Nanotechnology: Wastewater Treatment

Executive Summary

Nanotechnology is the study of minute things and can be applied in all science fields such as chemistry, biology, materials science, physics and engineering. The concept is to be able manipulate and control individual atoms and molecules. With the technology, nanoscale materials can be of an enhancement in strength, lighter weight and greater chemical reactivity. Nanotechnology products have been widely used in our daily life such as cosmetics, automotive parts, insulators, dental implants etc. It has also been developed for environmental applications such as water purification and waste water treatment and prevents pollution by source reduction, remediation and sensing of pollutants. The techniques will be extended from fabrication

When filtration and elimination of particles is done in suspension, the biological treatment will be the next ideal process. Unfortunately, organic pollutants are not always biodegradable and therefore advanced methods have to be applied. Various methods can be employed such as nanofiltration, photocatalysis, adsorption, and electrochemical oxidation which involve the use of TiO2, ZnO, nanowire membranes, carbon nanotubes, and magnetic nanoparticles, are used to counter problems involving water quality in natural environment. Nanoparticles when used as adsorbents, nanosized zerovalent ions or nanofiltration membranes cause pollutant removal/ separation from water whereas nanoparticles used as catalysts for chemical or photochemical oxidation allow the destruction of contaminants present. Nanoscale materials can be classified into four classes as shown in Table 1.

Table 1. Classification of Nanoparticles 2.1. Photocatalysis

Photocatalysis is a decomposition reaction when metal oxide that acts as catalyst absorbs UV radiation. Photocatalyst produces surface oxidation that can effectively disinfect, deodorize, clean and purify air. When hydroxyl radicals are formed, they can adsorb organic pollutants and react with oxidizing agents to induce oxidative degradation into inorganic compounding such as carbon dioxide and water. Fig 1. Photocatalytic Reaction. Retrieved from “Photocatalytic Materials

Catalysts also now being used in nanotechnology where materials such as titanium dioxide (TiO2) and iron nanoparticles can be used to degrade organic pollutants and remove heavy metals from liquids. Using catalytic particles either dispersed homogeneously in solution or deposited onto membrane structures could chemically degrade contaminants. Catalytic treatment of polluted water could be specifically targeted at degradation of chemical contaminants for which existing technologies are ineffective at.

3. Benefits of Nanotechnology

The use of nanotechnology has increased effectiveness in removing contaminants even at low concentrations. Specificity toward target contaminants has been increased. Nanotechnology has made removal of new contaminants possible. Contaminants that were previously impossible to remove could now be removed such as heavy metals. Nanotechnology has made things simples, helps to reduce the number of steps, materials and energy needed to purify water, making it easier to implement.

4. Toxicity of