Solar Powered Hydrogel Water Filter Removes Pollutants from Water
A new invention made from a study conducted by Princeton University uses sunlight to purify the water, helping to solve the problem of water pollution. This solar-powered hydrogel water filter is a low-cost water purification system, which works like a large sponge that soaks up the water but does not allow oil, lead, or pathogens to filter through. To collect the purified water from the sponge, it needs to be placed under the sunlight.
The gel material at the heart of the device was developed by Xiaohui Xu, a Princeton Presidential Postdoctoral Research Fellow in the Department of Chemical and Biological Engineering and co-inventor. He stated that the materials used to make the device are low-cost and non-toxic, making it a cost-effective and eco-friendly solution to generate pure water. The authors have also claimed that it has the highest passive solar water purification rate, compared to competing technology.
One of the most common ways to purify water using sunlight is installing a solar still. They are based on the concept of collecting pure water from condensed water vapors that evaporate from contaminated water after getting heated by the sun. It takes a long time to produce enough drinking water.
The gel present in the sponge can purify water contaminated by oil and petroleum, by filtering the water at least ten times with the same efficiency. The gel is surrounded by dark material known as polydopamine, which is in turn coated with a layer of a clear algae-derived substance known as alginate.
When the device is let loose in the cool water, the mesh of the gel remains open. Water soaks in through the pores of two layers, with the power of water-attracting molecules in the gel. Since the alginate has small pores, it blocks pollutants and pathogens from getting in.
Once the fiber is removed from the water and placed under the sun, the polydopamine boosts the solar gain, making the sponge heat up. The hydrophobic molecules in the gel attract each other, contracting the gel and ultimately wringing the purified water out of the material. The water is then collected in a container, placed below the filter.
Co-inventor Rodney Priestley stated that the device is inspired by pufferfish, a species that swells in danger and releases water when the danger passes by. The most interesting aspect of this project is that it can be operated at both large and small scales. It is a perfect solution for places where a low-cost non-powered water purification system is required.