CHARACTERISATION OF SYNTHESISED ZINC OXIDE NANOPARTICLES (EDUCATION PROJECT TOPICS AND MATERIALS)
CHAPTER ONE
1.0 INTRODUCTION
1.1 Background
Nanotechnology is the science that deals with matter at the scale of 1 billionth of a metre (i.e. 10-9m = 1nm), and is also the study of manipulating matter at the atomic and molecular scale.
Nanocrystalline materials may be considered as the challenge of this age as intensive investigations were stimulated for several applications for these new classes of materials. Recently, scientific and research community have shown great interest on metal oxide nanostructures and their applications due to their easy, safe, environmental friendly, cheap synthesis procedure and technological applications.
Nanomaterials are typically defined as materials smaller than 100nm in at least one dimension. At this scale, materials often possess novel size-dependent properties different from their large counterparts, many of which have been explored for applications in water and wastewater treatment.
Some of these applications utilize the smoothly scalable size-dependent properties of nanomaterials which relate to the high specific surface area, such as fast dissolution, high reactivity, and strong sorption. Others take advantage of their discontinuons properties such as superparamagnetism, localized surface Plasmon resonance and quantum confinement effect (Xiaolei et al, 2013.
Water containing unwanted substances which adversely affect its quality and thus making it unsuitable for use is termed wastewater.
Water is the most essential requirement in daily life that has been contaminated by the disposal of domestic, municipal and industrial waste. Anything, which is not needed, finds its way to the nearest watercourse or land, which further pollutes the ground water. So, there is a need to initialize the available resources effectively without polluting the eater (Prasad and Kumar, 2010).
Wastewater when left untreated may pose threat to living beings and the environment which makes it essential to treat wastewater before disposal.
Various physical, chemical and biological treatment processes are used for wastewater treatment. Among these methods, nanotechnology has been extensively studied by researchers as it offers potential advantages like low cost, reuse and high efficiency in removing and recovering the pollutants.
Adsorption is commonly employed as a polishing step to remove organic and inorganic contaminants in water and wastewater treatment. Efficiency of conventional adsorbents is usually limited by the surface area or active sites, the lack of selectivity and the adsorption kinetics. Nano-adsorbents offer significant improvement with their extremely high specific surface area and associated sorption sites, short intraparticle diffusion distance, and tunable pore size and size and surface chemistry (Xiaolei et al, 2013).
Mall et al (2005), reported that physiochemical processes are generally used to treat dyes ladder wastewater. These processes include flocculation, electro floatation, precipitation, electro kinetic coagulation, ion exchange, membrane filtration, electrochemical destruction, irradiation and ozonation. However, all these processes are costly and cannot be used by small industries to treat wide range of dye wastewater.
Adsorption process provides an attractive alternative for the treatment of contaminated waters, especially if the sorbent is inexpensive and does not require an additional pretreatment step before its application (Mall et al, 2005)
Mamadou and Savage (2009), reported that various methods such as photo catalysis, nanofiltration, adsorption and electrons, nanowire membranes, polymer membranes, carbon nanotubes submicron nanopoweder, metal (oxides), magnetic nanoparticles, nanostructure born doped diamond and used to resolve or greatly diminish problems involving water quality in natural environment.
Nanoparticles when used as adsorbents, nanosized zerovalent ions or nanofiltration membranes cause pollutant removal or separation from water whereas nanoparticl;es used as catalysts for chemical or photochemical oxidation effect the destruction of contaminants present (Nowack, 2008).
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CHARACTERISATION OF SYNTHESISED ZINC OXIDE NANOPARTICLES (EDUCATION PROJECT TOPICS AND MATERIALS)
