A waterwheel hybrid generator with disk triboelectric nanogenerator and electromagnetic generator as a power source for an electrocoagulation system

Electrocoagulation (EC) method has emerged as a state-of-the-art water purifying technology. Here, a self-powered EC system is proposed using a waterwheel hybrid generator (W-HG) based on disk-type triboelectric nanogenerator (D-TENG) and electromagnetic generator (EMG). D-TENG consists of a rotator and stator based on printed circuit board (PCB) technology. With electrospinning and sintering process for polytetrafluoroethylene (PTFE) as a dielectric layer of the D-TENG, the fabricated membrane exhibits superhydrophobic property with a water contact angle of 160.5°, which allows the device to show self-cleaning property and to operate at high relative humidity. Additionally, a fractal-design based switched-capacitor-converter (FSCC) is utilized with the high-frequency and high-output based D-TENG to operate commercial electronic devices. The hybridized W-HG exhibits 1.75 mW of the average power at the matching load resistance of 400 Ω. An energy conversion efficiency of the device between rotational input energy and electrical output energy marks at 8.75%. The D-TENG and EMG are combined with a rotating waterwheel to demonstrate their ability to power an EC purification system. A power management integrated circuit (PMIC) is utilized with the D-TENG for high current input to the EC module. Finally, the W-HG successfully purifies wastewater with a high removal ratio above 95% for 18 h.