Oct 21, 2020
The supply of clean drinking water has always been regarded as a basic human right in many regions, but the situation in many parts of the world is very different. The third world has been struggling for clean drinking water. A new type of laser-based aluminum sanitation system can help developing countries provide clean water and save lives.
A research team led by Subhash Singh of the Institute of Optics at the University of Rochester in New York believes that solar-based water sanitation may be the key to providing sustainable clean water to the rapidly growing world population. The research results were published in the journal Nature Sustainability.
There are many systems on the market that use sunlight to purify water. But these systems have obvious flaws: scalability issues. A system that can disinfect a small group of people or a family may not be of much use to an entire town or village. Coupled with the high cost of the water disinfection system, 1 in 9 people (approximately 785 million people) cannot get clean water. Every year, 1 million people worldwide die from lack of clean water.
The research team discovered several problems with the current water sanitation system, especially the problem of solar-driven interface evaporation. Another problem is the blocking effect that severely reduces equipment efficiency. In addition, there is a very important problem: current solar purifiers can only eliminate biological pollution. There are also a large number of other pollutants, especially heavy metals, that have not been treated.
The team recommends using a surface with super water absorption and super light absorption to sanitize the water with solar energy. This surface with super water absorption and super light absorption is composed of aluminum, which is easy to obtain and low in cost.
However, untreated aluminum does not have water-absorbing properties, and its surface is reflective. To solve this problem, the research team lasered aluminum with femtosecond laser pulses. The porous surface created by this laser treatment allows water to run at a steady speed of approximately 2 millimeters per second under the influence of gravity. This means that water can be transported to the surface of the solar absorption device for disinfection.
Therefore, this porous surface can be installed on the floating platform at any angle to increase the incidence of solar rays. This also means that this panel is connected to the sun tracking system to track the sun's trajectory and keep the disinfection level in the best condition.
The research team not only tested biologically contaminated water, but also tested water contaminated by metal, household and agricultural wastes and other pollutants, and found that it met the WHO standard for safe drinking water.