MINISTRY OF EDUCATION
AND TRAINING
VIETNAM ACADEMY OF
SCIENCE AND TECHNOLOGY
GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY-
----------------------------
NGUYEN THI HONG HOA
STUDY ON SYNTHESIS, CHARACTERISTICS AND
ADSORPTION PROPERTIES OF TOXIC ORGANIC
SUBSTANCES IN THE WATER ENVIRONMENT OF
MESOPOROUS CARBON MATERIALS
Major: Theoretical Chemistry and Physical Chemistry
Code : 62.44.01.19
SUMMARY OF CHEMISTRY DOCTORAL THESIS
Ha Noi – 2019
The work was completed at: Graduate Universty of Science and
Technology - Vietnam Academy of Science and Technology.
Science supervisor 1: Assoc.Prof.Dr. Dang Tuyet Phuong
Science supervisor 2: Dr. Tran Thi Kim Hoa
Reviewer 1: …
Reviewer 2: …
Reviewer 3: ….
The thesis will be defended in front of doctoral thesis, held at the
Graduate University Science and Technology - Vietnam Academy
of Science and Technology at ... o’clock, on day ... month ... year
2019.
Thesis can be found at:
- Library of the Graduate University Science and Technology
- National Library of Vietnam
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INTRODUCTION
1. The necessity of the thesis
Mesoporous carbon materials have an ordered structure,
uniform pore size. They often were synthesized by two methods:
soft-templating and hard-templating. With the soft-templating
method, materials have been prepared via self-assembly by using
soft-templating (surfactant). The obtained materials have less orderly
structure. The pore size of the material is difficult to control and the
template is difficult to remove. With the hard-templating method,
MCM-48, SBA-15, etc. are used as the templates. The materials have
highly order structure, uniform and easily controlled pore size.
Therefore, hard-templating method is used more widely. However,
the pore size of materials is smaller than that of the hard-templates
because obtained materials are inverse copies of the templates.
The thickness of the wall and the pore size are limited by size and
shape form of hard-templates. So far, the pore size of mesoporous
carbon materials are synthesized by hard-templating method only
reach the maximum of ~ 5.5 nm. The increasing in pore size is not
feasible because it is limited by the size of the templates, resulting in
framework collapse and pore breakage due to decrease stability.
Hence, it is necessary to find new methods to synthesize mesoporous
carbon materials with larger sizes, higher stability.
Mesoporous carbon materials are said to be a good adsorbent
of organic substances in water environment. However, these
materials are not stability. The structure of the materials is easily
broken during the reuse process and it is difficult to recover. So, the
regeneration and reuse of mesoporous carbon materials are very
difficult. Because of, if heat is used to remove completely adsorbed,
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it is necessary to perform high temperature causing to burn
mesoporous carbon materials. Also, the solvents are used to remove
the adsorbed, resulting less-economical effect and secondary
pollution. Therefore, the research to find the effective and feasible
methods for regeneration and reuse of mesoporous carbon materials
is necessary.
From the above reasons, the thesis topic “Study on synthesis,
characteristics, and adsorption properties of toxic organic
substances in the water environment of mesoporous carbon
materials” was studied.
2. The purpose of the thesis
Study on control the process of synthesizing mesoporous
carbon materials with an ordered structure, large pore size, high
stability. They are as an effective adsorbent for toxic organic
substances with different molecular sizes in water environment.
Synthesis of mesoporous carbon materials with desired order
structure, large pore size, high durability for effective adsorption of
different molecular size toxic organic substances in water
environment.
3. Scientific and practical significance of the thesis
The thesis has found a new method to increase the pore size
of mesoporous carbon by filling the liquid glass into the pore of the
template (silica SBA-15) before impregnating the carbon presource
to limit the penetration of carbon sealed the pore system of SBA-15.
Stability of mesoporous carbon is increases due to silicon are
partially retained in materials. This technique opens the way of
synthesis of mesoporous carbon as an adsorbent with a desired pore
size and stability.
3
Doping iron into the framework of mesoporous carbon
materials creates catalysts to decompose adsorbed, release the
adsorption sites, regeneration and reuse of mesoporous carbon,
extend the scope of application of materials for treatment of toxic
organic substances in water.
4. New findings of the thesis
1. For the first time, a new technique is used to control the
pore size of the mesoporous carbon materials which is synthesized
by hard – temlating method by filling the liquid glass into the pore of
SBA-15 before impregnating the carbon source to prevent
penetration carbon to seal the pore system of SBA-15. This
technique opens new direction for mesoporous carbon synthesis
technologies as the adsorbent with the desired pore size.
2. Retaining a silicon part in synthesiszed material to
increase the stability of the mesoporous carbon material.
3. Using atom-planting method to put iron into framework of
the mesoporous carbon material do not change the structure of the
materials. Iron exists on the surface of materials in the highly
dispersed Fe2O3 and FeO forms, favorable for adsorption and
decomposition of methylene blue, enhance the ability of
regeneration, reuse and do not cause secondary pollution.
5. The structure of the thesis
The thesis consists of 140 pages with 83 figures, 31 tables.
The thesis includes the following sections: Introduction (2 pages);
Chapter 1: Overview (44 pages); Chapter 2: Research methods and
experiment (16 pages); Chapter 3: Results and discussion (59 pages);
Conclusions(2 pages); Novel scientific contributions of the thesis;
List of publications; References and appendices.