Synthesis of silver sulfide acanthite phase nanoparticles for photothermal hybrid PSF membrane

Abstract

Membrane distillation (MD) is an energy-intensive desalination technique hindered by high energy consumption. To address this limitation, we selected silver sulfide (Ag₂S) Nanoparticles (NPs) for incorporation into a polysulfone (PSF) membrane, aiming to enhance the photothermal membrane distillation (PMD) process. Ag₂S was chosen due to its unique photothermal properties, including efficient light absorption and conversion into heat, making it an ideal candidate for improving the thermal efficiency of MD membranes. The Ag₂S NPs were synthesized using the Chemical Bath Deposition (CBD) method and characterized through SEM, UV-spectroscopy, FT-IR, and EDX. The NPs were integrated into the PSF membrane at varying concentrations (0.5–2 %). The PSF/Ag₂S composite membranes demonstrated significant photothermal properties, with surface temperatures rising from 45.7°C to 52.3°C under light exposure. The water flux also improved from 5.4 L/m²h without light to 7.8 L/m²h with light in the optimal membrane containing 1.5 % Ag₂S. Additionally, contact angle (CA) measurements indicated increased hydrophobicity, while liquid entry pressure (LEP) values rose, further enhancing membrane performance. The composite membrane achieved a remarkable salt rejection rate of 99.99 %. These findings suggest that integrating Ag₂S NPs into PSF membranes significantly improves energy efficiency, water flux, and desalination performance. This makes it a promising approach for solar-driven desalination, with Ag₂S acting as an effective photothermal agent. The study underscores the potential of Ag₂S as a sustainable solution for improving MD efficiency, offering a new pathway to tackle global water scarcity.