有机改性层状双金属氢氧化物与甲基橙联合暴露对小球藻的毒性影响

为探究有机改性层状双金属氢氧化物(O-LDH)与甲基橙(MO)联合暴露对微藻的毒性影响,选取小球藻(Chlorella vulgaris)作为受试藻种,考察O-LDH、MO单一及联合暴露对小球藻的生长抑制率、叶绿素含量、细胞结构等指标的影响,并通过测定溶液剩余MO浓度和藻细胞表面电位,探究O-LDH、MO与小球藻的吸附作用及毒性机制。结果表明：1)O-LDH、MO对小球藻96 h生长抑制率拟合均符合Logistic模型(R²>0.99),EC_50-96h值分别为122.18,26.73 mg/L,MO对小球藻的抑制作用大于O-LDH;2)O-LDH对小球藻的毒性机制包括纳米片层聚集在微藻细胞表面所产生的阴影效应以及纳米片层割裂细胞结构所造成的氧化损伤;3)在低O-LDH浓度范围(0～50 mg/L),溶液中O-LDH被微藻细胞强烈吸附,阻碍微藻光合作用并割伤微藻细胞结构,对微藻产生阴影效应和氧化损伤,导致O-LDH和MO对小球藻的联合毒性增强;在高O-LDH浓度范围(50～500 mg/L),溶液中O-LDH、O-LDH吸附MO后产物共...

TOXICITY EFFECT OF ORGANIC MODIFIED LAYERED DOUBLE HYDROXIDE COMBINED WITH METHYL ORANGE ON CHLORELLA VULGARIS

In order to explore the toxicity effect of organic modified layered double hydroxide (O-LDH) combined with methyl orange (MO) on microalgae, Chlorella vulgaris was selected as the experimental algae species in this study. The effects of single and combined exposure of O-LDH and MO on growth inhibition, chlorophyll content and cell structure of C. vulgaris were investigated. The adsorption and toxicity mechanism of O-LDH and MO on C. vulgaris were investigated by measuring residual MO concentration and cell surface potential of algae. The results were as follows:1) the fitting results of 96 h growth inhibition rate of algae by O-LDH and MO were in accordance with the Logistic model (R2>0.99), the EC_50-96h values were 122.18, 26.73 mg/L, respectively, and the inhibition effect of MO on C. vulgaris was greater than that of O-LDH. 2) the toxicity mechanisms of O-LDH to C. vulgaris included the shading effect caused by the aggregation of nanolamellae on the surface of microalgae cells and the oxidative damage caused by the fragmentation of cell structure by nanolamellae. 3) at low concentrations of O-LDH (0~50 mg/L), O-LDH in the solution was strongly adsorbed by microalgal cells, resulting in enhanced combined toxicity of O-LDH and MO to C. vulgaris. At high concentrations of O-LDH (50~500 mg/L), O-LDH and the products of MO adsorbed by O-LDH in the solution competed for charge sites on the surface of microalgal cells, and the hydrophobic layer was formed on the surface of O-LDH after adsorbing MO, which weakened the shadow effect of O-LDH on microalgae cells and reduced oxidative damage, leading to weakened combined toxicity of O-LDH and MO to C. vulgaris.