Copyright © 2022 Foshan MBRT Nanofiberlabs Technology Co., Ltd All rights reserved.Site Map
With the growth of the global population, the advancement of urbanization, and environmental pollution caused by industrialization, water scarcity and energy crises are becoming increasingly severe. Therefore, solar-driven interfacial evaporation (SDIE) technology has emerged as an effective solution to alleviate water scarcity. Due to their high porosity and renewability, cellulose nanofiber (CNF)-based aerogels show great potential in this field.
Recently, Professor Xu Jie's team at Wuhan Textile University published their latest research, "Cellulose nanofiber-based aerogel with Janus wettability for superior evaporation performance and synergistic photocatalytic activities," in the journal Carbohydrate Polymers. Wuhan Textile University is the sole affiliation. The first author is master's student Hu Bowen, and the corresponding authors are Professor Xu Jie and Associate Professor Fan Lingling.The research proposes a CuS-coated cellulose nanofiber (CNF)/polyvinyl alcohol (PVA) aerogel designed to improve solar-driven interfacial evaporation (SDIE) and photocatalytic degradation performance. This aerogel has a Janus structure, consisting of a CuS photothermal layer and a CNF/PVA substrate, and possesses a porous, hierarchical network structure. This structure promotes rapid water transport, prevents salt accumulation, and enhances photothermal and photocatalytic activity.
Figure 1: (a) Schematic diagram of the principle of high moisture evaporation rate of CuS@CNF/PVA aerogel; (b) Schematic diagram of the preparation process of CuS@CNF/PVA aerogel.
The team prepared cellulose nanofibers (CNF) with a dendritic branching structure using a deep eutectic solvent at room temperature; this biomimetic structure facilitates water transport. The CuS photothermal coating on the aerogel surface, bonded by sodium alginate, is superhydrophilic, favoring unidirectional water transport from bottom to top. The polymer-water interaction significantly increases the proportion of intermediate water, thus exhibiting characteristics of cold evaporation. The synergy between the hierarchical pore structure, directional channels, and surface engineering enhances photothermal conversion performance while maintaining structural stability.
Figure 2: Surface temperature changes of CNF/PVA and CuS@CNF/PVA aerogels in dry and wet states under one sun illumination.
Under one sun illumination, the dry surface temperature of the CuS@CNF/PVA aerogel rapidly increased from 24.5°C to 39.9°C and reached 53.2°C within 10 minutes, demonstrating excellent photothermal conversion capability. In the wet state, the surface temperature rose more slowly, reflecting the cold evaporation characteristic, which can significantly reduce heat loss and improve the energy conversion efficiency of evaporation.
Figure 3: Photothermal water evaporation performance of CuS@CNF/PVA aerogel.
The CuS@CNF/PVA aerogel exhibited a high evaporation rate of 3.20 kg/m²/h under one sun illumination, with an energy conversion efficiency of 98.4%. In a high-concentration NaCl solution (20 wt%), the evaporation rate reached 2.51 kg/m²/h, demonstrating its great potential for sustainable desalination applications. Furthermore, the CuS photothermal layer also possesses photocatalytic properties for degrading organic dyes, achieving over 70% degradation efficiency for common dyes like methyl blue (MB), rhodamine B (RhB), and methyl orange (MO) within 3 hours.This work provides an effective method for developing high-performance solar evaporators with synergistic interfacial evaporation and photocatalytic functions, offering novel design and manufacturing ideas for low-residue treatment of dye wastewater.
Figure 4: Photothermal water purification performance of CuS@CNF/PVA aerogel and its photocatalytic degradation performance for dyes.
