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العنوان
Separation and pre-concentration of some harmful ions from
wastewater using some natural clay minerals /
المؤلف
Sobeih, Marwa Mahmoud Abd El-hamied Suleiman.
هيئة الاعداد
باحث / مروة محمود عبد الحميد سليمان صبيح
مشرف / محمد فتحى الشحات
مناقش / عبد الفتاح بسطاوى
مناقش / محمد عبد الجواد زايد
تاريخ النشر
2022.
عدد الصفحات
221 P. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
Inorganic Chemistry
تاريخ الإجازة
1/1/2022
مكان الإجازة
جامعة عين شمس - كلية العلوم - قسم الكيمياء
الفهرس
Only 14 pages are availabe for public view

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Abstract

The world is facing an increasing shortage of surface and ground
water resources due to two main reasons, the increasing population
growth, and human activities to overcome this increasing growth. These
two reasons are considered among the most important environmental
problems related to water pollution.where water pollution results from
the discharge of highly polluted domestic, agricultural, and industrial
effluents into natural waterways.
Water pollution is one of the main environmental sources
associated with the outbreak of infectious diseases, as it was found that
about 80% of infectious diseases spread in the world are transmitted
through this polluted water. Therefore, the need for clean water has
become one of the most important environmental issues under
consideration.
from an economic and environmental point of view, this work
was focused on how to explore an efficient method for treating polluted
water.
The work carried out in this thesis is summarized in to three main
chapters; namely, introduction, experimental and finally results and
discussion.
Chapter 1: Introduction
The first chapter includes a brief outline of water pollution and
gives information about water pollutants categories depending on their
significance. It contains a survey on the selected ions under
investigation, which are F
-
, Mn2+, and Fe3+ ions that are introduced into
SUMMARY AND CONCLUSIONS
176
the environment through natural phenomena and human activities
especially, industrial activities, and waste disposal. Also, it involves a
literature survey and previous published papers for the most popular
methods used for the treatment of the studied ions as well as their health
effect. It gives an introduction about clay minerals especially, glauconite
and bentonite clays, which are widely used in water treatment. Finally, it
gives a brief outline of different previous modification methods of clay
minerals for enhancing their properties including especially, chemical
and physical methods such as acid activation and synthesis of polymer
modified clay composites.
Chapter 2: The experimental
The second chapter is the experimental chapter. It includes
reagents, chemicals, apparatus, instruments, and equipment’s used in the
experimental work. The analytical methods for the samples preparation
and the experimental procedures are also presented. It contains a
description of the different spectroscopic instruments used in materials
characterization, such as Fourier-transform infrared spectroscopy
(FTIR), X-ray diffraction (XRD), field emission scanning electron
microscopy (FE-SEM), nitrogen physical adsorption (BET), atomic
absorption spectrophotometry (AA), and thermal gravimetric analysis
(TGA). The adsorption process of the studied ions and the factors
affecting the adsorption activities of materials using a batch technique
such as contact time, pH, initial concentration, dosage, and temperature
are also presented.
SUMMARY AND CONCLUSIONS
177
Chapter 3: Results and discussion
The third chapter deals with the experimental results and
discussion. It is divided into three main sections. The first section is
concerned with glauconite clay and its modified products; it is
subdivided into three main parts namely, characterization of raw
glauconite and its modified products, adsorption study of the studied
ions, and the regeneration of these raw and its modified adsorbents. The
second section is concerned with bentonite clay and its modified
products; it is subdivided into three main parts namely; characterization
of raw bentonite and its modified products, adsorption study of the
studied ions, and the regeneration of these raw and its modified
adsorbents. While, the third section is relates to the application to
industrial effluents.
