A silicon membrane, an electric current, and a stubborn idea: the metals the clean-energy transition needs are already sitting in the water we throw away.
SiTration's silicon membrane, tuned somewhere between a molecule and a human hair, is the least glamorous object in the room - and the reason a mining major came knocking.
Walk the edge of any large copper or cobalt operation and you will find it: a holding pond of cloudy, chemical-laced water that the industry treats as a liability. Getting rid of it costs money. What almost nobody does is the harder thing - go back in and pull out the dissolved metal still swimming inside. SiTration, a nine-turned-twenty-nine-person company out of MIT, built its whole business on that second, unglamorous option.
The pitch is not a moonshot. It is a piece of hardware. A porous silicon membrane - durable enough to survive streams that would clog, corrode, or dissolve an ordinary filter - paired with an electro-extraction stage that pulls target metals out directly. No acid baths. No incineration. No sprawling chemical flow sheet. Just a filter that happens to conduct electricity and pores you can dial from the molecular scale up to the width of a hair.
Brendan Smith (PhD '18) and MIT materials-science professor Jeffrey Grossman were not thinking about mines. They were working on desalination - how to filter salt out of water. The membrane they kept refining turned out to be tougher and more tunable than the problem in front of them required. So they pointed it at a bigger one.
The name gives away the trick. Si, the chemical symbol for silicon, plus filtration. SiTration. The metals behind batteries, EV motors, wind turbines, and the data centers now feeding the AI boom - lithium, cobalt, nickel, copper - all share a bottleneck. Separation is expensive and dirty. A durable, conductive silicon membrane attacks exactly that.
We can produce membranes with pore sizes from the molecular scale up to the size of a human hair in diameter, and everything in between.
Conventional recovery leans on acid dissolution or smelting - energy-hungry, chemical-heavy, and rough on the surroundings. SiTration collapses that into a simpler line.
The ultra-durable silicon membrane separates target species from harsh, real-world streams, with pore sizes tuned to the job.
An electro-extraction stage recovers the metals directly, using the membrane's electrical conductivity instead of added reagents.
Out comes lithium, cobalt, nickel, copper, or precious metals - with a drastically simplified flow sheet and lower emissions.
Recover cobalt and copper from mine wastewater instead of paying to treat and discard it - turning a remediation cost into a revenue line.
Pull the nickel, cobalt, and lithium out of end-of-life lithium-ion batteries, closing the loop on EV supply chains.
Capture precious and critical metals from refining process streams that conventional methods leave on the table.
MIT PhD '18. Turned a materials-science thesis into a company and a Rio Tinto partnership. The public voice of SiTration's supply-chain thesis.
Professor in MIT's Department of Materials Science and Engineering. The membrane's scientific origin story runs through his lab.
The rest of the roughly 29-person team pulls from materials science, chemistry, mechanical engineering, and physics - many of them, like the founders, out of MIT. SiTration is a resident company at The Engine, MIT's tough-tech incubator in Cambridge.
Our solution can create a cleaner, more equitable, and more profitable critical materials supply chain across multiple industries, all with a single technology.
Return to that holding pond at the mine's edge. Nothing about it looks different - same cloudy grey, same chemical tang. What changed is the accounting. With a SiTration line running beside it, the pond stops being a disposal problem and starts being a stockpile: dissolved copper and cobalt waiting to be pulled out with a filter and a current instead of a smelter and a truckload of acid.
That is the quiet move. SiTration is not promising to reinvent mining or to make the energy transition painless. It is making one specific, useful bet - that the metals we already dug up are worth going back for, and that a piece of silicon can make going back cheap enough to bother. Boring on the surface. Which, for a climate technology, is usually the point.