THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURAL AND FORESTRY VU THI HOAI TOPIC TITLE: DEVELOPMENT OF NOVEL TITANATE NANOTUBES/ REDUCED GRAPHENE OXIDE COMPOSITE FOR THE REMOVAL OF HEAVY METALS FROM AQUEOUS SOLUTION BACHELOR THESIS Study Mode: Full-time Major: Environmental Science and Management Faculty: International Training and Development Center Batch: 2010-2015 Thai Nguyen, 15/01/ 2015 1 n DOCUMENTATION PAGE WITH ABSTRACT Thai Nguyen University of Agriculture and Forestry Degree Program Bachelor of environmental Science and Management Student name Vu Thi Hoai Student ID DTN1053110084 Development of Novel Titanate Nanotubes/ Reduced Thesis Tiltle Graphene Oxide Composite for the Removal of Heavy Metals from Aqueous Solution Prof. Nguyen The Dang, Thai Nguyen University of Supervisor(s) Agriculture and Forestry, Vietnam Prof. Ruey-an Doong, National Tsing Hua University Abstract Graphene oxide (GO), is a two dimensional carbon nano-material which exhibits a great adsorption potential. Graphene functionalized composites enhance its adsorption efficiency for toxic heavy-metals from contaminated waste water.
Titanium nanotubes and GO were assembled in basic medium via microwave-assisted hydrothermal method. The strong anchoring of TNT on the surface of GO sheets can be easily observed by TEM (Transmission Electron Microscopy), XRD (X-ray Diffraction). Diffraction on GO sheets confirmed through D-band and G-band ration by Raman Spectroscopy. As-synthesized TNT/rGO composite shows high efficiency and high selectivity toward heavy metals in aqueous solution.
The results indicated that TNT/rGO composite with high adsorption efficiency and fast adsorption equilibrium can be used as a practical adsorbent for heavy metals in aqueous solution. Titanate nanotube, Graphene oxide, composite, Keywords hydrothermal, adsorption Number of papers 44 pages Date of submission: 15/01/2015 2 n ACKNOWLEDGEMENTS I am deeply indebted to my research supervisor Prof. Ruey-An Doong, whose stimulating motivations and valuable ideas helped me to complete my thesis and I would like to offer my sincere gratitude to prof. Nguyen The Dang for his support throughout my thesis with his patience and knowledge whilst allowing me the room to work in my own way.
I attribute the level of my Bachelor degree to his encouragement and effort. I am grateful to Rama Shanker Sahu (PhD) and Yen-Tung Yang (PhD) for their valuable help, advices and constructive comments during all my experiments and writing thesis. I would like to thank Duncan, Sammy, Joyce (MS) for their great support in characterizing my samples, YC Ken Tsai (PhD) and Rudy (PhD) for their impressive help in adsorption studies. I would also like to thank Khanh, Linh and all FATECOL members, Biomedical Engineering and Environmental Sciences, National Tsing-Hua University, Taiwan, who provided their ongoing support, questions and suggestions.
Finally, I would like to express my love and gratitude to my beloved parents for their support & endless love. VU THI HOAI 3 n TABLE OF CONTENTS LIST OF FIGURES. 1 LIST OF TABLES. 2 LIST OF ABBREVIATIONS.
Overview of heavy metals. Definitions and sources of heavy metals. Characteristics of heavy metals. Heavy metal pollution in the world and Vietnam.
In estuary, coastal and marine areas. In acid sulfate soil areas. Characteristics and hazards of some heavy metals. Effects of heavy metal to environmental and human health.
Some of treatment methods for the removal of heavy metals from aqueous solution. Overview of handling heavy metals in aqueous solution using Titanate nanotube / reduced graphene oxide composite. Scientific Basis of handling heavy metals in aqueous solution by rGO-TNT composite. Some research results of absorption of heavy metals in water by rGO-TNT composite.
Prospects of technological rGO-TNT composite in removal of heavy metals in aqueous solution. Synthesis of TNT. Synthesis of Graphene oxide. Synthesis of rGO-TNT Composite.
