Using nano zero valent iron supported on diatomite to remove acid blue dye: synthesis, characterization and toxicology test

Abstract

The aim of this work was to synthesize and characterize nanoscale zero-valent iron (NZVI) supported on diatomaceous earth (DE) at two different molar concentration 3 M and 4M (nZVI-DE-1 nZVI-DE-2), to test the decolorization treatment of acid blue dye (AB) and perform a toxicological test using zebrafish. The synthesis of the nanoparticles was obtained using the chemical reduction method and the material was characterized by X-ray diffraction, Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray (EDX), and transmission electron microscopy and Specific Surface Area (BET). The results showed spherical forms in clusters between 20 to 40 nm of zero valent iron supported on diatomaceous earth. The removal of 1 g/l of AB from water treated with NZVI-DE-1 and NZVI-DE-2 reached the decolorization of 90% and 98% of all dye. While controls like NZVI and DE-1 and DE-2 achieved the removal of 40, 37 and 24 % of the dye. Toxicological analysis using zebrafish showed that AB causes a severe defect in development and embryos die after exposure. However, the water samples treated with NZVI-DE-1 and NZVI-DE-2 are not harmful for the zebrafish embryos during the first 24 hours. We conclude that the use of NZVI-DE-1 and NZVI-DE-2 is a promising treatment for dye pollution.