This study provides critical insights into hydrodynamic and measurement techniques in the NW Banda Sea, enhancing our understanding of oceanic processes. It focuses on the physical oceanography conditions in Eastern Indonesia, demonstrating the connection between a 2D hydrodynamic model simulation and oceanographic phenomena, including surface current patterns, waves, and tides. The model analyzes the east monsoon during August, September, and October 2023, encompassing spring and neap tides. The correlation results between the model and observed tidal data over 15 days showed a strong correlation value of 0.96 and an RMSD of 0.29. The tides are predominantly mixed and semi-diurnal, reflecting the complex interplay between lunar and solar gravitational forces. Spring tides exhibit higher elevations than neap tides. The highest ocean surface current speed was observed in August at 2.23 m/s (southeast to northwest), while the lowest was noted in September at a value of 0.95 m/s (northwest to southeast). Wave patterns indicate a monthly cycle increase in wave height from September to January, with notable wave heights (Hs) and peak periods (Ts) recorded during the east monsoon from August to October. We found the interplay between surface currents and tidal patterns significantly influences wave height and current dynamics.

Nano-membranes are gaining significant attention for various applications, including water treatment, ion concentration control, desalination, and a range of biomedical uses. However, this advanced technology faces challenges such as toxicity and fouling from contaminants, which raises safety concerns regarding the synthesis of green and sustainable membranes. In this study, green synthesized zinc oxide nanoparticles (ZnO NPs) derived from blue-green algae Arthrospira platensis were combined with cellulose acetate (CA) to fabricate ultrafiltration (UF) nanocomposite membranes designed for the removal of Chromium (VI) from aqueous solutions. This ensures that our material is environmentally friendly and poses no risk of ecotoxicity, unlike conventional synthetic materials that may have harmful environmental impacts. The membranes were synthesized using the phase inversion technique and characterized using Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), X-Ray diffraction (XRD), Energy dispersive X-ray analysis (EDX) and water contact angle (WCA) assess their chemical composition and morphological structure. The performance of the membranes was evaluated by measuring water flux and Cr(VI) removal. The concentration of ZnO NPs influenced the membranes’ morphology, performance, surface hydrophilicity, and Cr(VI) removal efficiency. Various concentrations of ZnO nanoparticles (0.5, 1, 2, and 3 wt%) were added to the CA membrane. The findings revealed that the membrane containing 3 wt% ZnO NPs achieved a Cr(VI) removal efficiency of 94.77 %, an adsorption capacity (qe) of 11.28 µg/cm2, and exhibited excellent hydrophilicity with a contact angle of 34.7°. Additionally, the water flux of the CA/ZnO NPs nanocomposite membrane was 53 % higher than that of the neat CA membrane. The kinetic data suggested that the adsorption of Cr(VI) onto the membrane followed a pseudo-second-order kinetic model. Among the isotherm models applied, the Langmuir adsorption isotherm provided the best fit for the experimental data. In summary, our study not only introduces an environmentally sustainable and economically viable method for producing ZnO NPs, but it also highlights the superior performance of the nanocomposite membranes in treating polluted water. This makes our approach a valuable contribution to the development of green technology for environmental applications, offering promising potential for industrial and ecological implementation.