水から抗生物質シプロフロキサシンを除去するための新しい鉄ナノ材料の合成

概要

九州大学学術情報リポジトリ
Kyushu University Institutional Repository

Synthesis of Novel Iron-based Nanomaterials for
the Removal of the Antibiotic Ciprofloxacin
from Water
オマル エイ エム ファリオウナ

https://hdl.handle.net/2324/6787659
出版情報：Kyushu University, 2022, 博士（学術）, 課程博士
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（様式３）Form 3

氏

名 ： OMAR A. M. FALYOUNA

Name

論 文 名 ：Synthesis of Novel Iron-based Nanomaterials for the Removal of the Antibiotic
Ciprofloxacin from Water （水から抗生物質シプロフロキサシンを除去するた
めの新しい鉄ナノ材料の合成）
Title

区

分 ：甲

Category

論 文 内 容 の 要 旨
Thesis Summary
The persisting occurrence of ciprofloxacin (CIP) and other antibiotics in our limited water resources has fatal
health and environmental consequences. This research adopts zerovalent iron nanoparticles (Fe0) as an
excellent remedial agent to propose novel iron-based nanomaterials with unique properties to efficiently remove
CIP from water.
The first project focused on coating Fe0 nanoparticles with a shell of magnesium hydroxide [Mg(OH)2] to
overcome the shortcomings of Fe0 nanoparticles and promote the remediation of CIP from aquatic
environments. The outcomes of the batch experiments demonstrated that encapsulating Fe0 nanoparticles by
Mg(OH)2 layer with a [Mg(OH)2/Fe0] mass ratio of 5% boosted the removal efficiency of CIP from 41.76% to
96.31%. Moreover, the optimization process for the treatment parameters revealed that CIP-polluted water was
optimally treated by Mg/Fe0 nanoparticles under the following conditions: [Mg/Fe0] = 0.5 g L–1, [CIP] = 100 mg
L–1, initial pH = 3 – 11, temperature = 25 ℃, and treatment time = 60 min. Also, the desorption experiments
confirmed that the removal of CIP by Mg/Fe0 nanoparticles was completely governed by chemical and physical
adsorption. Furthermore, the proposed regeneration protocol succeeded in recycling Mg/Fe0 nanoparticles for
five consecutive treatment cycles with removal efficiencies higher than 95%.
The second project aimed to enhance the reactivity of Fe0 nanoparticles in eliminating CIP from aqueous
solutions by adding the organic ligand oxalate. The outcomes of the batch experiments showed that adding 0.3
mM of oxalate to Fe0 nanoparticles increased the adsorption of CIP from 45.05% to 95.74%. Moreover, the
optimal removal of CIP by (Fe0/oxalate) nanoparticles was attained under the following circumstances: [Fe0] =
0.3 g L–1, [Oxalate] = 0.3 mM, initial pH = 7, temperature = 25 ℃, and treatment time = 30 min. Similar to Mg/Fe0
nanoparticles, the desorption experiments emphasized that the remediation of CIP by (Fe0/oxalate)
nanoparticles was fully controlled by adsorption instead of oxidation. In addition, the results proved that adding
oxalate is a cost-effective approach to improve the reactivity of Fe0 nanoparticles as the treatment cost of 1 L of
CIP-polluted water notably declined from ¥65.716 (Fe0 alone) to ¥29.124 (Fe0/oxalate). It is important to highlight
that the performance of Mg/Fe0 and (Fe0/oxalate) nanoparticles in remediating CIP-polluted water are reported
for the first time in this study. Also, their outstanding competence is promising and has great potential in tackling
CIP contamination in actual polluted waters.
The framework of the Ph.D. thesis consists of five main chapters as follows:
Chapter 1 provides background information about water pollution by antibiotics, particularly the
recalcitrant ciprofloxacin. In addition, it discusses the occurrence and fate of ciprofloxacin in the environment
and its health threats and ecotoxicity. Moreover, chapter 1 covers the state-of-the-art treatment technologies

for CIP pollution. Also, it includes an overview about zerovalent iron nanoparticles, their features and defects,
their modification techniques, and their applications in CIP remediation from polluted waters. Finally, chapter 1
summarizes the aim and objectives of the Ph.D. research projects.
Chapter 2 summarizes the list of chemicals utilized in all experiments. Moreover, it describes the
procedures to synthesize various kinds of iron-based nanomaterials in detail. Also, it explains the concepts of
the characterization techniques employed to reveal the physicochemical properties of the iron-based
nanomaterials. In addition, chapter 2 clarifies the specifications of each component of the prototype lab-scale
treatment system. Furthermore, it epitomizes the experimental plan for the research work, the procedures for
conducting the batch experiments, and the analytical instruments used in the laboratory. In addition, it clarifies
the concept of kinetics, isotherm, and thermodynamic modeling for the adsorption of CIP by iron-based
nanomaterials.
Chapter 3 covers the outcomes of remediating CIP-polluted water by Mg/Fe0 nanoparticles. In
detail, chapter 3 reveals the physicochemical properties of Mg/Fe0 nanoparticles, such as external
morphology, surface elemental composition, crystallinity, etc. It also discusses the effectiveness of Mg/Fe0
nanoparticles in eliminating CIP from water under different treatment conditions, for example, Mg/Fe0 dosage
(g L-1), initial pH of the polluted solution, reaction temperature (℃), and initial CIP concentration (mg L-1).
Moreover, the removal mechanism of CIP by Mg/Fe0 nanoparticles was illustrated in this chapter. In addition,
chapter 3 provides a regeneration and recycling protocol for Mg/Fe0 nanoparticles. Moreover, chapter 3
demonstrates the adequacy of utilizing Mg/Fe0 nanoparticles in a prototype treatment system to remediate
large volumes of CIP-polluted water. Also, chapter 3 illustrates the appropriate storage option for Mg/Fe0
nanoparticles for one month. Finally, chapter 3 includes an economic assessment of using Mg/Fe0
nanoparticles for environmental and remediation applications.
Chapter 4 presents the results of removing CIP from aqueous solutions by (Fe0/oxalate)
nanoparticles. In detail, it elucidates physiochemical changes of Fe0 nanoparticles before and after the
reaction with different concentrations of oxalate in water. Also, it explains the impact of various parameters, for
instance, oxalate concentration (mM), Fe0 nanoparticle’s dosage (g L-1), initial pH of polluted water, reaction
temperature (℃), and initial concentration of CIP in water (mg L-1), on the competence of (Fe0/oxalate)
nanoparticles to clean up CIP-polluted solutions. Moreover, it discloses the enhancement mechanism of
adding oxalate to Fe0 nanoparticles toward removing CIP from water. Furthermore, chapter 4 investigates the
influence of water matrix, such as ionic strength, dissolved organic matters, and coexisting ions (e.g., cations
and anions), on the remediation efficiency of (Fe0/oxalate) nanoparticles. Similar to Mg/Fe0 nanoparticles,
chapter 4 suggests regeneration and recycling procedures for reusing (Fe0/oxalate) nanoparticles for multiple
treatment processes. Finally, chapter 4 provides a cost estimation for the treatment of CIP-polluted water by
(Fe0/oxalate) nanoparticles.
Finally, Chapter 5 highlights each research project's significant findings and conclusions. In addition,
it summarizes the recommendations for prospective researchers. Finally, chapter 5 includes possible
research ideas for future work.

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