First section:
Part 1 describes the characterization of raw glauconite and its asprepared adsorbents as follows:
Chemical analysis of raw glauconite (G) confirmed the
aluminosilicate structure of this parent clay, as it is mainly composed of
oxides of silicon, iron, aluminum, and potassium in addition to some
minor exchangeable cations like, sodium, calcium, and magnesium,
which plays an important role in adsorption process. XRD patterns of G
showed that the predominant peaks appeared are due to different
inorganic phases like SiO2, Fe3O4, MgO, and Al2O3 together with some
other crystalline minerals like kaolinite and muscovite
(KAl2(Si3Al)O10(OH,F)2), with presence of non-clay mineral quartz,
confirming that the main phase in G is [((K,Na)(Fe3+
, Al, Mg)2 (Si,
SUMMARY AND CONCLUSIONS
178
Al)4O10(OH)2] with presence of some phyllosilicate minerals as minor
phases. After acid activation (AG), the XRD pattern exhibited a
reduction in the intensity and broadening of the normal positions peaks
as a result of acid attack of parent G. Moreover, an increase in the peak
intensity of quartz was observed, indicating a partial leaching of metallic
constituents of the parent clay without damaging their inherent layered
structure. On the other hand, XRD patterns of as-prepared G composites
such as GL-CS/G, EDTA-GL-CS/G, SDS-CS/G, and CTAB-CS/G
composites manifested a typical peak characteristic for chitosan along
with the diffraction peaks for G clay, confirming the interruption of
chitosan overall the interlayer spaces of G clay. Moreover, the XRD
pattern of all prepared G composites showed its characteristic diffraction
peaks as well as the characteristic peaks corresponding to the original
clay but with a slight shift in intensity compared with that of raw G
sample, indicating that the original clay layer structure is remained even
after the composite synthesis. The use of FT-IR spectrometry confirmed
the presence of all distinct groups of G molecule in all products after
treatment. Besides, presence of special additional functional group
corresponding to each composite indicated the co-existence of inserted
molecule along with chitosan and G clay skeleton in each composite.
Also, the thermal analysis technique confirmed the thermal stability of
raw glauconite and its modified products, despite the use of chitosan in
preparation of some of them. The surface morphology of raw G and its
as-prepared adsorbents showed a porous structure with different shapes
and sizes. The results obtained from the use of BET analysis showed an
increase in the surface area and surface porosity of G after acid
activation, giving more opportunity for ions to be absorbed. However,
SUMMARY AND CONCLUSIONS
179
the BET results showed a decrease in the surface area with an increase in
the pore size in the prepared composites (GL-CS/G, EDTA-GL-CS/G,
SDS-CS/G and CTAB-CS/G), which helps the ions to diffuse faster in
these pores.
Part II deals with the adsorption study of the studied ions as
follows: The effect of different parameters controlling the adsorption
process such as media pH, adsorbent dosage, contact time, initial ion
concentration, and temperature has been investigated. The obtained data
clarify that the preferred experimental conditions were selected as
following:
1. The optimum pH value at which the highest removal percentage
occurred was 3.5 for fluoride and iron, and 6.5 for manganese ions.
2. It was found that the equilibrium time for fluoride removal reached
120 minutes in case of using G and AG, while it reached 180 minutes
using GL-CS/G, EDTA-GL-CS/G, SDS-CS/G, and CTAB-CS/G
composites. In case of removing manganese ions, it was found that
the equilibrium time reached 60 minutes in case of using G and AG,
while it reached 120 minutes using GL-CS/G, EDTA-GL-CS/G,
SDS-CS/G, and CTAB-CS/G composites. In case of iron removal,
the equilibrium time reached 120 minutes in case of using all
adsorbents before and after treatment.
3. It was found that the % removal of the fluoride in the case of using
AG increased with increasing temperature, and the same was for
removing manganese using G and its modified products. That is, the
reaction is endothermic, while the opposite occurred for the %
SUMMARY AND CONCLUSIONS
180
removal of iron using G and its modified products, as well as fluoride
using as-prepared composites.
4. It was found that the % removal of fluoride, iron, and manganese
ions onto G and its modified products decreased with the increasing
of initial concentration of each ion.
5. It was found that the % removal of fluoride, iron, and manganese ions
increased with the increase of adsorbent dose.
6. For G and all its modified products, the removal of fluoride, iron, and
manganese ions was found to fit the isothermal langmuir model and
followed the pseudo-second-order kinetic model. Also, the estimated
thermodynamic constants indicated the feasibility and the
spontaneous nature of the adsorption processes for all studied ions.
Part III describes the regeneration of raw G and its modified
products. Regeneration was carried out using 0.5M NaOH for F
-
and 1M
HCl for Mn2+ and Fe3+ ions under optimum adsorption conditions. The
regeneration process was repeated for four cycles, and the results
exhibited that all adsorbents have a remarkable regeneration capability
and reliable performance for duplicated performance up to at least 4
cycles.
