Professional paper: Graphene, a universal material, can achieve high-efficiency water purification

Text / Chen Gen When two-dimensional nanomaterials like graphene are stacked together, tiny gaps are formed between these materials, which have a wide range of potential uses.
Now, scientists at Brown University have used the tiny gaps in the graphene stack to efficiently filter pollutants and demonstrated a promising new water purification technology.
In fact, as a two-dimensional carbon sheet, graphene is only one atom thick.
One of them is its ability as a water filtration tool.
This material can be made into a membrane that allows water molecules to pass through while trapping impurities in the liquid.
This includes extracting salt from seawater or removing pollutants from water sources in densely populated areas.
When these graphene sheets are stacked together, nanochannels that can be used for filtration are formed between them.
This means that water can enter the chimney and travel longitudinally through the material, filtering out contaminants.
The Brown University research team believes that if water can be filtered vertically, only through the thickness of the material, rather than the entire length, then the efficiency will be greatly improved.
Currently, the Brown University research team is studying how to improve these types of technologies, and is studying how to manipulate graphene sheet stacks in different ways to produce better results.
However, forming the necessary nanochannels in the vertical direction has proven difficult.
Based on this, the researchers developed a solution.
First, the graphene sheets are stacked on an elastic substrate, and then they are stretched.
After the sheet is deposited, the tension on the substrate is released, causing it to shrink.
When this happens, graphene gathers at the top to form sharp peaks and valleys.
The researchers said that when the graphene is crumpled, it is tilting the sheets and channels out of the plane.
If the graphene can be crimped to a certain extent, it will cause these channels to be arranged almost vertically in the end.
Once the channel is almost vertical, the assembly will be wrapped in epoxy and the top and bottom will be trimmed away so that the channel can be opened and all the way through the material.
The researchers named these assemblies VAGMEs (vertically arranged graphene membranes).
The researchers said that they will eventually get a membrane with very short and narrow channels through which only very small molecules can pass.
For example, water can pass, but organic pollutants or certain metal ions will be too large to pass.
This research shows the potential for development.
At present, researchers have planned to continue to develop this technology and focus on potential industrial or household filtration applications.
His research has been published in the journal Nature Communications.