A method for obtaining magnetisable composite carbon nanotubes comprising demiroxide nanoparticles

Abstract

The invention relates to the production method of carbon nanotube (CNT) / iron oxide (Fe3O4) composite carbon nanotube obtained by combining carbon nanotubes with iron oxide (Fe3O4) nanoparticles prepared using green tea leaves. In addition, in the given processes, the bark, leaf or fruit of other plants can be used instead of green tea leaves. By means of the use of green chemistry method during the production of Fe3O4 nanoparticles, composite carbon nanotubes are produced in an environmentally friendly and economical way. In addition, by means of the combination of Fe3O4 nanoparticles with CNT, the composite carbon nanotube is given the ability to be magnetised.

Description

[0001] DESCRIPTION

[0002] A METHOD FOR OBTAINING MAGNETISABLE COMPOSITE CARBON NANOTUBES COMPRISING DEMIROXIDE NANOPARTICLES

[0003] Technical Field

[0004] The invention relates to the production of magnetisable carbon nanotube (CNT) / iron oxide (FeaC ) nanocomposite particles by a green chemistry method. In the invention, nano composites are obtained by accumulating iron oxide nanoparticles prepared by a fast, environmentally friendly and economical green chemistry method on carbon nanotubes.

[0005] State of the Art

[0006] Carbon nanotubes (CNTs) were first synthesised in the early 1990s and have since found many different applications. In its simplest definition, carbon nanotubes are formed by graphene layers spiralling into a cylindrical tube. CNTs have superior thermal, mechanical and electrical properties and are therefore considered the most promising building blocks for the production of high-performance nanostructured composite materials.

[0007] Due to the high mechanical properties of CNTs, nanocomposites formed by bonding CNTs with metal oxides are used for the production of nanocomposite materials (such as conductive polymer nanocomposites) where new functions are needed. These nanocomposites formed by bonding CNTs with metal oxides have the properties of both materials and are thus used in many different areas

[0001] .

[0008] CNT / metal oxide nanocomposites are widely applied in electrochemical catalysts, electrochemical sensors, supercapacitors and batteries by means of their electrochemical properties.

[0009] In addition, CNT / metal oxide nanocomposite structures can be used in optics. Due to their wide usage areas, CNT / metal oxide nano composite production is increasing day by day. Today, the first step of the widely preferred method for obtaining CNT / metal oxides requires activating the CNT surfaces. With this process, the internal energy of the CNTs is basically increased and active regions are created on the surfaces of the CNTs. Thus, the binding, embedding or incorporation of metal oxide nanoparticles into the wall surfaces of the CNTs is facilitated. Two main methods are used for surface activation of CNT materials: physical and chemical modification. In the physical method, mechanical means such as ultrasonic, milling, crushing and friction are used to stimulate the surface of CNTs, while the chemical activation process is carried out using oxidising agents such as nitric acid, sulphuric acid, sulphuric acid-nitric acid mixture, potassium permanganate, sulphuric acid in the presence of potassium permanganate, hydrogen peroxide in the presence of nitric acid, hydrogen peroxide, ozone, an inductively coupled plasma or microwave energy and an oxygen-based atmosphere with water [2], In addition, wet chemistry methods are widely used in the synthesis of CNT / metal oxide nanocomposites, in which CNTs serve as nucleation sites for metal oxides. In these methods, a large number of processes including refluxing with strong acids under ultrasonic vibrations lasting for long hours or even days, and then chemical reduction of the precursor metal salts are required. In addition, in traditional methods, the mixture needs to be heated to accelerate the reactions, and usually the liquid mixture is directly heated with a microwave or the reaction vessel is heated with a heat source such as an oil bath, then the liquid mixture is heated by heat conduction. These processes cause significant problems due to the long processing times, the high energy consumption, the use of many different chemicals and the environmental pollution effects. In addition, these methods carry significant risks in terms of occupational safety and human health. Moreover, the size and morphology of the CNT / metal oxide particles obtained in these methods cannot be controlled well and high amounts of material and energy are used for production.

[0010] Due to the limitations and inadequacies of the solutions in the state of the art, the use of environmentally harmful acids, the need for high energy and heat, the very long production period, and the inability to control the size and morphology of the obtained nano composites, it has become necessary to make a development in this area. Brief Description and Aims of the Invention

[0011] The invention describes the method of obtaining carbon nanotube (CNT) / iron oxide (FeaC ) composite carbon nanotube. In said method, FeaC nanoparticles are prepared by green chemistry and combined with CNT, providing the composite with magnetisability.

[0012] The aim of the invention is to provide an environmentally friendly composite carbon nanotube preparation method. In the invention, FeaC nanoparticles are synthesised using green tea leaves and combined with CNT, eliminating the need for the use of hazardous acids such as sulphuric acid. Since such hazardous acids are not included in the method of obtaining the composite, both environmentally harmful wastes are not generated and exposure of employees to hazardous acids is prevented.

[0013] Another aim of the invention is to provide a method of obtaining composite carbon nanotubes without the need for high temperatures. In the invention, high temperatures are not required during obtaining the FeaC nanoparticles obtained by the green chemistry method and during the process of combining these nanoparticles with CNT. The fact that these temperature values are not high both reduces high costs and contributes to employee safety.

