多孔铝镁氧化物除氟效果对水化学性质的响应机制及适应性

发布时间：2018-02-02 23:00

本文关键词： 高氟地下水水化学性质吸附材料除氟效果竞争吸附适应性　出处：《中国水利水电科学研究院》2015年博士论文　论文类型：学位论文

【摘要】：我国高氟地下水分布广泛,且呈区域性存在的特点,很多地区往往没有可选择优质水源,除氟技术是解决高氟水地区居民饮用水问题的有效途径。本文通过总结除氟技术发展现状以及前期工程调研,确定吸附法除氟技术作为本文开展除氟技术研究的方向。结合目前吸附法除氟技术所面临的应用难点,以目前最急需解决的应用问题展开实验研究,以阐述高氟地下水的关键水化学特征为基础,以提高吸附材料与高氟地下水的关联性为核心,以阐述吸附材料除氟效果对水化学性质的响应机制和适应性为最终目标。通过研究,得到的主要结论如下：(1)研究尺度上,基于渤海湾、皖北以及山东、内蒙、吉林、陕西等地区水文地质调查,遵循水化学性质分析和多元统计分析相结合的原则,描述不同地区高氟地下水的水化学性质和关键水化学特征。结果表明不同地区高氟地下水水化学性质有差异,但具有共性水化学特征,主要体现在pH值大于7.5(p=0.95),水化学类型以Na-HCO3型为主,pH值、总碱度、HCO3-、Na+、剩余碱度等指标与F-密切相关,是影响高氟地下水形成的关键水化学因素。高氟地下水的形成是长期水-岩相互作用下的阳离子交换以及氟矿物的溶解。此外,Mg2+、Ca2+含量决定高氟地下水中氟化物其他赋存形态的含量。(2)充分利用高氟地下水的阴阳离子分布状况,克服地下水对吸附材料的挑战,制备了取材简单、方便易得的无定形氢氧化铝和MgO等两种吸附材料。其中无定形氢氧化铝吸附材料的制备采用共沉淀法并控制反应过程中pH值,MgO吸附材料的制备采用水热法并煅烧前驱体的方法。所制备的吸附材料均具有良好的吸附性能,在pH值为7.0的条件下,Langmuir最大吸附容量分别为166.67mg/g和125mg/g,可以重复利用5个周期,提高了适应地下水pH值的能力以及与天然高氟地下水的关联性。(3)结合高氟地下水水化学性质以及离子组分分布状况,基于模拟含氟水试验,无定形氢氧化铝和MgO吸附材料的除氟效果对地下水中pH值、HCO3-、SO42-、Cl-、P043-等指标产生不同程度的响应,均会随着溶液中的pH值、HCO3-、 SO42-、Cl-、PO43-等指标值(含量)的升高而降低,其中pH值和HC03-尤为突出,属于倍数级和差量级竞争吸附。吸附材料对地下水中HC03-和S042-的吸附过程符合Freundlich吸附等温模型,且属于优惠型吸附,吸附容量均大于31mg/g和14mg/g。阴离子竞争吸附导致吸附材料对F’的吸附速率减缓、亲和力下降。(4)通过非高氟地下水和天然高氟地下水的吸附材料吸附试验,从首次吸附的除氟效果角度而言,无定形氢氧化铝和MgO吸附材料均对天然高氟地下水具有适应性,在投加量为0.5-1.0g/L的基础上,将氟化物浓度降至1.0 mg/L以下。吸附材料在吸附氟的同时也吸附了大量共存阴离子,特别是HCO3-,吸附量大于10mg/g,但所吸附的差量级共存阴离子均对首次吸附过程的除氟效果没有显著影响。(5)与纯水配水试验相比,在天然高氟地下水试验条件下(F=1.72 mg/L)吸附材料的可重复利用性能显著降低。无定形氢氧化铝和MgO吸附材料运行至第4个周期时,无法将初始溶液中氟化物浓度降至1.0 mg/L以下。基于纯水配制高氟水试验条件下的再生手段满足不了实际高氟水再生手段的需求,再生手段不仅仅需考虑脱附F-,更应全面考虑如何脱附HCO3-、SO42-和C1-等阴离子从而释放更多的吸附位点。多孔铝镁氧化物除氟效果对地下水水化学性质的响应机制及适应性这一基础研究,描述了我国不同地区高氟地下水的水化学性质和关键水化学特征,明确了制约多孔铝镁氧化物除氟效果的关键因素,解释了共存阴离子与F-的竞争吸附机理,阐述了多孔铝镁氧化物除氟效果对水化学性质的响应机制和适应性,为吸附法除氟技术的发展和应用提供了新的方向,为高氟地下水地区饮用水问题的解决奠定基础。
[Abstract]:The distribution of groundwater with high fluorine extensively in our country, and a regional characteristics exist in many areas, often have no choice of high-quality water, fluoride removal technology is an effective way to solve the problem of drinking water in residential areas of high fluoride water. In this paper, through summarizing the current situation of the development in technology and Engineering Research of fluorine, determination of fluoride adsorption technology is carried out in this paper study on fluorine removing technology. Combining the adsorption method in addition to the application of difficulties to the current application of fluoride, the need to resolve the issue of study, the key characteristics of water chemistry on high fluorine groundwater as the basis, to improve the relevance of adsorption materials and high fluorine groundwater as the core, to explain the adsorption material in addition to the response mechanism and adaptability of the chemical properties of water fluoride effect as the ultimate goal. Through the research, the main conclusions are as follows: (1) research scale, based on the Gulf of Bohai, North Shandong, Anhui Inner Mongolia, Jilin, Shaanxi and other regions, hydrogeological investigation, follow water chemistry analysis and multivariate statistical analysis of the principle of combining the description of water chemistry and key hydrochemical characteristics of groundwater with high fluorine in different regions. The results show that different areas of high fluoride groundwater chemical properties are different, but with common hydrochemical characteristics, mainly reflected in the pH value greater than 7.5 (p=0.95), water chemistry type Na-HCO3, pH, HCO3-, Na+, total alkalinity, residual alkalinity index is closely related with F-, is a key factor affecting the formation of high fluoride groundwater water chemistry factors. The formation of high fluoride groundwater is cation exchange long-term water rock interaction and the dissolved fluorine minerals. In addition, Mg2+, Ca2+ content in determining high fluoride fluoride in ground water