【作者】 常晓仆；

【导师】 李淑英；

【作者基本信息】 大连理工大学 ， 化学工程， 2007， 硕士

【摘要】 多孔阳极氧化铝膜具有孔密度高、孔径分布均匀、孔与孔间相互平行等特点，可制成新型的超精密分离膜，在分离领域有较大的应用潜力。但由于氧化铝膜较脆，缺少支撑体，在去除铝基体及分离的过程中极易破裂，所以很难大面积生产，只有在实验室有部分应用。本文采用正交实验方案，用一次阳极氧化法制得阳极氧化铝膜，研究了阳极氧化时温度、时间、电压对氧化铝膜厚度、孔径和孔有序度的影响。实验结果表明，氧化时间对膜厚影响最大，其次是温度和电压，而对膜孔径和有序度的影响主次因素依次为电压、温度和时间；正交实验获得的最佳工艺条件为氧化温度13℃、氧化时间2h、氧化电压130V；用数学方法定量的分析了氧化工艺对孔有序度的影响。本文在一次阳极氧化铝膜的基础上以电化学的方法制得了两面贯通以大孔铝为支撑体的多孔阳极氧化铝膜，研究了多种影响因素对膜结构的作用。结果表明，该膜具有较好的机械强度和韧性，可弯曲180°、在0.3MPa下不破裂，从而使膜的脆性问题在一定程度上得以改善。膜平均孔径和纯水通量随浸蚀时间的增加而增大，而PEG20000的截留率随之减小，浸蚀时间对膜的孔隙率影响不大。随着氧化时间的增加，膜的纯水通量降低而膜的截留率升高，膜的纯水通量和PEG20000的通量随着过滤时间的增加而减少。相比磷酸膜，草酸膜具有更小的孔径和更大的厚度，在同样压力下，草酸膜的稳定纯水通量小于磷酸膜，但截留率却大于磷酸膜。随着阳极反应时间的增加，膜的稳定纯水通量增大，但膜的截留率变化不大。随着操作压力的增加，膜的纯水通量和PEG20000通量都变大。本文通过膜的耐蚀性实验，用扫描电镜、X射线衍射仪进行了膜的表面形貌及成分分析，研究了膜在退火前后的耐蚀性。结果表明，未经高温下退火的膜在中性环境中是完全耐蚀的，相比碱性溶液，膜在酸性溶液中耐蚀性较好，而在pH值大于12时膜不耐蚀。膜在800℃及910℃下退火5h后，由非晶态的氧化铝转变成为晶态的α-Al₂O₃，但同时也有铝单质和无定形结构的氧化铝存在，膜在800℃下退火5h后的正面没有太大变化，背面由无规则的分布变为簇状分布。经高温下退火的膜在中性和强酸性溶液中完全耐蚀，在强碱性溶液中膜的耐蚀性也有较大提高。更多还原

【Abstract】 Porous anodic alumina membrane enjoys a number of advantages such as uniform diameter, higher pore density, parallel aperture, so it can be made of new type of ultra-precision membrane, and it has great potential applied value in separation filed. But the anodic alumina membrane is easily broken in the process of removing back aluminum and separation for its brittleness and lack of support. So it is very difficult to produce with large area, and it has only been used in laboratory.In this paper, we chose orthogonal experiment, and anodic alumina membranes were fabricated by one-step anodizing process. The effects of oxidation temperature, time and voltage on membrane thickness, pore diameter and orderly degree were investigated. Experimental result showed that the maximum influencing factor on membrane thickness was oxidation time, followed by temperature and voltage, and the maximum influencing factor on pore diameter and orderly degree was voltage, followed by temperature and time. The best parameters of the techniques were obtained as follows: 13℃, 2 hours , 130V. The effect of oxidation processes on orderly degree was analyzed quantitatively by mathematical method.In this paper, we fabricated through-hole porous anodic alumina membranes supported by macropore aluminum by electrochemical method, which based on one-step anodic alumina membranes. We studied the effects of several influencing factors on membrane. The results showed that the membrane had better mechanical intensity and tenacity, which could be curved to 180 degree and was not broken under 0.3MPa and brittleness of membrane was improved in a certain extent. Mean pore diameter of membrane and pure water flux increased with the increase of etching time, while rejection of membrane for PEG 20000 decreased, which had little effect on porosity. Pure water flux of membrane decreased with the increase of oxidation time, while rejection of membrane increased; Pure water flux and PEG flux of membrane decreased with the increase of filter time. Compared with phosphoric acid membrane, the pore diameter of oxalic acid membrane was smaller, and the thickness of oxalic acid membrane was thicker; Under the same pressure, the stable pure water flux of oxalic acid membrane was smaller than phosphoric acid membrane, while the rejection of oxalic acid membrane was higher than the latter. The stable pure water flux of membrane increased with the increase of anodic reaction time, while it had little effect on the rejection of membrane. The pure water flux and PEG 20000 flux increased with the increase of operation pressure.In this paper, we studied the anticorrosion property of membranes with and without annealing by anticorrosion experiment, and investigated the surface morphology and composition of membranes by using SEM and XRD. The results showed that the membranes were completely anticorrosion in neutral environment without annealing, and they had better anticorrosion property in acid environment than alkaline environment. When pH was above 12, the membranes could be corrupted. The membranes were transformed from amorphous phase toα-Al₂O₃ crystalline phase by 5 hours annealing at 800℃and 910℃. At the same time, aluminum and amorphous alumina were found by XRD patterns. The membrane had little change in front side after 5 hours annealing at 800℃, while the back side was transformed from ruleless distributing to cluster distributing. The membranes were completely anticorrosion in neutral and violent acid environment with annealing at 800℃, and the anticorrosion property of membranes had greater improved in violent alkaline solution.更多还原