Recent UNSW SHARP hire Professor Kourosh Kalantar-zadeh and his former colleagues at RMIT showed that nano-filters made of aluminium oxide could be cheaply produced using virtually no energy from a fixed amount of liquid metal gallium.
“Lead and other heavy metals have a very high affinity to aluminium oxide. As the water passes through billions of layers, each one of these lead ions get attracted to one of these aluminium oxide sheets.
“But at the same time, it’s very safe because with repeated use, the water flow cannot detach the heavy metal ions from the aluminium oxide.”
There are portable filtration products available that do remove heavy metals from water, but they are comparatively expensive, often costing more than $100.
By contrast, aluminium oxide filters produced from liquid gallium could be produced for as little as 10 cents, making them attractive to prospective manufacturers.
“Up until now, to produce aluminium oxide, you need to process aluminium at above 1000 degrees or use other energy intensive processes,” Professor Kalantar-zadeh said.
While aluminium is a plentiful and cheap metal, gallium is relatively expensive. But what makes gallium the hero in the process is the fact that it remains pure and unchanged after each production of aluminium oxide. Science bulletin.