and other forms. (2) make full use of ions distribution of fluoride in groundwater, groundwater to overcome adsorption material The challenge was prepared from simple, easy to obtain amorphous aluminium hydroxide and MgO two adsorption materials. The amorphous aluminum hydroxide adsorption materials were prepared by co precipitation method and control the reaction process of pH, MgO adsorption materials were prepared by hydrothermal method and calcination method. The precursor the adsorption material prepared has good adsorption properties, the pH value is 7, the maximum adsorption capacity of Langmuir were 166.67mg/g and 125mg/g, can be reused for 5 cycles, improve the ability to adapt to the pH value of groundwater and the related natural fluoride in groundwater. (3) with high fluorine water chemistry groundwater and ion component distribution, simulation of fluoride test based on amorphous aluminum hydroxide and MgO adsorbent fluoride effect on groundwater in pH, HCO3-, SO42-, Cl-, P043- and other indicators of different levels of response, both with A solution of pH, HCO3-, SO42-, Cl-, PO43- and other indicators of value (content) increased, the pH value and HC03- is particularly prominent, belongs to the multiple level and poor level of competitive adsorption. Adsorption process of adsorption of HC03- and S042- in underground water with the Freundlich adsorption isotherm model, and belongs to the preferential adsorption the adsorption capacity was more than 31mg/g, and the 14mg/g. anion adsorption leads to competitive adsorption materials on the adsorption rate slowed down, F 'affinity decreased. (4) through the adsorbent non high fluoride groundwater and natural fluoride in groundwater from the first test, the adsorption of fluoride removal effect perspective, amorphous aluminum hydroxide and MgO adsorption on natural materials the high fluoride groundwater adaptability in the dosage of 0.5-1.0g/L based on the fluoride concentration is below 1 mg/L. At the same time, adsorbent in the adsorption of fluoride is the large amount of adsorbed CO existing anions, especially HC O3-, the adsorption amount is greater than 10mg/g, but the difference in magnitude of adsorbed anions on the first adsorption process of fluoride removal had no significant effect. (5) compared with the pure water test in natural high fluoride groundwater conditions (F=1.72 mg/L) adsorption material can be reused can significantly reduce the amorphous aluminum hydroxide. And MgO adsorption materials run to fourth cycles, the initial fluoride concentration in solution cannot be reduced to below 1 mg/L. Water recycled means high fluorine water under the experimental conditions can not meet the actual demand of high fluoride water regeneration method based on the students not only need to consider the means to the desorption of F-, it should comprehensively consider how the desorption of HCO3-, SO42- C1- and anion releasing more adsorption sites. This is the foundation of study on the response mechanism of the effect of fluoride on water chemistry of groundwater and adaptability in porous aluminum magnesium oxide, described our country different Water chemistry and water chemical characteristics of key area of high fluorine groundwater, the key factor restricting the porous aluminum magnesium oxide fluoride removal effect, explained the mechanism of competitive adsorption of anions and F-, expounds the porous aluminum magnesium oxide fluoride effect on water chemistry response mechanism and adaptability, provides a new direction for the development and application of fluoride removal by adsorption, which lays the foundation for solving the problem of drinking water with high fluoride groundwater area.

【学位授予单位】：中国水利水电科学研究院
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU991.266

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