Green Nanotechnology

Green Nanotechnology: Hope for future

Nanotechnology is the fastest growing discipline of science providing vast applications from house hold appliances, drug delivery, diagnostic and therapeutic techniques, nanorobotics, nanochips to powerful building materials. However, besides tremendous benefits of nanotechnology there are some concerns leading towards the thoughts that it might be unsafe for environment and human health to use nanomaterials. To overcome such environmental issues there is a new branch developed named as ‘Green Nanotechnology’ which is sometimes refers as clean nanotechnology. Now, scientists are giving priority to green nanotechnology because it promises to produce clean technologies in present and also in future. 

 In Green Nanotechnology, eco-friendly nano-products and processes are used to increase the environmental sustainability and to reduce human health risks due to the use of unsafe nanoparticles. Green nanotechnology actually uses the principles of Green chemistry and Green engineering.
Objectives of green nanotechnology:
There are two main objectives of green nanotechnology i.e.;

• Designing such nanoparticles which are harmless to human health as well as environment.
• To remove toxicity from environment by using techniques of nanotechnology (provide solutions to environmental pollution).

Principles of green nanotechnology:

The principles of green chemistry and green engineering are applied on green nanotechnology which are;

• To make nanoproducts without toxic composition.
• To use low temperature and low energy during production of nanoproducts.
• To use renewable resources.
• To use such engineering processes that are not harmful to the lifecycle .

 Solutions provided by green nanotechnology to environmental problems
Following are some ways to improve the nanotechnology and provide solutions to health and environmental hazards.

•  It provides nano-scale separating membranes to separate the chemical reaction products from waste or toxic particles.
• Nanomaterials are used as catalysts to enhance the efficiency of processes and to avoid wasteful chemical reactions.
• Nano-scale sensors are used in manufacturing process for detection of waste particles and to manage the fabrication techniques.

Recent advances in Green Nanotechnology
Recent researches in green nanotechnology shows that it will be helpful to clean the environment from waste and toxic materials by using nano-materials. There are a number of vast applications of green nanotechnology such as water treatment, nano-remediation, renewable energy sources, treat air pollution and oil spill treatment etc. These applications of green nanotechnology are a hope for clean and safe environment of Earth in future.
1. Water Treatment
Many countries of the world are facing shortage of clean water for drinking and it is probably one of the biggest shortcomings expected in future. Traditional water filtration techniques use certain chemicals for cleaning of water which are harmful for human health and these methods are also expensive for third world countries. On the other hand, green nanotechnology is treating water pollution by using catalysts adsorbent and sensors based on nanomaterials. Carbon Nano tubes (CNT) are playing crucial role in containment filter technology because CNT are highly permeable, having
large surface area, thermally and mechanically stable nanomaterials. Function of CNT in water treatment.

•  Remove bacteria and viruses
•  Removes heavy metals
•  Removes Organic solutes 

Thermonuclear trap technology (TTT) was developed by Ringwoodite Co Ltd. in 2017.
The main purpose of developing such nanotechnology-based method is to purify river, lake and sea water which will be used for drinking purposes. Even radioactive isotopes were also being removed by using this technology. 
Titanium oxide photocatalysis is being in research trials to disinfect water from microbial species Nano-filtration method is used to clean ground and surface water by using nano-sized separating membranes. 

2. Nano-remediation
Nanomaterials are used in environmental remediation refers as nano-remediation. Nano-remediation is being applied on treatment of

• Water pollution
• Soil and sediments toxicity
• Gas from toxic particles

Zero valent iron nanoparticles are used for ground water waste treatment. 
Buckminsterfullerene have the ability to control pollution and protect environment against reactive oxygen species. Recent researches show that it will provide cheap access to hydrogen fuel. 

3. Green nanotechnology for renewable energy
Nanotechnology is producing more powerful and efficient solar and fuel cells. The main objective of using nanotechnology in battery cells, solar cells and fuel cells is to store more energy in them because nanomaterials have greater surface area that’s why they have more capacity to store energy which also assist to waste less thermal energy. Hydrogen fuel cells may increase its hydrogen storage capacity by using nano-based catalysts.
Nanomaterial such as titanium dioxide, silver nanoparticles, quantum dots and nanocrystals are used for solar cells and photovoltaic cells coatings because they are providing toxic free environment with efficient energy storage. 

4. Oil spills treatment
Oil spills is yet another major source of environmental pollution which directly affect the aquatic life and indirectly human life. Conventional methods to remove oil spills are not very successful. Nanotechnology researches shows that nanowires are useful to remove oil spills as well as it can absorb much oil in them which means oil can also be recovered by using nano-based technology. As nanowires are made of hydrophobic interaction these can repel water and absorb as mush oil in them. Nanowires are being successfully developed on industrial scale to control and clean oil spills in future.

5. Air pollution treatment
Nanotechnology is being used to remove hazardous particles from air. Nano-based catalysts and nano-based membranes are very helpful to control air pollution. Catalysts are used to enhance chemical reaction, less energy wastage and are able to convert toxic chemicals from industrial gas pollution to less harmful gasses. Nanoparticles have larger surface area which have the ability to enhance the activity of catalysts by interacting with them. These nano-based catalysts are lower in cost and have greater efficiency to clean air. Following catalyst from nanoparticles are being manufactured:

•  Gold nanoparticles catalyst are used to convert volatile compounds into harmless gases by breaking down the organic bonds in them.
•  Nanocrystals are used to absorb carbon dioxide gas.
•  Cobalt and platinum-based nano-catalysts can be used to extract nitrogen from chimney smoke.

Nano-based membranes are used for filtration and separation of hazardous chemicals and dust particles from air. It has so small pores inside membranes that it can absorb dust particles as well as other harmful substances.

• Carbon nano-fiber membranes are useful to clean indoor air from formaldehyde which is usually treated with photocatalysts which are harmful.
• Carbon dioxide from smoke of industrial plants can be removed by using carbon nanotube membranes.

NanoStellar and Poriferia are the nanotechnology companies which are manufacturing nano-based catalysts and nanostructured membranes patents are in trials.
Nano-sensors are used to detect harmful chemicals, microbial and viral agents in the environment. Their sensing ability is increased by using different coats of biological ligands upon them. Carbon nanotubes-based sensors act as electrochemical sensors and their electrical resistance changes when they interact with harmful gases like O, NH 3 and NO 2 .
Green nanotechnology is thus a hope for future to clean environment of Earth from toxic substances by using renewable resources and safe nanoparticles. Some of the applications ofgreen nanotechnology are under trials which are hopeful to maintain the sustainability of ecosystem.

By: Maryam baig