Safe, clean drinking water.
We take it for granted every time we turn on the faucet,
and yet we are highly dependent on it.
In fact, approximately 86% of the U.S. population,
about 270 million people, relies on a public water supply,
using about 42 billion gallons per day.
Water is in almost every single aspect of our lives.
We need water to irrigate our crops,
so our food also depends on water.
We need water to produce energy in power plants.
Water, food and energy are part
of something called the human water cycle,
a concept that shows how these three vital aspects
of human life are interconnected.
Orlando Coronell is a professor of environmental sciences
and engineering at the University of North Carolina at Chapel Hill
and funded by the National Science Foundation.
His research focuses on the connection between water and energy.
To produce water for drinking purposes, we need to use energy.
Energy is used to move the machinery that cleans water.
Drinking water comes from lakes, streams and underground aquifers,
and it can become contaminated in a number of different ways.
For example, from fertilizer runoff and animal waste from agriculture,
to chemicals discharged from factories,
to viruses and bacteria in sewage systems.
Water treatment plants remove these contaminants before water flows
into the public supply.
While necessary for public health, water treatment plants use a lot
of energy and are expensive,
a cost which is eventually passed on to consumers.
Membrane technology is currently used to purify water.
There are two types: Low-pressure membranes are used
to remove what we consider
in the water treatment world big contaminants.
Micro-organisms for example, protozoa or parasites or bacteria.
High-pressure membranes on the other hand are used to remove things
that are much, much, much smaller.
But like any filter, membranes can ultimately become clogged.
To help solve this problem,
Coronell and his research team are developing something called
thin-film nanocomposites, a type of high-pressure membrane embedded
with nanoparticles that allows water to flow
through faster and more efficiently.
These membranes are just 300 microns thick,
roughly 3 times the diameter of a human hair,
and are composed of three different layers:
the top active layer and two support layers.
The top layer is what we call the active layer
and we call it the active layer because it is the layer responsible
for the water productivity
and contaminant removal capabilities of the membrane.
The top active layer of the membrane is fabricated in the lab
by taping the two pre-fabricated support layers to a glass plate
and dipping it into two different chemicals.
This is a finished thin-film composite membrane
and then the polyamide active layer
that we fabricate is the really shiny layer that you can see.
It's ready to turn on the pump.
The team tests the membrane's efficiency by pumping dirty water
through a cross-flow filtration system and increasing the pressure
over a set period of time.
Samples of the clean and dirty water are then taken and compared
to see how much of the contaminants are being removed by the membrane.
Ultimately, we want to make the technology more affordable
to benefit communities all over the world that are
in need of drinking water.
Coronell's team incorporates nanoparticles with different properties
in this top active layer that allow water to flow more efficiently
through the membrane, while still maintaining or increasing the amount
and types of contaminants it removes.
Some of the nanoparticles that I am working
with basically self-assemble into these very unique like structures,
and as a result of that, they form these highly,
highly porous framework like materials or scaffolds.
Coronell hopes creative new technologies like his will save energy
and money and ensure a safe, plentiful supply of drinking water
for a more sustainable human water cycle.