Investigation of chitosan/polyvinyl alcohol based three-dimensional photothermal evaporator for solar-driven water desalination

The desalination evaporation system with solar energy as the primary driving energy has received extensive attention in recent years. This thesis studied the preparation method of hydrogels with chitosan and polyvinyl alcohol (PVA) as the framework and carbon nanoparticles (CNP) as the light-absorbing particles. The evaporation rate of hydrogels obtained can reach 2.25 kg m−2 h−1. Simultaneously, the three-dimensional structure is designed based on the two-dimensional double-layer evaporation system in this study. An evaporator with a tiny puddle structure and a hydrogel with a dome-arrayed structure has been designed. These two structures achieve the evaporation rates of 2.783 kg m−2 h−1 and 3.8 kg m−2 h−1, respectively. These optimized designs can improve the desalination efficiency of the overall system by ~25% and ~36.5%. These designs provide a promising pathway for developing the double-layer evaporators, which promote the new development of water purification with a solar-driven evaporation system.--Author's abstract