Efficiences and Mechanisms of Arsenic (As) Uptake from Aqueous Solution by Vivianite

为各种用途提供适当质量的可持续水资源是当前和未来社会面临的最大和最重要的挑战之一。在这种情况下，对饮用水的需求随着人口的增长而增加，并在气候改变水资源可获得性的时候变得更加发达，而这些资源的质量正因许多地区的过度使用而受到损害。此外，还有一个问题，即许多大型水资源的质量受到自然污染的影响。例如，许多为全世界数千万人提供唯一水源的缺氧湖、河流和地下水系统被砷(As)污染。饮用这些水可能会导致动物中毒，并导致人类黑色素沉着症、坏疽、癌症，最终导致死亡。这种情况在西孟加拉邦和孟加拉国得到了最好的说明，根据世界卫生组织的数据，这两个国家发生了世界上最严重的大规模中毒事件。显然，如果完全有可能补救问题，就不能允许这种情况继续下去。为此，如果矿物能够吸收和稳定潜在的有毒元素，如砷，那么它们可能提供一种解决方案。矿物蓝晶石[Fe3(PO4)2.8H2O]在这些缺氧环境(酸性矿坑、河流、湖泊、城市水体)中形成并稳定存在，初步的实验工作表明它可以吸收As，但其吸收能力和吸收机理尚不清楚。我们的项目将确定蓝晶石吸收砷的效率和机制，以便将其开发为缺氧、受砷污染的水系统的修复工具，从而保护人类和生态系统。这一目标将通过以下两个方面来实现：(1)通过间歇实验确定As3+和As5+在人造蓝晶石上的吸附效率；(2)用光谱学方法研究As3+和As5+在人造蓝晶石上的吸附机理。该项目直接属于NERC的优先领域“可持续经济--确定并提供可持续的解决方案，以应对与能源、土地利用和减灾相关的挑战”。这项研究的结果将被世界各地研究缺氧水系统污染的机理和解决方案的大量科学家和工程师使用，并有望为社会面临的最严重的自然灾害提供解决方案。这项研究将为进一步研究人造和天然蓝晶石，包括动力学和细菌对蓝晶石形成和砷吸收的影响奠定基础。

The provision of sustainable water resources of appropriate quality for various uses is one of the greatest and most important challenges facing society now and in the future. Within this context, demands on potable water are increasing as the human population grows and becomes more developed at a time when climate is changing the availability of water resources, and the quality of these resources is being undermined by overuse in many areas. Added to these is the problem that the quality of many large resources of water is compromised by natural contamination. For example, many anoxic lake, river and groundwater systems that provide the only sources of water for tens of millions of people worldwide are contaminated with arsenic (As). Consumption of these waters can lead to As toxicosis in animals, and to melanosis, gangrene, cancer and, ultimately, death in humans. Such a situation is best illustrated in West Bengal and Bangladesh, where, according to the World Health Organisation, there is the worst case of mass poisoning in the world. Obviously such a situation must not be allowed to continue if it is at all possible to remediate the problem. To this end, minerals may offer a solution if they are capable of uptaking and stabilizing potentially toxic elements such as As. The mineral vivianite [Fe3(PO4)2.8H2O] forms and is stable in these anoxic environments (acid mine drainage sites, rivers, lakes, urban water bodies), and initial experimental work shows that it can take up As, but its capacity for, and mechanisms of, uptake are not well understood. Our project will determine the efficiencies and mechanisms of uptake of As by vivianite so that it may be developed as a remediation tool in anoxic, As-contaminated water systems, thus protecting humans and ecosystems. This aim will be fulfilled by determining (1) the efficiency of sorption of As3+ and As5+ on synthetic vivianite by batch experiments, and (2) the mechanism of uptake of As3+ and As5+ on synthetic vivianite by spectroscopy. The project falls directly under NERC's priority area 'sustainable economies - identifying and providing sustainable solutions to the challenges associated with energy, land use and hazard mitigation'. The results of this study will be used by the large number of scientists and engineers worldwide studying the mechanisms of, and solutions to, As contamination of anoxic water systems, and, hopefully, offer a solution to the worst natural disaster facing society. The study will form the basis for further studies on synthetic and natural vivianite, including the influence of kinetics and bacteria on vivianite formation and As uptake.