Water is essential to life, but water scarcity and access to clean drinking water is a major global issue, especially in developing countries. As the climate crisis unfolds, severe drought, such as the one that plagued Cape Town, South Africa, in 2018, will become an even greater problem.
One of the UN’s Sustainable Development Goals aims to increase access to clean water and improve sanitation conditions. According to the UN, more than 80% of wastewater from human activities is discharged into waterways without pollution removal and three out of ten people lack access to safe drinking water. As a consequence, a death toll arises from preventable water and sanitation-related diseases.
Point-of-use (POU) water disinfection has tremendous utility in rural areas or in the event of a natural disaster such as flooding, another consequence of climate change that affects water quality by contaminating groundwater with bacteria and nitrates from septic facilities and farms. Chlorination, ultraviolet radiation, and membrane filtration are among the most widely used POU disinfection methods. Alternatives such as photocatalytic, electrochemical, low-voltage electroporation, and microwave-based methods are also effective but come with drawbacks, such as relying on an electrical power supply or high cost.
The triboelectric nanogenerator (TENG), which mechanically harvests energy, is a promising technology for water disinfection, and a team of researchers has proposed an inexpensive, hand-powered pump based on the TENG for this purpose. Their “TriboPump” can be operated by a family for as little as $10 US for a two-year period.
The disinfection chamber of the TriboPump has a sleeve-tube structure with two electrodes. The outer electrode consists of a rolled copper foil located on the inner surface of the tube and is wired to the negative electrode of the power source, a disk TENG (D-TENG). The center electrode is a coaxial thin copper wire in the center of the disinfection chamber and is connected to the positive electrode of the D-TENG.
The copper ions generated when the power source is turned on act as disinfectants, allowing for a high removal efficiency of E. coli in deionized water with a copper ion release well below the limit set by the United States Environmental Protection Agency for drinking water.
The ease of operation combined with its cost-effectiveness and disinfection efficiency make the TriboPump a feasible option for water sanitation in remote areas and emergencies.