الفهرس 
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Abstract
The aim of this thesis is to study the interaction of some metal ions,
of nuclear. and environmental importance, with the most widely distributed
materials on the earth’s surface; humic materials.
The metal ions investigated are cs”, Pb2+,C02+,’Cd2+,Hi+, Th4+and
La3+, in addition to the radionuclides 60Co,(IS2.1S4lEu and 137Cs.The study
. involved .separation,. purification as well as characterization of humic
fractions, (humic acid, fulvic acid and humin) and the determination of the
parametrs that govern the interaction of these ligands with the metal ions.
The fulvic acid sample used in these studies is separated from organic soil
(peat), a sample of humin (Hn) and soil humic acid (SRA) are separated
from agricultural soil and a sample of humic acid (ICRA) was separated
from the bottom sediments of Ismailia canal.
The characterization methods include elemental analysis.
potentiometric titration, infrared and UV-visible spectroscopies. The thesis
is classified into three chapters.
Chapter one: The introduction, contains some aspects of the radionuclides
(natural and artificial) in the environmental, the essential properties of the
investigated elements and the properties of humic substances with a special.
emphasis on their: occurrence.. formation, fractions, extraction and
characterization, with a reference to the elemental content, the reactive
functional groups, the spectroscopic characteristics and the potentiometric
titration. This part is ended with some information about the molecular
weight of humic substances, their” structure, properties, uses and a survey
for peat humic substances, with reference to ion selective electrode.
Chapter two: the experimental, includes: The source of samples and the
methods of separation, purification and characterization of humic materials.
This chapter includes also the preparation of the investigated radioactive
tracers; the different chemicals used, the instrumental procedures applied
for the preparation of the organic and aqueous solutions for the ion
selective electrode and radiometrical investigations, and the working
procedures used.
Chapter three: the results and discussion, includes the experimental results
and their explanation as follows:
I-Characterization of humic materials:
a) Elemental analysis:
The elemental analysis of the humic materials indicates that the
humic compounds have nearly identical elemental composition. The OIC
ratios of humic acid samples were found around 0.6 while for fulvic acid it
found of higher ratio (0.7) and for humin it was oflower ratio (- 0.5). The
HlC ratios are clustered around 1.0 for humic and fulvic acid samples. The
ratio in case of humin is higher (1.3), which indicates a lower degree of
unsaturation and a higher aliphatic character in both humic and fulvic acids.
b) The pI(” values and the carboxylate capacities
The investigated humic compounds were titrated potentiometrically
to evaluate the total carboxylate capacities which were calculated from the
second maxima of the first derivative to be 6.00, 6.60, 7.75, 12.96,7.75 and
5.81 meq OR Ig for PFA, ICHA, BHA, GHA, SHA and humin,
respectively. The pK. at 50% ionization (a = 0.5) were found 2.94, 4.625,
4.25, 3.81, 4.56 and 5.99 for PFA, ICHA, BHA, GHA, SHA and humin,
respectively.
IS2
c) The IR spectroscopy:
The infrared analysis of the investigated humic materials were
found to have more or less similar spectra with a variety of bands that are in
good agreement with the results of the titration; indicating the major
constituents of the humic materials (aliphatic, aromatic, carboxylic, ..... )
and the purity of these samples.
d) Ultraviolet and visible spectroscopy
UV-visible spectroscopy is useful in the estimation of the degree of
humification using the EJ E6 ratio by measuring the absorbancies of dilute
aqueous fulvic and humic acid solutions at 465 and 665 DID. The values of
the EJ ~ ratio were found 4.07,4.03,5.79 and 6.00 for ICHA, BHA, SHA
and PFA, respectively.
The data obtained indicates that PFA and SHA have higher EJ E6
ratio than the other fractions. This means that it has a low aromatic
condensation and smaller molecule which contains less carbon, more
oxygen and - COOH groups. The results of EJ E6 ratio, elemental
composition, potentiometric titration and IR spectra of the investigated
humic materials indicate that they are in good agreement with each other.
d) Functional group analysis
The determination of functional groups of humic acid is based on
the acidic properties of the group involved. The values of oxygencontaining
functional groups in ICHA was found 856, 495, 360, 676.5, 316
and 793 for total acidity, COOH, phenolic OH, total OH, Alcoholic OH and
carbonyl C=O, respectively. The data obtained were found in agreement
with that obtained prevuiosly.