The method of determining the characteristics of the material. Characterization of GO and titanate nanotubes/rGO composite. Morphology of TNT, GO and rGO-TNT composite. Application into removal of heavy metal ions.
DISCUSSION AND CONCLUSION. 42 5 n LIST OF FIGURES Figure 3. Schematic of TNT synthesis. Schematic of GO synthesis…….
Adsorption experiment of Copper by TNT and rGO-TNT ………………27 Figure 3. Atomic adsorption spectroscopy (AAS)……………………. Schematic of TEM ……………………………. The process TEM characterization…….
Raman spectra of GO, rGO-TNT materials……………. XRD patterns of GO………………………………………………. XRD patterns of TNT and rGO-TNT composite……………. TEM images of the synthesis TNT and rGO-TNT composite………….
The adsorption of Cu(II) by TNT at pH=5 in aqueous solution at room temperature. The adsorption of Cu(II) by rGO /TNT composite in aqueous solution at room temperature.38 1 n LIST OF TABLES Table 4. The results of Cu (II) adsorption experiment by TNT, was observed by Atomic adsorption spectroscopy (AAS). The results of Cu (II) adsorption experiment by rGO-TNT, was observed by Atomic adsorption spectroscopy (AAS)…………………………………………….38 2 n LIST OF ABBREVIATIONS Abbreviations Full text content TNT Titanate nanotube GO Graphene oxide TNT-rGO Titanate nanotube and reduced graphene oxide XRD X-Ray Diffraction TEM Transmission Electron Microscopy AAS Atomic adsorption spectroscopy 3 n PART I.
Research rationale Pollution of air, water and soil is a worldwide issue for the eco-environment and human society. Most of the earth's surface is covered by water, and most of the human body is composed of water. These are the two facts illustrating the critical linkages between water, health and ecosystems. It can be seen that, water is the most essential compound on the earth for the human activities.
Providing clean water is the prime requirement of the human being for their better health. Since the fast growing sector of industries, expansion of population, and urbanization have largely contributed to the severe contamination of water, air and soil. Chemical and fertilizers use in domestic and agricultural activities leads to the lifetime threatening diseases. Intense use of heavy metals in industries for dyeing, paint etc.
is becoming one of the most serious environment problems globally. Its presence in low concentration of heavy metals in various water resources could be harmful to human health. The treatment of heavy metals is so important due to their persistence in the environment. In order to remove the heavy metals, various techniques have been developed.
The traditional treatment processes for heavy metals include chemical precipitation, electrolysis, adsorption, and ion exchange. Among these methods, adsorption is an efficient technology, which has been widely used for the removal of metal ions in aqueous solutions. A wide variety of adsorbents including activated carbon, water treatment sludge, zeolite, fly ash, and biomass have been reported to effectively adsorb metal ions, showing varying extent of effectiveness in removing the toxic pollutants from air, water and soil. 4 n More recently, one-dimensional (1-D) titanate nanotube (TNT) have been reported to be an attractive adsorbent to effectively adsorb a wide variety of metal ions including Cu, Pb, Cd, and Zn because of their large specific surface areas and layered structures.
TNT is considered as a modified structure in photo catalysis owing to its special electronic and mechanical properties, high photo catalytic activity, large specific surface area and high pore volume, a potential material for removal of metal ions in the aqueous solution. Besides, in the past few years, Graphene oxide (GO) have attracted tremendous interest in the world. Graphene is a two-dimensional carbon nanomaterial with single layer of sp2 hybridized carbon atoms arranged in six membered rings. Graphene has strong mechanical, thermal, and electrical properties with a theoretical value of specific surface area at 2630 m2/g.
GO is a functionalized graphene with varying oxygen containing groups. Several views have been reported on applications of GO in different areas such as physics, chemistry, biology, and material science. In particular, graphene based materials are used as adsorbents for pollutants removal since graphene oxide possesses several functional groups and has strong acidity, exhibiting high adsorption for basic compounds and cations. Graphene also has a hydrophobic surface and presents high adsorption to chemicals due to strong π–π interaction.
