Saudi Press

Saudi Arabia and the world
Friday, Aug 22, 2025

Elevated design keeps solar stills salt-free

A solar distillation device can purify brine from reverse osmosis plants with over 10 percent salinity, as well as water taken directly from the Red Sea. The technology offers double the freshwater production rate of existing salt-rejection solar stills.
Inspired by the floating solar still in “The Life of Pi” movie, KAUST professor Qiaoqiang Gan has developed several nanomaterials and thermal isolation processes to enhance the evaporation of brackish water into pure steam.

In 2016 he launched a startup, Sunny Clean Water, that produces low-cost inflatable stills capable of generating 10-20 liters of fresh water per day.

When it comes to seawater purification, however, Gan admits that even his devices have limits.

“Over time, you’ll always see salt accumulation on the solar absorbing material — the accumulated salt reflects sunlight and degrades the still’s performance,” he said.

In 2021, Gan joined KAUST and teamed up with fellow KAUST professor Yu Han and researcher Kaijie Yang to improve the efficiency of salt rejection, a strategy that employs techniques such as hydrophobic surfaces or fluid convection to limit mineral buildups.

The team’s new evaporator is a centimeter-scale plastic cube that contains several glass fiber membranes — thin materials normally used for filtration.

A horizontally aligned membrane coated with carbon nanotubes acts as a light-absorbing layer on the cube’s upper surface.

Underneath it, a series of vertically oriented membranes, or “mass transfer bridges,” separate the solar absorber from the bulk salt water.

Yang, who conceived the design, explains that the bridges contain hydrophilic microchannels that soak up seawater to the top solar layer for distillation into steam.

And when salt accumulation reaches a threshold, the same microchannels transport brine back into the seawater due to the capillary action of concentration gradients.

The elevated bridges allow the conductive heat that occurs during salt backflow to flow into the solar still, improving evaporation efficiency.

“Other evaporators can realize good salt rejection, but with a short backflow process, there’s a lot of heat energy loss and it impacts water generation rates,” said Yang.

“Our system has the advantage that it can adjust the tradeoff between salt rejection and water generation.”

Testing in both indoor labs and outdoor field stations revealed the solar still could meet the drinking needs of two people daily, with estimated raw material costs of $50 per square meter.

“We can scale up to a larger architecture by assembling the cubes together,” says Han. “Because this device offers long-term operation without any maintenance, we’re preparing for commercialization.”
Newsletter

Related Articles

Saudi Press
0:00
0:00
Close
Dogfights in the Skies: Airbus on Track to Overtake Boeing and Claim Aviation Supremacy
Tim Cook Promises an AI Revolution at Apple: "One of the Most Significant Technologies of Our Generation"
Are AI Data Centres the Infrastructure of the Future or the Next Crisis?
Miles Worth Billions: How Airlines Generate Huge Profits
Zelenskyy Returns to White House Flanked by European Allies as Trump Pressures Land-Swap Deal with Putin
Beijing is moving into gold and other assets, diversifying away from the dollar
Cristiano Ronaldo Makes Surprise Stop at New Hong Kong Museum
Zelenskyy to Visit Washington after Trump–Putin Summit Yields No Agreement
High-Stakes Trump-Putin Summit on Ukraine Underway in Alaska
Iranian Protection Offers Chinese Vehicle Shipments a Cost Advantage over Japanese and Korean Makers
Saudi Arabia accelerates renewables to curb domestic oil use
Cristiano Ronaldo and Georgina Rodríguez announce engagement
Asia-Pacific dominates world’s busiest flight routes, with South Korea’s Jeju–Seoul corridor leading global rankings
Private Welsh island with 19th-century fort listed for sale at over £3 million
Sam Altman challenges Elon Musk with plans for Neuralink rival
Australia to Recognize the State of Palestine at UN Assembly
The Collapse of the Programmer Dream: AI Experts Now the Real High-Earners
Armenia and Azerbaijan to Sign US-Brokered Framework Agreement for Nakhchivan Corridor
British Labour Government Utilizes Counter-Terrorism Tools for Social Media Monitoring Against Legitimate Critics
WhatsApp Deletes 6.8 Million Scam Accounts Amid Rising Global Fraud
Nine people have been hospitalized and dozens of salmonella cases have been reported after an outbreak of infections linked to certain brands of pistachios and pistachio-containing products, according to the Public Health Agency of Canada
Texas Residents Face Water Restrictions While AI Data Centers Consume Millions of Gallons
Tariffs, AI, and the Shifting U.S. Macro Landscape: Navigating a New Economic Regime
India Rejects U.S. Tariff Threat, Defends Russian Oil Purchases
United States Establishes Strategic Bitcoin Reserve and Digital Asset Stockpile
Thousands of Private ChatGPT Conversations Accidentally Indexed by Google
China Tightens Mineral Controls, Curtailing Critical Inputs for Western Defence Contractors
OpenAI’s Bold Bet: Teaching AI to Think, Not Just Chat
BP’s Largest Oil and Gas Find in 25 Years Uncovered Offshore Brazil
JPMorgan and Coinbase Unveil Partnership to Let Chase Cardholders Buy Crypto Directly
British Tourist Dies Following Hair Transplant in Turkey, Police Investigate
WhatsApp Users Targeted in New Scam Involving Account Takeovers
Trump Deploys Nuclear Submarines After Threats from Former Russian President Medvedev
Germany’s Economic Breakdown and the Return of Militarization: From Industrial Collapse to a New Offensive Strategy
IMF Upgrades Global Growth Forecast as Weaker Dollar Supports Outlook
Politics is a good business: Barack Obama’s Reported Net Worth Growth, 1990–2025
"Crazy Thing": OpenAI's Sam Altman Warns Of AI Voice Fraud Crisis In Banking
Japanese Prime Minister Vows to Stay After Coalition Loses Upper House Majority
President Trump Diagnosed with Chronic Venous Insufficiency After Leg Swelling
Man Dies After Being Pulled Into MRI Machine Due to Metal Chain in New York Clinic
FIFA Pressured to Rethink World Cup Calendar Due to Climate Change
"Can You Hit Moscow?" Trump Asked Zelensky To Make Putin "Feel The Pain"
Nvidia Becomes World’s First Four‑Trillion‑Dollar Company Amid AI Boom
Iranian President Reportedly Injured During Israeli Strike on Secret Facility
Kurdistan Workers Party Takes Symbolic Step Towards Peace in Northern Iraq
BRICS Expands Membership with Indonesia and Ten New Partner Countries
Elon Musk Founds a Party Following a Poll on X: "You Wanted It – You Got It!"
AI Raises Alarms Over Long-Term Job Security
Saudi Arabia Maintains Ties with Iran Despite Israel Conflict
Russia Formally Recognizes Taliban Government in Afghanistan
×