改性凹凸棒土处理低温高色高氨氮水源水研究

发布时间：2018-11-02 18:45

【摘要】：本研究依据新《生活饮用水卫生标准》（GB5749-2006）的规范要求，针对常规工艺处理北方寒冷地区低温高色高氨氮水源水效果不佳的问题，将凹凸棒土改性为一种新型载体絮凝吸附剂与分子筛，从反应动力学与物质转化等方面探索反应机理，并运用表面络合-吸附-混凝理论与正交-响应面分析法，研究基于改性凹凸棒土的“载体絮凝-高效沉淀-预涂膜过滤”的脱色脱氨氮水处理工艺集成技术，为保障北方寒冷地区的饮用水安全提供技术方案。 通过X射线荧光光谱、旋转阳极X射线衍射、傅立叶变换红外光谱、扫描电子显微镜、BET比表面积与孔径分布等测试方法，研究改性凹凸棒土的微观结构、矿物特征与形成机理，分析适于低温脱色脱氨氮的凹凸棒土的最佳改性方式。结果表明：壳聚糖改性凹凸棒土（CPA）脱色效果显著，机理以静电吸附、化学反应为主；提纯凹凸棒土脱色效果次之；热、酸改性凹凸棒土不脱色反而增色。碱改性凹凸棒土（4A分子筛）脱NH_4~+-N效果显著，机理以离子交换为主；热、酸改性凹凸棒土对NH_4~+-N去除率低；有机改性凹凸棒土无法脱NH_4~+4-N。以上分析与结果对正确理解凹凸棒土的纳米效应具有重要的理论意义。 通过吸附等温线、吸附动力学与热力学等理论，，研究低温状态下CPA的吸附脱色性能，以及4A分子筛对共存溶液中NH_4~+-N、腐殖酸（HA）的吸附性能。结果表明：CPA对HA的吸附符合Langmuir Freundlich吸附等温式，同时受膜扩散和颗粒内扩散控制，其最大吸附量qe,max为121mg/g。4A分子筛对NH_4~+-N、HA的吸附均符合Freundlich吸附等温式，受颗粒内扩散控制，qe,max分别为61mg/g，21mg/g；对NH_4~+-N吸附受离子交换、分子色散力、诱导力与静电吸附影响，当HA存在时，NH_4~+-N的吸附受到抑制；对HA吸附依靠静电吸附、阳离子桥以及HA与4A分子筛表面铝盐的羟基化合物的络合作用，NH_4~+-N存在会促进HA被吸附。CPA和4A分子筛在低温状态下均表现出良好的吸附能力，且具有较强的可再生能力，可循环使用。以上分析为吸附剂的开发应用提供理论依据，具有重要的经济意义。 分析了低温高色水处理效能与混凝机理，并采用响应面分析法设计确定“回流污泥-PFA-CPA”强化混凝的最优参数组合。结果表明：pH值与污泥回流量是影响色度去除率的显著性因素。HA-颗粒溶液主要与PFA水解产生的络合物发生反应。CPA能有效去除溶解性有机物，并作为“凝核”增大了絮体强度与粒径以及破碎后絮体的恢复能力。回流污泥能促进CPA对HA的吸附，改善低温低浊现象。强化混凝后，出水受色度、温度影响程度降低。以上分析与结果为优化运行与调试提供了技术支持。 分析了新型高密度沉淀池与4A分子筛预涂膜过滤器的出水水质变化规律，探索不同条件下优化运行控制方式。结果表明：通过控制污泥回流比，使污泥浓度（SS）在498~900mg/L，可有效降低混凝剂投加量。精确控制排泥量与斜板下泥水界面，能防止“翻池”现象，保证悬浮泥渣面低、底部污泥浓度高。水力负荷低于50L/h、原水有机物低于8mg/L时沉淀出水水质无明显变化。4A分子筛在最优涂膜条件下形成动态膜后过滤高密池出水，NH_4~+-N去除率达95%。基膜采用物理清洗，34d更换。该组合工艺处理低温青顶水库水源水效果显著，运行费用低。以上研究为产业化推广提供了切实可行的理论技术支撑。
[Abstract]:According to the specification of New Standard for Drinking Water for Drinking Water (GB5749-2006), this study deals with the problem that the water-water effect of high-color and high-color high-color ammonia-nitrogen source in cold regions of northern China is not good, which is a new type of carrier flocculation adsorbent and molecular sieve. The reaction mechanism was explored from the aspects of reaction kinetics and substance conversion, and using surface complexation-adsorption-mixing theory and orthogonal-response surface analysis method to study the integrated technology of decolorization and denitrification water treatment based on modified attapulgite carrier flocculation-high efficiency precipitation-pre-coating membrane filtration. and provides a technical scheme for ensuring the safe drinking water in the cold areas in the north. The microstructure, mineral characteristics and formation of modified attapulgite were studied by X-ray fluorescence spectrum, rotating anode Xray diffraction, Fourier transform infrared spectrum, scanning electron microscope, BET specific surface area and pore size distribution. Mechanism and Analysis of the Optimum Modification of Attapulgite suitable for Low Temperature Decoloration and Removal of Ammonia Nitrogen The results showed that chitosan modified attapulgite (CPA) had significant effect on decolorization, and the mechanism was mainly electrostatic adsorption and chemical reaction. The removal of NH _ 4 ~ +-N by alkali-modified attapulgite (4A molecular sieve) was significant, the mechanism was mainly ion-exchange, the removal rate of NH _ 4 ~ +-N was low by heat and acid-modified attapulgite, and the organic modified attapulgite could not deNH _ 4 ~ + 4. The above analysis and results have an important theoretical basis for correctly understanding the nano-effect of attapulgite. The adsorption and decolorization properties of CPA in low temperature state were studied by adsorption isotherm, adsorption kinetics and thermodynamics, and NH _ 4 ~ +-N, humic acid (HA) in the coexistence solution of 4A molecular sieve were studied. 鐨勫惛闄勬

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