14 DAY TRIAL // Chinese researchers developed an easy and efficient way of removing arsenic from drinking water, thanks to an iron-rich, porous material, than can do the job in under two hours.
Kang Li and colleagues from Harbin Medical University have used a low cost, natural mineral that can be found on Earth's surface – ferrihydrite, and managed to remove arsenite – the more dominant arsenic ion, from water samples.
Ferrihydrite was already known to absorb arsenite, but the problem was its low surface area, that affected its efficiency, so the scientists thought of combining two layers of ferrihydrite, to increase its surface area and loading capacity.
The experiment was successful, and the arsenite was selectively removed from water, even if the samples contained other anions that had similar molecules.
Once the ferrihydrite material finished absorbing the arsenite, the researchers removed it very easily from its surface, by simply washing it with an alkali solution.
Once the ferrihydrite material was arsenite-free, it underwent a heat treatment and the mesoporous material was ready to be reused, up to ten times.
The greatest challenge for future practical applications of this material is its recycling, said the researcher, according to RSC.
He says that “if magnetic nanoparticles could be loaded in the channels of the two-line ferrihydrite, recycling would become even easier.”
Radek Zboril, an expert in nanocrystalline iron oxides from Palacky University in the Czech Republic, said that “the next step should be related to the investigation of the mechanism and efficiency of arsenic removal by nanocrystalline iron oxides depending on their structure and crystallinity.
“The incorporation of arsenic into the structure of the in situ formed iron oxide nanoparticles seems to be a more promising way from the viewpoint of real applications,” he added.
Arsenic is a natural element found in soil and minerals, extremely toxic and fatal for the majority of living organisms, in high doses.
Elevated levels of arsenic in groundwater in countries such as Bangladesh pose a serious threat to human health, because arsenic exposure can cause many health problems, like changing the color of the skin, causing corns and small warts and, in high doses, causing death.