A Self-Powered UV/O₃ Disinfection System for Drinking Water Based on a Double-Ring Triboelectric Nanogenerator

Drinking water security is a significant component of public health. However, the majority of disinfection methods depends on a power grid, restricting their application prospects. This work proposes a self-powered combined (UV/O3) disinfection system for drinking water based on a double-ring triboelectric nanogenerator (DR-TENG) consisting of an inner-ring TENG (IR-TENG) and an outer-ring TENG (OR-TENG). The artificially introduced air gap in the OR-TENG circuit increases the UV irradiance to 31.63 μW/cm2, significantly improving the disinfection efficiency to 12.02 mL/min at 300 rpm. For IR-TENG, an instant voltage of over 31.24 kV and an O3 concentration of 31.96 mg/m3 at 500 rpm were achieved. Consequently, a UV/O3 disinfection method is proposed to enhance the disinfection performance under insufficient UV irradiance such as in high-turbidity environments or large-diameter water reactors. The UV/O3 disinfection efficiency of E. coli solution with 0.35 McFarland (MCF) and within a 60 mm diameter water reactor is enhanced to 4.43 and 17.23 mL/min, respectively, at 300 rpm. Furthermore, 10 mL of Rhodamine B solution with a concentration of 5 ppm is almost completely degraded by O3 within 15 min at 300 rpm due to the strong oxidizing properties of O3. To expand the function of the O3 disinfection system, a buck circuit is integrated into the current loop without disturbing the generation of the O3 to power a water quality detector. In summary, this work provides a strategy for water disinfection and TENGs with high-voltage DC output.