生物-纳米改性滤料用于典型溶解性微污染物的强化过滤效果与形态学特性研究

There is a tough problem in the process of surface water treatment. Dissolved micropollutants (especially low molecule weight organic matters) contained in raw water are very hard to be removed by conventional processes, conventional enhanced processes or some advanced treatment technologies. A new filter material, Nanomaterials modifier- coated filter media(for short: NMCFM), has strong adsorption abilities and huge adsorption capacity. After combination with biodegradation of microorganisms, removal rate to dissolved micropollutants will be improved greatly in a high efficiency and low energy consumption way by the help of fractal mathematical theory and morphological theory. Enhanced treatment properties of bio-NMCFM to micropollutants and morphological characteristics of its surface porosity will be investigated. This project mainly focuses on discussing following points:●to investigate influence factors of biofilm formation on the surface of NMCFM, such as types of nanomaterial modifiers and micropollutants, configuration characteristics of porosity in nanometer on the surface of modified filter media, biological species, aeration ways and etc, then to determine the best biofilm formation conditions;●to analyse the change of surface electric potential properties, adsorption behaviors, action mechanisms and its efficiencies of NMCFM combined with biological treatement technology, to discuss the characteristics of collaborative adsorption, enrichment and condensed biodegradation, then to determine isothermal adsorption curve model and optimize filtration conditions and controllable parameters threshold value;●to compare morphological properties and fractal characteristics on the surface of different filter materials before and after biofilm formation and backwashing with the aid of online microscopic camera and atomic force microscope,etc., and optimize backwashing conditions, preparation process conditions, surface structures with nanopores, and parameters threshold value.●Then, to establish the changing regularities of morphological parameters with fractal dimension which are related to filtration efficiencies. Morphological factors include porosity, specific surface area, adsorption capacity, specific deposit volume, biomass, and etc. From all mentioned above, the conditions and ways to remove dissolved micropollutants efficiently will be achieved by using NMCFM combined with biofilm treatement process. Thus, it is hopeful to develop and utilize new water treatment processes and technologies in a high efficiency and low energy consumption way on the basis of biofilm treatment process and nanotechnologies. after achieving results, experiments and pilots will proceed on in Fo Shan Wateer Affairs Group Ltd, and/ or Guangzhou You Yi Electronic Science and Technology Company Ltd, then to solve the tough problem- a low removal rate to dissolved micropollutants (especially low molecule weight organic matters) .Meanwhile,bio-NMCFM makes water treatment processes simple and easy to be improved, the flow chart is short and cost is low.

本项目将分形理论、纳米改性滤料与生物技术相结合，对水源中难以去除的溶解性微污染物（尤其是小分子有机物），进行高效低耗处理与形态学特性研究：探讨纳米改性滤料表面生物挂膜的影响因素:纳米改性剂与微污染物种类、表面孔隙构型、生物菌种、曝气方式等，确定最佳挂膜条件；分析纳米改性滤料与生物结合的表面电动特性、吸附性能、作用机理与效果的变化，探讨两者的协同吸附、富集与凝聚降解特性，确定吸附特征模式，优化过滤条件与参数阈值；借助在线显微摄像与原子力显微镜等，研究滤料表面挂膜与过滤前（后）的形态学特征与分形特性，优化反冲洗条件、制备工艺条件与参数阈值，确定反映过滤效果的形态学参数（孔隙率、比表面积、吸附容量、比沉积量、生物量等）随"分维"的变化规律，寻求生物-纳米改性滤料有效去除微污染物的条件与方法，开发利用基于生物与纳米技术的高效低耗新型水处理工艺，并在合作单位佛山水业集团与广州友一电子科技有限公司进行小试与/或中试，解决溶解性微污染物(尤其是小分子有机物和金属离子)去除率低的难题。

如何有效提高常规水处理工艺对溶解性低分子微污染物的去除率，是水处理领域的难点问题之一。 项目首次将分形理论与纳米表面改性技术及生物技术相结合，借助现代结构表征技术，对典型溶解性微污染物进行强化去除研究，对生物挂膜机理与群落演变特性、吸附特性、表面截留性能与分形结构的形态学特性、生物-纳米改性滤料协同作用与效果以及制备条件优化等进行了深入探讨。.主要研究成果有：（1）纳米改性滤料比表面积增加10-80倍，表面更加粗糙多孔，分维值从改性前的1.8-2.0下降至1.5-1.8，反应速度加快（生物挂膜时间缩短一半，初滤水成熟期缩短至原来的1/3），对低分子污染物的吸附去除率提高1-3倍，过滤周期延长2-5倍；（2）纳米改性滤料对微污染物具有选择吸附性，吸附特征均满足Langmiur与Freundlich等温吸附模式（化学吸附特性略占优势）。吸附速率符合Langergren二级速率方程。（3）反冲洗采用NaOH溶液辅助的气水联合方式。但与生物预处理联用时，反冲洗强度与时间与传统气水反冲洗一致。（4）生物-纳米改性滤料表面生物物种丰富，活性增加，孔隙变小，分维值增加至1.6-1.9，吸附容量增加。自然挂膜时间缩短40%%-50%，对氨氮去除率高达99%。主要优势菌群为变形菌门、厚壁菌门、放线菌门、拟杆菌门。能抵抗高浓度氨氮（5-10mg/L）冲击，去除效果稳定。（5）当增加C/N比为1:1-2:1，生物-纳米改性滤料对总氮的去除率提高1-3倍。硝酸螺旋菌为主要硝化功能菌，还有多种反硝化菌、好氧反硝化菌及异养硝化菌存在。（6）与其它纳米改性滤料比较，氧化石墨烯GO与其它纳米材料复合改性滤料表面粗糙度与孔隙率最高，分维值为1.8-1.9，表面亲水性与抗污染性能强，过滤周期延长2-3倍，处理效果好，水质稳定。（7）本项目开发了4种新型改性滤料，获得2项发明专利与1项实用新型专利授权、发表论文13篇(SCI期刊论文4篇)，专著1部，参加国际国内会议5次与国际合作交流4次，培养了12位研究生与2位青年教师。.研发的新型高效低耗纳米改性滤料以及基于“分维”的表面结构性能与水处理效果之间的关系，国内外尚未见诸报道。部分研究成果已经在佛山市水业集团的应急平台与中试基地进行了实验验证，效果显著，有着广泛的应用前景。