Applications of Nanomaterials

Advances and Key Technologies

Sneha Bhagyaraj, Oluwatobi Samuel Oluwafemi, Nandakumar Kalarikkal, Sabu Thomas, Sneha Mohan Bhagyaraj

• Publisher: Woodhead Publishing
• Year: 2018
• Print ISBN: 9780081019719
• eBook ISBN: 9780081019726
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Applications of Nanomaterials: Advances and Key Technologies discusses the latest advancements in the synthesis of various types of nanomaterials. The book's main objective is to provide a comprehensive review regarding the latest advances in synthesis protocols that includes up-to-date data records on the synthesis of all kinds of inorganic nanostructures using various physical and chemical methods. The synthesis of all important nanomaterials, such as carbon nanostructures, Core-shell Quantum dots, Metal and metal oxide nanostructures, Nanoferrites, polymer nanostructures, nanofibers, and smart nanomaterials are discussed, making this a one-stop reference resource on research accomplishments in this area. Leading researchers from industry, academia, government and private research institutions across the globe have contributed to the book. Academics, researchers, scientists, engineers and students working in the field of polymer nanocomposites will benefit from its solutions for material problems. - Provides an up-to-date data record on the synthesis of all kinds of organic and inorganic nanostructures using various physical and chemical methods - Presents the latest advances in synthesis protocols - Includes the latest techniques used in the physical and chemical characterization of nanomaterials - Covers the characterization of all the important materials groups, such as carbon nanostructures, core-shell quantum dots, metal and metal oxide nanostructures, nanoferrites, polymer nanostructures and nanofibers

Chapter 1

Nanocomposites and Its Applications

Gunvant H.Sonawane^⁎; Sandip P.Patil^†; Shirish H.Sonawane^{‡ ⁎}Department of Chemistry, Kisan Arts, Commerce and Science College, Parola, India
^†Nano-Chemistry Research Laboratory, G.T. Patil College, Nandurbar, India
^‡Chemical Engineering Department, National Institute of Technology, Warangal, India

Abstract

In the recent past, nanocomposites have gained a great deal of attention due to their versatility. The present study reports on how some of the recent developments in nanocomposites can aid environmental protection through photocatalytic degradation of organics. Nanocomposites are prepared by three methods, intercalation, precipitation and evaporation. Techniques like SEM, TEM, XRD, EDS, Raman, IR spectroscopy are used to characterize nanocomposites. Nanocomposites drive the photocatalytic properties of the semiconductor-based nanomaterials in the visible range. They are also responsible for the separation of electron-hole pairs to enhance photocatalytic power nanomaterials. The combination of photocatalysis and photoinduced super hydrophilicity are applied for antibacterial sanitary surfaces through self-cleaning construction materials, odor-eliminating textiles, and pollutant-diminishing paints. In addition, there has recently been development toward multifunctional cotton fabrics with nanocomposite coating. Such fabric exhibits excellent antibacterial and UV blocking activities. Various types of clay, graphene, and graphene oxide are used as supports in nanocomposites. Nanocomposites of binary and ternary metal oxides, or heterostructures, can also be useful in photocatalysis and other applications.

Keywords

Nanocomposites; Semiconductor oxides; Photocatalysis; Antibacterial activity; Hydrophilicity

1.1 Introduction

Today, environmental pollution is a major area of concern due to its impact on living organisms, both directly and indirectly. Various industries pollute through the discharge of organic and inorganic materials into local water streams. But rapid advances in the fields of science, engineering and technology have yielded specific materials and methods to tackle this problem. Wastewater treatment involves adsorption, destruction by photocatalysis and/or oxidation processes, and enzymatic and microbial decomposition. Among the various wastewater treatment methods, adsorption is considered more effective due to its convenience, ease of operation, and simplicity of design. Activated carbon is one of the adsorbent used efficiently. However it‘s high cost is a drawback. Cost is the decisive parameter for the choice of adsorbent. According to Crini [1], a sorbent can be considered low cost if it requires little processing, is abundant in nature, or is an industrial by-product [2]. Sometimes these methods are ineffective and partial oxidation of organic contaminants produces secondary pollutants more toxic than parent compounds [3].

The adsorption method suffers from difficulties in the treatment of insoluble dyestuff effluent as well as in finding the desorption process [4]. The main drawbacks of these techniques are the disposal of the spent contaminated activated sludge and difficulties in controlling the appropriate reaction conditions and amount of by-products [5,6].

Various developments in nanoscience/nanotechnology wherein nanoscale materials are synthesized with the ability to change harmful pollutants into less/non harmful ones have shown a major impact.

