Energy harvesting from acid-base neutralization using GO-PDDA composite membranes with asymmetric ion transport

Energy harvesting from acid-base neutralization through the reverse electrodialysis technique provides a sustainable route to recover the chemical potential inherent in industrial effluents, thereby preventing the dissipation of Gibbs free energy as thermal waste. However, conventional reverse electrodialysis relies on homogeneous charge-selective membranes, which induce severe concentration polarization and consequently result in low power densities. Herein, we report an asymmetric Janus graphene oxide/poly (diallyldimethylammonium chloride) (GO-PDDA) composite membrane, featuring contrasting surface charges. This design facilitates directed H + /OH − translocation, which effectively suppresses polarization effects and promotes neutralization within the channels. Under a 1 M HCl/NaOH gradient, the GO-PDDA membrane delivered a peak power density of 265.92 W m −2 at an active area of 0.03 mm 2 and 16.87 W m −2 at 3.14 mm 2 , indicating promising performance for neutralization-energy harvesting. These results demonstrate that the asymmetric GO-PDDA membrane is a promising platform for recovering neutralization energy from acid/base waste streams and for advancing scalable nanofluidic energy-conversion technologies.