Solar evaporator offers a fresh route to fresh water

Phys.org ^ | April 16, 2019 | University of Maryland

[BenLurkin]

Interfacial evaporators are made of thin materials that float on saline water. Absorbing solar heat on top, the evaporators continuously pull up the saline water from below and convert it to steam on their top surface, leaving behind the salt, explains Hu...

However, over time salt can build up on this evaporative surface, gradually degrading performance until it is removed...

Hu and his colleagues minimized the need for this maintenance with a device made out of basswood that exploits the wood's natural structure of the micron-wide channels that carry water and nutrients up the tree.

The researchers supplement these natural channels by drilling a second array of millimeter-wide channels through a thin cross-section of the wood, says Yudi Kuang, a visiting scholar and lead author on the paper. The investigators then briefly expose the top surface to high heat, which carbonizes the surface for greater solar absorption.

In operation, as the device absorbs solar energy, it draws up salty water through the wood's natural micron-wide channels.

The evaporator approach also is effective in other types of wood with similar natural channels. The researchers now are optimizing their system for higher efficiency, lower capital cost, and integration with a steam condenser to complete the desalination cycle.

Hu's lab also recently developed another solar-heated prototype device that takes advantage of carbonized wood's ability to absorb and distribute solar energy—this one created to help clean up spills of hard-to-collect heavy oils. "Our carbonized wood material demonstrates rapid and efficient crude oil absorption, as well as low cost and scalable manufacturing potential," says Kuang, lead author on a paper about the research in Advanced Functional Materials.

[Jeff Chandler]

Graphene-based nanotechnology desalination membranes make reverse osmosis desal suprisingly cost-effective. It would take a tremendous leap in technology to compete. Add the emerging 3D printing of the RO filters and it’s game over.

[Does so]

You are going to have to mineralize the water as you can not drink distilled water very long without leaching out minerals form [sic] your body.

I tried drinking distilled water to prevent kidney stone reoccurrence. It didn't work.