Preparation of ZnO Nanopariticles by a Microwave Hydrothermal Method and Their Toxicity to Chlorella

Zinc oxide nano powders were prepared by a microwave hydrothermal method with Zn(NO3)(2).6H(2)O and NaOH as start materials and CTAB as dispersant. The as-synthesized powders are 50 similar to 100 nm in diameter and dispersed well. In the toxicity experiments, chlorella was used as the tested organisms, a concentration gradient on zinc ion was set in the system mixed with ZnO nanoparticles and broth. Hemocytometer measurement shows nano-zinc oxide has a strong inhibition to chlorella, the higher the concentration the greater the inhibition. When the zinc ion concentration is 50 mg/L and above, compared to the exponential growth trend into the zero concentration and the low dose group, the chlorella growth is extremely slow and even almost no growth occurs.