基于离子耦联的钽酸盐基PN异质结的构筑及水环境药物残留的光催化深度降解处理

It is significant to completely degrade and mineralize drug residues because there are a wide variety of pharmaceutical compound with the complex components in water environment. Moreover the by-products produced from degradation process are toxicity, even in a lower level of contents. Thus the photocatalyst had to be with the higher redox ability for the purpose to remove the pharmaceutical pollutants. In this project, the novel PN heterostructures of MA-MB with an Mx+/My+ ions-coupling were synthesized by using Tantalate and correspongding metal oxide.In such unique structure, the visible response can be improved by self-doping through in situ redox way.The photo-catalytic activity can be increased by synergistic action between electric field formed by the PN heterojunction and the matched structure of the conduction and valence band in two composite semiconductors. The recombination of photogenerated electrons and holes can be reduced in this PN heterojunction due to the transition of the electrons being consistent with the direction of the built-in electric field in PN heterojunction. The stability can be increased by promoting the separation of electrons and holes and balancing charge and ions through the effect of the ionic coupling. This project will provide valuable therical and technical support for the remedy of water environment pollution in Inner Mongolia region. It is expected that a novel photocatalytic material integrated with high redox ability,enhaned catalytic activity, the wide solar light response and good stability will be developed, which will completely degrade and mineralize drug residues in water environment.

水环境中药物分子，由于种类多、成分复杂，降解过程副产物多、残留物毒性大，深度降解和完全矿化对处理药物残留污染物显得非常重要，因此对催化剂的氧化还原能力提出了更高的要求。本项目面向内蒙古自治区水环境药物污染，选用宽带隙的钽酸盐类半导体为基础材料，制备一系列基于M(高价)/M(低价)离子耦联结构的MA-MB异质结。通过耦联离子对的原位氧化还原方式实现自掺杂并构筑成内建电场与半导体组分材料的价带、导带位置匹配的PN结，从而拓宽太阳光响应范围，同时促进电子空穴分离，还可维持材料的电荷平衡和离子平衡，达到提高材料稳定性的目的；本项目的成果为内蒙古面临形势严峻的水环境污染治理提供有价值的数据积累，预计开发出集成高氧化还原能力、高量子效率和宽光谱的太阳能吸收以及优秀的稳定性等多重功效的具有实用前景的水环境药物残留深度降解光催化剂。

水环境中的药物分子污染物由于种类多、成分复杂，导致降解过程副产物多、残留物毒性大，因此深度降解和完全矿化对处理药物残留污染物显得非常重要，故催化剂的氧化还原能力必须足够高。本项目选用宽带隙的变价钽酸盐类半导体为基础材料，制备了Ag0/Ag+-Ag2Ta4O11/g-C3N4, Ag0/Ag+-Ag3PO4/Bi2MoO6, Ag0/Ag+-Ag2Ta4O11/Ag8(Nb0.5Ta0.5)26O69, Ag0/Ag+- Ag3PO4/CeO2, Fe3+/Fe2+-ZnFe2O4@Bi, Bi0/Bi3+-BiVO4/Bi3TaO7, Cu+/Cu0-Cu2O/Bi/Bi2MoO6, Bi3+/Bi0-Bi2MoO6/Bi/g-C3N4, Ru-Bi2MoO6/g-C3N4等一系列M高价/M低价离子耦联结构的MA-MB异质结，研究了这些材料对药物污染物的降解性能。研究结果证明制备的Mx+/My+离子耦联结构的异质结具有高的氧化能力、高的量子效率和宽光谱的太阳能吸收以及持久的稳定性等优秀性能；进一步我们还探索了应用废弃羽毛制备高比表面、表面功能化的生物活性炭，将光催化剂拟合在制备的生物炭材料上，获得了对药物残留及抗生素具有的良好富集和强氧化能力的可再生材料，可将工业废水中高浓度抗生素完全矿化并在太阳光下自再生，因此制备的材料具有实用化/工业化应用的潜力；同时我们采用密度泛函理论对半导体催化分解抗生素的机理进行了研究，获得了Mx+/My+离子耦联结构对光吸收、光催化和稳定性的协同促进机理。内蒙古地区聚集了国内很多大型制药企业，制药废水和药物残留水平远远高出国内的平均水平，本项目的成果可为治理内蒙古制药企业的水环境污染提供有价值的数据积累，因此项目的研究具有重要的社会意义和潜在的应用价值。.经过本项目四年的研究，已发表SCI收录论文25篇，其中1区论文4篇；获得内蒙古自治区自然科学一等奖1项；申请专利4项，其中1项已获授权。本课题组成员参与组织“全国第十九届大环化学暨第十一届超分子化学学术讨论会”会议，参加国内外学术交流14人次，其中出国参加国际会议5人次，国际会议上做大会邀请报告3人次。本项目已培养博士研究生3人，硕士研究生13人。