He found a way to mine copper, cobalt and lithium from the stuff everyone else throws away. It started in a desalination lab.
Most people see a tailings pond and see a problem. Brendan Smith sees a bank vault that nobody bothered to open. The clean-energy machines the world wants - electric motors, wind turbines, batteries - run on copper, cobalt, nickel and lithium. The conventional way to get those metals is brutal: heat, acid, and as much as ten tons of chemical input for every single ton of metal recovered. Smith's company, SiTration, runs a different math.
The technology at the center of SiTration was not invented to clean up mines. It was invented to clean up water. As a PhD student at MIT around 2013, Smith joined the research group of Professor Jeffrey Grossman and started working on desalination - the unglamorous, planet-scale problem of pulling salt out of seawater. The tool they built was a porous silicon membrane, a filter etched with holes of exquisitely controlled size.
Then came the realization that turns a thesis into a company. The same membrane that could sort salt from water could sort one metal from another. Tune the pores, run an electrical charge across the silicon, and you have a filter that selects by both size and electrochemistry. A desalination filter had quietly applied for a second career in metals.
Smith spent years inside MIT's startup machinery - the Deshpande Center, MIT Sandbox, the Venture Mentoring Service - before he formally founded SiTration in 2020 to commercialize what he had co-invented. Grossman did not wave goodbye from the lab. He came along as chief scientist and board member.
Conventional extraction and recycling lean on chemicals and heat. It is effective and it is filthy. Smith likes to put a number on it: as much as ten tons of chemical input to produce one ton of recovered critical material. That is the inefficiency hiding inside the clean-energy supply chain - dirty metals at the heart of green machines.
SiTration's pitch is electrification instead of chemistry. The membrane is electrified and combined with electro-extraction, separating materials by their electrochemical properties rather than dissolving everything and sorting the soup. The company says the result uses up to ten times less energy and consumes half the water, at half the original operating cost. No mountain of reagents required.
"There is a major missing link between the clean energy technologies we so desperately need and the sourcing of the materials that are at their core." That gap - between the demand for batteries and the dirt they come from - is the whole business.
SiTration's first public act, back in 2022, was a $2.35 million pre-seed led by Azolla Ventures aimed squarely at recycling spent lithium-ion batteries from electric vehicles. The vision was bigger than one waste stream, though. The same single technology, Smith argues, can serve mining waste valorization, metals refining, and battery recycling. One filter, many industries.
The mining world noticed. In June 2023, SiTration signed a development partnership with Rio Tinto - one of the largest mining companies on Earth. Rio Tinto wanted to recover valuable metals like cobalt and copper from the wastewater that mines normally treat as a liability. SiTration tuned its membranes against real feedback from real mine sites. A lab filter went to work where the dirt is.
In June 2024, SiTration closed an $11.8 million seed round led by climate fund 2150, with BHP Ventures - the venture arm of another mining giant - joining alongside Extantia, Orion Industrial Ventures, and returning backers. By the time the company opened its new pilot facility, total venture capital raised stood around $14.4 million. When two of the planet's biggest miners both put money behind the same membrane, it stops being a science project.
In April 2025, SiTration moved into an 11,000-square-foot R&D and pilot facility in Watertown, Massachusetts, built to make pilot systems bigger and faster than before. Smith called it "an inflection point" - the moment a chemistry-free idea gets to grow up into industrial steel.
Smith trained as a scientist, but the role he describes most fondly is the people one. "What's most fun to me about being a CEO is that there are 100 different factors, most people-oriented, that you have to navigate every day." His own bio says it plainly: he enjoys building great teams as much as transforming jagged-edge technologies into industrial-scale value. The founding-era team was almost entirely MIT alumni, scattered across departments and reassembled around one filter.
The clean-energy transition is usually told as a story about software, finance, or policy. Smith tells it as a materials story. The hardest part of decarbonizing is not the wind turbine - it is the dirty, chemical-heavy job of getting the metals to build it without wrecking a river in the process. SiTration is a bet that the unsexy middle of the supply chain is exactly where the leverage is. Pull the metal out of the waste, skip the acid, halve the water, and the whole green machine gets a little less hypocritical.
"Every ounce of effort and resource we put into developing our product is geared towards creating real-world value," Smith says. From a Canadian undergrad in nanotechnology engineering to a desalination lab at MIT to a partnership with Rio Tinto, the through-line is consistent: take a precise, durable filter and point it at problems too big and too dirty for it to ignore.
Built to desalinate seawater, the membrane turned out to be just as good at sorting one metal from another. Same silicon, new mission.
By electrifying the membrane, SiTration separates by electrochemistry - skipping the ten-tons-of-chemicals tax of the conventional route.
Rio Tinto signed a partnership; BHP's venture arm invested. The industry being disrupted is helping fund the disruption.