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Improving cost-efficiency for MPs density separation by zinc chloride reuse

MethodsX 2020 117 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count. Score: 40 ? 0–100 AI score estimating relevance to the microplastics field. Papers below 30 are filtered from public browse.
Mariana Rodrigues, Ana M. M. Gonçalves, Fernando Gonçalves, Nélson Abrantes

Summary

Researchers developed a cost-efficient protocol for reusing zinc chloride (ZnCl2) solution in density-based microplastic separation from aquatic samples, demonstrating that the reagent can be recovered and reused multiple times without significant loss of separation effectiveness. The approach reduces the financial and environmental costs associated with using high-density salt solutions in microplastic extraction workflows.

The methodology used to extract and quantify microplastics (MPs) in aquatic systems are still not standardized. Salt saturated solutions, such as sodium chloride (NaCl), zinc chloride (ZnCl) and/or sodium iodide (NaI), are normally added to separate dense plastics from aquatic samples. However, the most effective reagents are also the most expensive (e.g. ZnCl and NaI). To decrease this cost, a reuse process of the salt solutions should be applied. The reuse process has been widely investigated for the NaI solution neglecting the ZnCl. Hence, the aim of this study was to present a simple methodology to reuse the ZnCl solution ensuring the efficiency of the product. Results of the present study showed that ZnCl solution could be reused at least five times maintaining an efficiency above 95 %. •The ZnCl reuse decreases the cost of the methodology.•The efficiency of ZnCl solution after five filtrations remains above 95 % (all polymers are detected and recovered).•The use of this salt solution is the most cost-effective methodology to isolate MPs from aquatic samples.

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