Development of Eco-Friendly Microplastic Removal Filter For Sea Salt Farm

Abstract

The increasing contamination of microplastics (MPs) in marine environments poses significant risks to aquatic ecosystems and human health, particularly in sea salt production. This study aimed to develop a sustainable coconut coir filter to remove MPs from seawater at sea salt farms. Experiments were conducted using a batch glass column (10 cm × 10 cm × 40 cm) containing cleaned Coconut coir, supported by layers of gravel (10 cm) and sand (4 cm). In order to establish optimum performance, three variables were tested: fiber length (short: 2-5 cm vs. long: 6-29 cm), packing density (37-148 g/dm), and thickness (3-5 cm). The essential performance indicators were MP removal efficiency, salinity stability, and flow rate of effluents. The results showed that salinity did not decrease across all experiments. The optimal length of coconut coir is short fibers (2-5 cm), which performed significantly better than long fibers, achieving 90% removal efficiency versus 45% with long fibers. It was established that the optimal filter setup was a density of 111 g/dm3 and 3 cm thickness, which had a removal efficiency of over 90 percent and a flow rate of 0.045 dm3/s. Results demonstrated high removal efficiencies across all tested polymers and concentrations (1-10 mg/L), with performance improving at higher MP concentrations. The efficiency of removal was polymer-dependent (300 μm-1 mm) and was in the following order: PS (92-98%), PP (90-97%), and PET (87-95%), which was attributed to differences in polymer hydrophobicity and surface chemistry. These findings indicate that coconut coir, particularly short fibers, is an effective and eco-friendly solution for mitigating microplastic contamination in sea salt, which provides a promising approach to enhancing environmental sustainability and food safety in marine-based industries.