改性小麦秸秆去除赤潮异弯藻的实验研究

Removal of Heterosigma akashiwo by Modified Wheat Straw

研究了改性小麦秸秆对赤潮异弯藻的去除作用和机制.结果表明,在与未改性秸秆相同用量(0.10 g/L)的情况下,在120 m in时,改性秸秆对赤潮异弯藻的去除率可以从10%左右提高到80%以上.为了探讨改性秸秆对赤潮异弯藻的去除机制,测定了核苷酸在260 nm时的吸光度,结果发现水体内核苷酸物质浓度增大,说明在此作用过程中,藻细胞膜结构遭到破坏,核苷酸物质由胞内释放.当改性秸秆用量为0.15 g/L时,释放核苷酸在260nm时吸光度与正常细胞的吸光度比值为1.17,此时改性秸秆对赤潮异弯藻造成的损害是不可逆的.实验发现,改性秸秆对赤潮异弯藻同时具有吸附作用和灭杀作用.当浓度较低时,改性秸秆通过吸附细胞体,或者与细胞膜结合,从而导致部分藻细胞的絮凝;而当浓度进一步增加时,改性秸秆可以破坏细胞膜的结构,导致大量膜内物质的释放,进而导致藻细胞的死亡.

The modified wheat straw （MWS） was prepared and used to investigate the removal and the mechanism of Heterosigma akashiwo. The results showed that under the same loading of 0. 10g/L, the algal removal efficiency could reach 80% by MWS in 120 minutes, while 10% by the unmodified wheat straw. To investigate the mechanism, we measured the optical density of the supernatant at 260 nm. The result showed that the nucleotides were released, which meant disruption of the cytoplasmic membrane. More than 15% of the nucleotides were released from the cytoplasm under the effect of 0. 15g/L of MWS, indicating the irreversible damage on the cellular membrane, which resulted in the disintegration of the harmful algal ceils. It is suggested that the low concentration of MWS might adsorb onto the algal cell surface and bind to the cytoplasmic membrane, which resulted in the flocculation. While the high concentration might cause the penetration into the cellular membrane, which resulted in the leakage of cytoplasm material and hence the death of cell.