Metal-organic framework HKUST-1 derived CuO integrated reduced graphene oxide@ polyaniline for advanced solar seawater desalination

Abstract

Seawater desalination holds great promise for solving the freshwater deficiency. However, their performance has been limited by the high consumption of energy in the current desalination techniques. Herein, the pyrolysis of HKUST-1 transforms the framework into a mesoporous carbon decorated with CuO nanoparticles with the features of the pristine HKUST. The resultant material is capable of absorbing sustainable and abundant solar energy and increasing light trapping while simultaneously facilitating vapour generation. Moreover, HKUST-1 was functionalized by graphene oxide before pyrolysis to prepare the CuO/rGO evaporator. The synergistic coupling of the highly conductive rGO and CuO nanoparticles increases the solar absorptivity, photothermal conversion, and hydrophilicity of the evaporator. Also, polyaniline (PANI) was combined with the evaporator to enhance the absorptivity of the membrane and its salt resistance properties through the ionic repulsion with metal ions. Meanwhile, the CuO/rGO@PANI evaporator exhibited a 1.25 kg m⁻² h⁻¹ evaporation rate with an 85.5 % solar-to-thermal conversion efficiency. Additionally, the membrane showed excellent reusability and desalination ability owing to the electrostatic repulsion of metal ions with the ionic structure of PANI. Hence, the fabricated evaporator can be provided for the application of solar vapour generation in the future.