Nanotechnology has the potential to substantially benefit environmental quality and sustainability through pollution prevention, treatment, and remediation. Such benefits include improved detection and sensing, removal of the finest contaminants from air, water and soil, and the creation of new industrial processes that reduce waste products and are themselves "green".
Nanotechnology could also lead to serious environmental problems. It is largely unknown how nano structured materials, nano particles, and other related nanotechnologies will interact in the environment. As the use of nanotechnology is scaled up, emissions to the environment may also increase, and perhaps a whole new class of toxins or other environmental problem may be created.
We will elaborate on the specific areas positive side of nano technology where we anticipate the greatest impact of nanotechnology on the environment-- pollution prevention via green chemistry and green manufacturing, pollution treatment and remediation, and sensors. We will review specific examples of current nanotechnology research efforts and applications, and highlight the areas of particular interest and critical need to protecting the environment. and negative effects of the nano technology that mainly organized into environmental ,health of people involved in the manufacturing process.
Introduction:
Nanotechnology refers most broadly to the use of materials with nano scale dimensions, a size range from 1 to 100 nanometers (billionths of a meter).Many things we are already familiar with are nano scale. Living organisms from bacteria to beetles rely on nano sized protein-based machines that do everything from whipping flagella to flexing muscles. Nanotechnology has been contributing to commercial products for many years;
For example,
1) Nanometer-sized carbon (carbon black) improves the mechanical properties of tires;
2) Nanometer silver particles initiate photographic film development;
3) Nanometer particles are the basis of catalysts critical to the petrochemical industry.
Nanotechnology, however, is more than just being at the nano scale. It is the ability to work at the molecular level, atom by atom, to create large structures with fundamentally new molecular organization. Nanotechnology results in materials and systems whose structures and components exhibit novel and significantly changed physical, chemical, and biological properties resulting from the ability to control structures and devices at atomic, molecular, and supramolecular levels.
Behavior at the nano scale is not necessarily predictable from what we know at macro scales. At the nano scale new, often highly desirable, properties are created due to size confinement, dominance of interfacial phenomena, and quantum mechanics. These new and unique properties of nano structured materials, nano particles, and other related nanotechnologies lead to improved catalysts, tunable photo activity, increased strength, and many other useful characteristics known at macro scales:
As a revolutionary science and engineering approach that affects the existing infrastructure of consumer goods, manufacturing methods, and materials usage, nanotechnology has the potential to have major consequences – positive and negative -- on the environment. Nanotechnology can be of benefit to environmental protection in applications such as reducing use of raw and manufactured materials (dematerialization), minimizing or eliminating the generation of wastes and effluents, and reducing toxics. The environment is also protected in applications that more effectively treat waste streams and remediate existing polluted sites.
At the same time, the potentially harmful effects of nanotechnology applications need to be anticipated and prevented or minimized. These effects may relate to the nature of nano particles themselves, the characteristics of the products made from them, or the aspects of the manufacturing process involved. It is also possible that nanotechnology could lead to societal changes that influence transportation, urban development, information management, and other activities of our society that directly or indirectly effect the quality of the environment.
Positive Impacts of Nano Technology on Environment:-
Pollution Prevention
Pollution prevention means "source reduction" and other practices that reduce or eliminate the creation of pollutants through increased efficiency in the use of raw materials, energy, water or other resources, or protection of natural resources by conservation. Pollution prevention includes substitution of less toxic substances in processing, as well as the production of more environmentally benign materials and manufactured products. The application of nanotechnology to pollution prevention is two-fold. Nanotechnology could be used to make a manufacturing process environmentally safe, or it could itself be an environmentally safe product that replaces raw materials or a toxic substance.
