Shining the Way to Clean Drinking Water | weatherology°
By: Meteorologist Michael Karow
Updated: Jul 28th 2020

Shining the Way to Clean Drinking Water

In the present day, where hand washing is such an important part of staying healthy, access to clean water is more important than ever, especially in developing countries where enough clean water for even drinking has become more scarce in recent years. Solutions for purifying water and the desalination of sea water need to be relatively cheap and less reliant on electric power, which is itself a scarce commodity in many of these regions with clean water shortages. One promising new development from the University of Rochester promises to harness the power of sunlight for the purification and desalination of water with nearly 100% efficiency using a new laser-etched material.

This material is manufactured from a normal piece of aluminum. An incredibly short, but powerful burst of laser light, called a femto-second laser, etches the surface of the aluminum such that it contains tiny microcapillaries which effectively wick up water against the force of gravity. This laser etching also turns the aluminum black, which allows the most absorption of incoming sunlight to ensure the most efficient evaporation of the water that has been wicked up by the microcapillaries.

The purification of water using sunlight has long been recognized as an important avenue for further development. In the past, the boiling of water using sunlight has been employed, which does eliminate many of the pathogens which can cause gastrointestinal issues, but which doesn't eliminate heavy metal contamination. This new method, using a super absorbing and super wicking material, is nearly 100% energy efficient because it doesn't need to boil large quantities of water, as all of the heat for evaporation is focused at the point where the evaporating actually takes place. Furthermore, lab tests have shown that after purification using this process, heavy metals are removed to a degree that the drinking water meets safe standards set by the World Health Organization.

water wicking laser etched University Rochester
Close-up of water getting wicked up the laser-etched surface - [University of Rochester]
water sanitation desalination Singh
Diagram of the water sanitation/desalination setup - [Singh et al., 2020]
metal purifaction water WHO Singh
Levels of various metals before (black) and after (green) solar sanitation, compared to WHO levels for safe drinking water (blue) - [Singh et al., 2020]