以疏浚底泥为原料的高性能陶瓷膜制备

PREPARATION OF HIGH PERFORMANCE CERAMIC MEMBRANE USING DREDGED SEDIMENT AS RAW MATERIAL

梁琨

11749212

硕士

环境工程

唐圆圆

2019-05-28

2019-06-28

哈尔滨工业大学

深圳

我国城市河道底泥污染严重，其中所含有的重金属等污染物质会对水体造成二次污染。目前虽然有技术能够对污染底泥进行原位或异位修复，但是存在成本高、流程复杂、修复效果不明显等缺点。因此，将底泥疏浚并进行资源化利用，将其作为公路路基填料、建筑陶粒等建筑应用以及园林绿化、用作填方材料和堆肥发酵等利用方式逐渐受到广泛的关注。然而，上述利用过程并不能有效阻止底泥中原有重金属的进一步溶出。通过烧结过程，重金属可镶嵌于稳定的铝硅酸盐晶体结构中，从而能够被有效的稳定化。因此，基于烧结的无机固废处理技术逐步受到重视。底泥体系以硅铝酸盐为主，是典型的制备陶瓷的材料。因此，将烧结技术进行应用既可将重金属稳定化，同时又可制备能够高值化利用的陶瓷产品。 在诸多陶瓷产品中，陶瓷膜因其在污水处理过程中的优越性能得到了广泛应用。然而目前的陶瓷膜制备多以纯化合物质为原材料，且烧结温度在1500 ºC左右，较高的烧结温度，导致制备陶瓷膜成本过高，限制了陶瓷膜的广泛应用。因此，本课题结合底泥重金属污染难以高效解决以及陶瓷膜制备成本过高的两个难题，创新性的提出一种新型陶瓷膜制备方案，即就地取材，以深圳茅洲河底泥为陶瓷膜基体原材料，通过干压成型法和旋转涂覆法制备基体陶瓷膜和双层陶瓷膜，配置不同浓度的旋涂液得到三种双层膜。通过X射线荧光光谱分析（XRF）、扫描电子显微镜（SEM）、X射线衍射仪（XRD）对陶瓷膜进行表征。实验室研究结果表明，相比于纯相材料陶瓷膜，底泥陶瓷膜在900 ºC即可制备；通过压汞孔隙率测定仪对陶瓷膜测定，陶瓷膜的孔径为70 nm，孔隙率为39.86%。对陶瓷膜成孔剂的种类及配比进行选择，以及对陶瓷膜通量、稳定性、安全性、抗腐蚀性和对医疗废水、重金属废水的分离率测定。实验结果表明疏浚底泥为材料的陶瓷膜的分离性能良好，相较其他陶瓷膜产品，成本更低。 将疏浚底泥制备为陶瓷膜，不仅通过烧结将重金属稳定于矿物晶体结构中，有效的解决了底泥重金属污染问题，同时还能够大大降低陶瓷膜原材料成本。通过引入底泥这一混合体系，大幅度降低陶瓷膜烧结温度，在有效控制成本的基础上制备出性能良好的陶瓷膜，从而达到“以废治废、化废为宝”的可持续循环利用目标，具有非常优异的环境效益。

The heavy metal pollution has become one of the most serious concern for the river sediments all over the world. Although some technologies have been developed for the remediation of contaminated sediment, most of them need relatively high cost, complicated processes, and ineffective the remediation results. Therefore, dredging the sediment out for the beneficial utilization have been received widespread attention, including for highway subgrade filling, architectural ceramsite, landscaping, filling materials, compost fermentation and other utilization method. However, the above utilization process cannot effectively prevent the further release of the original heavy metals in the sediment. Through sintering processes, heavy metals can be incorporated into the stable aluminosilicate crystal structures, achieving effective stabilization. The river sediment system is mainly composed of aluminum- and silicon- compounds, and therefore, heavy metals might be well immobilized after the sintering process. Moreover, as the aluminum- and silicon- compounds are major ceramic materials, the sintered samples may be potentially used as ceramic products.Among many ceramic products, ceramic membranes are widely used due to their superior performance during the wastewater treatment processes. However, the preparation of ceramic membranes is usually based on pure chemicals at an extremely high temperature (around 1500 ºC), which limits the wide application of the ceramic membranes.Therefore, this study proposed a strategy for a high-value utilization of the dredged sediments through the preparation of ceramic membrane based on the sintering technology, with simultaneous heavy metal stabilization. The sediment collected from Maozhou River in Shenzhen was used as the raw materials for the preparation of the ceramic membrane, which may reduce the cost of the ceramic membranes while solving environmental problems. The support layer of the membrane was fabricated by the dry pressing method, while the double-layer was prepared by the spin coating method with coating liquid of different concentrations. The obtained ceramic membrane was characterized by X-ray fluorescence spectrometry (XRF), scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The optimum condition was obtained for the preparation of the ceramic membrane. Compared with the membrane production from pure chemicals, the sediment ceramic membrane can be prepared at a much lower temperature (900 ºC), with the pore diameter as 70 nm, the porosity as 39.86%. The optimal pore-forming agent was also confirmed for ceramic membranes, together with the determination of the flux, stability, safety, corrosion resistance. The experimental results show a better filtration performance by using the ceramic membrane prepared from the dredged sediment with much lower cost.Through this study, the dredged sediment can be potentially used as raw materials for ceramic membrane, which not only stabilized the heavy metals by incorporating them in mineral structures, but also effectively reduced the cost of the ceramic membrane through the adoption of solid waste and significant reduction in sintering temperature.

资源化 疏浚底泥 烧结 陶瓷膜 分离性能

beneficial utilization dredged sediment sintering ceramic membrane separating property

中文

联合培养

南方科技大学

梁琨. 以疏浚底泥为原料的高性能陶瓷膜制备[D]. 深圳. 哈尔滨工业大学,2019.