基于铁形态分析的磁絮凝—膜过滤工艺研究

发布时间：2018-01-10 02:18

本文关键词：基于铁形态分析的磁絮凝—膜过滤工艺研究　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：磁絮凝膜过滤(Magnetically Enhanced Flocculation Ultrafiltration,MEF-UF)已成功的应用于微污染水处理工艺。本文研究了不同的磁强化处理手段对混凝剂中铁形态分布的影响,深入分析了磁强化混凝减缓膜污染的机理。通过分析磁絮凝膜过滤工艺中磁化后磁种对混凝剂铁形态分布、混凝效果、絮体特性产生的影响,研究磁强化混凝减缓膜污染的机理。磁种在磁场强度H =0.2 T的磁场中经过1到10 min不同时间的磁化后,其剩余磁场强度随磁化时间先增大后减小,在磁化时间为4 min时,磁种剩余磁场强度最大,为0.92 mT。由于微米级磁种的磁滞效应,其磁化后的剩磁对混凝剂FeC13中铁形态的分布产生影响,与混凝剂水解产物也存在明显的关联性。磁化后的磁种不仅提高了混凝剂中Fea和Feb的百分含量,尤其是Fea的含量,而且增加了待处理水体中的颗粒物含量。磁种磁化时间为4 min时,混凝剂中Fea与Feb含量之和达到92.9%。单体及低聚体铁形态的增加,利于改善混凝效果,形成的絮体平均粒径大,具有更高的强度以及更好的再生性能,形成的滤饼层可压缩性差而疏松多孔,有助于减缓膜污染。本研究从磁化磁种干预混凝剂中铁形态分布的角度对磁强化混凝减缓膜污染的机理作进一步的分析。通过对比常规FeCl_3、磁化FeC13、FeCl_3与未磁化磁种复配以及FeCl_3与磁化磁种复配四种混凝剂之间的区别,研究磁场直接磁化混凝剂与磁化磁种对混凝剂中铁形态分布的影响,对比磁场及磁种在磁絮凝膜过滤工艺中所起的作用。研究结果表明,磁场直接对混凝剂进行磁化后Fea和Feb含量增加优于磁化磁种对铁形态分布的影响。傅里叶变换红外谱图(Fourier Transforrm Infrared Spectrometer,RT-IR)结果表明,添加磁种与磁场直接磁化均对对混凝剂中-Fe-与-O-或者-OH-结合的化学键产生影响。添加磁化磁种进行的膜过滤,其跨膜压差(Transmembrane pressure,TMP)增加速率最慢,而且被污染膜的zeta电位最低。这首先是因为磁化的磁种提高了混凝剂中单体及低聚体铁形态含量,改变了混凝剂中化学键结合方式;再者是因为添加磁种增加了水体中颗粒物含量,提高混凝剂与污染物碰撞效率,磁种作为混凝的核心可以吸附更多的污染物。因此,在磁絮凝膜过滤工艺中,对磁种进行磁化预处理后与混凝剂复配使用可达到有效减缓膜污染的目的。
[Abstract]:Magnetic flocculation membrane filtration (Magnetically Enhanced Flocculation Ultrafiltration, MEF-UF) has been successfully used in micro polluted water treatment process. The effects of different processing means of magnetic iron coagulant affect distribution, in-depth analysis of the mechanism of coagulation and membrane fouling. Through the analysis of magnetic flocculation magnetic enhanced membrane filtration process after magnetization the magnetic coagulant iron speciation, coagulation effect, influence of floc characteristics, the mechanism of coagulation and membrane fouling. The magnetic enhancement of magnetic field strength H =0.2 T in the magnetic field after 1 to 10 min in different time after magnetization, the magnetic field strength with the residual magnetization time increases first and then decreases. In time, the magnetization is 4 min, the maximum magnetic residual magnetic field strength is 0.92 mT., because the hysteresis effect of micron magnetic remanence, the magnetized impact on the distribution of iron coagulant FeC13 form, The existence and coagulant hydrolysis products have obvious relationship. The magnetized magnetic not only improves the content of mixed Fea and Feb retarder, especially Fea content, but also increase the particle concentration of the water to be treated. The magnetic magnetization time is 4 min, the content of Fea and Feb mixed agent the increase of 92.9%. and the monomer and oligomer of iron species, to improve the coagulation effect, the formation of floc mean diameter, with higher strength and better regeneration performance, cake layer compressibility and porosity, can reduce membrane fouling. This study from magnetized coagulant intervention iron morphology distribution of membrane fouling mechanism of coagulation enhancement on magnetic further analysis. By comparing the conventional FeCl_3, FeC13 magnetization, the difference between FeCl_3 and non magnetized compound and FeCl_3 and magnetized compound four kinds of coagulant, Study on the magnetic field directly magnetize coagulant and magnetization of iron coagulant affect distribution of magnetic field and magnetic contrast, which plays in the magnetic flocculation membrane filtration process. The results show that the magnetic field is better than that of directly increase the magnetization of magnetic iron form distribution of coagulant was Fea after magnetization and Feb content. Fourier transform infrared spectra (Fourier Transforrm Infrared Spectrometer, RT-IR). The results show that the addition of magnetic and magnetic field are directly impact on the magnetic coagulant -Fe- and -O- or -OH- combined with chemical bond formation. Membrane filtration in a magnetized add, the transmembrane pressure (Transmembrane, pressure, TMP) increase rate the slowest, and the contaminated membrane potential of zeta minimum. This is primarily because the magnetic magnetization improves coagulant in monomer and oligomer form of iron content, changed with mixed type chemical bonding agent; and Because of adding magnetic particles increased in water, improve the coagulant and pollutant collision efficiency, as the core of magnetic coagulation can adsorb more pollutants. Therefore, the magnetic flocculation membrane filtration process, the magnetization pretreatment on magnetic and coagulant used can effectively alleviate membrane fouling purpose.

【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU991.24

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