We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Mechanistic Analysis of Microplastic Incorporation during Supersaturation-Driven NaCl Crystallization
Summary
Scientists found that filtering seawater before turning it into salt removes over 97% of microplastics, and by carefully controlling how the salt crystals form (like slowing down the cooling process), they can further reduce how much plastic gets trapped inside. This matters because table salt is a known source of microplastic exposure in our diets, and this research points to practical ways salt producers could make their products cleaner without major changes to how salt is made.
Microplastic (MP) contamination in edible salt raises increasing food-safety and environmental concerns, yet the mechanisms governing their incorporation during crystallization remain poorly understood. In this study, targeted experiments and mechanistic modeling were combined to quantify and control MP entrapment in NaCl crystals. A synthetic seawater feed (200 g L –1 NaCl) was pretreated using ceramic ultrafiltration (20 nm pores, 0.358 m 2 ), removing >97% of MPs and reducing their concentration from 6,760 to 188 particles L –1 . The clarified brine was then evaporatively concentrated and subjected to batch crystallization under varied saturation levels, solution volumes, and cooling rates. MPs in harvested salt were quantified using Nile Red fluorescence microscopy coupled with automated MATLAB image analysis (median size deviation 2.95%). A first-principles dynamic model incorporating evaporation-driven concentration changes and heterogeneous nucleation kinetics reproduced salt yield and MP incorporation within 8% error. Results show that higher supersaturation and slower cooling increase particle-assisted nucleation, whereas larger solution volumes reduce mass-normalized MP capture.