Access to clean, safe drinking water is thought to be a basic human right. Yet, according to the World Health Organization (WHO), over 785 million people across the globe are without access to a basic drinking-water source. This has researchers around the world researching and developing a series of water treatment solutions and applications using nanotechnology.
Current WHO statistics are damning, making this an issue that must be addressed urgently as it is thought that around 2 billion people are using a contaminated water supply. In addition, over 485,000 people die each year from diarrhoeal related illnesses and diseases such as polio, typhoid, and cholera are once again being transmitted as a further consequence. Based on current trends and data, it is thought that by 2025 half of the total global population will be living in water-stressed or water-scarce areas.
While there are a wide-range of effective water purification methods and techniques including boiling, filtration, oxidation, and distillation, these often require high amounts of energy. Other treatment processes may include the use of chemical agents which is only possible in areas with an infrastructure that is up to par.
The more affordable and portable devices currently available are not always fit for purpose as they cannot guarantee 100% removal of harmful viruses, bacteria, dust, and even microplastics. So, it is thought that nanotechnology could offer affordable and accessible clean water solutions to the world’s most vulnerable populations.
Nanotechnology is a process that involves manipulating and controlling matter on the atomic scale. In the process of water purification, this involves using nanomembranes to soften the water and eradicate biological and chemical contaminants as well as other physical particles and molecules.
What’s more is that nanotechnology is portable and can be incorporated into existing commercial devices which increases the likelihood that nanotech solutions could become a feasible option for areas of the developing world and places with limited infrastructure.
In recent years scientists have improved on conventional methods that use coagulants by taking their cues from nature, notably the ocean dwelling Actinia organism. Traditional coagulants, such as aluminum sulfate and other metallic salts can pull out larger contaminants by causing them to group together and settle. However, this method is not effective for smaller particles and molecules and often requires additional methods to ensure the water is clean. Thereby increasing the cost and use of energy as several techniques are required to ensure the water is safe.
Using nanocoagulants, scientists were able to synthesize organic and inorganic matter to replicate the structure of the Actina sea anemone. The researchers produced a reversable core-shell that can catch larger particles as well as the smaller ones when it turns inside-out. This is also a one-step process which removes the need for additional technologies and opens up the potential for minimizing water purification costs.
Another viable method of water purification currently in development that makes use of nanotechnology includes utilizing magnetically active nanoparticles to extract chemicals from water. The process enables the removal of toxins from drinking-water contaminants attracting nanoparticles that consist of magnetic phases. This solution would also be low-energy and could provide an economic advantage as well as health and environmental benefits.
Other proposals for nanotech solutions include using nanoparticles to break down microplastics and a rapid nano-filter that can clean dirty water 100 times faster than current methods. Researchers are also aware that most water purification methods require access to a constant electricity supply, but this can be a significant obstacle in places with limited infrastructure or areas damaged by extreme weather conditions.
One such approach is the creation of a self-sustaining biofoam that conducts heat and electricity by combining bacteria-produced cellulose with graphene oxide. The graphene-fused foam draws water up to the surface via the cellulose layer which accelerates evaporation. This results in a layer of freshwater which can be easily collected and is safe to drink. The biofoam is also lightweight and relatively inexpensive to manufacture making it an attractive alternative to conventional methods.
Thus, as the need for clean, safe water is very much still an urgent global issue, nanotech solutions offer new and essential possibilities for the water treatment industry. The next phase of development is the scaling up of nanotechnologies to improve access to clean water. Perhaps then the future can be one that offers a new hope to the expanding global population experiencing water-stressed and water-scarce conditions.
Re-Posted from AZ NAno – David J. Cross MA