改性水滑石对黑臭水体磷的去除和资源化利用机理研究

Phosphorus (P) removal and recovery from P-rich wastewater could ensure the long-term treatment effect of water pollution, and is becoming a hot topic in the research field of water science due to the twin problems of obstructed development of water treatment and increasing scarcity of global phosphate resources. The excellent P adsorption properties of modified hydrotalcite materials have been reported in previous studies. However, the removal efficiency and working mechanism of hydrotalcite-type materials on P in malodorous black water are not clear yet. Moreover, there is a critical research gap in how to effectively reuse the extracted P from wastewater in hydrotalcite-type materials. Based on the characteristics of malodorous black water, this study aims to improve the modification methods of hydrotalcite materials specialized for malodorous black water, preparing modified hydrotalcite adsorbents with high selectivity and high adsorption capacity of phosphates; to reveal the influence mechanism of iron-sulfur reactions on P adsorption dynamics onto modified hydrotalcite materials, to analyze the P releasing behavior and mechanisms from P-rich hydrotalcite materials as well as to identify the boundary conditions and suitable soil types for the application of P-rich hydrotalcite material as a slow-release fertilizer. The outcomes of this study should enrich the theory and technology studies of malodorous black water treatment and phosphorus recovery from wastewater.

在水环境治理遭遇瓶颈和全球磷矿资源日益匮乏的双重驱动下，治理富磷水体同时回收利用磷素可长效化保障水环境治理效果，因此成为当前水科学的研究热点。已有研究表明改性水滑石在磷吸附方面具有优良性能，但其对黑臭水体中磷的去除效果和作用机制还不明确，以及如何高效利用被水滑石从污水中提取的磷是目前尚未解决的难题。本研究针对富磷黑臭水体，根据其水质特征进行水滑石改性优化，制备对磷酸根高选择性高吸附容量的改性水滑石材料；揭示黑臭水体中硫铁行为对改性水滑石磷吸附动力学的影响机制；阐明富磷水滑石的释磷行为与机理，明确富磷水滑石作为缓释肥的边界条件与适用土壤类型，从而提升水环境治理和磷资源回收的理论与技术。

在水环境治理遭遇瓶颈和全球磷矿资源日益匮乏的双重驱动下，治理富磷水体同时回收利用磷素可长效化保障水环境治理效果。已有研究表明改性水滑石在磷吸附方面具有优良性能，但其对黑臭水体中磷的去除效果和作用机制还不明确，以及如何高效利用被水滑石从污水中提取的磷是目前尚未解决的难题。本研究基于黑臭水体磷过剩、溶解性有机质含量较高的特点，开展了改性水滑石在黑臭水体模拟溶液中磷吸附实验，探究了改性水滑石在不同磷含量和pH溶液中对磷酸根的吸附动力学，阐明了改性水滑石磷吸附过程中溶解性有机质和铁离子与磷酸根的相互影响与作用机制。发现在pH值为6.5~8.0范围内，改性水滑石对磷的吸附量受pH值影响较小。在磷初始浓度为2.10 mg/L~22.00 mg/L范围内，改性水滑石对磷的吸附量随磷初始浓度的升高而增大，磷吸附量从2.04 mg/g增加到21.96 mg/g。磷酸根相比于腐殖酸在改性水滑石的层间交换反应中更具优势。通过营养质缓释实验，分析了富磷水滑石中磷素和有机质的缓释行为，评价了富磷水滑石的稳定性和资源化利用潜力。缓释实验结果显示365小时后富磷水滑石在碳酸氢钠溶液和去离子水中磷的缓释率分别为14.5%、7.3%，腐殖酸的缓释率分别为4.5%、3.6%。富磷水滑石在缓冲溶液体系中表现出较高的营养质缓释率，并且相比于腐殖酸，其对磷素具有更好的的缓释效果，具有成为缓释磷肥的潜力。本研究揭示了改性水滑石在黑臭水体中除磷的机制与影响因子，并阐明了富磷水滑石的磷释放行为，拓展了水环境治理和磷资源回收的理论与技术。