Environmentally Safe Manufacturing and Processing
One highly desirable application for nanotechnology is in developing “green” or environmentally safe technologies that eliminate or minimize harmful emissions and material waste from industrial processes. Ideally, Nanotechnology would greatly enhance environmental protection by providing a cost-effective way to reduce toxic chemicals, such as Persistent Bio-accumulative Toxics (PBTs), Hazardous Air Pollutants (HAPs) and Volatile Organic Compounds (VOCs). Nanotechnology could be used for green chemistry to eliminate or reduce these wastes by: synthesizing new and improved catalysts at the atomic level for industrial processes, building information into molecules(analogous to DNA) which build new molecules; self-assembling molecules as the foundation for new chemicals and materials; and building molecules just in time in micro scale reactors. Nanotechnology could also be useful for waste management and waste reduction practices such as nano scale information technologies for product identification and tracking to manage recycling, remanufacture, and end of life disposal.
Examples of nanotechnology applications that address pollution prevention include manufacturing processes which can occur at ambient temperature and pressure, use of non-toxic catalysts with minimal production of resultant pollutants, use of aqueous-based reactions, or elimination of solvents.
(1) Use biomimetic methods of organizing metal particles 1.5 nanometers in diameter. The approach “Bio Molecular Nano-Lithography”, involves assembling these small metal particles on a biopolymer template or scaffold stretched out on a surface. The goal is to organize the nanostructures into well-defined chip architectures, such as lines and grids, and replace current process chemicals that are harmful to the environment. This approach has already led to nano scale assemblies that demonstrate stable, room temperature electrical behavior that may be tolerant of defects and useful in building nano scale circuits.
Negative Impacts on Environment:
Basically these effects can be divided into two specific areas
1) environment as whole
(2) Health risks to a person
Environment as a Whole
In addition to interest in development of pollution prevention technologies, there is also concern about certain nanotechnologies producing pollution that requires control measures.
For instance, a very promising area in nanotechnology is the development of nano particles called quantum dots – made from semiconductors like CdS or CdSe. These particles have very useful applications in biomedical research and disease diagnosis among other areas. Considering the environmental implications of this area of nanotechnology, some very important questions arise:
As these quantum dots are manufactured,
- What materials are used?
- What waste is produced?
- What toxicity does it have?
- What happens to these materials when they get into the air, soil or ground water?
We know that bulk scale cadmium and cadmium compounds (CdS, CdSe,CdCl2, etc.) are highly toxic. It is possible that nano scale CdS or CdSe quantum dots will be also be toxic. However, we do not know the extent of the toxicity. In addition, Di-Methyl Cadmium Cd(CH3)2, a Pyrophoric, extremely toxic, liquid that decomposes violently in water is used to make these semiconductor Nano crystals.
This leads to another set of questions that need to be addressed as Nano technologies, such as semiconductor quantum dots, are being developed.
• As researchers explore this area of nanotechnology, are they considering what the positive and negative impact on the environment will be?
• Are these safer precursor materials or synthetic methods that can be used to make the quantum dots?
• How are these semiconductor nano particles being introduced to their target?
• Will it be possible to recover the quantum dots for reuse?
• Are there measures that can be taken now to minimize or avoid the negative impact quantum dots (or other nanotechnologies) may have on the environment?
The point is that while nano particles may be released into the environment to clean up existing contaminants, they may also serve to become a new kind of non-biodegradable pollutant that may also remain in the environment indefinitely Understanding how these “dissemination routes” operate—whether they are through the conscious release of industrial waste or an accidental leak of unpurified, nano particle rich air—is key with respect to the environment, “the elimination of nano particles from the environment would be extremely difficult—a major challenge to the manufacturing industry”. There is virtually no information available about the effect of nano particles on species other than humans or about how they behave in the air, water or soil, or about their ability to accumulate in the food chains.”
Health Risks for a Person:
Nano particles may have undue negative health consequences for the heart, lungs, and brain if they are able to enter the body through skin contact, inhalation, or ingestion. “Systematic defects only emerge over time” and may remain “undetected for a long time.”