Being a green, highly efficient, and effective technology, heterogeneous photocatalysis is regarded as a promising technology to address environmental challenges in the near future [7,8]. It is an excellent method over the others due to its use of oxygen as an oxidant and oxidation of organics at low temperature and low concentrations with complete mineralization. Thus some of the semiconductor metal oxides like TiO₂ and ZnO have a higher band gap for the excitation of electrons from valence band to conduction band and require high energy UV radiations. Therefore, many studies have been devoted either to modify the energy band gap of these semiconductor metal oxides or to find alternatives to them in order to utilize solar energy. These methods involve (a) doping with other elements, (b) the fabrication of heterojunction structure by combining a semiconductor with metals or other semiconductors, (c) the use of clay or graphene/graphene oxide as a support to enhance solar light sensitivity [9].

Clay or graphene/graphene-oxide supported nanocomposites are found to exhibit versatile degradation properties as clay minerals possess good adsorption-desorption properties. They change the photocatalysis from UV to the visible region. They also are responsible for the separation of electron-hole pairs to enhance the photocatalytic power of nanomaterials.

1.1.1 Advanced Oxidation Processes

Advanced oxidation processes (AOPs) are one of the most useful techniques for the degradation of organic compounds in wastewater treatment. The mechanism of AOPs relies on the formation of highly reactive oxidant species, mainly hydroxyl radicals, which can react with harmful compounds until their degradation [10]. However, the application of AOPs to degrade all pollutants from wastewaters can be not sustainable. Their combination with heterogeneous photocatalysis can be considered as an equally valid option. It has been extensively proven that AOPs can improve the degradation efficiency of wastewaters, thus enhancing the degradation of both organic and recalcitrant compounds. Advanced oxidation processes that involve the in situ generation of highly potent chemical oxidants such as the hydroxyl radical (OH^•) have recently emerged as an important class of technologies for accelerating the oxidation and destruction of a wide range of organic contaminants in wastewater [11]. AOPs, when applied in the right place, give a good opportunity to reduce the contaminant concentration from several hundred ppm to less than five ppb. That is why they are called “the treatment processes of the 21^st century”. The improving degradation ability of AOPs in recalcitrant compounds in wastewater depends on both chemical and physical properties of contaminants as well as on the generation of reactive free radicals, in most cases hydroxyl radicals [12]. The oxidation reaction between these radicals and the contaminants is the mechanism behind the degradation of the contaminant itself. The generation of these reactive agents can be achieved by means of several processes, including sonolysis [13], ozone-based processes [14], Fenton-based reactions [15], heterogeneous photocatalysis [16] and various combinations of these technologies [17,18]. Each one can be characterized according to its specific method for the production of free radicals. The AOP procedure is particularly useful for cleaning biologically toxic or nondegradable materials such as aromatics, pesticides, petroleum constituents, and volatile organic compounds in wastewater [19]. Additionally, AOPs can be used to treat effluent of secondarily treated wastewater, which is then called tertiary treatment [20]. The pollutant materials are mostly converted into stable organic and inorganic compounds such as water, carbon dioxide, and salts, that is, they undergo mineralization. The aim of wastewater treatment through AOPs is the reduction of pollutants and toxicity to such an extent that the purified wastewater may be reintroduced into receiving streams, or at the least into conventional sewage treatment.

AOPs have several unparalleled advantages in the field of wastewater treatment: they can effectively degrade organic compounds in aqueous phase, rather than collecting or transferring pollutants into another phase; the remarkable rea...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Chapter 1: Nanocomposites and Its Applications
• Chapter 2: Semiconductor/Graphene Nanocomposites: Synthesis, Characterization, and Applications
• Chapter 3: Nanomaterials as Catalysts
• Chapter 4: The Electrochemical Conversion of Carbon Dioxide to Carbon Monoxide Over Nanomaterial Based Cathodic Systems: Measures to Take to Apply This Laboratory Process Industrially
• Chapter 5: Green Nanotechnology—A Road Map to Safer Nanomaterials
• Chapter 6: Nanobiosensors Based on Graphene Electrodes: Recent Trends and Future Applications
• Chapter 7: Applications of Nanofibers in Tissue Engineering
• Chapter 8: Nano-Enabled Immunosensors for Point-of-Care Cancer Diagnosis
• Chapter 9: The Role of Nanomaterials in Analytical Chemistry: Trace Metal Analysis
• Chapter 10: Comparative Study on Doxorubicin Loaded Metallic Nanoparticles in Drug Delivery Against MCF-7 Cell Line
• Chapter 11: Nanomaterial Toxicity: A Challenge to End Users
• Chapter 12: Biomedical Applications of Magnetic Nanomaterials
• Chapter 13: Carbon Nanotube Tube Filled Polymer Nanocomposites and Their Applications in Tissue Engineering
• Chapter 14: Cellulose Nanocrystals for Health Care Applications
• Index