Enhancement of photothermal membrane distillation efficiency with octylamine-functionalized copper oxide nanoparticles

• Photothermal Membrane Distillation (PMD) enables energy-efficient solar-driven desalination. • Octylamine-functionalized CuO NPs enhance membrane hydrophobicity and photothermal response. • 10 wt% Octy-Cu/PVDF membrane achieved a 143.5% flux increase with 99.9% salt rejection. • CuO NP integration improves UV–Vis-NIR absorption, boosting photothermal conversion. • Solar-driven PMD with functionalized CuO NPs advances sustainable desalination efficiency. Desalination of water is an important strategy for combating global water scarcity. However, conventional methods often consume a lot of energy and increase the CO 2 footprint. Photothermal Membrane Distillation (PMD) is a promising long-term solution for desalination using solar energy. In this study, we have investigated the incorporation of octylamine-functionalized copper oxide nanoparticles (Octy-Cu NP) into the membranes to improve their performance. The synthesis of Octy-Cu NPs with tuned surface functionalization enables efficient hydrophobization of the membranes, making them ideal for desalination applications. Membrane-based Octy-Cu NPs in loading ranges of 0–60 wt% (based on the total weight of PVDF) improved the photothermal properties as evident from photothermal efficiency, dry surface temperature of the membranes, UV–Vis-NIR spectrophotometry, etc., resulting in increased water vapor generation and desalination efficiency using an air–gap membrane distillation system. The 10 wt% Octy-Cu/PVDF membrane outperformed the pristine PVDF membrane with a 143.5% increase in water flux and 99.9% salt rejection. Moreover, the utilization of renewable solar energy diminishes dependence on fossil fuels, thereby fostering sustainable desalination methods and benefiting the environment. This study demonstrates the potential of functionalized CuO NPs in advancing PMD technology for efficient and eco-friendly water desalination solutions.