. 1S3.
2- Interaction of humic materials with metal ions
A) Cs -humate complexation
I) Radioactive investigations
a) Effect of shaking time
The formation of Cs-humate complex was studied radiometrically
using 137Cs. The process was carried out by shaking the system at different
periods of time, as a preliminary test, to know the suitable time of
equilibration. The formation of complex increases with time and becomes
constant at 60 minutes, which was taken as the minimum time needed for
the reaction.
b) Effect of metal ion concentration
The Cs-humate precipitate was found to increase with increasing the
metal ion concentration and the pH. A concentration of 10.3gil humic acid
was completely precipitated by lO-3M ofCs+ ion at pH 5.8.
c) Effect of pH
The precipitation of Cs+ by humic acid was found to increase by
increasing the pH. This behaviour is discussed in the light of exchange
properties of the hydrogen ions and their competitive effect for the
available exchange sites. Increasing the pH of the solution results in an
additional ionization of the acidic groups of the humic acid. This can
enhance the attraction of the Cs” cations to the humic acid, with subsequent
formation of Cs-humate complex.
d) Effect of humic acid concentration
The formation of Cs-humate complex was found to increase by
increasing humic acid concentration where lO-3M of Cs+precipitated lO·3
gil of humic acid
II) Ion-selective electrode investigation
A) Cs-humate complexation
The formation of Cs-humate complex was studied using ISE after
calibration of the sensor by Cs”, The effect of shaking time, metal ion
concentration, and humic acid concentration were studied. It was noted
that the behaviour is almost similar to that obtained radiometrically
where the time needed for equilibration was found 60 minutes.
B) Cs-fulvate complex
The complexation of Cs+ with fulvic acid was studied by ISE.
The effect of metal ion concentration and fulvic acid concentration were
investigated and found that fulvic acid has no ability to complex with
Cs+.
C) Sorption of Cs+ by humin
The sorption of Cs+ by humin was studied by the batch technique
using ISE and the percentage of uptake values were calculated.
a) Rate of uptake
The rate of sorption of the investigated element showed a sharp
increase in % uptake with increasing the time then attains a constant
value after equilibration at 60 minutes.
b) Humin weight
The results indicated that the percentage of uptake increases sharply
with increasing the humin weight then becomes constant after saturation
at 0.01 g of humin.
b) Effect of metal ion concentration
The percentage of uptake of Cs+ by humin was found to decrease by
increasing the metal ion concentration. This behavior is attributed to the
saturation of humin by the metal ion and the consumption of the
exchangeable protons of the acidic groups in the humin molecule.
B) Lead-humate complex
The formation ofPb-humate complex was studied using ISE after
calibration for the sensor by Pb2+. The effect of shaking time, metal ion
concentration, and humic acid concentration was evaluated using the
sensor. The time required for equilibration was found 20 minutes.
C) Lead-fulvate complex
The complexation of Pb2+ with fulvic acid was investigated by
ISE. The effect of shaking time, metal ion concentration and fulvic acid
concentration was evaluated. The free metal concentration was found to
decrease graduaIly with the time, showing an increase in the formation
oflead-fulvate complex.
D) Sorption ofPb2+ by humin
The sorption of Pb2+ by humin was studied by the batch technique
using ISE and the percentage of uptake values were calculated.
a) Rate of uptake
The rate of sorption of the investigated element showed a sharp
increase in % uptake with increasing the time then attains a constant
value and the equilibration time was 30 minutes.
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b) Humin weight
The results obtained indicated that the percentage of uptake increases
sharply with increasing the humin weight then it becomes constant after
saturation at O.15gof humin.
c) Effect of metal ion concentration
The percentage of uptake of lead by humin was found to decrease by
increasing the metal ion concentration. This behavior is attributed to the
saturation of humin by the metal ion and the consumption of the
exchangeable protons of the acidic groups in the humin molecule.
d) Effect of competing cations on lead-humate complex
The lead-humate complex was prepared and investigated using ISE.
The competition effect of the investigated cations on the formation of leadhumate
complex was studied using radioactive isotopes of 137Cs,6OCOand
(152-154)EuT.he results indicated that Pb2+ forms a stable lead-humate
complex.
F) Disposal of radioactive waste by humic materials
The decontamination of radioactive waste solution of the radioelements
137Cs,6OCOand (152.154!Eduepends on the interaction of these metal ions
with humic acid or humin.