3D nested solar evaporator based on CuO MF/OH-MWCNT for high-efficient desalination of seawater

Abstract

Continuing climate deterioration and accelerated population growth are creating unprecedented pressure on limited freshwater supplies. The development of efficient and stable solar desalination devices is emerging as an effective way to alleviate this crisis and ensure a sustainable water supply. In this study, a 3D nested evaporator composed of CuO microflowers (CuO MFs) and hydroxylated multi-walled carbon nanotubes (OH-MWCNTs) integrated into air-calcined melamine sponge (AMS) was designed for solar desalination. The innovative structure of the evaporator not only enhances water transfer capacity but also minimizes heat loss. Among them, AMS acts as the matrix skeleton that provides structural support and possesses great photothermal conversion performance. Because of the unique micro-nano hierarchical structure and the synergistic photothermal effect of CuO MF/OH-MWCNT, the evaporator demonstrates remarkable evaporation performance and salt resistance, achieving an evaporation rate of 4.25 kg∙m⁻²∙h⁻¹ and an efficiency of 180.76 % under standard solar illumination (1 kW∙m⁻²). Additionally, the evaporator exhibits excellent self-cleaning capabilities and long-term stability, maintaining consistent performance across various complex environments. This study contributes to the development of sustainable water treatment technologies and provides a feasible approach to constructing high-performance solar vapor generation devices.