化学沉淀法去除饮用水中微量超标的氟、硬度及硫酸根

发布时间：2018-06-07 07:00

  本文选题：化学沉淀法 + 氟　； 参考：《太原理工大学》2012年硕士论文

【摘要】：安全的饮用水是维持人体正常的新陈代谢,保障人体健康的必要条件。山西省属于水资源严重匮乏的省份加之独特的气候和地形条件及近年来水资源的污染导致很多地区尤其是农村居民的饮用水安全问题一直比较突出。《生活饮用水卫生标准(GB5749-2006)》中规定氟化物浓度1.0mg/L、总硬度450mg/L、硫酸盐250mg/L,饮用水中超出此限值均为超标水质。虽然反渗透、膜法及离子交换等工艺对此类水源有较好的处理效果,但不同程度地存在着设备一次性投资大、运行费用高、操作困难等缺点。较适合用于大型集中供水,对一些农村分散用户并不一定适用。本文针对地下水源中常见的氟、硬度、硫酸根、氟和硬度及氟和硫酸根微量超标五种水质进行模拟,皆选用化学药剂为沉淀剂,对五种水质采用化学沉淀法处理,实验结果如下： 1、用CaO和CaCl2作为沉淀剂处理氟超标的原水,最佳投加量分别为450mg/L和350mg/L,经磁力搅拌器搅拌1h后,水中的氟离子浓度可从1.65mg/L分别降到0.96mg/L和0.87mg/L,处理后水中的pH值和总硬度均未超出《生活饮用水卫生标准(GB5749-2006)》。CaCl2为沉淀剂时除氟的最佳反应时间30min,最适pH值为7。处理相同量的水所需两种沉淀剂的费用相差不大。 2、用KH2PO4、CaO和Na2CO3作为沉淀剂处理硬度超标的原水,最佳的投加量分别为1.5g/L、215mg/L和160mg/L,经磁力搅拌器搅拌1h后,水中的总硬度可从812mg/L分别降为402mg/L、340mg/L,处理后水中的pH值为8.37未超出《生活饮用水卫生标准(GB5749-2006)》,KH2PO4为沉淀剂的最佳反应时间为40min。处理相同量的水CaO和Na2CO3的费用要低于KH2PO4O 3、用BaCl2和CaCl2作为沉淀剂处理硫酸根超标的原水,最佳投加量分别为650mg/L和330mg/L,经磁力搅拌器搅拌1h后,水中硫酸根浓度可从512mg/L降到227mg/L和263g/L,处理后水中的pH值为7.61未超出《生活饮用水卫生标准(GB5749-2006)》,用BaCl2为沉淀剂时的最佳反应时间为30min。处理相同量的水用CaCl2的费用要低于BaCl2。 4、用CaO和Na2CO3作为沉淀剂处理硬度和氟混合超标的原水,最佳投加量为280mg/L和180mg/L,经磁力搅拌器搅拌1h后,氟离子浓度可从1.55mg/L降到0.82mg/L、总硬度可从683mg/L降到264mg/L,此时,水中的pH值为8.53未超出《生活饮用水卫生标准(GB5749-2006)》,最佳反应时间为60min。 5、用CaCl2作为沉淀剂处理氟和硫酸根混合超标的原水,最佳投加量为720mg/L,经磁力搅拌器搅拌1h后,氟离子浓度可从1.42mg/L降到0.94mg/L,硫酸根离子浓度可从612mg/L降到327mg/L,达到了《生活饮用水卫生标准(GB5749-2006)》,最佳反应时间为60min。 本实验对五种模拟水质均采用化学沉淀法,经过反应沉淀后水中的各项超标指标均达到国家饮用水标准。虽没有反渗透、膜法和离子交换等工艺的出水水质好,但方法简单易操作,经计算处理相同体积的水源费用远远低于其他工艺。故此方法可有效地缓解一些不能进行集中供水的偏远山区和分散用户的饮用水安全。
[Abstract]:Safe drinking water is a necessary condition to maintain the normal metabolism of the human body and ensure the health of the human body. In Shanxi Province, a province with serious water shortage and the unique climate and terrain conditions and the pollution of water resources in recent years, the safety of drinking water in many areas, especially in rural areas, has been prominent. In the health standard (GB5749-2006), the fluoride concentration is 1.0mg/L, the total hardness is 450mg/L, and the sulfate 250mg/L, the drinking water exceeds the limit value. Although the reverse osmosis, membrane method and ion exchange technology have good treatment effect on this kind of water source, there is a large amount of equipment investment, high operating cost and operation in varying degrees. It is more suitable for large centralized water supply, which is not necessarily suitable for some rural dispersed users. In this paper, five kinds of water, such as fluorine, hardness, sulphuric acid root, fluorine and hardness, and fluorine and sulphuric acid root, are simulated in this paper. Chemical agents are used as precipitant and chemical precipitation is used to treat five kinds of water. The experimental results are as follows:
1, CaO and CaCl2 are used as precipitant to treat the raw water of excess fluorine. The optimum dosage is 450mg/L and 350mg/L respectively. After mixing 1H by magnetic stirrer, the concentration of fluorine ions in water can be reduced from 1.65mg/L to 0.96mg/L and 0.87mg/L respectively. The pH value and total hardness of water after treatment are not beyond the sanitary standard of drinking water (GB5749-2006) >.CaCl2. The best reaction time for fluoride removal is 30min, and the optimum pH value is 7.. The cost of two precipitating agents for treating the same amount of water is not significant.
