2021-06-02

Researchers at Northwestern University develop nano-films to remove phosphate pollution in water

By yqqlm yqqlm

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Researchers at Northwestern University develop nano-films to remove phosphate pollution in water

Inspired by many water bodies near Chicago, a team led by Northwestern University has developed a method , Repeatedly remove and reuse phosphate from polluted waters. Researchers liken this development to the “Swiss Army Knife” of pollution remediation because they have developed a membrane to absorb and then release pollutants. The research will be published in the Proceedings of the National Academy of Sciences on May 31, 2021.

Phosphorus is the foundation of the world’s food system and all life on earth. Every organism on the planet needs it: Phosphorus is found in cell membranes, DNA scaffolds and our bones. Although other key elements such as oxygen and nitrogen can be found in the atmosphere, phosphorus has no similar elements. A small part of the available phosphorus comes from the earth’s crust, and it takes thousands or even millions of years to weather away. And the phosphate field is exhausted.

In view of the shortage of such non-renewable natural resources, it is sad that many of our lakes are suffering from a process called eutrophication, when too many nutrients enter a natural water source At that time, eutrophication will occur. As phosphate and other minerals accumulate, aquatic plants and algae become too dense, depleting oxygen in the water, and ultimately killing aquatic organisms.

In the past, human beings used phosphate more and more repeatedly. Now we just pull it out of the ground, use it once, and then flush it into the water source after use. Therefore, this is a pollution issue, a sustainable development issue, and a circular economy issue. Traditionally, ecologists and engineers have developed strategies to solve the growing environmental and public health problems by eliminating phosphates in water sources. Until recently, the focus has shifted from eliminating phosphates to recovering phosphates.

Now the Northwestern University research team has developed the Phosphate Elimination and Recovery Lightweight (PEARL) membrane, which is a porous flexible matrix that can selectively separate up to 99% from contaminated water Of phosphate ions. The PEARL membrane is coated with phosphate-bound nanostructures, which can be adjusted by controlling the pH value to absorb or release nutrients, so as to achieve phosphate recovery and multiple cycles of the membrane.

The current method of phosphate removal is based on a complex, lengthy, multi-step method. Most of them do not recover phosphate during the removal process, and eventually generate a large amount of physical waste. PEARL membrane provides a simple one-step method to remove phosphate while efficiently recovering phosphate. It can also be reused without generating any physical waste.