A 3D aerogel evaporator for efficient solar interfacial evaporation: Breaking through the upper limit of steam production rate

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-11, Vol.499, p.156520, Article 156520
• Main Authors: Zhang, Zhaoshun, Zhang, Qi, Zhang, Hui, Zuo, Xueqin, Yang, Qun, Tang, Huaibao, Jin, Shaowei, Li, Guang
• Format: Article
• Language: English
• Subjects: Aerogel; Desalination; Low evaporation enthalpy; Self-discharge salt
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.156520

The formation of hydrogen bonds between polar functional groups in aerogels and free water transforms free water into bound water. Then, hydrogen bonds are formed between bound water and free water to convert free water into intermediate water. Due to the weak bond energy between the intermediate water molecules, the evaporation enthalpy is lower. Therefore, the MCAM evaporator can break through the limit of steam production rate and reach 1.92 kg⋅m−2⋅h−1. [Display omitted] •The steam production rate of MCAM-10 reaches 1.92 kg⋅m−2⋅h−1.•The energy utilization efficiency of MCAM-10 reached 118.2 %.•Self-discharge salt ability. The evaporator can discharge 9 g salt in 10 h.•The light absorption performance in the full spectrum is as high as 96.96 %.•The evaporation enthalpy of water can be reduced by the MCAM evaporator. Solar desalination is the most effective way to obtain clean and cheap fresh water. However, its lower upper limit of steam production rate limits its development and practical applications. In this paper, a microcrystalline cellulose aerogel composite Mo2C evaporator (MCAM) was prepared by combining Mo2C with microcrystalline cellulose aerogel (MCA). The evaporator consists of MCAM photothermal layer, polyurethane (PU) sponge insulation layer and one-dimensional water channel. Mo2C has high-light absorption efficiency. At the same time, the vertical channel inside the MCA makes the incident light be reflected and absorbed for many times inside. Benefiting from the synergistic effect of the vertical channel of MCA and the light absorption ability of Mo2C, MCAM obtained a high light absorption efficiency of 96.96 %. The interaction between the MCAM evaporator and water can reduce the evaporation enthalpy, thereby breaking the upper limit of the steam generation rate. Therefore, the evaporator achieved a steam production rate of 1.92 kg⋅m−2⋅h−1 and an energy utilization efficiency of 118.2 %. In addition, MCAM shows excellent salt tolerance and self-discharging salt ability, which ensures its stable operation in high-salinity environment. Besides its high efficiency, MCAM has significant purification effect on simulated seawater, heavy metal wastewater, and organic wastewater. This study provides a new strategy for further improving the steam production rate of the solar interface evaporator.