二氧化钛原位合成纳滤膜成膜研究

发布时间：2018-06-20 05:57

  本文选题：界面聚合 + 纳米复合膜　； 参考：《浙江工业大学》2017年硕士论文

【摘要】：二氧化钛纳米粒子由于其出色的亲水性和光催化性能,而被广泛应用于纳米复合膜的制备当中,来提高膜的抗污染性和分离性能。但是,纳米颗粒的团聚现象是制备掺杂纳米颗粒的复合膜中不得不面对的问题。一些研究者通过对纳米颗粒表面的改性来改善分散性,并取得了一定的效果。然而这样做不仅步骤繁琐,而且也损失了一部分纳米颗粒的亲水性。本文采用钛酸四丁酯(TBOT)代替二氧化钛纳米颗粒添加到TMC油相中。TBOT在油相中溶解性很好,并能在界面聚合的同时水解生成二氧化钛,这提高了二氧化钛在复合膜中的分散性,并有效抑制团聚的发生。与其它减少团聚的方法相比,这更加简单有效,并且容易工业化。首先以哌嗪PIP为水相单体,均苯三甲酰氯TMC为油相单体,在油相中添加TBOT,通过原位合成TiO_2的方法制备了新型纳米复合纳滤膜。对原位生成的二氧化钛进行表征分析,研究了TBOT添加量对纳米复合膜性能和结构的影响。优化了界面聚合工艺条件:PIP浓度为2g/L,TMC浓度为1 g/L,TBOT添加量为250 mg/L,热处理条件为80℃,10 min时,所制备的纳米复合纳滤膜性能最佳,Na2SO4和NaCl的截留率分别为95.3%和54.1%,纯水通量为78 L/m~2h(1 MPa,2000 ppm)。复合膜表征实验结果显示,在TBOT添加量较少时,TFN膜表面二氧化钛纳米颗粒分散较好,并未发现明显团聚。通过相同的界面聚合工艺条件制备了直接在油相和水相添加二氧化钛的两种传统纳米复合膜,并且进行膜性能和结构上的对比。实验结果表明,原位生成二氧化钛制备的新型TFN膜具有更出色的分离性能。用X射线光电子能谱(XPS)、原子力显微镜(AFM)、扫描电子显微镜(SEM)和静态接触角表征了复合膜,结果显示这得益于在界面聚合的同时原位生成纳米颗粒在膜中具有出色的分散性,并且有效的抑制了团聚的发生。同时在复合膜表面粗糙度增加和亲水性提高的双重作用下,新型纳米复合膜在通量大幅提升的同时又保持了很高的截留率。最后将制备的新型纳米复合纳滤膜应用到染料脱盐中,并进行了耐污染性能测试,显示了比较理想的染料分离性能。
[Abstract]:Titanium dioxide nanoparticles have been widely used in the preparation of nanocomposite membranes because of their excellent hydrophilicity and photocatalytic properties to improve the fouling resistance and separation performance of the membranes. However, the agglomeration of nanocrystalline particles is a problem to be faced in the preparation of composite films doped with nano-particles. Some researchers improve the dispersion by modifying the surface of nanoparticles and obtain certain results. However, this process is not only cumbersome, but also lose some of the hydrophilicity of nanoparticles. In this paper, tetrabutyl titanate (TBOT) was added to the oil phase of TMC instead of titanium dioxide nanoparticles. TBOT has good solubility in the oil phase and can hydrolyze to form titanium dioxide at the same time of interfacial polymerization, which improves the dispersion of titanium dioxide in the composite film. And effectively inhibit the occurrence of agglomeration. This is simpler and more effective than other ways to reduce agglomeration, and it is easy to industrialize. A novel nano-composite nanofiltration membrane was prepared by in-situ synthesis of TiO2 with piperazine PIP as aqueous phase monomer and benzoyl chloride TMC as oil phase monomer and TBOT added in oil phase. The in-situ formation of titanium dioxide was characterized and the effect of Tbot addition on the properties and structure of nanocomposite films was studied. The optimum conditions of interfacial polymerization were optimized when the concentration of 2 g / L PIP was 2 g / L, the concentration of TBOT was 1 g / L, the amount of TBOT was 250mg / L, and the heat treatment condition was 80 鈩，

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