丙烯酸树脂负载纳米水合氧化铁复合吸附剂的制备及其深度除磷研究

The organic fouling of polystyrene-supported hydrated ferric oxide (HFO) had adverse effects on its long-time reuse in wastewater. To solve this problem, this study will focus on the preparation of a hybrid adsorbent with anti-organic fouling, fast adsorption rate, large adsorption capacity and high selectivity. It will supply theoretical and practical significance for enhanced phosphorus removal from wastewater and eutrophication control. In the present study, a process of FeCl4- ion exchange, NaOH precipitation and thermal treatment was proposed to immobilize nanoparticulate HFO within an acrylic anion exchange resin D213. The HFO loadings of hybrid adsorbents were controlled by regulating FeCl3 concentration. The variation of material properties and adsorption properties in hybrid adsorbents and HFO was discovered, then a hybrid adsorbent HFO-213 with optimal performance was selected. Subsequently, it was illuminated preliminary that the influence and interaction mechanism of phosphorus adsorption by HFO-213 under certain condition, including pH, temperature, adsorption time, inorganic anions and organic matter. Furthermore, the adsorption mechanism of phosphorus on HFO-213 was revealed, and the anti-organic fouling mechanism of HFO-D213 and stability of HFO during the reuse were also studied. Based on the above study, the stability of long-time reuse of HFO-D213 in secondary effluent (adsorption and elution effects of phosphorus, as well as HFO content and crystal structure) and feasibility of phosphorus recovery from eluent were studied. The results will supply theory and technology for future in application of HFO-213 for enhanced phosphorus removal from wastewater.

对于苯乙烯树脂基纳米水合氧化铁（HFO）复合吸附剂，有机物污染影响其在污水中长期重复利用。针对这一问题，本研究研发抗有机物污染、吸附速率快、选择性高及吸附容量大的新型除磷复合吸附剂，对污水深度除磷和水体富营养化控制有重要理论和实际意义。本研究采用FeCl4-离子交换-NaOH沉淀-热处理，将纳米HFO负载至丙烯酸阴离子交换树脂D213。通过调节FeCl3浓度控制HFO负载量，并揭示不同负载量下复合吸附剂及负载HFO的材料性能和吸附性能的变化规律，筛选出具备最优性能的复合吸附剂HFO-D213。随后阐明pH、温度、吸附时间、无机阴离子及有机物的影响规律及作用机理，揭示磷吸附机理，并研究重复利用时HFO-D213的抗有机物污染性能及HFO稳定性。在上述基础上，考察其在二级出水中长期重复利用稳定性（磷吸附和洗脱效果、HFO含量和晶型）和磷回收可行性，为其用于污水深度除磷提供理论基础与技术支持。

污水深度除磷是控制水体富营养化的关键。苯乙烯树脂基纳米水合氧化铁复合吸附剂，有效结合了水合氧化铁颗粒优良的除磷能力与载体树脂突出的机械强度等特点，但有机物污染影响其在污水中重复利用。本项目利用FeCl4-离子交换-NaOH沉淀-热处理方法，将纳米HFO颗粒负载至丙烯酸系阴离子交换树脂。首先通过调控溶液浓度和混合方式制备复合吸附剂，揭示材料性能和吸附性能的变化规律，并筛选出最佳性能复合吸附剂。增加溶液浓度及混合时间利于水合氧化铁含量，但吸附容量随水合氧化铁增加呈先增加后下降趋势。阐明了投加量、pH、吸附时间、温度、无机阴离子和有机物等因素对复合吸附剂除磷的影响规律，随后建立响应面模型，确定了最佳除磷条件。利用FTIR、XPS及SEM-EDX等方法分析了吸附磷前后材料，阐明了复合吸附剂的磷吸附机理，复合吸附剂主要通过负载水合氧化铁的络合作用和载体树脂的静电作用吸附磷酸盐。揭示了有机物对复合吸附剂除磷的影响规律和机制，有机物与磷酸盐主要竞争载体树脂季铵基的吸附位点。通过考察复合吸附剂在重复利用时磷吸附和洗脱效果，探讨其抗有机物污染性能。优化固定床反应器运行参数，考察复合吸附剂处理二级出水时磷去除和洗脱效果、水合氧化铁含量及晶体结构等，验证了复合吸附剂在污水中长期重复利用的可行性和稳定性，表明了其在深度除磷领域具有良好的应用潜力。项目研究成果为污水深度除磷及水体富营养化控制提供了新思路。