Food and Water - Micro-/Nanotechnology

Nanofilter for Quick and Clean Water

A nano-filter that can rapidly clean dirty water over 100 times faster than current technologies.

Water contamination remains a significant global challenge, with 1 in 9 people having no access to clean water close to their home. Decontamination of water is therefore a pressing area of research, which would benefit from the ability to filter both heavy metals and oils from water in a time-efficient speed.

Researchers from RMIT University and the University of New South Wales (UNSW) have developed a nanofilter that does just this, as well as being “sustainable, environmentally-friendly, scalable, and low cost,“ according to Dr. Ali Zavabeti, who helped develop the filter.

“Heavy metal contamination causes serious health problems, and children are particularly vulnerable,” he added. Concerning the nanofilter, “we’ve shown it works to remove lead and oil from water, but we also know it has potential to target other common contaminants. Previous research has already shown the materials we used are effective in absorbing contaminants like mercury, sulfates, and phosphates. With further development and commercial support, this new nanofilter could be a cheap and ultra-fast solution to the problem of dirty water.”

The liquid metal chemistry process developed by the researchers has potential applications across a range of industries, including electronics, membranes, optics, and catalysis. “The technique is potentially of significant industrial value, since it can be readily upscaled, the liquid metal can be reused, and the process requires only short reaction times and low temperatures,” Zavabeti said.

Project leader Prof. Kourosh Kalantar-zadeh said the liquid metal chemistry used in the process enabled differently shaped nanostructures to be grown, either as atomically thin sheets used for the nanofilter or as nanofibrous structures. “Growing these materials conventionally is power intensive, requires high temperatures, extensive processing times and uses toxic metals,” he said. “Liquid metal chemistry avoids all these issues, so it’s an outstanding alternative.”

Experiments showed the nanofilter made of stacked atomically thin sheets was efficient at removing lead from water that had been contaminated at over 13 times the safe drinking level, and was highly effective in separating oil from water. The process generates no waste and requires just aluminium and water, with the liquid metals reused for each new batch of nanostructures. These characteristics give this nanofilter a promising future in applied water decontamination.

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