In 2013 a team of chemists showed that seawater can be partly desalted on a plastic chip using about three volts, roughly what two small batteries supply. There is no membrane and no boiling. The catch is scale and strength: the device removed about a quarter of the salt, while drinking water needs around 99 percent removed, and each tiny channel produced only nanolitres per minute. It was a clever proof of principle, not a ready-made answer to the world's water shortage.
Here is what the researchers actually built, how it works, where it fits beside the desalination plants already running today, and why a few of the bigger claims that travelled with this story online do not hold up.
Who made it and what they reported
The work came from Richard Crooks's group at the University of Texas at Austin and Ulrich Tallarek's group at the University of Marburg in Germany. Kyle Knust was the lead author. The paper, titled "Electrochemically Mediated Seawater Desalination", appeared in the chemistry journal Angewandte Chemie International Edition in 2013, and the university announced it in late June that year.
The headline numbers were modest and the team said so openly. Their chip achieved 25 percent desalination. A single channel, about as wide as a human hair, delivered around 40 nanolitres of partly desalted water a minute. A nanolitre is a billionth of a litre, so a useful home or village unit would need a vast number of channels working in parallel. Knust called the result a proof of principle, and Crooks said the method still had to be refined and scaled up.
A start-up, Okeanos Technologies, licensed the idea. Its founder, Tony Frudakis, talked about a self-contained unit roughly the size of a vending machine that could serve a small village. That was a goal, not a product, and no such machine has become a common sight since.
How a few volts can push salt aside
Seawater is salty because it carries dissolved ions, mainly positively charged sodium and negatively charged chloride. Most desalination either forces water through a membrane that holds those ions back, or boils the water and collects the vapour. The Texas and Marburg chip does neither.
Instead, seawater flows through a microchannel that splits into two branches, like the letter Y. At the fork sits a small embedded electrode. When about 3.0 volts are applied, the electrode neutralises some of the chloride ions passing by. That creates a pocket with far fewer ions, called an ion depletion zone. Because there are fewer charge carriers there, the local electric field becomes much stronger than in the rest of the channel.
That strong field acts like a traffic officer at the junction. Charged salt ions are steered into one branch, while water with less salt continues down the other. No filter has to physically block the salt, which is why the researchers called the method membrane-free.
The appeal is easy to see. Membranes are expensive, they can clog or foul with minerals and microbes, and they must be replaced. A method without them could, in theory, be cheaper to maintain and small enough to carry.
From a lab chip to a glass of water
The gap between the chip and a usable supply is large in two directions at once.
The first is purity. Taking out a quarter of the salt leaves water that is still far too salty to drink or to use on most crops. The team said reaching 99 percent seemed achievable, based on progress they had made in related experiments, but that was a forecast. Getting there usually means running water through several stages, which adds energy, complexity and cost.
The second is volume. Forty nanolitres a minute works out to well under a teaspoon a day from one channel. To provide even a few litres daily, a device would need many thousands of channels side by side, each behaving reliably with real seawater that carries sand, algae and organic matter. Problems that do not appear in a clean lab often show up in exactly that step.
It is also worth being careful with the "store-bought battery" image. Low voltage does not automatically mean low energy per litre. What matters is how much energy it takes to produce a cubic metre of clean water, and for this chip that figure had not been shown at a meaningful scale.
How seawater is desalinated today
Desalination is already a large industry. The two main families are thermal methods, which heat seawater and condense the vapour, and membrane methods, above all reverse osmosis, which uses high pressure to push water through a membrane that holds back salt. Reverse osmosis is now the leading technology by installed capacity.
Its efficiency has improved enormously. Average energy use for seawater desalination fell from roughly 20 to 30 kilowatt-hours per cubic metre around 1970 to about 3 kWh per cubic metre by 2018, and the best plants now report figures under 2. Global capacity was about 97 million cubic metres a day in 2020, from more than 16,000 plants, with Saudi Arabia, the United Arab Emirates and Israel among the biggest users.
That progress raises the bar for any newcomer. A new method has to beat a mature, steadily improving technology on cost and reliability, not just on elegance.
The brine problem
Every method that removes salt has to put it somewhere. Desalination plants discharge concentrated brine, often warmer than the surrounding sea and sometimes carrying treatment chemicals. Global brine output is estimated to exceed the volume of fresh water produced. Because brine is denser than seawater it can sink and spread across the seabed, harming marine life unless it is diluted and dispersed carefully. A membrane-free chip would still produce a salty waste stream; the second branch of the Y is exactly that.
Related electrical methods
The Texas chip belongs to a wider family of approaches that use electric fields rather than pressure. One that has reached practical use is capacitive deionisation, where porous carbon electrodes pull ions out of the water. Because its energy cost rises with the amount of salt removed, it works best on mildly salty brackish water rather than full-strength seawater. That pattern is a useful rule of thumb: electrical methods tend to shine on lower-salinity water first.
How many people lack safe water
The need behind this research is real. According to the World Health Organization, in 2022 about 2.2 billion people did not have safely managed drinking water, meaning water at home, available when needed and free from contamination. Of those, 115 million still collected untreated water straight from rivers, lakes, ponds or streams.
Older figures often quoted with this story, such as 780 million people without access to an improved water source, came from earlier counting methods and are not directly comparable with today's numbers. Most people without safe water also do not live on a coast, and many of the problems are about pipes, treatment, pollution, maintenance and money rather than a lack of seawater technology. Desalination helps most in dry coastal regions that can afford the energy and infrastructure.
Myths that travelled with the story
"Ocean water is now drinkable." Not from this device. The chip reached 25 percent salt removal in a microscopic channel. It showed a new mechanism, not a finished purifier.
"It only needs a battery, so it is nearly free." Low voltage is not the same as low cost per litre. Real costs include building huge numbers of channels, pre-treating seawater, maintenance and handling the brine.
"The UN and IMF are plotting to control the world's water." Earlier versions of this story ran into claims that United Nations water bodies and the International Monetary Fund were scheming to seize water and "enslave" nations. The documents cited do not support that. UN-Water is the United Nations' coordination mechanism on freshwater and sanitation, not a secret controller, and in July 2010 the UN General Assembly formally recognised safe drinking water and sanitation as a human right. There are genuine, long-running debates about privatising water utilities and the conditions attached to international loans, including legal disputes such as Biwater Gauff v. Tanzania over Dar es Salaam's water system. Those debates deserve scrutiny on their evidence, not a conspiracy frame.
What this research still tells us
The value of the 2013 chip lies in the idea. It showed that a modest electric field, shaped cleverly at a junction, can sort salt from water without a membrane. Ideas like that sometimes become niche tools, such as small units for brackish water or for lab and medical use, long before they matter for city water supplies.
When you see a headline promising that seawater has suddenly become drinkable, three questions cut through the hype: how much salt was removed, how much water came out per day, and how much energy each litre took. For this invention, the honest answers were a quarter, a tiny amount, and not yet known at scale.
Sources: ScienceDaily (27 June 2013): Chemists work to desalt the ocean for drinking water, one nanoliter at a time; Wikipedia: Desalination; Wikipedia: Capacitive deionization; World Health Organization: Drinking-water fact sheet; Wikipedia: Human right to water and sanitation; Wikipedia: UN-Water. Original study: Knust, Hlushkou, Anand, Tallarek and Crooks, Angewandte Chemie International Edition (2013), doi:10.1002/anie.201302577.
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