水化硅酸钙/生物炭耦合材料对水体中磷的高效富集和资源回用机理研究

The direct discharge of phosphorus in sewage will lead to lake water eutrophication and phosphorus resources waste. Calcium silicate hydrate has an immense potential at the phosphorus recovery in water. However, it is prone to agglomeration in water resulting in limited enrichment performance. biochar as a carrier can stabilize nanomaterials in water. And it also shows good performance in phosphorus adsorption. Nevertheless, the mechanism of recovery and resource utilization of phosphorus in water by calcium silicate hydrate and biochar coupling material is still unclear. Therefore, this project aims to study the main factors affecting the material properties and their relation mechanisms through the regulation of the preparation process. Besides, the batch experiments and internal circulating fluidized bed reactor experiments will be carried out to investigate the influence mechanism of environmental factors on phosphorus recovery performance and the continuous dynamic phosphorus recovery efficiency of the coupling material. Finally, the analysis of the existing form of phosphorus in the recovered products and its transformation mechanism in soil will be conducted to reveal the bioavailability of phosphorus in the recovered products of the coupling material and the potential of phosphate fertilizer. This project is expected to provide an important theoretical basis for the development of a green, cheap, efficient and economic phosphorus recovery and resource utilization method.

污水中大量的磷未经回收而排放会引发水体富营养化和磷资源浪费的双重问题。水化硅酸钙用于水体中磷的回收具有较大的前景，然而其易在水体中发生团聚，富集性能有限。生物炭能作为纳米材料的载体，使其能在水体中稳定化，同时生物炭对磷具有一定的吸附性能，但水化硅酸钙/生物炭耦合材料对磷的富集和资源回用机理尚不清楚。为此，本项目拟通过对制备过程的调控，研究影响耦合材料性能的主要因素及其作用机理；通过静态条件下的批量实验和动态条件下的内循环式流化床反应器实验，研究环境因子对耦合材料磷富集性能的影响机制，探究耦合材料对磷的连续动态富集效能，并从分子水平和微尺度上综合揭示耦合材料对磷的富集机理；最后通过对回收产物的磷素赋存形态及其在土壤中转化规律的分析，探究耦合材料回收产物的磷素生物有效性，评估其用作磷肥的潜能。本项目有望为发展一种绿色、廉价、高效、经济的磷回收及资源回用方法提供重要的理论依据。

含磷污水对的排放不仅会引发水体富营养化，还会造成磷资源浪费。水化硅酸钙（CSH）无毒无害在去除和回收水体中磷方面具有较大的应用前景。本项目通过通过简单快速、绿色高效的微波水热处理方法，将水化硅酸钙负载到生物炭表面和多孔化处理，制备出具有最佳性能的水化硅酸钙/生物炭耦合材料（w-HC/CSH）。通过续批吸附实验，研究投加量、反应时间、反应pH值对磷去除性能的影响，揭示反应动力学与热力学规律，阐明水化硅酸钙/生物炭耦合材料对磷的去除机理。通过室内盆栽实验和高通量测序，研究回收产物（w-HC/CSH/P）作为农作物磷肥的潜能，揭示回收产物加入土壤后各磷组分的转化规律和核心功能微生物驱动磷形态转化的共发生网络。研究结果表明，当微波水热温度为160℃、时间为2h时，制备出的w-CH/CSH吸附性能最佳，CSH均匀分布在生物炭表面，其比表面积可达98.76 m2/g。投加量为2g/L、反应pH为9、反应时间为4 h时，w-CH/CSH的磷去除效果最好。拟二阶吸附动力模型和Freundlich模型能更好的拟合吸附过程，膜扩散和颗粒内扩散是吸附过程的限速步骤。去除机理主要归因于磷酸盐表面微沉淀和配体交换。施用回收产物能促进辣椒生长，有一定的肥效。添加后土壤随着辣椒的生长Resin-P和NaHCO3-Po的比例下降，NaOH-Po比例上升。psOTU 331(g_latescibateria)、psOTU377(g_Lysobacter)和psOTU461 (g_Pseudoxanthomonas)是土壤微生物共生网络中驱动磷形态转化的关键微生物。乳酸菌（Latescibacteria）和溶杆菌（Lysobacter）与NaHCO3-Po向NaOH-Po的转化密切相关，假黄色单胞菌(Pseudoxanthomonas)与Resin-P的减少显著相关。本项目有望为发展一种绿色、高效、经济的磷回收及资源回用提供重要的理论依据。