DETERMINATION OF TRACE METALS IN SOME PETROLEUM PRODUCTS
DETERMINATION OF TRACE METALS IN SOME PETROLEUM PRODUCTS
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Date
1984-01
Authors
NWABUEZE, OGBUEHI,
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Abstract
Petroleum and its products contain a high
percentage of hydrocarbon in addition to sulphur,
phosphorous and measurable quantities of metals.
The metallic constituents are either indigenous to
the oil or are present as additives. When intentionally
added, these metals help to impart desirable
properties (e.g. increase stability, improve
combustion characteristic and act as film-strength
improver) to the oil. Often the presence of these
metals in oils may cause the finished product to have
undesirable properties such as corrosion of refinery
equipment, reduction of the activity of process
catalyst and premature failures in engines due to
excessive wear. Again, when these petroleum products
are burnt in engines, these metals are lost to the
environment as pollutants.
The quality of the air in large cities is now,
more than ever before recognised (47) as an important
factor in the standard of urban life. It impinges
directly, but often subtly and unquantifiably, on
public health, enjoyment of surroundings, plant life,
property fabric and even local meteorology. As one
one of the great conurbation of the world, Nigeria
is not exempted from most of the environmental
pollution problems that are found elsewhere.
In view of the effects of metals discussed
above, the present work presents a study of some
trace metal levels in gear and brake fluids. The
analysis of the entire commercially available
product was not practical and therefore sample
from the major marketings companies were studied
and they include six brake fluids namely Agip SAE
J1703, Mobil SAE J.1703C, National (Etonax B) SAE J1703,
TEXACO SEA 1703, TOTAL SAE J1703C BP. Super SAE
J1703 and four gear oils - Agip SAE 85W/140, Mobil
HD140, TEXACO SAE 85W/90 and TOTAL,extreme pressure
gear oil.
Two methods of sample preparation were used.
In the first case, the oil was dried under an,
infrared lamp and ashed with the aid of a muffle
furnace using sulphuric acid as an ashing aid. In
the second case, dithizone was used to extract lead
and cadmium into 40% nitric acid.
Flame photometric technique was used for the
determination of sodium,, potassium) calcium while
atomic absorption spectrometric technique was
empxoyed for zinc, copper, lead, manganese, magnesium
cadmium, Nickel, chromium and cobalt. Iron was
spectrophotometrically estimated,
There were variations in results of sodium,
potassium, calcium, zinc, manganese obtained for
the different oils while copper, magnesium, cadmium,
nickel, lead and iron gave results that show little
or no variation from oil to oil.
Of the metals determined, nickel has the least
value of 4.0 mg/kg and potassium the high value of
20956.0 mg/kg.
Chromium and cobalt were either absent or
present in an amount that was below the detection
limit of the instrument used.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY, ZARIA, IN PARTIAL
FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE
OF MASTER OF SCIENCE (ANALYTICAL CHEMISTRY).
DEPARTMENT OF CHEMISTRY,
FACULTY OF SCIENCE,
AHMADU BELLO UNIVERSITY,
ZARIA - NIGERIA.
JANUARY, 1984
Keywords
DETERMINATION,, METALS,, PETROLEUM