Flexible and reusable piezo-responsive ternary bionanocomposite membrane for energy generation and catalytic removal of organic pollutants

Abstract

Growing concerns regarding energy scarcity, water contamination, and microbial pollution have increased the demand for sustainable multifunctional materials. In this study, we developed a flexible piezo-responsive membrane composed of chitosan (CHS), biowaste-derived carbon nanofibers (MCCNFs), and perovskite CoMnO₃ (CMO) nanoparticles through a simple solution-casting process. The resulting ternary bionanocomposite efficiently converted non-invasive mechanical stimuli into electrical output, delivering a power density of 9.885 mW cm⁻³ with an open-circuit voltage of 10.15 V and a short-circuit current of 22.4 µA under gentle finger tapping (16.7 N), and generating 3.1 V under water flow. It is worth noting that under mild ultrasonic stimulation, the membrane produced abundant ˙OH-dominated reactive oxygen species (ROS), enabling rapid degradation of carcinogenic dyes such as Congo red (99.27%), methylene blue (89.93%), and methyl orange (82.37%), and mixed-dye matrices (76.35%) within 35 minutes, while maintaining high reusability over eight cycles. Optimized operational conditions (alkaline pH, 60 W, 2.5 ppm) further facilitated an 85.65% reduction in total organic carbon (TOC) within 60 minutes and resulted in 96.21% and 98.23% contaminant removal from real drinking water and wastewater, respectively, with pot studies confirming reduced phytotoxicity in the tulsi (Ocimum tenuiflorum) plant. Motivated by these promising results, the membrane was subsequently employed for pharmaceutical and bacterial remediation, achieving 97.9% ciprofloxacin degradation, 90.8% tetracycline degradation, and ∼99% inactivation of Enterococcus faecalis within 20 minutes. Mechanistic investigations revealed that MCCNFs significantly improved dielectric behavior and interfacial charge transport, thereby enhancing piezocatalytic efficiency. Therefore, this scalable, biocompatible membrane offers a robust platform for self-powered energy generation, water purification, and antimicrobial treatment.