Effects Of Morphology And Crystalline Phase Of BiVO₄on Their Toxicity To Fresh Microalgae

Bismuth vanadate （BiVO₄） is one of the visible-light driven semiconductor photocatalyst.Its excellent photocatalytic properties make it widely used in many fields. More attention is paidto evaluate its influence on ecological environment.BiVO₄with different crystalline phases and morphologies were synthesized by thehydrothermal method and the precipitation method. They were characterized by X-ray diffraction（XRD） and scanning electron microscopy （SEM）. Then, dose test of BiVO₄with differentcrystalline phases and morphologies was carried out on Chlorella vulgaris and Scenedesmus sp.Effects of morphology and crystalline phase of BiVO₄on their toxicity to fresh microalgae werestudied by detecting cell density, chlorophyll a content, MDA content, chlorophyll fluorescenceparameters and analyzing cell morphology.Results showed that morphology and crystalline phase of BiVO₄have different effects ontheir toxicity to fresh microalgae. BiVO₄exerts great inhibition on the growth of Chlorellavulgaris, whereas slight inhibition on the growth of Scenedesmus sp. Morphology and crystallinephase of BiVO₄have great effects on their toxicity to fresh microalgae. Tetragonal phase showedno significant inhibition to both algaes, while monoclinic phase showed different inhibition.Monoclinic samples with octahedron and tetragonal samples with sphere-shaped showed nosignificant inhibition on growth of both algeas, while monoclinic samples with lamellar andegg-shaped toward Chlorella vulgaris and noodles-shaped toward Scenedesmus sp. showedsignificant inhibition with EC₅₀values at19.49mg/L,70.93mg/L and61.94mg/L respectively.