黑磷基杂化材料的制备及其光催化去除水中抗生素与抗性基因机制研究

The pollution of antibiotics and antibiotic resistance genes (ARGs) is attracted more attention. Photocatalysis technique has been confirmed to be an efficient method for the removal of antibiotics and ARGs in water. However, the correlational researches are still at the primary stage. Especially, the degradation mechanisms of photocatalytic degradation for ARGs are unclear. In this project, several black phosphorus (BP)-based hybrid materials will be synthetized by chemical vapor transport and liquid phase microwave heating synthesis method, using red phosphorus as raw materials. To evaluate the optical adsorption properties, preparation pathways, and stabilization mechanisms of BP-based hybrid materials, a series of characterizations will be carried out. Using the prepared BP-based hybrid materials with favorable stability and high photocatalytic property as photocatalysts, the reaction pathways, influencing mechanisms, and stabilities of the photocatalytic degradations for tetracycline, ampicillin, and ARGs will be studied. The combination of structure analysis and theoretical calculation will be applied to assess the toxicities and potential risks of the incomplete mineralization products from the photocataltic degradations for tetracycline and ampicillin, in addition, the reaction active sites of ARGs will also be revealed. The photocatalytic degradation mechanisms for antibiotic and ARGs, coexisting in water, will be also investigated. This project will not only provide the referential technology for the practical application of photocatalytic degradation for antibiotics and ARGs in water, but also furnish scientific basis for the remediation and restoration of the polluted water.

抗生素及抗生素抗性基因（ARGs）污染日益受到人们的关注。光催化技术可有效去除水中抗生素和ARGs，但相关研究尚处于起步阶段，尤其是ARGs的光催化反应机制尚不清楚。本项目拟以红磷为原料，采用气相传输法及液相微波加热合成法，制备多种黑磷（BP）基杂化材料；通过系统表征，考察BP基杂化材料的光吸收特性，探究制备途径及杂化后BP的稳定机理；选取稳定高效的BP基杂化材料作为光催化剂，研究BP基催化剂光催化降解水中四环素、氨苄青霉素及ARGs的反应途径、影响机制及循环使用稳定性；结合结构分析和理论计算，预测四环素及氨苄青霉素光催化降解过程中，生成未完全矿化产物的毒性和潜在风险，揭示ARGs光催化降解的反应活性点位；阐明水中抗生素及ARGs共存时，抗生素与ARGs的光催化降解机制。本项目不仅可为光催化降解水中抗生素和ARGs的实际应用提供可参考的技术，而且为其污染水体的修复及恢复提供理论依据。

我国水环境抗生素污染日趋严重，亟需开展水环境中抗生素、耐药菌(ARB)与抗生素抗性基因(ARGs)的反应机理及控制技术的研究。项目围绕黑磷(BP)基杂化材料的制备、催化降解水中抗生素药物等与ARB、ARGs的反应途径、毒性变化、反应机理及影响机制等开展了系列研究，具体情况如下：(1)以红磷(RP)等为原料，采用气相传输法、微波热法等制备多种BP基杂化材料(如BP/CN(石墨相氮化碳)等)，并对制备方法进行了优化，进而将其用于抗生素污染物的光催化处理。模拟可见光照射下，BP/CN(BP掺杂量为6%)在30 min内可将99%的四环素(TC)脱除，表观速率常数是P25-TiO2的2.7倍，这归因于CN等上负载BP可以增强载流子的分离，增强对可见光的吸收能力，从而使催化剂具有更高的催化活性。此外，设计了多种去除水中污染物的AOPs装置，如光催化、电催化及光电催化、MFC(微生物燃料电池)等并应用于水中抗生素等、大肠杆菌(E. coli)及耐药基因的去除与灭活，均取得了较好的降解效果，并对反应机理、影响机制和毒性变化进行了深入探究；(2)采用AOPs技术有效的氧化了水中耐AMP的E. coli及其ARGs(blaTEM-1)，并系统研究了抗生素耐药的传播风险，耐药大肠杆菌(AR E. coli)的灭活主要是由于活性氧对细胞膜的破坏和胞内细胞质的泄漏，降解过程中，blaTEM-1因链断裂而降解。此外，以含有四环素抗性基因(TC-ARG)的AR E. coli为代表，研究了ARB的光灭活情况。由于直接辐照产生的膜损伤，AR E. coli发生了明显的光失活。模拟的阳光照射特异性地抑制了TC耐药性的表达，这是由于TC特异性外排泵的破坏所致。由于TC具有对AR E. coli的选择性压力和竞争性光吸收效应，因此抑制了AR E. coli的光失活；(3)对无细胞TC-ARG在模拟阳光照射下的光降解途径进行研究。TC-ARG可以发生直接的光降解，这大大降低了其水平转移效率。苏万尼河富里酸(SRFA)促进了TC-ARG的光降解，并通过产生反应性中间物进一步抑制了其水平转移。TC-ARG的光降解归因于四个碱基和脱氧核糖组的降解。尽管ARGs在阳光照射下可以在地表水中进行快速的光降解，但不能完全消除，因为ARGs可以随着抗生素耐药菌的扩散而产生。