The recent crises in Flint, Michigan and Newark, New Jersey demonstrate that water supply contamination is a problem in the United States, not just in developing nations. Pollution from mines, factories and even aging supply pipes can have devastating effects on human heath and the environment.
It's tough to remediate water supplies because of the need to detect and remove heavy-metal toxins such as lead and mercury at very low levels before concentrations accumulate.
This health challenge inspired researchers at Rutgers University to design tiny, glowing crystals that can simultaneously detect and remove heavy metals from water. Known as luminescent metal-organic frameworks (LMOFs), these crystals selectively bind to the harmful metals and then stop glowing — permitting the toxins to be detected and absorbed at a parts per billion level from aqueous solutions.
The researchers used Berkeley Lab’s Advanced Light Source to study the structure of their crystals. Their Berkeley collaborator Simon Teat, PhD, struck the 100-micron crystal samples with intense X-ray light, producing diffraction patterns used to map out the 3-D structure with atomic resolution.
These experiments provided the researchers with a better understanding of how their crystals work. The large, open channels in the LMOFs allow the heavy metals to enter, chemically bind and become trapped. And its open framework with a large surface area allows the LMOFs to take up large amounts of contaminants. The LMOFs can even be reused for three cycles before the performance degrades.
However, there is more research to be done. According to Jing Li, PhD, a chemistry professor at Rutgers University who led the research, her team plans to explore lower-cost and more durable LMOFs that can be reused additional times. They would also like to combine their LMOFs with polymers to create a solid film that could be used in water filters. A recent news story explains:
'We would like to continue with this research,' Li said, adding that her team would like to test the system’s performance on actual contaminated water sources if funding becomes available. 'These are promising results, but we have a long way to go.'
Previously: Water purification: tiny solar device may have global impact and Clean water for Dhaka, one pump at a time
Photo, of Simon Teat at the ALS Beamline, by Roy Kaltschmidt/Berkeley Lab
