Environmentally safe and cost-effective microplastic isolation using a salt–sugar flotation approach

Microplastics are emerging environmental pollutants that are contaminating every sector of the biosphere due to their small size. Studies have shown that microplastics act as a potent vector for transferring hazardous contaminants into the soil fauna, terrestrial plants, and they can further seep into groundwater or nearby water bodies. Density separation is a conventional technique to remediate microplastics, but the salts used for remediation are quite expensive, and each has its own disadvantages. The current study focused on developing an environmentally benign flotation media whose disposal in the environment is safe after extracting microplastics and is cost-effective. Three cost-effective and easily available salts were tested and reported to include food-grade common salt, table sugar, and an equal volume of a common salt and table sugar solution. In all the tested solutions, the food-grade salt-sugar solution (1:1) was found to be efficient in separating microplastics with an efficiency equal to that of the most frequently used AR-grade sodium chloride solution. Sugar-salt solution was an effective density separation medium with a performance efficacy of 100 % for low-density microplastics and 43.3-76.7 % for high-density microplastics, when tested with spiked samples.