mineralization by bacteria
Fraction of humic substances which are not soluble in
alkali (high pH) and are not soluble in acid (low pH)
Not soluble in water at any pH
Humins present within the soil is the most resistant to
decomposition (slow to breakdown) of all the humic
substances
To improve the soils water holding capacity, to improve
soil structure, to maintain soil stability
Measurement
Precipitation Methods
Spectrophotometric
methods
Ash containing
measurement methods
standard approach for humic acidstandard approach for humic acid
rapid, less accurate methodrapid, less accurate method
typically only used for
measuring humic
content
Scheme for the isolation of humic substances from soil