The use of 'waste' Mn oxides as contaminated land remediation products

土地是一种宝贵但有限的资源。环境局估计，英国约有30万公顷土地在某种程度上受到工业活动留下的污染的影响，在全球范围内，问题的程度要大得多，因为受污染的土地与贫困有着千丝万缕的联系。在英国，对新住房的需求不断增加，加上政府的目标是在棕地上实现60%或更多的新住房，这使得就地修复受污染土地的技术成为优先领域。目前领先的补救技术往往要么无法处理金属和持久性有机污染物(持久性有机污染物)混合的“鸡尾酒”场地，要么无法成为具有成本效益和可持续的技术。如果被证明是可行的，所提议的技术没有这些缺点。因此，它可以在国际土地补救部门占有非常强大和有利可图的市场份额。我们正在使用一种目前被视为‘废物’的材料作为补救产品，这一事实使商业可行性变得更加复杂。最近欧盟垃圾填埋场指令的出台也对欧洲受污染土地的修复产生了巨大的影响，人们对开发新的具有成本效益的就地修复棕地场地的方法越来越感兴趣。锰(锰)氧化物自然存在于土壤中，部分解释了土壤降解和隔离污染物的天然能力。锰氧化物是一种强大的氧化剂，既能固定两种金属，又能促进POPs的就地降解。在这个项目中，我们将研究是否可以通过添加额外的氧化锰来增强这种自然防御机制，以及这对土壤有任何积极和消极的影响。由于锰氧化物还能刺激土壤中的腐殖化速率，因此有可能加强碳的固存，改善土壤的整体健康状况。这个项目将通过一系列因素设计的实验来研究氧化锰的潜在有益作用(金属固定、POP固定和土壤有机质腐殖化)是如何相互作用的。光谱分析技术的使用将提供机制信息，以评估锰氧化物修复受污染土地的长期潜力，从而评估土壤中天然锰氧化物的作用。达勒姆大学已经确定了数十万吨目前没有市场的高活性锰氧化物“废物”(Johnson等人，2006年)。达勒姆大学最近的工作在这些纯锰氧化物吸附特定持久性有机污染物(PAHs)的潜力方面取得了非常有希望的结果。该项目建议在这项工作的基础上，彻底调查在这些天然矿物表面运行的基本过程，以及这些过程如何在真实土壤和不同环境条件下竞争活性矿物表面。我们的目标是用光谱技术研究这些污染物分解和固定的机制。这项工作的新颖性在于调查了锰氧化物作为修复产品的潜在用途，这些产品能够处理具有挑战性的“鸡尾酒”场所。如果该项目证明，氧化锰可以为这些“鸡尾酒”场地提供单一的解决方案，那么这项技术的应用市场就相当可观，仅英国的污染土地修复市场就价值10亿英镑。

Land is a valuable but finite resource. The Environment Agency estimates that there are approximately 300,000 hectares of land in the UK affected to some extent by contamination left by industrial activity and worldwide, the extent of the problem is much greater as contaminated land is inextricably linked to poverty. In the UK, the increasing demand for new housing coupled with the Government targets of achieving 60% or more of new homes on brownfield land have made in situ techniques for contaminated land remediation a priority area. Current leading remediation technologies often fail either to deal with 'cocktail' sites where there are mixtures of metals and Persistent Organic Pollutants (POPs) and/or be cost-effective and sustainable technologies. If demonstrated to be viable, the technology proposed has none of these failings. As such it could command a very powerful and lucrative market share of the international land remediation sector. Commercial viability is compounded by the fact that we are using a material currently considered as a 'waste' as a remediation product. The recent introduction of the EU Landfill Directive also has huge implications for the remediation of contaminated land in Europe and there is increasing interest in the development of new cost effective in situ methods to remediate brownfield sites. Manganese (Mn) oxides occur naturally in soils and explain in part soil's natural ability to degrade and sequester contaminants. Mn oxides are powerful oxidising agents capable of both immobilising both metals and enhancing the degradation of POPs in situ. In this project we will investigate if this natural defence mechanism can be enhanced by adding extra Mn oxide and any positive and negative effects this has on the soil. Since Mn oxides also stimulate humification rates in soils there is the potential for enhancing carbon sequestration and improving general soil health. This project will investigate how the potential beneficial actions of Mn oxides (metal immobilisation, POP immobilisation and humification of Soil Organic Matter, SOM) interact via a series of factorially designed experiments. The use of spectroscopic analytical techniques will provide mechanistic information to assess the long term potential for Mn oxides to remediate contaminated land and therefore the role of natural Mn oxides in the soil.Durham University have identified hundreds of thousands of tonnes of highly reactive Mn oxide 'wastes' which currently have no market (Johnson et al, 2006). Recent work at Durham has produced very promising results on the potential of these pure Mn oxides to sorb specific POPs (PAHs). This project proposes building on this work with a thorough investigation into the fundamental processes operating at the surface of these natural minerals and how these processes compete for reactive mineral surface in real soils and under different environmental conditions. We aim to study these mechanisms of contaminant breakdown and immobilisation using spectroscopic techniques. The novelty in the work lies in investigating the potential use of Mn oxides as remediation products capable of treating the challenging 'cocktail' sites. If this project proves that Mn oxide could provide a single solution for these 'cocktail' sites, the markets for application of this technology are considerable with the contaminated land remediation market in the UK alone valued at >1bn.