Information about releases, emissions, transport, distribution, and transformation is necessary to estimate exposure potential.
1. By what means do (can) manufactured nano materials enter the environment?
2. What are the modes of dispersion for nano materials in the environment?
3. Do manufactured nano particles undergo transformation in the environment?
Likely routes of exposure
–Inhalation –Dermal–Eye –Oral
Among them eye and dermal exposure predominates
The three main particles that effect human more are
–Titanium Dioxide particles
–Carbon Black particles
–Diesel particles
These inhaled materials which may cause cell/lung injury
–inhaled materials which promote ongoing inflammation
–inhaled materials which reduce alveolar macrophage function
So, we now want the equipment that sense and control them
Existing and Purposed Measures:
One way of controlling they are by nano sensors Protection of human health and ecosystems require rapid, precise sensors capable of detecting pollutants at the molecular level.
Environmental decision-making could be achieved if more accurate, less costly, more sensitive techniques were available. Of particular interest are remote and continuous monitoring devices that yield real time information or that can detect pollutants at very low concentration levels.
Examples of applications of nanotechnology would be the development of nano sensors for efficient and rapid biochemical detection of pollutants and specific pathogens in the environment; sensors capable of continuous measurement in large areas of the environment, sensors connected to nano-chips for real-time continuous monitoring; and sensors that utilize lab-on-a-chip technology. Another important area of application would be in development of sensors that can be used in monitoring or process control to detect or minimize pollutants or their impact on the environment.
Current sensor applications under development include detection of heavy metals at ppm levels, organic contaminants from air and water, bio-pathogens. Additional applications include sensing in impure streams water quality monitoring of biological and chemical species, and studying interactions of pollutants in the environment such as aerosols, fine particles or particle surfaces.
Scientists at Purdue for example, have created the first protein "Biochips" mating silicon computer chips with biological proteins. These “Biochips” contain highly specific protein functional groups that can sense low concentrations of target substances and organisms. Future chips containing thousands of Nano-scale proteins could be organized into a device about the size of a handheld computer that could quickly and cheaply detect specific microbes, disease cells and harmful or therapeutic chemicals.
And other measures that are to be taken are
1) “If the risks of Nano-technological products are to be assessable and manageable, tests to determine their long-term toxicity are advisable. New kinds of testing and experimental methods may be required.”
2) “Research into the hazards and exposure pathways of nano particles and nano tubes is required to reduce the many uncertainties related to their potential impacts on health, safety, and the environment,” all of which should be undertaken by “an interdisciplinary centre” focusing on “the toxicity, epidemiology, persistence, and bioaccumulation of manufactured nano particles and nano tubes.”
3) Since factory workers interact with substances directly and continuously, their health and safety should be of paramount concern. Workers must be careful throughout the entire production process, from fabrication to transportation to storage.
4) Workers must be especially careful “during loading and unloading of semi-finished or end-products at the production facility”.
5) “Nanotechnologically manufactured products were not subject to any special legislation. There were neither special regulation, recommendations on how such products or their base materials were to be handled, nor any obligate on to label such products for what they were.”
Conclusion:
Whatever may be innovations made in this world to help the mankind will severe its purpose only when the negative impacts of that are either controlled or eliminated. We hope and expect that the negative impacts of the nanotechnology on environment will be restricted and SEVERE THE MANKIND BETTER
References:
- Nano science and Nanotechnology: Opportunities and Uncertainties,” produced by The Royal Society and the Royal Academy of Engineering of Great Britain.
- “Nanotechnology: Small Matter, Many Unknowns,” produced by the Swiss Reinsurance Company (heretofore known as Swiss Re).
- Industrial Application of Nano materials: Chances and Risks,” produced by the Future Technologies Division of Technologiezentrum in Germany.
- Report given by U S Environmental Protection Agency.
Technical paper on Implications of Nano Technology on environment
4/
5
Oleh
siva
