Removal microplastic contamination methods for raw material sea salt production: Review

Microplastic contamination in sea salt originates from entrainment of particles within high-salinity brine during saltworks operations. We conducted a scoping review (2015-2025) to map field-ready and emerging options for MP removal tailored to salt production trains. Searches in Scopus, ScienceDirect, and Google Scholar identified studies reporting MP size classes, polymer types, salinity, co-contaminants, operating conditions, and removal efficiencies. Evidence shows that multi-stage physical separation-coarse screening (3-5 mm), drum/mesh filtering (1-2 mm to 100 µm), settling/lamella and dissolved air flotation (DAF), provides robust removal for fragments/fibres >100 µm. Polishing microfiltration (0.1-0.2 µm) can target smaller MPs, albeit with higher energy and fouling risk. Biological options (biofilm/microalgae) can adsorb MPs in controlled reactors but require biomass management to preserve brine quality. Chemical routes (coagulation/advanced oxidation/photocatalysis) face constraints in hypersaline matrices and potential residues. We propose a process-integrated train—screening, to lamella/DAF, disc filter, microfiltration (polishing); with monitoring of MP size spectra, salinity-dependent performance, and cost. This framework supports safer sea-salt production while highlighting research gaps in nanoplastics and long-term fouling control. This paper conclusion that various methods for microplastic removal, so physical and biological methods such as filtration and microalgae-based treatments are identified as the most promising due to their environmentally friendly and cost-effective nature to enhance quality and safety of sea salt supporting.