Tartrazine removal by ZnO nanoparticles and a zeolite-ZnO nanoparticles composite and the phytotoxicity of ZnO nanoparticles

Abstract ZnO nanoparticles (nanZnO) and a zeolite-ZnO nanoparticles composite (Ze-nanZnO) were prepared and characterized. These materials were used for the removal of tartrazine from aqueous solutions by an adsorption-photocatalysis coupled process. The adsorption using nanZnO showed a rapid decrease of the concentration of tartrazine and the adsorption by using the composite Ze-nanZnO was slower. The degradation of tartrazine by using both materials in the presence of ultraviolet light seems to be a highly efficient process for both materials, 87 and 81% degradation were observed for nanZnO and Ze-nanZnO respectively, although the first material seems to be more efficient than the second, this first material is difficult to remove from the aqueous solution after the process. The mineralization was monitored by measuring the total organic carbon at different contact and irradiations times. The degradation of the dye was high between 85 and 90%, higher degradation was observed using Ze-nanZnO as catalyst than nanZnO. “Lactuca sativa” species suffer “low toxicity” when they are in contact with solutions containing the dye and solutions that were in contact with nanZnO.