Membrane research shows potential to solve water quality problems
By Colleen MacPherson
Lee Wilson’s father is doing well after three years of treatment and numerous surgeries to deal with a severely perforated large intestine. His life is getting back to normal; he has returned to work in a First Nations community west of Calgary. For the son though, life has taken a turn – his father’s experience has set him on a unique and potentially revolutionary research path at the University of Saskatchewan.
Wilson, an assistant professor of chemistry, has no doubt as to the cause of his dad’s illness – water. More specifically, the poor quality water he drank while working in the small Alberta community. Since the illness, authorities in Alberta have “modified” the water supply in anticipation of litigation, Wilson said, but no one in that province has publicly acknowledged any connection between the man’s illness, which ultimately led to the complete removal of his large intestine, and the state of the water supply. No one, that is, except Wilson: “I can make the link”.
Supported by studies that show Canada has higher incidence and prevalence rates of inflammatory bowel disease, including ulcerative colitis, than almost anywhere else in the world, Wilson has his sights set on finding a new, more effective way to deal with contaminated water in Saskatchewan, across the country and potentially around the world.
“There are a lot of contaminants we can’t deal with now using conventional technology,” said Wilson, a soft-spoken 35-year-old who was the first Métis to earn a PhD in chemistry from the U of S. “We can’t remove dioxins, for example, and I would challenge any politician who says we can to drink a glass of that ‘treated’ water.”
The basis of the research Wilson and his team are doing is in fact an imitation of nature’s own ability to remove impurities from water as it passes through the porous architecture (sandstone, graphite, soil) of aquifer systems. In the lab, the researchers are designing and developing materials with nanoscale pores that, like sandstone and soil, trap and hold contaminant molecules and let clean water pass through.
Wilson, who grew up in Lake Francis near Lake Manitoba and was the first person in his family to complete university, said the essence of his work is the immobilization of nanocapsule-shaped molecules within a 3-D framework. The framework can be used to form a porous membrane. A perfect analogue, he said, is to imagine a sponge cut in half – the holes in the sponge are the nanocapsules within the sponge’s internal skeleton holding the connector units together.
The material has a rather ordinary white opaque look to it, and it can be used in place of the membrane in any conventional point-of-use water filtration systems. But the real breakthrough is in Wilson’s ability to manipulate the size of the nanocapsules, thereby tailoring the material according to the nature of the water contaminants.
“That’s the beauty of chemistry. We can continually adjust the molecular architecture to improve the performance of these materials. That opens it up to a broad array of contaminants – carbonate, sulfates, nitrates, benzene, methyl mercury, and hydrocarbons. I can’t imagine anything that can’t be trapped by this material – organic, inorganic, minerals, the whole shootin’ match. Our goal is to produce something that’s better than anything commercially available now.”
This fall, the material will get its first field test in a situation all-too-familiar in this province. The Muskoday First Nation near Birch Hills will be the first community to use the membrane to filter water from contaminated groundwater sites.
Wilson explained that gas and diesel fuel has leached into the groundwater from an abandoned gas station on the reserve. As a result, “water is piped in, but ideally they’d like to use their own water.” The installation of the experimental membrane and the follow-up of its effectiveness gives one community at least some hope of eventually being able to access clean drinking water again.
For Wilson, the Muskoday First Nation partnership is just the start. A Sept. 14 report from Saskatchewan Environment lists 70 communities and locations in the province operating under precautionary drinking water advisories and emergency boil-water orders, or both. Another 27 advisories and orders have been issued by various health districts. Effluent from mining, chemical production or pulp and paper plants, high amounts of suspended particles in water, the presence of E. Coli, even the runoff from farming operations can all potentially do “horrific things” to a population’s health, Wilson said, “so our hope is to remove any type of consistent contaminant, including dioxins.”
While Wilson’s nanocapsule materials research has so far looked at point-of-use applications, “we’re not discounting use at an industrial water treatment level” and he’s actively pursuing funding to do just that. And, in addition to displaying good mechanical stability, low manufacturing cost and the ability to be recycled, “the applications for these kinds of materials are very wide.”
Among the uses Wilson envisions are as transdermal patches that will give health providers “a wider therapeutic envelope” for drug delivery. Cast into thin films, the material can enhance the ability of sensors to detect specific compounds, and it may be used in the timed release of pesticides and herbicides, for example.
Even more significant for scientists is Wilson’s expectation the porous membrane will revolutionize the biotechnology process of extracting protein molecules from various sources. Current extraction methods rely on chemicals, but those compounds often kill off the protein’s enzyme activity that is so critical in making everything from insulin to protein-based drugs.
“This material will selectively trap proteins and everything else washes through. The proteins can then be harvested without using chemicals. This will certainly have some resonance here in Saskatoon because we’re the up-and-coming hub of biotechnology.”
Despite his suggestion Saskatoon is gaining in the biotech sector, Wilson still sees his research as “fairly unique for the University of Saskatchewan. I might even go further and say it’s fairly unique in Canada. I know that what we’re doing here will have wide, wide interest, and this is only Generation 1 of these materials. Generations 2 and 3 will be further expansion on this idea, with much more elaborate nanocapsule materials.”
Wilson knows he’s taken on “a lifetime of work”. He knows too that the commercial success of his nanocapsule materials will hinge more on where the issue of the environment falls on the political spectrum than on the need to filter hydrocarbons out of some community’s drinking water.
“All of this sounds great to the consumer, but industry may have absolutely no interest. The environment is a relatively low priority right now, and it will stay that way until it starts to affect the economy.”