生物阴极型微生物燃料电池从含铀废水中回收铀的效能与机理研究

Although uranium-bearing wastewater is a conventional wastewater generated from the uranium mining and metallurgy, there is lack of a reliable technology to treat it with resource recovery. The serious environmental threats always exist on and around the field of the uranium mining and metallurgy. In our opinion, the introduction or development of a new treatment and resource recovery technology should be one of effective methods to leave this awkward situation. Microbial fuel cell (MFC) as one of equipment can recover resource and generate electricity simultaneously during the wastewater treatment. Some reports have shown that heavy metal and energy were recovered from the treatment of heavy metal-containing wastewater with high efficiency. Therefore, MFC technology has great research potential and many application valves to the uranium-bearing wastewater with uranium recovery. In this research, the MFC with an excellent biocathode should be structured to recover uranium from the uranium-bearing wastewater. Based on the development and optimization of a new MFC biocathode for the recovery of uranium from the uranium-bearing wastewater with high efficiency and durability, the effects of anions and cations in uranium-bearing wastewater on the uranium recovery will be investigated, and the mechanism of the uranium recovery from this biocathode will also be carefully analyzed on the basis of various types of characteristics. More innovative ideas should be come out and the electrode of the MFC will also be developed all due to the introducing of the MFC to treat the uranium-bearing wastewater.

含铀废水是铀矿冶常见的废水，因缺乏可靠的处理与资源化技术，其对铀矿冶工业区及周边地区均造成了巨大的环境危害。引入或者研究新的处理与资源化技术将是减少这类危害的有效方法之一。微生物燃料电池（Microbial fuel cell, MFC）是一种新型的可同步处理废水产电且回收资源的装置，已有研究结果显示其可高效回收含重金属废水中的各类重金属并产出电能。因此，利用MFC技术来处理含铀废水并回收铀的方法具有较大的研究潜力与应用价值。本项目提出利用生物阴极型MFC来处理含铀废水并回收铀资源，在研制并优化新型MFC生物阴极高效持久回收含铀废水中铀的基础上，考察含铀废水中其他阴阳离子对铀回收的影响，重点解析MFC生物阴极体系电化学催化回收铀的机理。该研究为含铀废水的处理与资源化提供新的思路，也可有效促进MFC阴极体系的发展。

含铀废水为铀矿采冶过程或后续的常见废水。因铀离子的存在，该类废水具有放射性和金属毒性双重危害。目前尚缺乏较可靠的技术用于含铀废水的处理或资源化。若含铀废水未妥善处理而被排入环境中，将会对周围环境与人类健康等造成巨大危害与恐慌。为同时实现含铀废水的处理和资源化，本项目引入了生物阴极型微生物燃料电池（MFC）进行其的处理。项目首先通过不同阴极材料、不同启动方式等手段构筑可进行铀回收的生物阴极型MFC；在此基础上，优化了MFC处理含铀废水的各项重要运行参数；然后借助扫描电镜、能谱扫描、X射线衍射和X射线光电子能谱等表观表征手段，结合生物阴极型MFC的电化学效能，解析了生物阴极型MFC体系对含铀废水的中铀高效处理机制；最后利用Illumina高通量测序技术解析了生物阴极型MFC各部位的微生物群落结果和结构动态学特征。各项结果表明，利用污水处理厂厌氧池的污泥可构筑具有稳定效能的生物阴极型MFC，虽然含铀废水对生物阴极型MFC长期产电具有一定的抑制作用，但优化的生物阴极型MFC可高效长期稳定分离含铀废水中至少95%的铀；此外，MFC阳极同时也保持了对污染物的高效处理；MFC的各室均参与了含铀废水中铀的去除，主要方式包含磷酸基团为主体的化学沉淀、物理吸附和化学吸附以及阴极上的电化学还原等。在营养液的驯化作用下，阴阳各室和阴阳各极上形成了以变形菌门和拟杆菌门为主要产电菌门及耐重金属性菌门。含铀废水的驯化作用驱使阴极上形成了以Azospirillum（固氮螺菌属）、lgnavibacterium、Saccharibacteria_genera_incertae_sedis（丁酸盐细菌）和Thiobacillus（硫杆状菌属）四类为主的铀分离特定菌属，形成的特定菌属是生物阴极型MFC对铀电化学还原的重要要素。本项目的开展可为生物阴极型MFC构筑并处理特种废水提供参考意义，同时对生物阴极型MFC回收铀资源的机理发展具有促进作用。