[0014] Another aim of the invention is to provide a fast composite carbon nanotube production method. By means of the green chemistry method and other process steps preferred in the invention, composite carbon nanotubes are obtained much faster than the state of the art.

[0015] Detailed Description of the Invention

[0016] The invention describes the production of carbon nanotube (CNT) / iron oxide (FesC ) composite carbon nanotube using the green chemistry method.

[0017] The production method of a composite carbon nanotube comprising iron oxide nanoparticles synthesised with green chemistry, which is the subject of the invention, comprises the process steps of: - taking iron (III) chloride hexahydrate (FeCl3.6H2O) into distilled water and adding green tea leaves,

[0018] - stirring the mixture under optimised conditions in a magnetic stirrer until the colour of the mixture turns black,

[0019] - washing the mixture cooled to room temperature with ethanol, incubating it at a certain temperature for a certain period of time and turning it into powder,

[0020] - obtaining the powdered FeaC structure by burning the resulting powdered mixture at a certain temperature for a certain time,

[0021] - preparing the solution by dissolving the obtained powder FeaC and carbon nanotube (CNT) and distilled water in an ultrasonic bath with the addition polyvinyl alcohol (PVA).

[0022] - stirring the solution on a magnetic stirrer for a certain period of time at a certain temperature, and

[0023] - incubating the solution at a certain temperature for a certain period of time after stirring.

[0024] With the invention, CNT / FesC composite is obtained in powder form. By means of the FeaC in this composite powder, non-magnetised CNTs gain magnetic properties. After combining with FeaC , CNTs show super paramagnetism. Thus, the obtained composites can be used in magnetic data storage technology by means of both their small size and advanced magnetic coercion properties. Due to these magnetic properties, they can be used in advanced technology fields such as nanoelectronics and nanomedicine and also as adsorption materials due to their porous and hollow structures.

[0025] In the invention, iron (III) chloride hexahydrate (FeCl3.6H2O) is taken into distilled water and green tea leaves are added. This mixture is stirred in a magnetic stirrer under optimised conditions until the colour turns black (in other words, until the product appears). The mixture cooled to room temperature is washed with ethanol and the mixture is incubated at a certain temperature for a certain period of time. The dry powder mixture obtained by incubating this mixture is burned at a certain temperature for a certain period of time. As a result of this burning, powders with FesC structure are obtained. After dissolving FesC powder and CNT with distilled water in an ultrasonic bath, polyvinyl alcohol (PVA) is added to the solution. Then, this solution is stirred in a magnetic stirrer at a certain temperature for a certain period of time. The final product is incubated at a certain temperature for a certain period of time. Thus, the synthesis (accumulation) of FeaC nanoparticles, which were obtained as a result of the reduction reactions between FeCl3.6H2O and green tea leaves, on the CNTs is ensured. In the processes given here, instead of green tea leaves, the bark, leaf or fruit of other plants can be used.

[0026] In the invention, reduction reactions are carried out between FeCh.6H2O and green tea in a mixture environment where CNTs are present, and CNT / FeaC composite powders are obtained. Therefore, the need for many chemicals used in traditional methods is eliminated with the invention. In addition, there is no need for the use of reactions that need to be carried out under high heat for a long time. Since no residual products harmful to human health and the environment are formed as a result of the reactions, problems regarding the disposal of harmful chemicals are also eliminated.

[0027] REFERENCES

[0028] [1] S. Mallakpour, E. Khadem, Carbon nanotube-metal oxide nanocomposites: Fabrication, properties and applications, Chemical Engineering Journal (2016), doi: http: / / dx.doi.Org / 10.1016 / j . cej .2016.05.038

[0029] [2] Flahaut E, Peigney A, Laurent Ch, Marliere Ch, Chastel F, Rousset A. Carbon Nanotube-Metal-Oxide Nanocomposites: Microstructure, Electrical Conductivity And Mechanical Properties. Acta mater. 48, 3803 - 3812, 2000

Claims

CLAIMS1. A method for obtaining a magnetisable composite carbon nanotube comprising iron oxide nanoparticles, comprising the process steps of:- taking iron (III) chloride hexahydrate (FeCl3.6H2O) into distilled water and adding green tea leaves,- stirring the mixture under optimised conditions in a magnetic stirrer until the colour of the mixture turns black,- washing the mixture cooled to room temperature with ethanol, incubating it at a certain temperature for a certain period of time and turning it into powder,- obtaining the powdered FeaC structure by burning the resulting powdered mixture at a certain temperature for a certain time,- preparing the solution by dissolving the obtained powder FeaC and carbon nanotube (CNT) and distilled water in an ultrasonic bath with the addition polyvinyl alcohol (PVA).- stirring the solution on a magnetic stirrer for a certain period of time at a certain temperature, and- incubating the solution at a certain temperature for a certain period of time after stirring.

2. A composite carbon nanotube comprising iron oxide nanoparticles obtained by a method according to claim 1 .

3. A method according to Claim 1 , wherein the bark, leaves or fruits of different plants can be used instead of green tea leaves.