2, KH2PO4, CaO and Na2CO3 are used as precipitant to treat the raw water with excessive hardness. The best dosage is 1.5g/L, 215mg/L and 160mg/L respectively. After mixing 1H by magnetic stirrer, the total hardness of water can be reduced from 812mg/L to 402mg/L, 340mg/L, and the pH value of the water after treatment is 8.37 not beyond the sanitary standard of drinking water (GB5749-2006) >. The best reaction time of the precipitant is 40min.. The cost of treating the same amount of water CaO and Na2CO3 is lower than KH2PO4O.
3, BaCl2 and CaCl2 are used as precipitant to treat the super standard water of sulphuric acid root. The optimum dosage is 650mg/L and 330mg/L respectively. After mixing 1H by magnetic stirrer, the concentration of sulfate in water can be reduced from 512mg/L to 227mg/L and 263g/L. The pH value of water after treatment is 7.61 not beyond the sanitary standard of drinking water (GB5749-2006), and BaCl2 is used as precipitant. The best reaction time is 30min.. The cost of treating the same amount of water for CaCl2 is lower than that of BaCl2..
4, CaO and Na2CO3 are used as precipitant to treat the raw water of hardness and fluorine mixture exceeding standard. The optimum dosage is 280mg/L and 180mg/L. After mixing 1H by magnetic stirrer, the concentration of fluorine ion can be reduced from 1.55mg/L to 0.82mg/L, and the total hardness can be reduced from 683mg/L to 264mg/L. At this time, the value of pH in water is 8.53 not beyond the sanitary standard of drinking water (GB5749-2006). The best reaction time is 60min.
5, CaCl2 is used as precipitant to treat the raw water which is mixed with fluorine and sulphuric acid root, the optimum dosage is 720mg/L. After stirring 1H by magnetic stirrer, the concentration of fluorine ion can be reduced from 1.42mg/L to 0.94mg/L, the concentration of sulfate ion can fall from 612mg/L to 327mg/L, and the hygienic standard of drinking water (GB5749-2006) is reached, and the optimum reaction time is 60min.
In this experiment, chemical precipitation method was used for five kinds of simulated water. After the reaction and precipitation, all the above standard indexes in water reached the national drinking water standard. Although there was no reverse osmosis, membrane method and ion exchange, the water quality was good, but the method was simple and easy to operate. The cost of water source in the same volume was far lower than that of other processes. This method can effectively alleviate the safety of drinking water in remote mountainous areas and decentralized users who can not concentrate water supply.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R123.1

【引证文献】

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1 汪顺才;余学勇;袁荣灼;刘安平;彭志伟;;南京梅山铁矿选矿厂环水软化技术研究[J];环境污染与防治;2013年05期

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