稻壳基活性炭脱氟剂的动态吸附性能研究

发布时间：2018-09-01 13:05

【摘要】：氟在自然界的分布十分广泛,同时也是人体生理活动中必不可少的微量元素之一。少量的氟有助于骨骼,特别是牙齿的健康成长,提高牙齿珐琅质对细菌酸性腐蚀的抵抗力,有效预防龋齿的发生;同时,氟对骨骼的健康,尤其是预防骨质疏松症有明显的帮助。但过量的氟也会影响人体健康,导致氟斑牙等疾病的发生。中国是全世界受区域性氟中毒危害最严重的国家之一,目前仍有数千万人引用高氟水,严重威胁了人体的健康。针对这一严峻的现象,国内外加强了对含氟废水处理的研究,其处理方法主要包括:沉淀法,离子交换法,吸附法,反渗透法等。其中吸附法以其操作简单,效果稳定,成本低廉的优势被广泛应用。本文在遵循“以废治污”的基本理念下,通过NaOH干法活化法制备了表面性能良好、廉价易得的稻壳基活性炭,并通过负载MgO,Pullulan多糖进行改性,制备出MgOPC复合吸附剂。并采用固定床做为反应器,研究了MgOPC吸附剂的动态吸附性能。为确定在固定床反应器中的最佳脱氟条件,需探究脱氟性能在不同运行参数及环境条件下的差异,实验运用了Thomas及Yan模型数学拟合了固定床反应器的穿透曲线(BTC)。研究表明:吸附性能受多种因素的影响,在吸附床层质量较高,流速较低的情况下,脱氟效果良好;吸附剂对初始浓度,环境温度,pH的适应能力强;干扰离子中,除HCO3-外,Cl-、SO42-、NO3-对F-的吸附不仅不存在竞争关系,还有一定的促进作用。本文还探讨了MgOPC的再生性,结果表明:热再生是吸附剂再生的最佳方法,其他单一的再生方式对吸附剂的再生效果不明显,酸洗-热再生和碱洗-热再生也能达到很好的再生效果。总之,MgOPC吸附剂降低了原料成本,吸附性能良好,且具有良好的环境适应能力和对共存离子的抗干扰能力,无二次污染,是一种理想的脱氟剂,有很好的实际应用前景。
[Abstract]:Fluorine is widely distributed in nature and is one of the essential trace elements in human physiological activities. A small amount of fluoride is beneficial to the healthy growth of bones, especially teeth, increases the resistance of tooth enamel to bacterial acid corrosion, and effectively prevents the occurrence of dental caries. Especially the prevention of osteoporosis has obvious help. But excessive fluoride can also affect human health, leading to dental fluorosis and other diseases. China is one of the countries most seriously affected by regional fluorosis. At present, tens of millions of people still use high fluorine water, which is a serious threat to human health. In view of this severe phenomenon, domestic and international research on the treatment of fluorine-containing wastewater has been strengthened. The main treatment methods include precipitation, ion exchange, adsorption, reverse osmosis and so on. Among them, adsorption method is widely used because of its advantages of simple operation, stable effect and low cost. In this paper, based on the basic idea of "treating pollution with waste", the rice husk based activated carbon with good surface performance and cheap and easy to get was prepared by NaOH dry activation method. The MgOPC composite adsorbent was prepared by modifying the surface of MgO,Pullulan polysaccharide. The dynamic adsorption performance of MgOPC adsorbent was studied in a fixed bed reactor. In order to determine the optimal defluorination conditions in a fixed bed reactor, the difference of defluorination performance under different operating parameters and environmental conditions should be explored. The Thomas and Yan models are used to simulate the breakthrough curve (BTC). Of the fixed bed reactor. The results show that the absorbability is influenced by many factors, such as high mass of adsorption bed and low flow rate, good defluorination effect, strong adaptability of adsorbent to initial concentration, environmental temperature and pH, and interference ion, In addition to HCO3-, the adsorption of F- by Cl-so _ 42-O _ 3- has not only no competition relationship, but also has a certain promoting effect. The regeneration of MgOPC is also discussed. The results show that thermal regeneration is the best method for the regeneration of adsorbent, and other single regeneration methods have little effect on the regeneration of adsorbent. Acid pickling-hot regeneration and alkali-washing-thermal regeneration can also achieve good regeneration effect. In a word, MgOPC adsorbent reduces the cost of raw materials, has good adsorption performance, and has good environmental adaptability and anti-interference ability to co-existing ions, and has no secondary pollution. It is an ideal defluorination agent and has a good prospect of practical application.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;O647.3

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