Sustainable light-driven water pump using Büttiker–Landauer ratchet

Abstract

40% of the world's population faces a serious water shortage. To open the way for this problem, we here propose a light-driven water pump using a Büttiker–Landauer ratchet and examine the performance. Specifically, by using a small-scale model of a channel hydraulic radius of ∼3 mm, we demonstrate that the light-driven water pump having light-absorbing and reflecting parts produces a net flow of ∼0.27 mm/s (flow rate ∼10  μl/s) in a circular channel under the irradiation intensity of 160 W/m2. That is, we have developed a light-driven water pump that works under sunlight without a special energy supply. Furthermore, through the discussion about the scale-up model, we estimate that a 10-times larger-size light-driven water pump has the performance of flow rate ∼1 l/s with a high-pressure difference in the future. Therefore, our technology can help to achieve sustainable transport of water or fluids.