Among several physical, chemical and biological treatment techniques, the adsorption is one of the simplest, fastest and most efficient processes or the removal of heavy metals. Considering all aspects and issues mentioned above, I have paid attention to the preparation of titanate nanotube/reduced graphene oxide composite and subsequently used them as adsorbents. Research's Objectives The primary objective of this study is to develop and investigate a graphene based nano composite for the removal of toxic heavy metals from aqueous solution. Titanium nanotubes and GO were assembled in basic medium via microwave-assisted hydrothermal method.
Estimation of the adsorption capacity of some heavy metal ions in aqueous solutions. Characterization of material composites using techniques like XRD, TEM, SEM, FTIR, Raman Spectroscopy. Synthesizing the TNT and performing the adsorption experiments to evaluate its properties. The fabrication of new materials Titanate nanotubes / reduced graphene oxide composite will make a significant contribution in wastewater treatment produced due to mining in the country and improving the domestic water efficiency as well as contributing to the environmental protection.
Overview of heavy metals 2. Definitions and sources of heavy metals The origin of the term "heavy metal" is not clear. An early use dates from 1817, when Gmelin divided the elements into nonmetals, light metals and heavy metals (Habashi F 2009). Light metals had densities of 0.0 gm/cm3; heavy metals 5.
Heavy metals are divided into three types: toxic metals (Hg, Cr, Pb, Zn, Cu, Ni, Cd, As, Co, Sn etc.), precious metals (Pd, Pt, Au, Ag, Ru etc.), radioactive metals (U, Th, Ra, Am,etc.The proportion of these metals is usually greater than 5g/cm3 (Bishop, 2002). Heavy metals are found naturally in the earth, which become concentrated as a result of human caused activities. Common sources are from mining and industrial wastes; vehicle emissions; lead-acid batteries; fertilizers, paints and treated woods. Lead is the most prevalent heavy metal contaminant.
Characteristics of heavy metals Heavy metals are not biodegradable (Tam & Wong, 1996) and are non-toxic in the form of elements, but are dangerous to living organisms when they are in the form of cations due to its linkage capacity with short carbon chain, which leads to the accumulation in the organism after several years. For humans, approximately 12 elements of heavy metals cause toxic such as lead, mercury, aluminum, arsenic, cadmium, nickel. Some heavy metals are found in the body and essential for human health, such as iron, zinc, magnesium, cobalt, manganese, molybdenum and copper, although the amount is very small but it is present in metabolism. However, at excess 7 n level of the essential elements can endanger the life of the organism (Foulkes, 2000).
The remaining metal elements are unnecessary elements and can be highly toxic when present in the body; however, the toxic is only present when they enter the food chain. These elements include mercury, nickel, lead, arsenic, cadmium, aluminum, platinum and copper in the form of metal ions. They enter the body through the streets of the body to absorb as respiratory, gastrointestinal and through the skin. If heavy metals enter the body and accumulate inside the cell is greater than the resolution of them, they will increase and the poisoning will appear (Foulkes, 2000).
The toxicity of heavy metals is expressed through: (1) Some of heavy metal can be moved from low to higher toxicity in the form of some environmental conditions, such as mercury. (2) Accumulation and biological amplification of these metals through the food chain may damaging the normal physiological activity and ultimately endanger human health. (3) Toxicity of these elements may be at a very low concentration of about 0.L-1 (Alkorta et al. Heavy metal pollution in the world and Vietnam 2.
In estuary, coastal and marine areas Metal pollution in the marine environment has increased in recent years due to increasing global population and industrial development. Heavy metal pollution in many estuaries, coastal areas around the world have long been known by toxic threat to the life of aquatic organisms, risk to human health. Pb and Zn pollution is one of great concern due to their toxic effects on the ecosystem in the estuaries in Australia, with very high levels of 1000µg.g-1 Zn 8 n can be found in the contaminated sediments. Bryan et al.