25.2 Nanotechnology and Nanobiotechnology – The Green Processes and Technologies

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Nanotechnology and nanobiotechnology are having immense applications

in medicine, drug delivery, surgery from the biological side and nanochips,

nanobiosensors, nanorobots being the outcomes in engineering domain; this

chapter focuses on the “greener and cleaner” aspects of the technologies, their

versatile applications, and their role in achieving “zero waste economy.”

25.2

Nanotechnology and Nanobiotechnology – The

Green Processes and Technologies

The main goal underlying “green technology” is to conserve natural nonrenewable

resources; provide a sustainable basis so that present need do not compromise the

requirements of the future generations; devise alternative technologies that are cost

effective, eco-friendly, utilize renewable energy sources, e.g. sunlight, energy from

tidal waves, wind, water current in contrast to fossil fuel, e.g. oil, gas, coal. The aim

of the technology is also to develop products and by-products that can be reused

and recycled and overall improve the quality of human life and society. However

to justify the word “green,” the main aim of the technology is to reduce waste or

achieve “zero waste economy.” Thus, green technology (GT) is also known as envi-

ronmental technology or clean technology. GT encompasses different domains, viz.

green chemistry that focuses on the development of products by processes that mini-

mize the use and generation of hazardous substances; Green nanotechnology aims to

develop eco-friendly products at nano scale, minimize use of starting materials, and

reduce waste generation. Again the concept of green building that involves sustain-

able design in raising buildings by utilizing water, energy, and material resources,

the basic concept that extends much beyond the walls of the buildings and focuses

on the impacts on human health, society, and environment throughout the lifes-

pan of the building. Green building concept aims to protect biodiversity, ecosystems,

reduce waste production, conserve natural resources, minimize the strain on local

infrastructure, and boost the overall quality of life [5, 8].

If nanoparticles be considered as the building blocks of nanotechnology, they

can be synthesized by different physical, chemical, biological, and hybrid methods

by either top down or bottom up approaches. The top-down approach begins with

microsystems and miniaturizes them, whereas the bottom-up approach starts at

atomic or molecular level and then proceeds for build-up procedures by different

physical and chemical processes. In “top-down” approach, there is much waste

generation and thus “bottom-up” approaches are gaining priority in developing

nanostructured materials. Such materials can be one-dimensional (1-D), e.g.

nanofilms and nanocoatings, two-dimensional (2D), e.g. nanotubes and nanorods,

three dimensional (3D), e.g. fullerenes and nanoparticles [5, 7, 9]. Physical methods

associated with nanomanufacturing include arc discharge method, electron beam

lithography, mechanical grinding, milling, spray pyrolysis, ion implantation, vapor

phase synthesis; chemical methods include electrochemical method, pyrolysis,

microemulsion method, coprecipitation method, phytochemical method, sonochem-

ical method, sol–gel process, solvothermal synthesis. Manufacturing at nanoscale