Analysis of the presence of surfactante in the removal of microplastics by electrocoagulation

Various types of pollutants are found in effluents, which can combine to form even more toxic components or impair the treatments used in effluent purification. Among the emerging contaminants, microplastics and surfactants can be mentioned, which coexist in different types of wastewater. The present work evaluated the effects caused by the anionic surfactant LAS and nonionic Tween 20 in the removal of pristine and aged PVC microplastic, added in synthetic water, by the method of electrocoagulation with aluminum electrodes. For the experiments, a bench reactor was developed, which operated in batches and with synthetic water, in order to avoid interference from other substances. For the analyses, counting was used with the aid of a magnifying glass, gravimetry and scanning electron microscopy. The results showed that there was a reduction in the removal of plastic microparticles when surfactant was added, the only one that showed improvement was with the new microplastic in the presence of LAS at a concentration of 10 ppm. The worst removal percentages were for the concentration of 100 ppm, and when adding Tween 20 there was a decrease of 23% and 45% for pristine and aged microplastic, respectively, while for LAS the decrease was 6% and 24 %, for intact and deteriorated microplastic, respectively. Therefore, it is clear that the drop in removal was greater for degraded microplastics, both for the tests with Tween 20 and for the LAS. Comparing the decrease in removal between the two types of surfactant, it is observed that the non-ionic one reduces microplastic removal to a greater extent.