Silver Nanoparticles for Water Purification
Are you skeptical of drinking water directly from the tap or from a natural source like a river or a lake without any treatment? If you answered yes, then your concern is completely valid. Our water resources such as rivers, reservoirs, lakes, and seas are drowning in chemicals, waste, plastic, and other pollutants. According to the National Defense Research Committee (NDRC),more than 80% of waste water is dumped back into these resources with any treatment. In fact, tap water across the US has been found to be contaminated with arsenic, lead, and copper in all of the states in our nation. We know that our earth is covered by 71% water. Yet, it is critical for all of us to acknowledge that our drinking water resources are finite and make up less than 1%. Because of this, water pollution is proven to be detrimental to both humans and the environment.
There are many ways to process water that is filled with harmful contaminants to make it safe to drink. These methods include but are not limited to boiling, filtering, treating water with chlorine or iodine, and using UV rays to kill harmful bacteria. With the current technological inventions on the rise, there are breakthrough results from nanotechnology-based water purification methods, which are highly effective and fast-acting.
Nanotechnology in its simplest definition is the science of very small matter (Dimensions between 1-100 nanometers). Nano means very small, and a nanometer is a one-billionth of a meter. To put it further in the context, a sheet of paper is 100,000 nanometers thick. Looking at everyday objects measured in nanometers helps when understanding how small nanoparticles are:
A fly is about 1 cm = 10 mm = 10, 000, 000 nm (ten million nanometers)
Algae are 100 µm = 100, 000 nm (hundred thousand nanometers)
E.Coli bacteria is 1 µm = 1000 nm (one thousand nanometers)
Now, you might be wondering how scientists research matter that is this tiny. The answer is that they have a piece of special equipment called the Scanning Electron Microscope (SEM) to inspect nano materials.
One such great discovery in the nano material world are silver nanoparticles. Despite their small measurements of 25 nm, they still make a huge impact on nanotechnology healthcare inventions. Silver has been very popular for medical ailment treatments for over 100 years because of its antibacterial and anti-fungal properties. You may be questioning that if silver has been recognized for such a long time, what is so revolutionary about silver nanoparticles? Their tiny size is the revolutionary aspect! The magic of silver nanoparticles is that though they have a very small size, their relative surface area is extremely large, which gives them the ability to easily interact with microbial matters such as bacteria and fungi. The small size helps the nanoparticles to spread evenly across the material that they come into to contact with. For example, if any material is coated with silver nanoparticles, then its surface area seamlessly increases by several million times than if the surface were to be covered by a silver foil. This enlarged surface area provides a strong antibacterial and anti-fungal effect while using a very small amount of silver.
Scientists have discovered promising results with water purification techniques using silver nanoparticle-based water filters, tablets, and water bottles coated with silver nanoparticles. When silver nanoparticles are combined with the plastic of water bottles, silver nanoparticles stay within the plastic and do not get into your body or the environment. However, silver nanoparticles within the plastic actively interact with the bacteria/fungus by directly getting inside the bacteria and quickly combining with the sulphydryl (-SH) of the oxygenic metabolic enzyme to deactivate them by blocking inhalation and metabolism and suffocating the bacteria. In other words, they kill harmful bacteria/fungi by adversely affecting their cell metabolism growth to stop multiplication and growth. Silver nanoparticles are especially popular in healthcare innovations for water purification because they are highly efficacious, non-poisonous, fast-acting, non-stimulating, nonallergic, and hydrophilic. It is now clear that though we have many ways to purify water, the silver nanoparticle method is one of the most effective, fast-acting, and safest methods!
Now, let’s look at some fun facts about the usage of silver from ancient to modern times:
NASA uses silver to purify water in both US and Russian space shuttles.
There are modern electronic ionizer units with silver and copper that are used to sanitize swimming pool waters eliminating the need for the harmful chlorine treatments.
Currently, there are 50+ silver-based medicines in the market in various forms.
Ancient Europeans used silverware to avoid poisoning from food.
Early western settlers used silver coins in their water and milk jugs to prevent spoiling and contamination.
Indian people use a variety of silver tableware, drink-ware, and thin silver films when storing food that is easily spoiled.
It is a very common practice in Australia to keep a piece of silverware in water tanks to avoid contamination.
Picture Source: ceramics.org
