过氧化钙缓释氧剂的制备及其释氧特性研究

采用硬脂酸在无水条件下包埋过氧化钙(CaO2)来制备缓释氧剂,为水环境修复提供氧气。经红外光谱和扫描电镜分析,证实硬脂酸可以有效包埋CaO2,且缓释氧剂的表面较包埋前更加紧密、平整。通过研究粉末CaO2与缓释氧剂在灭菌无氧水中的释氧行为,发现随着硬脂酸含量的增加,释氧速率降低,pH值变化也趋于平缓。在模拟底泥试验中,在25℃、CaO2投加量为720 g/m2的条件下,投加的缓释氧剂(硬脂酸含量为1.2%)可以在42 d范围内使DO浓度保持在5.0 mg/L左右,同时,依靠底泥自身的缓冲能力可使pH值从8.7逐渐降到7.7,这将有利于微生物的生长及抑制水体内源性污染物的释放。

Preparation and Oxygen Release Properties of Calcium Peroxide-based Oxygen Slow-release Composite

Stearic acid was used to embed calcium peroxide under anhydrous conditions in order to prepare an oxygen slow-release composite that supplies oxygen for water environment remediation.The infrared spectroscopy and scanning electron microscopy confirmed that stearic acid could effectively embed calcium peroxide,and the surface of oxygen slow-release composite was more closely and flat than before.Based on the tests in aseptic and oxygen-free water,it was found that the oxygen release rate decreased with the stearic acid concentration increase,and the pH value also leveled off.The results from the simulation sediment showed that with calcium peroxide dosage of 720 g/m2,the oxygen slow-release composite(stearic acid content of 1.2%) maintained the dissolved oxygen concentration around 5.0 mg/L within 42 d at 25 ℃,and pH value gradually reduced from 8.7 to 7.7 relying on sediment self-buffering,which was conducive to microbial growth and inhibition of endogenous pollutants release.