Adsorption of phosphorus pollutant from water and wastewater by ferrihydrite-modified diatomite

本研究项目旨在进一步了解我前期工作开发的一种高效磷吸附材料--高铁酸盐改性聚碳酸酯（FHMD）的作用机理，探索这种新型吸附剂成功应用于去除和稳定湖泊水体中磷污染物的方法和条件。溶解性磷污染物是浮游植物生长的限制性营养盐，因此是地表水体中浮游植物生长和富营养化的主要决定因素。由于城市和工业废水的各种点源以及农业和城市径流的非点源的溶解磷排放，内陆湖泊和河流的富营养化已成为加拿大和许多其他国家水环境质量的最严重威胁之一。它会严重影响水的使用。为缓解水体富营养化，必须开发切实可行的除磷技术。推荐采用吸附法除磷，因为它在湖泊中易于操作。在我以前的研究中开发的FHMD是通过含Si的水铁矿沉积到粘土的孔隙中形成的。FHMD是一种有效的磷吸附剂，因为它具有211平方英尺的Brunauer-Emmett-Teller比表面积。m/g，对磷的吸附容量为37. 3 mg-P/g。FHMD的磷吸附能力显著大于其它常规低成本吸附剂。为了获得最佳的吸附容量，同步辐射X射线吸收近边结构光谱（XANES）已被用来优化条件，以合成具有最少的结晶水铁矿和最大的比表面积的FHMD。FHMD作为一种高效、环保的磷吸附剂，可应用于湖泊富营养化治理。将在富营养化湖泊中进行湖泊封闭实验，以评估吸附过程的性能并估计FHMD的成本效益。

This research project is to further understand the mechanisms of an efficient phosphorus adsorbent material known as ferrihydrite-modified diatomite (FHMD) developed in my previous work and explore the ways and conditions for successful field application of this novel adsorbent for removal and stabilization of phosphorus pollutant in lake water.**Dissolved phosphorus pollutant is the growth limiting nutrient and therefore is the main determinant in phytoplankton growth and eutrophication in surface water bodies. As the results of dissolved phosphorus discharge from various point sources of municipal and industrial wastewater effluents and non-point sources of agricultural and urban runoff, eutrophication in inland lakes and streams has become one of the most serious threats to water environmental quality in Canada and many other countries. It can significantly impair water use. A feasible technology for removing phosphorus pollutant from water must be developed to alleviate the eutrophication. The phosphorus removal via adsorption process is recommended because it can be operated easily in lakes.**FHMD developed in my previous research is formed through the deposition of Si-containing ferrihydrite into pores of diatomite. FHMD is an efficient phosphorus adsorbent because it has a Brunauer-Emmett-Teller specific surface area of 211 sq. m/g and has a phosphorus adsorption capacity of 37.3 mg-P/g. The phosphorus adsorption capacity of FHMD is substantially greater than other conventional low-cost adsorbents. In order to obtain the optimum adsorption capacity, synchrotron X-ray absorption near edge structure spectroscopy (XANES) has been employed to optimize the conditions to synthesize FHMD with the least crystalline ferrihydrite and the largest surface area. As an efficient and environmentally safe phosphorus adsorbent, FHMD can be applied to lake eutrophication control. Lake enclosure experiments will be conducted in a eutrophic lake to evaluate performance of the adsorption process and estimate cost benefits of FHMD.**