Nanosponge absorbs toxins in water

MONASH U. (AUS) — Researchers have shown the potential of a new kind of nanomaterial to filter out environmental poisons from water.

The uniform structure of highly porous metal organic frameworks (MOFs) makes them very efficient filters, says Mainak Majumder of the mechanical engineering department at Monash University.

MOFs are clusters of metal atoms connected by organic molecules and known for their exceptional abilities to store or separate gases such as carbon dioxide. This is one of the first studies to demonstrate their separation applications in an aqueous environment.


Researchers demonstrated the filtering ability of the new nanomaterial by sieving paraquat—a herbicide that has been linked to the onset of Parkinson’s disease. (Credit: Monash University)

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“These are crystalline materials with a difference—they have pores that are all exactly the same size. So while one substance can fit in the pores and be captured, another, just one tenth of a nanometer bigger, can’t fit,” Majumder says. “As a result you can detect and capture substances that are present in low concentrations, or in a mixture with other materials.”

Majumder and colleagues demonstrated the filtering ability of the new MOF by sieving paraquat—a herbicide that has been linked to the onset of Parkinson’s disease. The MOF removed the paraquat, but left other contaminants. The findings are published in the journal Chemistry of Materials and were highlighted in Science.

“Because MOFs are flexible, we found that their structure changed when they absorbed the paraquat. This means that our MOF could form the basis of a device for quickly and easily testing for the contaminant in water,” says Matthew Hill, from the Commonwealth Scientific and Industrial Research Organization.

“Due to its very precise filtering properties, this testing application could deliver very accurate contamination readings in the field.”

Paraquat was the only contaminant tested, but the researchers say the MOF could be altered to filter out others.

Source: Monash University