【作者】 武曲寅；

【导师】 马伟；

【作者基本信息】 大连理工大学 ， 无机化学， 2008， 硕士

【摘要】 磷是动物和植物生长所必要的元素,但随着工农业的迅猛发展,每年均有数以万吨的含磷废水排入水体,造成江河、湖泊等富营养化日益严重。目前处理含磷废水的方法有许多,主要有物理化学除磷法,生物除磷法,膜技术除磷以及人工湿地除磷法等,但由于经营成本和导致二次污染等因素,应用受到很大的限制,利用工业产生的废弃物作为人工湿地的填埋污泥,不但具有操作简便、运营成本低等优点,而且同时具有变废为宝的优势,从而成为近年来的研究热点和重要课题。利用自来水厂铁污泥净化工农业废水具有极大的潜在价值。本文是在经过详细调研后,首次提出利用水厂铁污泥对磷的强吸附性能,可将水厂铁污泥应用于人工湿地的下层土壤填埋,不但可以起到固磷供给至湿地植物,还可以将水厂无处排放的污泥合理消耗掉。本实验主要考察铁污泥对磷的吸附能力,其中摸索出了其运行的最佳条件为pH值5左右,吸附时间约为24h,铁污泥的吸附容量较大,在低浓度5～50的状态下未达到饱和,去除率随吸附剂加入量增加而升高,并可达到99%以上,共存离子SO₄^2-和Cl^-对吸附过程影响较小。并通过等温吸附模型,Langmuir、Freundiich和Temkin方程对其进行吸附模拟,模型较符合Freundlich,在一级、二级和幂函数动力学方程模拟中,吸附过程更接近于幂函数动力学方程,说明吸附更接近多层吸附,应该为化学动力学和运移过程共同制约的吸附过程。另外,利用XRD,SEM,FT-IR,TG等方法进行铁污泥表征,对其吸附前后表面变化规律及其吸附特征曲线进行了研究,推断其吸附机理主要是内层配位吸附,对其PZC的测量结果与实际实验结果相比较,其吸附过程为＜PZC的反应。对铁污泥的吸附条件确定后,设计吸附柱实验,实验结果表明吸附柱的穿透率以铁污泥的吸附能力达到接近饱和为结束点,与树脂等柱状实验结果类似,这为铁污泥的工业应用提供了很好的依据。在柱状实验放置过夜的结果现象表明,铁污泥对磷的吸附应为深层吸附,这与机理探讨所得结果相吻合。更多还原

【Abstract】 Nitrogen and phosphate are essential elements for animals and plants. But with the rapid development of industry and agriculture, there are thousands of tons phosphate and nitrogen releasing into surface water system. Because it enhances the growth of organisms in most ecosystems such as rivers, lakes, result in eutrophication and deterioration of water quality. Many techniques have been carried out for the removal of phosphorus and nitrogen from wastewater, for examplephysical chemistry method, biologic method, and membrane technique and constructing wetland to remove phosphate. Because of high cost and secondary pollution, they are largely limited to be applied. The application of iron sludge used as a sorbent to construct wetland is low cost and easily available. So it becomes a research hotspot and an important task. It has a large potential value to utilize iron sludge from waterworks to pure wastewater.After a detailed research, the iron sludge from waterworks is first used to remove phosphorus for its strong adsorption properties in this study. It can be applied for the deep deck of wetland soil landfill, not only can play a solid phosphorus supply to wetlands Plants, can also manage the water plant sludge reasonable consumed. A series of experiment have been carried out for the adsorption capacity to remove phosphorus, then the results showed that the pH around 5 was the best condition for phosphate adsorption.Batch adsorption studies on dried iron sludge were conducted to optimize various equilibrating conditions like the effect of contact time, initial concentration, pH, mass of sorbent, coexisting ion and so on. The results show that strong acid and strong base went against the adsorption of phosphate; while the optimal pH was around 5 and the maximal adsorption reach 24mg/g. The adsorption capacity decreased with the increase of adsorbent doze and ion strength. Simple ions had no obvious effects on adsorption. Iron sludge had good selectivity for adsorption of phosphate. Longmuir and Freundlich adsorption isotherm constants and correlation coefficients were calculated and compared. It was concluded that the adsorption data of phosphate onto iron sludge fitted to the Langmuir model more than Freundlich model.XRD, SEM, TEM, FT-IR and TG were used for the characterization of the sorbent. It is concluded that the coordination mechanism of ligand ion exchange outer surface and electrostatic adsorption were dominant. In addition, the column of iron sludge was experimnented at different column length , flux, initial concentration. The conclution suggested that the iron sluge can be used in the wetland for it chemical characteristic.更多还原