Paper-Mill Waste Reinforced Nanofluidic Membrane as High-Performance Osmotic Energy Generators

摘要

Nanofluidic membranes consisting of 2D materials and polymers areconsidered promising candidates for harvesting osmotic energy from riverestuaries owing to their unique ion channels. However, micron-scale polymerchains agglomerate in the nanochannels, resulting in steric hindrance andaffection ion transport. Herein, a nanofluidic membrane is designed fromMXene and xylan nanoparticles that are derived from paper-mill waste. Thedemonstrated membrane reinforced by paper-mill waste has the characteristicsof green, low-cost, and outstanding performance in mechanical propertiesand surface-charge-governed ionic transport. The MXene/carboxmethylxylan (CMX) membrane demonstrates a high surface charge (ζ-potentialof ?44.3 mV) and 12 times higher strength (284.96 MPa) than the pristineMXene membrane. The resulting membrane shows intriguing features ofhigh surface charge, high ion selectivity, and reduced steric hindrance, enablingit high osmotic energy generation performance. A potential of the nanofluidicmembrane is ≈109 mV, the corresponding current of up to 2.73 μA, andthe output power density of 14.52 mW m~(?2) are obtained under a 1000-fold saltconcentration gradient. As the electrolyte pH increases, the power densityreaches 56.54 mW m~(?2). This works demonstrate that CMX nanoparticles caneffectively enhance the properties of the nanofluidic membrane and provide apromising strategy to design high-performance nanofluidic devices.