关键词: 纤维素, 纳米纤维, 纳米流体, 离子传输, 渗透能收集

Abstract:

Significance The significant osmotic pressure difference between river water and seawater presents a promising and renewable energy source ready for development. Unlike other renewable energies such as wind, solar, and tidal energy, osmotic energy depends less on environmental conditions and can offer a stable energy output. Efficient collection and utilization of osmotic energy can help reduce energy supply pressures. Ion-selective materials are crucial for osmotic energy harvesting technologies. Cellulose, the most abundant and widely distributed polysaccharide in nature, is notable for its plentiful availability and low cost. Its ease of modification and diverse processing techniques have contributed to its extensive application across various industries. Modified cellulose, with its abundant surface charges, can be processed into desired structures in a controlled manner, making it highly applicable in the field of osmotic energy harvesting.

Progress Cellulose is a versatile biopolymer commonly derived from wood, cotton, and bacterial cultures. Cellulose nanofluid systems with nanochannels that match double-layer thickness, high charge density, and elevated ion transport flux demonstrate ionic conductivities significantly surpassing bulk solutions at very low salt concentrations. This property grants the system high sensitivity and responsiveness to changes in solution concentration driven by pressure, temperature, and material composition, resulting in enhanced osmotic energy harvesting performance under 50-fold salinity gradients. Wood is particularly notable due to its naturally oriented structure and distinct porous cross-section, which can be manipulated through twisting and compressing to densify micropores to the nanoscale, which is ideal for ion transport control. Modification treatments like N-oxo-1,2,2,6,6-pentamethylpiperidine-N-oxyl(TEMPO) oxidation or quaternization enhance the wood's ion management capabilities by imparting a rich surface charge. Techniques such as crushing and acid hydrolysis break down macro-sized wood and cotton into nanofiber structures, which can be processed into nanofluid membranes for improved ion transport. These nanofibers can be combined with two-dimensional materials like MXenes to enhance ion management and reduce production costs. The NaOH/urea/water dissolved regenerated cellulose system is gaining traction, producing highly ordered and closely packed porous structures that create shorter ion transport pathways. The combination of cellulose's surface charges and functional materials facilitates directed ion transport, making cellulose a versatile solution for various applications.

Conclusion and Prospect Cellulose is an eco-friendly natural polymer with significant potential in ion management due to its renewability, sustainability, and low cost. Found abundantly in plants, cellulose's hydroxyl groups allow for easy modification, providing diverse surface charges to regulate ion transport. Its versatility supports osmotic energy harvesting, desalination, ion monitoring, and energy storage applications. Challenges include its crystalline structure limiting ion migration speed and hydrophilicity, which potentially reduce performance in aquatic environments. Recent advancements like ion coordination improve performance primarily in cellulose nanofibers. Continuous research and new construction strategies aim to enhance cellulose's role in high-performance material applications.

Key words: cellulose, nanofiber, nanofluid, ion transport, osmotic energy harvesting