氧化性碳基纳米过滤器对饮用水中微污染有机物的深度去除

It is always a big challenge for the purification technologies to effectively remove the lowly-concentrated organics in drinking water. Low concentration, slow mass transfer and weak reaction-driving force are the main technical bottlenecks of the removing process, and consequently large reactor volume, long hydraulic retention time, low removal efficiency, small treatment capacity and high operation cost are the main technological characteristics of these water purification technologies. In this proposal, we proposed a combined method, "organics adsorbing concentration - adsorbed absorbates degradation - adsorbents in situ regeneration", for advanced treatment of drinking water. In the method, the slightly-polluted organics were firstly concentrated on carbon nanotube filtration layer, then the concentrated substrates were rapidly degradated and mineralized by photocatalyst and electrocatalyst that loaded within carbonaceous filtration layer under UV and external bias, finally the adsorption active sites and observed adsorption capacity of carbon nanotube filtration layer were effectively and in-situly regenerated, by all of which the water purification technology could be promised to operate effectively, continuously and stably. Systematic investigations on removal efficiency, mechanisms and properties of the proposed method were carried out, so as to provide informative guidance and useful technology for the advanced treatment of drinking water.

饮用水中微污染有机物的去除一直是水质净化工艺的重点和难点。浓度低、传质慢和反应推动力小是制约饮用水中低浓度有机物有效去除的主要技术因素，而反应构筑物体积大、水力停留时间长、处理能力小、去除效果差和运行成本高是此类水质净化工艺的主要技术特征。本项目拟通过首先将饮用水中微污染有机物快速、高效富集到一维碳纳米管微滤层，再利用负载于微滤层的光催化剂和电催化剂在光源和电场共同作用下将被富集的微污染有机物进一步降解和矿化，从而达到吸附活性点位和吸附容量的完整再生，最终实现饮用水深度处理过程高效、持续和稳定运行的"污染物吸附富集-吸附质氧化降解-吸附剂原位再生"耦合新工艺。深入研究和探讨耦合工艺在微污染有机物深度去除过程中的去除效果、作用机制和工艺特性，为饮用水深度处理提供新的实用技术。

项目执行期内，重点研究了几类典型纳米材料作为环境光催化剂和电催化剂在吸附、催化反应过程中表面/界面的结构、活性中心、配位环境的微观变化及电子转移规律，提高了纳米功能材料和纳米组装结构针对饮用水中几类典型微污染物的高容量富集以及催化转化效率，发展了基于纳米材料与技术高效富集与无害化转化的新体系和新技术。重点发展了弱电场作用下以活性炭纤维碳纸为基底、高能晶面功能化TiO2单晶材料为阳极材料的电催化富集-转化系统，阐明了有机微污染物在上述体系中富集和无害化转化原理和规律。建立了饮用水中典型微污染有机物的选取及检测方法、系统研究了以暴露高能001晶面TiO2单晶、氮掺杂TiO2异相结、Bi2S3和MoS2 3D复合异质结和暴露高能001晶面的缺陷态TiO2纳米颗粒等几种纳米材料为代表的结构、性能和制备条件之间的内在联系；在此基础上，我们设计和运行了几套“富集-降解-再生”的水处理耦合反应器并完成了其系统优化，为降解有机污染物反应器设计单元提供帮助。. 所研究的暴露高能晶面TiO2单晶、掺杂态TiO2单晶、还原态TiO2单晶、Bi2S3/MoS2 3D复合异质结以及ZnO/CdS/TiO2三元复合异质结等纳米材料可有效实现饮用水/地表水源水中典型低浓度有机污染物双酚A、阿特拉津和腐殖质的高效和彻底去除；同时，所设计和运行的2套“富集-降解-再生”的电催化和光辅助电催化反应器可以很好地将针对饮用水中的微污染有机物的吸附、降解和再生三大独立的物化过程进行耦合集成，尤其适用于饮用水中低浓度持久性有机污染物的高效清除，为后续的应用系统集成提供了理论依据和技术支持。