Natural clay-based reusable piezo-responsive membrane for water droplet mediated energy harvesting, degradation of organic dye and pathogenic bacteria

Nowadays, scientists have paid attention to utilizing natural and biocompatible materials for combating global challenges such as water pollution and the energy crisis. Moreover, pathogenic bacteria have also posed a severe threat to human health and the overuse of conventional antibiotics makes this situation even worse by evolving multidrug-resistant strains (MDR). Herein, we developed a natural clay (kaolinite) and multi-walled CNT (MWCNT) based nanocomposite, which has been encapsulated in the polymeric matrix of Poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) to achieve a multifunctional piezo-responsive membrane. This membrane is capable to generate piezoelectric energy under the perpendicular flow of water droplets. Such stimulus generates a 4.1 V voltage and 1.5 μA current maintaining a piezoelectric power density of 50 Wm⁻³. It is worth noting that this membrane can eliminate around 96% Rhodamine-B concentration in only 60 min in water under ultrasound. A closer look suggests that the generation of reactive oxygen species (ROS), especially OH* accelerates the catalytic process under ultrasonic vibration. Such an interesting result motivated us to implement this piezocatalytic process to eradicate pathogenic bacteria, which shows a radical bactericidal effect (almost 99% killing) and evolves as an alternative antibacterial technique.