Management of nanomaterials

 Introduction Of Nanomaterials .

Nanomaterials are usually considered to be materials with at least one external dimension that measures 100 nanometres or less or with internal structures measuring 100 nm or less. They may be in the form of particles, tubes, rods or fibres.

What are nanomaterials?

Nanomaterials are particles that are so small that we can only see them using a microscope. Some nanomaterials are natural (e.g. pollen and sand), others are unintentionally made (e.g. car exhaust fumes), while others are purposely manufactured. Being small sometimes means that nanomaterials behave differently compared to the same substance in bigger sizes, which may influence the potential risk. There are large gaps in our knowledge about their associated health hazards, therefore particular care must be taken in the management of these materials.

In a legal context, the European Commission has provided a recommendation on how to define a nanomaterial based solely on the size of the constituent particles of a material, without regard to the hazard or risk. This definition covers natural, incidental or manufactured materials and underpins the implementation of regulatory provisions for this group of materials.

The recommended EU Commission definition for nanomaterials states that a nanomaterial is:

A natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50 % or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm - 100 nm.

In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50 % may be replaced by a threshold between 1 and 50 %. By derogation from the above, fullerenes, graphene flakes and single wall carbon nanotubes with one or more external dimensions below 1 nm should be considered as nanomaterials.

Nanomaterials Healthy and Safety Concerns. 

Just like any other chemical substance, some nanomaterials are hazardous and others not. The nanoscale of the particles does not in itself imply a hazard. Instead the potential effects are based on the adverse effects a nanomaterial may cause and the amount taken up by an organism (humans or an animal).

A number of manufactured nanomaterials have however been associated with health hazards. Research by the scientific committee on emerging and newly identified risks (SCENIHR) has indicated that some nanomaterials can be taken up in the lungs causing inflammation and tissue damage, fibrosis and tumour generation. The cardiovascular system may also be affected. Some types of carbon nanotubes can lead to asbestos-like effects. As well as the lungs, nanomaterials have been found to reach other organs and tissues including the liver, kidneys, heart, brain, skeleton and soft tissues.

As a result of their small size and large surface area, particulate nanomaterials in powder form may present risks of explosion, whereas non-nanosized versions of the same substance may not.

What are the four types of nanomaterials?

Nanomaterials can be categorized into four types [9, 10] such as: (1) inorganic-based nanomaterials; (2) carbon-based nanomaterials; (3) organic-based nanomaterials; and (4) composite-based nanomaterials.

Nanomaterials in consumer products

The use of nanomaterials is rapidly expanding and a large number of everyday products on the European market contain nanomaterials. Nanomaterials offer significant technical and commercial opportunities in the EU, and nanotechnology has been identified by the European Commission as a key enabling technology.

Consumers may be exposed to manufactured nanomaterials contained in paints, sun-screens and other cosmetics, food and food packaging, textiles, sports equipment, electronics and batteries. Their function may be:

UV-blocking

self-cleaning

 anti-bacterial

water repellent

thermal insulation

enhanced strength

enhanced colour, texture, flavor and consistency of food

water purification.

Properties

The quantum properties of the materials get affected as the sizes are reduced. The small size of these materials makes them free from internal imperfections present in structures and gain protection from mechanical failures. Even thermal and catalytic properties are observed once the bulk material is broken down to the nanoscale.

An increase in the ratio of the area of the surface to volume leads the system to become more reactive. These materials can rearrange the crystalline structure on dispersion.

Examples

In the field of cosmetics, the material called titanium oxide is used in the sunscreens. The field of sports utilizes nanotubes of carbons to produce bats used in baseball. Because the bats made from this will be lighter in weight resulting in the improvement of performance. Further, antimicrobial items like mats and towels are made using nanotechnology so that illness due to bacteria can be prevented and are used by sportspersons.

The systems made of sensors use nanomaterials called titanium dioxide in their development. It is helpful in the military to detect the presence of biological agents.  The plastic chairs used in gardens uses the coatings of nanomaterial called titanium dioxide. A film on the creating is created so that any dirt is dissolved can be removed with the next shower. and cleans the chairs.

Classification of Nanomaterials

The classification of nanomaterials is based on various approaches. One of the approaches is based on the size of the material and they are classified as

Zero Dimension

These materials don’t have any dimensions. Point materials including oxides, semiconductors, quantum dots, hollow spheres, etc…

Zero Dimension Nanomaterials

One Dimension

The one billionth of any given unit that is a film of thin type is known as one dimension nanoparticles. It is used in engineering, electronics, chemistry, and so on for many decades. These are used in the construction of nanorods, nanowires, nanotubes, etc…

One Dimension

Two Dimension

This structure consists of two dimensions that are outside the range of nanometric size. It has characteristics dependent upon the shapes. Monolayer, Multilayer, Self- assembled, etc… comes under this category.

Two Dimension Nanomaterials

Three Dimension

In this, the structure consists of three dimensions. These are most widely used in magnetic materials, catalysts, and so on.  These 3-D structures are further categorized as Fullerenes, Dendrimers, and Quantum Dots.

Three Dimension

From the classification, it is evident that the behavior of these particles is purely based on shapes, sizes, morphologies.

What are the advantages of nanomaterials?

The advantages of the nanomaterials are: The small size of these materials offers the possibilities of manipulation easier, and multiple functions can be accommodated. Porosity is high in nanomaterials leads to an increase in its demand in the industries.