石墨烯量子点对畜禽废水微藻资源化过程的作用机制与调控研究

The cultivation of oil-microalgae can realize the ammonia nitrogen and phosphate recovery in livestock wastewater. However, the high turbidity and dark color in livestock wastewater would hinder the light transfer, which would limit the microalgae production and nutrients removal. Graphene quantum dots (GQDs), which have unique fluorescent properties, excellent water solubility and good biocompatibility, show their great potential in improving efficiency for solar energy utilization. The addition of GQDs in the livestock wastewater utilization system for microalgae cultivation was proposed to enhance the photosynthesis efficiency of microalgae. In this study, the effect of GQDs on the growth and composition of microalgae using the nutrients in the livestock wastewater was investigated. To illustrate the action mechanism of GQDs on microalgae growth, photoluminescence transfer and electron delivery were measured, as well as the dynamics of bioaccumulation process was analysed. In order to reveal the regulation mechanism of metabolic network in microalgae, metabonomics and transcriptomics were adopted. Furthermore, a technology system about the regulation of GQDs on microalgae cultivation in livestock wastewater was established. This study provides a bran-new method and theoretical support for the industry production of microalgae cultivation in wastewater, which has great realistic meaning and environmental economic benefits.

通过产油微藻培养可实现畜禽废水中高氨氮及磷酸盐的资源化处理，然而畜禽废水的高色度与浊度削弱了光在废水中的传递过程，导致微藻生产力和废水处理效率低下。基于石墨烯量子点独特的荧光特性，优异的水溶性以及良好的生物相容性，本课题创新性地提出添加石墨烯量子点以增强产油微藻在畜禽废水资源化过程中的光合作用效率。通过研究石墨烯量子点对畜禽废水微藻资源化过程的影响规律，探讨石墨烯量子点与微藻作用过程中荧光能量及电子转移方式，分析微藻生物累积过程的动力学，从而确定两者之间的相互作用机制，并基于代谢组学与转录组学进一步揭示石墨烯量子点对微藻细胞内在代谢网络的调节机制，最终建立畜禽废水微藻资源化过程中石墨烯量子点调控技术体系。本研究为实现畜禽废水微藻资源化大规模应用提供新的思路与理论基础，具有重大的现实意义和环境经济效益。

基于微藻培养可以实现养殖废水资源转化及CO2高效固定，能有效缓解能源危机、减少碳源排放，助力“3060”双碳目标的实现。然而，养殖废水具有高色度、高浊度等特征，导致微藻光能利用率不高，微藻生产力及光合作用效率远低于理论值。而碳量子点作为新型的半导体纳米碳材料，具有优异的光学特性，在环能、能源等众多领域具有潜在的应用价值。本研究选取激发波长为380 nm、发射波长为460 nm的氧化石墨烯量子点及在废水处理、能源生产领域极具优势的小球藻为研究对象，构建了氧化石墨烯量子点-微藻资源化系统，明确氧化石墨烯量子点强化微藻生长及光合固碳条件：当氧化石墨烯量子点投加量为100 mg/L时，微藻生物质含量提高了17%、油脂含量提高了34%，同时增加了二氧化碳的固定效率；探究了氧化石墨烯量子点强化小球藻光能利用机理：氧化石墨烯量子点可以有效转化太阳光中的紫外波段，减少UV对小球藻的破坏、提高微藻光能利用效率；揭示了小球藻PSII光系统活性对量子点响应机制：氧化石墨烯量子点可以促进小球藻中能量传递，强化微藻光合固碳，上调脂质生物合成代谢产物。相关成果在Water Research、Chemical Engineering Journal等环境领域国内外著名期刊发表论文25篇，其中SCI论文22篇，中文核心3篇；申请中国发明专利5项，其中授权4项。本研究将为畜禽养殖废水污染治理与固碳减排协同增效提供理论和技术支撑。