Electrospinning Machine | In-situ growth of CNTs on porous carbon fibers for solar-driven enhanced interfacial evaporation

As global freshwater resources become increasingly scarce, seawater desalination technology has become an important approach to address water shortages. Interfacial evaporation technology has gained widespread attention in recent years due to its high efficiency and low energy consumption. However, challenges remain in preparing efficient interfacial evaporation devices for practical applications.

Recently, the team of Libang Feng/Dianming Li at Lanzhou Jiaotong University published their latest research, "In-situ growth of CNTs on porous carbon fibers for solar-driven enhanced interfacial evaporation," in the Journal of Membrane Science. The researchers prepared a Porous Cobalt-Carbon Nanotube/Carbon Fiber (Porous-Co-CNTs/C) interfacial solar evaporator via electrospinning and chemical vapor deposition processes, demonstrating significant potential in seawater desalination and wastewater recovery applications.

Figure 1: Schematic diagram of the Porous-Co-CNTs/C evaporation device process.

Figure 2: SEM characterization of the Porous-Co-CNTs/C evaporation device.

The morphological evolution of the electrospun membrane was systematically characterized using SEM. As shown in Figure 2 (a-c), the electrospun membrane consists of uniformly distributed nanofibers with a rich porous structure. After chemical vapor deposition treatment, a dense layer of carbon nanotubes successfully grew on the carbon fiber surface.

Figure 3: TEM characterization of the Porous-Co-CNTs/C evaporation device.

HRTEM showed that the Co nanoparticles have clear lattice fringes (Figure 3d-g), with an interplanar spacing of 0.198 nm corresponding to the (111) plane of metallic cobalt. The interplanar spacing of the carbon nanotubes (Figure 3h-k) is 0.338 nm, matching the graphite carbon (002) plane, indicating a high-quality graphitic structure.

Figure 4: Structural and optical properties of the Porous-Co-CNTs/C evaporation device.

Figure 5: Evaporation performance of the Porous-Co-CNTs/C evaporation device.

Under 1 kW m⁻² illumination, the evaporator achieved an evaporation rate of 1.46 kg m⁻² h⁻¹ in pure water, approximately 10 times the rate of pure water itself, primarily attributed to the excellent photothermal conversion performance of the carbon nanotubes and the porous structure. In different aqueous solutions, the evaporator maintained high evaporation rates (1.03 ~ 1.41 kg m⁻² h⁻¹) in acidic (pH=1), alkaline (pH=14), seawater (3.5 wt% NaCl), and high-concentration brine (20 wt% NaCl) environments, and exhibited good long-term stability, with a stable rate of 1.40 kg m⁻² h⁻¹ during a 10-day cyclic seawater test.

Figure 6: Application of the Porous-Co-CNTs/C evaporation device.

This device demonstrates exceptional efficacy during the evaporation process, offering a potentially feasible solution for seawater desalination.

Paper link::https://doi.org/10.1016/j.memsci.2025.124542