Photothermal Composite Film Based on AuNP@SiO2-APTES/PSF for Enhanced Solar-Driven Evaporation in Tunnel Salt Production Systems Pebriana Ika Kurniawati S (a*), Aep Patah (b)
Inorganic & Physical Chemistry Research Division, Institut Teknologi Bandung
Abstract
Geomembrane-based tunnel systems have been widely implemented in salt production due to their ability to enhance salt purity and enable continuous operation independent of weather conditions. However, evaporation efficiency in such systems remains limited by high internal humidity and restricted air circulation, which reduces the mass transfer rate of water vapor. Therefore, the development of advanced photothermal materials is essential to improve light-to-heat conversion and accelerate the evaporation process. This study aims to develop a polysulfone-based composite film incorporated with silica-encapsulated and APTES-functionalized gold nanoparticles as a photothermal material for tunnel-based salt production systems. Gold nanoparticles were synthesized via the Turkevich method by reducing HAuCl₄- with citrate, followed by silica encapsulation using a sol-gel process to enhance stability and provide a functional surface. The nanoparticles were subsequently functionalized with APTES to improve compatibility with the polymer matrix. The resulting nanoparticles were then dispersed into the PSF matrix and fabricated into composite films via solution casting. Material characterization was conducted using UV-Vis spectroscopy, FTIR, DLS, and TEM. Photothermal performance was assessed based on temperature elevation under light irradiation, while evaporation performance was evaluated through the saline water evaporation rate under simulated tunnel conditions. The results are expected to demonstrate that the composite film exhibits enhanced photothermal conversion and improved evaporation rates compared to conventional systems.
Keywords: Photothermal materials- Polysulfone- Gold nanoparticles- APTES functionalization- Solar-driven evaporation- Geomembrane tunnel system- Salt production
