【作者】 张蔚霞；

【导师】 曹吉林； 徐芳；

【作者基本信息】 河北工业大学 ， 化学工艺， 2007， 硕士

【摘要】 近年来水体富营养化现象是水体面临的最为严重的问题。在水体营养物中,磷是导致富营养化现象的重要因素。要解决富营养化问题,首先要从水体中去除磷。为此筛选并合成了三种铁系纳米材料,并且考察了其去除磷酸根的主要影响因素。确定了三种铁系纳米材料对磷酸根的吸附平衡时间:Fe₃O₄对磷酸根的吸附5小时后达到平衡,磁性铁氧化物/纳米β沸石复合组装体以及Fe掺杂型β沸石对磷酸根的吸附6小时后达到平衡。并且确定了铁系纳米材料对磷酸根吸附的最佳pH值在3-5之间。筛选比较三种铁系纳米功能材料对磷酸根的吸附效果,Fe₃O₄的饱和吸附量最大,磁性铁氧化物/纳米β沸石复合组装体居中,而Fe掺杂型β沸石材料对磷酸根的饱和吸附量最低。三种铁系纳米材料对磷酸根的吸附等温线对Freundlich方程有较好的拟合度。采用嗜热四膜虫模型,探讨在水体富营养化治理中三种铁系纳米材料的环境生物安全效应。分别将Fe₃O₄、纳米磁性铁氧化物/β沸石复合体、Fe掺杂型纳米β沸石材料作用于嗜热四膜虫生物模型,采用血球计数法观察不同铁系纳米材料对于嗜热四膜虫生长的抑制作用,并用热台偏光显微镜观察相应嗜热四膜虫形态变化。结果表明:Fe₃O₄对四膜虫抑制作用最强烈;并且嗜热四膜虫的生长抑制率同铁系纳米材料的浓度间存在明显正相关性。综合考虑,磁性铁氧化物/纳米β沸石分子筛组装体对磷酸根的吸附效果虽然比纳米磁性Fe₃O₄稍低,但其对四膜虫的影响作用却比纳米磁性Fe₃O₄微弱,其成本也比Fe掺杂型纳米β沸石大大降低。因此将磁性材料和纳米多孔材料相结合的磁性铁氧化物/纳米β沸石分子筛组装体是一种既对磷酸根吸附效果良好,又具有较好生物环境安全性的新型环境功能材料。更多还原

【Abstract】 Recently, eutrophication has become one of the most significant and worldwide water quality problems. Among many nutrient in water, phosphorus compounds have been revealved as a major cause of eutrophication. Thus, phosphorus should be removed in order to avoid eutrophication.Three kinds of nano-sized materials of iron were selected and the synthetic conditions of these compound adsorbents have been studied in this paper, and the main influence factors on the phosphates removal capacity have been discussed too.The effect of adsorption time on the removal of phosphate by nano-sized materials of iron was discussed. Equilibrium time of removing phosphate by Fe₃O₄ was about 5h,while equilibrium time of removing phosphate by magnetic iron oxide-βzeolite composite and iron-spikedβzeolite were about 6h. And the optimum pH value of phosphate removal was between 3-5. The phosphate adsorption capability of different nano-sized iron materials was compared. The saturated absorption amount of Fe₃O₄ was the biggest, while the saturated absorption amount of iron-spikedβzeolite was the smallest. Result also showed that the adsorption process of nano-sized materials of iron for phosphorus accords with the Freundlich isotherm.A study of biological environmental safety effect of nano-sized iron materials including Fe₃O₄, magnetic iron oxide/βzeolite composite and iron-spikedβzeolite using a tetrahymena thermophila model were studied by hemocytometer measurement. We used polarizing microscope to observe configuration changes of tetrahymena thermophila. Results show that: magnetic nano-sized Fe₃O₄ is the most sensitive to the suppression of the grouth of tetrahymena thermophila, as compared with the magnetic iron oxide/βzeolite composite and iron-spikedβzeolite. Also, the growth suppression of tetrahymena thermophila was increased with the nano-sized materials of iron concentration.Although magnetic iron oxide/βzeolite composite is less effective on the absorption of phosphate than Fe₃O₄, the toxicity of magnetic iron oxide/βzeolite composite was much lower. Meanwhile, the cost of magnetic iron oxide/βzeolite composite was also less than iron-spikedβ zeolite.Therefore, magnetic iron oxide/βzeolite composite, combination of magnetic and nanometer porous material, is a novel environment functional material, which can provide the best performance of removing phosphorus and has a good safety on biological environment.更多还原