Green Nanotechnology for the Remediation of Cyanotoxins from Contaminated Waters ^†

Abstract

The presence of contaminants in water may involve a risk to human and animal health. Conventional water treatment methods such as coagulation, flocculation, and sedimentation are ineffective for cyanotoxin removal. In addition, high amounts of cyanotoxins can be released during those processes if cells lyse. Thus, new mitigation strategies must be developed to ameliorate the consequences of harmful algal blooms. In this sense, nanotechnology has become a promising tool for the treatment of contaminated water. Several nanomaterials with specific chemical affinities can be combined into hybrid structures, leading to nanostructured agents with a large surface area and with the ability to absorb different contaminants. In addition, these structures can include magnetite, which enables separation from the detoxified substance by magnetic extraction, which is considered a green technique. This approach has been successfully applied to the removal of dyes, endocrine disruptors, and heavy metal ions. Recently, we have described the use of carbon nanoparticles to remove around 60% of microcystins from contaminated solutions, but with a low efficiency in the adsorption of anatoxin-a and cylindrospermopsin. In this work, a new set of biocompatible magnetic nanocomposites were tested using artificially contaminated water. The toxin content in solutions was determined before and after treatment by ultra-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). With these new nanocomposites, cyanotoxin elimination was highly improved, reaching toxin removal rates of up 80%. Therefore, the implementation of the nanotechnology in water treatment could be a promising approach to reduce the presence of natural toxins in the water.