Designing salt transmission channel of solar-driven multistage desalination device for efficient and stable freshwater production from seawater

Solar-driven passive multistage distillation (MSD) device provides a new approach for environmentally friendly freshwater production. However, the MSD device easily forms salt crystals on the evaporation surface when treating brine, resulting in performance degradation. Here, we design an MSD device with an effective salt resistant structure to enable rapid and automatic removal of high-concentration brine by a gravity drive. The structure was optimized by laboratory experiments and simulation. As a result, the stable freshwater production rate of the 4-stage device can reach 1.98 kg m(-2) h(-1) under a 1 kW m(-2) light intensity. In particular, the MSD device can work stably at a high light intensity of 4 kW m(-2) with an evaporation rate of 8.26 kg m(-2) h(-1), making its freshwater yield more than 1.7 times higher than that of a device without a salt-blocking structure. In summary, we explored a new method for salt removal in MSD devices, which is a meaningful method for long-term seawater desalination.

Automated summary

This study designs a solar-driven multistage distillation device with an effective salt resistant structure, enabling rapid and automatic removal of high-concentration brine. Experimental results show that the device has a stable freshwater production rate and higher yield compared to conventional devices under high light intensity.