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陶瓷膜具有耐高温、耐腐蚀、耐微生物侵蚀、强度高、处理能力大等特点，在分离领域得到了广泛的关注和应用，并在食品、医疗、化工等行业得到了广泛的应用。在各种形态的陶瓷膜中，中空平板式陶瓷膜结构规则，支撑体薄，运行阻力小，通量大，易形成高填装密度膜组件。然而陶瓷膜制备过程中存在一些问题，不规则的颗粒烧结形成的陶瓷膜表面易产生裂缝、不均匀的孔结构和粗糙的膜表面，对陶瓷膜的截留性能及渗透通量产生一定的影响。本论文针对以上问题，利用热等离子体制备的粒径约为100 nm的超细球形氧化铝具有光滑的表面，高Zeta电位的特点制备陶瓷超滤膜，通过调控烧结温度、浆料的固含量、浸渍时间、聚乙烯醇的浓度和施加的电压来调控陶瓷膜表面的微孔结构形貌，制备了膜表面无缺陷、孔结构均匀、渗透通量高，膜表面平整的陶瓷超滤膜。主要工作为：（1）以致密球形氧化铝颗粒为原料进行紧密堆积，堆积后进行烧结，形成较为均匀的烧结颈部，制备孔径分布窄，膜表面无缺陷的陶瓷膜。主要表征了氧化铝粉体的粒径分布和氧化铝胶体的zeta电位，氧化铝粉体粒径分布窄，zeta电位较高，pH为7时，zeta电位为54.06 mV。并且氧化铝浆料很稳定，在室温下放置14天仍然没有发生分层。主要研究了陶瓷膜的烧结温度、氧化铝浆料的固含量、聚乙烯醇的浓度、浸渍时间对陶瓷膜微孔结构形貌及其性能的影响，通过过滤纳米硅水分散液来评价不同陶瓷膜的性能，同时获得了不同条件对陶瓷膜微孔结构形貌的调控规律。最后研究了不同烧结温度陶瓷膜的烧结机理，并探究了不同烧结温度陶瓷膜过滤纳米硅水分散液的过滤堵塞模型。陶瓷膜用来处理邯郸钢铁厂冷轧乳化油废水，处理后的渗透液油含量9.34 mg/L，油含量截留率为98.58%。（2） 针对陶瓷膜表面平整度的不足，利用球形氧化铝zeta电位较高的特点，在氧化铝浸渍提拉完成后，通过施加电场来调控氧化铝颗粒在陶瓷膜表面及断面的排列，使氧化铝粒子滑动，产生重排，制备孔结构均匀，陶瓷膜表面平整光滑的陶瓷超滤膜。研究了施加不同电压对陶瓷膜表面微孔结构形貌和性能的影响，研究发现，随着施加电压的增加，陶瓷膜颗粒的烧结程度增大，陶瓷膜表面的粗糙度逐渐减小。通过过滤切削液乳化油来评价施加不同电压陶瓷膜的性能，结果发现施加电压80 V时，乳化油截留率为97.83%。并且随着施加电压的增加，过滤切削液乳化油达到平衡的时间增加，平衡渗透通量增加。最后对不同表面粗糙度的陶瓷膜过滤乳化油的膜污染过程进行了研究，研究发现，粗糙度越大的陶瓷膜，乳化油颗粒容易黏附陶瓷膜表面堵塞孔道，减小渗透通量，因此表面光滑的膜表面有利于降低膜污染。;Ceramic membranes have the characteristics of high temperature resistance, corrosion resistance, microbial resistance, high strength, and large processing capacity. They have received extensive attention and application in the field of separation, and have been widely used in food, medical, chemical and other industries. Among various types of ceramic membranes, the hollow flat ceramic membrane has the regular structure, the thin support body and the large flux. The ceramic membrane is also easy to form the high-packing density membrane module. However, there are still some problems in the ceramic membrane preparation process. The surface of the ceramic membrane fabricated by the irregular particles is prone to cracks, uneven pore structure and rough membrane surface, which has an adverse impact on the performance of the ceramic membrane. In view of the above problems, this paper proposes the preparation of ceramic ultrafiltration membranes using ultrafine spherical alumina with the particle size of about 100 nm prepared by thermal plasma. The sintering temperature, the solid content of the slurry, the dipping-coating time and the applied voltage are used to control the microstructure of the ceramic membrane surface. The ceramic ultrafiltration membrane with no defects, uniform pore structure, high permeate flux are prepared. The main tasks are shown below:(1) Dense spherical alumina particles are used as the raw material for close-packing, and sintering is used to form the relatively uniform sintered neck after the stacking. The ceramic membranes with narrow pore size distribution and no defect are prepared. The alumina powders have the narrow particle size distribution and the zeta potential of the alumina powders is relatively high. At the pH of 7, the Zeta potential is 54.06 mV. In addition, the alumina slurry was very stable, and delamination did not occur after being left at room temperature for 14 days. The effect of the sintering temperature, solid content of alumina slurry, concentration of polyvinyl alcohol, and dipping-coating time on the microstructure of ceramic membrane and their properties are studied. The performance of ceramic membranes is evaluated by filtering nano-silicon dispersion slurry. Finally, the sintering mechanism of ceramic membranes with different sintering temperatures is studied, and the blocking model of ceramic membranes with different sintering temperatures for filtering nano-silicon dispersion slurry is also explored to understand the filtering process. The ceramic membrane is used to filter the cold-rolled emulsified oil wastewater of Handan Iron and Steel Plant. After treatment, the oil content of the permeate is 9.34 mg /L, and the objection rate was 98.58%.(2) Considering the insufficient flatness of the ceramic membrane, the spherical alumina of high zeta potential is used to adjust the arrangement of alumina particles on the surface and section of the membrane by applying the electric field after the dipping-coating is completed. Alumina particles slide and rearrange, and ceramic ultrafiltration membranes with uniform pore structure, smooth surface are prepared. The effect of applying different voltages on the morphology and the properties of the ceramic membrane is studied. It is found that as the applied voltage increased, the degree of sintering increased, and the roughness of the membrane gradually decreases. By filtering the emulsified oil of cutting fluid to evaluate the performance of ceramic membranes under different voltages. When the applied voltage is 80 V, the objection rate of the emulsified oil was 97.83%. As the applied voltage increases, the time to reach equilibrium increases, and the equilibrium permeate flux increases. Finally, the membrane fouling process of filtering emulsified oil with different surface roughness is studied. It is found that the larger the roughness of the ceramic membrane is, the emulsified oil particles are more likely to adhere ceramic membrane surface to block the pores and reduce the permeation flux. It is found that the smooth membrane surface is beneficial to reduce membrane fouling.
|罗盼. 超细球形氧化铝制备陶瓷超滤膜及应用污水处理的研究[D]. 中国科学院大学,2020.|
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