Second section:
Part I describes the characterization of raw bentonite and its
modified products as follows:
Chemical analysis of raw bentonite (B) confirmed the
aluminosilicate structure of the parent clay, as it is composed mainly of
silicon, aluminum, and iron oxides, in addition to sodium, calcium,
SUMMARY AND CONCLUSIONS
181
potassium, and magnesium oxides as minor components. XRD patterns
of the parent B clay showed clearly that the clay is primarily composed
of montmorillonite (mainly sodium bentonite) with presence of
kaolinite, quartz, and calcite as impurities. According to XRD data, the
surface of B clay after acid treatment showed a slight shift to lower
intensity. Besides, a broadening of the in-situ peaks of B with an
increase in the intensity of the quartz peak. On the other hand, XRD
patterns of as-prepared B composites such as GL-CS/B, EDTA-GLCS/B, SDS-CS/B, and CTAB-CS/B composites showed its characteristic
diffraction peaks for each composite as well as the typical characteristic
peaks for chitosan along with that of original B clay, but with a slight
shift in intensity compared with the raw B sample, retaining the original
clay layer structure even after composites synthesis.
The spectra of raw bentonite and its modified products has very
similar FT-IR profiles: the same bands are appearing on all spectra with
presence of special additional functional group corresponding to each
composite, indicating to the co-existence of inserted molecule along with
chitosan and B clay skeleton in each composite. Also, the thermal
analysis technique confirmed the thermal stability of all as-prepared
adsorbents, despite the use of chitosan in preparation of some of them.
The surface morphology of raw B and its modified products showed a
porous structure with various shapes and sizes. The results obtained
from the BET analysis showed an increase in the surface area and the
porosity of B after acid activation, and a decrease in the surface area
with an increase in pores size in the prepared composites (GL-CS/B,
EDTA-GL-CS/B, SDS-CS/B, and CTAB-CS/B), indicating the
SUMMARY AND CONCLUSIONS
182
morphological changes at the surfaces of the B sample, which offered
more opportunities to ions removal.
Part II deals with the adsorption study of the studied ions as
follows:
The influence of various factors controlling the adsorption
process such as pH of the medium, dose of adsorbents, contact time,
initial ion concentration, and temperature was studied. The obtained
results showed that the preferred experimental conditions were chosen as
following:
1. The optimum pH value at which the highest removal percentage
occurred was 4, 3.5, and 6.5 for fluoride, iron, and manganese ions,
respectively.
2. It was found that the equilibrium time for fluoride, iron, and
manganese ions removal reached 60 minutes in case of using B and
AB, while it reached 120 minutes using GL-CS/B, EDTA-GL-CS/B,
SDS-CS/B, and CTAB-CS/B composites.
3. It was found that the % removal of fluoride, iron, and manganese
ions B and its modified products increased with increasing
temperature.
4. It was found that the % removal of fluoride, iron, and manganese
ions onto B and its modified products decreased with increasing
initial concentration of each of these ions.
5. It was found that the removal process of fluoride, iron and manganese
ions on B before and after treatment was fitted to langmuir isotherm
model and followed the pseudo-second-order kinetic model.
SUMMARY AND CONCLUSIONS
183
6. The estimated thermodynamic constants indicated the feasibility and
the spontaneous nature of the adsorption processes for all studied
ions.
Part III describes the regeneration of raw bentonite and its
modified products. Regeneration was carried out using 0.5 M NaOH for
F
-
and 1M HCl for Mn2+ and Fe3+ ions under optimum adsorption
conditions. The regeneration process was repeated for four cycles, and
the results exhibited that all adsorbents have a remarkable regeneration
capability and reliable performance for duplicated performance up to at
least 4 cycles.
Third section:
It describes the practical application for the treatment of real
wastewater samples from the treatment unit in Abu-Zaabal for Fertilizers
and Chemicals Company (AZFC), Egypt. SDS-CS/G, CTAB-CS/G,
SDS-CS/B, and CTAB-CS/B adsorbents were selected as they showed
the highest removal efficiency during the practical study. The adsorbents
shows higher efficiency in the subsequent order: Fe3+> Mn2+ > F-
. These
results indicated the high chemical stability and the efficiency of the
aforementioned adsorbents for removing the studied ions from
wastewater although, the wastewater samples contains various types of
ions (cations and anions), which can well compete and interfere with the
adsorption process.