PAC与硅藻土强化混凝处理水中铜绿微囊藻影响因素的研究

发布时间：2018-05-26 14:13

本文选题：混凝 + 聚合氯化铝　；参考：《华南理工大学》2014年硕士论文

【摘要】：水源地藻华爆发对水处理工艺产生了巨大挑战，水源中的藻类能引起水中浊度、溶解氧、pH、嗅味等的变化，并产生藻毒素，形成消毒副产物，对水质产生不利影响，威胁到饮用水安全。因此，亟须寻求一种高效、安全的去除水源中藻类的方法。水中的藻细胞因其比重小，Zeta电位高，稳定性较高，传统处理工艺很难达到理想的去除效果。藻细胞带负电荷，聚合氯化铝（PAC）为阳离子型聚电解质混凝剂，，混凝过程中可与藻细胞发生电中和，吸附桥联或网捕卷扫作用，辅以助凝剂粘土矿物，可望使其高效沉降去除。本实验以原水中常见的铜绿微囊藻为研究对象，考察了PAC以及联合硅藻土强化混凝去除铜绿微囊藻的效果。探讨了PAC和硅藻土的投加量、溶液pH值、天然有机物腐植酸(HA)、表面活性剂、阴离子以及重金属离子对藻和浊度去除的影响，从絮体性质的角度分析其除藻性能，并用zeta电位分析方法对混凝剂的静电中和能力进行表征。主要研究表明：（1）PAC能有效去除水中的铜绿微囊藻；PAC混凝除藻的最佳pH值大约为7.00~8.00；KMnO4预氧化可提升混凝除藻效果，但用量大于1.0mg/L或预氧化时间超过10min时，反而会使水质恶化；超过0.5mg/L的HA会显著影响Zeta电位，严重抑制絮凝过程；一定浓度的阳离子表面活性剂CTMAB可促进混凝除藻；H--2PO4和Cl以及高浓度的SO2-4均会干扰PAC除藻，且影响絮体的迅速形成；而阴离子表面活性剂SDS、阴离子NO-2+3以及重金属离子Cd2+和Pb对PAC混凝除藻的总体影响不大。（2）粘土矿物能促进铜绿微囊藻的混凝去除。硅藻土的投加对于PAC混凝除藻具有优越的助凝效果，可显著提高铜绿微囊藻的混凝去除效果，同时可节省约50%的PAC投加量。硅藻土联合PAC强化混凝，比较经济的复合配比是6.0mg/LPAC+30.0mg/L硅藻土，此时叶绿素a(Chl-a)去除率可达96.06%，剩余浊度降至0.89NTU。（3）考察pH值、HA、CTMAB、共存阴离子SO2-4、H-2PO4和Cl-等因素对联合硅藻土与PAC强化混凝去除铜绿微囊藻的影响。研究发现，强化混凝联合工艺对这些影响因素敏感性较小；硅藻土的加入，在一定程度上缓解了HA、CTMAB、共存阴离子SO2--4、H2PO4和Cl-等因素对混凝除藻的负面作用，体现了优越的除藻性能。
[Abstract]:The outbreak of algal blooms in water source places a great challenge to the water treatment process. Algae in water source can cause changes in turbidity, pH of dissolved oxygen, smell, etc., and produce algal toxins, form disinfection by-products, and have adverse effects on water quality. It threatens the safety of drinking water. Therefore, it is urgent to find an efficient and safe way to remove algae from water. Because of the high Zeta potential and high stability of algal cells in water, it is difficult to achieve ideal removal effect by traditional treatment technology. Algal cells with negative charge, polyaluminum chloride (PAC) as cationic polyelectrolyte coagulant, can be electroneutralized with algal cells during coagulation, adsorption bridging or net trapping, assisted by coagulant clay minerals, which is expected to make its high efficiency sedimentation removal. The effect of PAC and diatomite enhanced coagulation on removal of microcystis aeruginosa from raw water was investigated. The effects of dosage of PAC and diatomite, pH value of solution, humic acid, surfactant, anions and heavy metal ions on algae and turbidity removal were discussed. The electrostatic neutralization ability of coagulant was characterized by zeta potential analysis. Major studies indicate that: The best pH value of PAC can effectively remove microcystis aeruginosa from water. The best pH value is about 7.00 ~ 8.00% KMnO _ 4 preoxidation can improve the effect of coagulation removal, but when the dosage is more than 1.0mg/L or the pre-oxidation time is longer than 10min, the water quality will deteriorate. The HA over 0.5mg/L significantly affected the Zeta potential and seriously inhibited the flocculation process, and a certain concentration of cationic surfactant CTMAB could promote the coagulation removal of algal h-2 PO4 and Cl, as well as the high concentration of SO2-4, which would interfere with the algal removal of PAC and affect the rapid formation of flocs. However, anionic surfactants, anionic NO-2 _ 3, and heavy metal ions Cd2 and Pb had little effect on PAC coagulation and algal removal. Clay minerals can promote coagulation removal of microcystis aeruginosa. The addition of diatomite has a superior coagulant effect on PAC coagulation and removal of algae, and can significantly improve the coagulation removal efficiency of microcystis aeruginosa, and save about 50% of PAC dosage at the same time. Diatomite combined with PAC was used to enhance coagulation. 6.0mg/LPAC 30.0mg/L diatomite was the more economical ratio. The removal rate of chlorophyll a Chl-a reached 96.06, and the residual turbidity decreased to 0.89 NTU. (3) the effects of pH value (pH value), co-anions so _ 2-4H _ 2PO _ 4 and Cl _ (-) on the removal of microcystis aeruginosa by enhanced coagulation with diatomite and PAC were investigated. It was found that the enhanced coagulation combined process was less sensitive to these factors and that the addition of diatomite alleviated to some extent the negative effects of HACT-MAB, co-anions so _ 2--4H _ 2PO _ 4 and Cl _ (-) on coagulation and algae removal, and reflected the superior algal removal performance.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU991.22

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