【作者】 谭娟；

【导师】 于衍真；

【作者基本信息】 济南大学 ， 市政工程， 2010， 硕士

【摘要】 研究了利用粉煤灰提取液制备聚高铁硅混凝剂,通过试验处理模拟含铅废水考察新型混凝剂的化学性能及混凝机理。主要内容包括:(1)研究开发出了用粉煤灰提取液制备聚高铁硅混凝剂的工艺。通过正交试验确定了粉煤灰的最佳提取条件及制备聚高铁硅混凝剂的最佳工艺。其最佳工艺条件为:在60℃温度下,以NaOH溶液浸取粉煤灰(NaOH浓度为1.8mol/L)反应38小时,获得粉煤灰提取液;经过滤后,调节滤液pH至1.4左右,活化2.5小时,以高铁酸钾为复合剂(Si/FeO42-摩尔比为3.5),在45℃下进行聚合反应,即制得新型无机高分子混凝剂聚高铁硅。(2)聚高铁硅混凝剂的化学特性。利用此工艺合成的聚高铁硅混凝剂,其全铁含量、pH值、密度、聚合度和盐基度等几个主要指标,与我国聚合铁类混凝剂的评价指标对比,可以看出其在密度、全铁含量、pH和盐基度等方面均达到一等品的指标。说明在没有外加氧化剂的条件下,粉煤灰提取液与高铁酸钾发生聚合反应可以得到性能较高的新型混凝剂。在最佳条件下制备的复合型混凝剂聚高铁硅其自然存放时间可达90天,而选择氯化镁作为稳定剂加入后,稳定时间可延长至240天以上。(3)聚高铁硅混凝剂处理模拟含铅废水的混凝机理研究。考察聚高铁硅混凝剂处理含铅废水,结果表明:聚高铁硅混凝剂对含铅废水的色度、浊度、Pb2+的去除效率极佳且处理效果稳定,尤其是在Pb2+的去除方面表现出极强的处理性能,可以达到96%以上。而且与同类混凝剂(PPFS)相比聚高铁硅混凝剂的投加量低、作用的pH值适应范围广。因此,通过比较可以发现,自制的聚高铁硅混凝剂对含铅废水的处理具有极强的针对性。(4)聚高铁硅混凝剂的结构形貌表征。在优化筛选的基础上,合成聚高铁硅混凝剂,利用FTIR、TEM、LPSA等现代分析方法研究了聚高铁硅混凝剂中各物质间的相互作用,表征了混凝剂的形态、微观结构,探讨了聚高铁硅的混凝机理。研究结果表明,混凝剂中存在高铁基团和活性硅酸聚合成的共聚物,聚高铁硅的聚集态呈枝杈链状结构,且聚硅酸与聚铁的水解产物的相互作用受Si/FeO42-摩尔比的影响较大。可以得到聚高铁硅混凝剂的混凝作用机理:一方面,依靠高电荷的聚合态的高铁水解产物发生电中和作用;一方面,依靠活化硅酸和高铁离子熟化生成的聚合物的吸附架桥等作用。两方面的共同作用使聚高铁硅混凝剂表现出优良的除浊脱色及去除Pb2+的效果。(5)对聚高铁硅混凝剂的制备工艺及处理含铅废水的研究表明,将聚高铁硅混凝剂用于处理含铅废水,不但可以获得优良的混凝处理效果,而且能充分发挥资源和技术优势,以废治废,节约能耗。因此有广阔的市场前景和良好的经济效益、环境效益。更多还原

【Abstract】 This paper studies the preparation of poly-high-ferric-silicic coagulant from fly ash extract , the performance and chemical properties of the new type coagulant through the experiments of treatment analog lead wastewater.It mainly includes aspects as follows:(1)The technology of preparing the poly-high-ferric-silicic by using fly ash extract has been designed.Through orthogonal experiment,the optimum extraction conditions from fly sah and the optimum technology of preparing the poly-high-ferric-silicic have been designed.Under 60℃, Leaching fly ash with NaOH when NaOH concentration of 1.8mol / L response to 38 hours to obtain fly ash extract. After filtration, the filtrate has been adjusted pH to around 1.4 and activated about 2.5 hours.Then by means of the polymerized reaction under 45℃and using potassium ferrate as complexing agent when Si/FeO42- is about 3.5,the poly-high-ferric-silicic can be obtained.(2)The chemical properties of poly-high-ferric-silicic.The comparison on index of coagulant between poly-high-ferric-silicic and poly-iron coagulant, the poly-high-ferric-silicic belongs to first-class product.The index of coagulant contains total fe, pH, density, polymeric level and basicity. The poly-high-ferric-silicic is the high performance coagulant in the absence of additional oxidant conditions. Under the optimum conditions, the poly-high-ferric-silicic natural storage time is up to 90 days. After adding magnesium chloride,the poly-high-ferric-silicic natural storage time is up to 240 days at least.(3)Coagulation properties of poly-high-ferric-silicic in treatment lead wastewater.The results showed that color, turbidity and Pb2+ removal efficiency are excellent and treatment effects are stable in treatment lead wastewater, especially the removal of Pb2+ has been up to 96% more. The comparison on coagulantion between poly-high-ferric-silicic and PPFS, the poly-high-ferric-silicic dosage is low and adapt to a wide pH. Therefore, by comparison, the poly-high-ferric-silicic is a superior coagulant in lead wastewater treatment.(4) The structure morphology of poly-high-ferric-silicic.Many modern analysis methods such as laser particle size analysis, transmission election microscopy and infrared spectrum have been applied to investigate those interactions among hydrolyzed ferric and the structure of poly-high-ferric-silicic.Then, discussing the mechanism of poly-high-ferric-silicic.The results shows that there are copolymer between high-iron group and activated silica in the polymerizing process. Poly-high-ferric-silicic is a sort of polymer with a state of branches structure.The Si/FeO42- value has remarkable effects on hydrolyzate of polysilicate and polyferric.There are two aspects about poly-high-ferric-silicic .On the one hand, relying on chargeneutrality of high-ferric hydrolysis products; on the other hand, relying on adsorption bridge of polymer between activated silicic acid and high-ferric. poly-high-ferric-silicic shows superior removal of turbidity color and Pb2+ by two aspects.(5)The research of poly-high-ferric-silicic reparation and treatment lead wastewater shows that it not only can get a good coagulation effect, but also save energy and play resources and technological advantages.This technology can produce important benefit on both environment and economy.更多还原