Electrohydrodynamic drying of pollens based on a dual-polarization induction mode triboelectric nanogenerator

Abstract

Drying pollen and other powders are important procedures of the food industry. Here we demonstrate a self-powered cold plasma drying system for collecting and drying pollen powders based on a dual-charge-induction mode triboelectric nanogenerator (TENG). The charge accumulation strategy of TENG has been modified by a dual-polarized module, where both ultra-high voltage output (over 30 kV) and sufficient output charge density could be generated to enhance drying efficiency. Comparing with all the other direct-current TENGs with an output voltage over 15 kV, this as-fabricated TENG can provide the highest transferred charge density so far. The electrohydrodynamic forces generated by the high-voltage TENG can be used to evaporate moisture from pollen. Within 20 min, it can lower the moisture content of fresh pollen from 35% to 7%, presenting a straightforward design for storing pollen at present. As for the same electrohydrodynamic drying process, the energy consumption of this self-powered TENG-based drying system for evaporating 1 kg water is about 5.36 kJ, which is only 36.4% of energy consumption of commercial high-voltage power source. This design provides a simple yet effective low-power consumption drying system for current pollen storage, which can be a promising environment-friendly alternative for food industry.