Angewandte Geologie, Universität Göttingen, Göttingen, Germany.
J Hazard Mater. 2010 Sep 15;181(1-3):1170-4. doi: 10.1016/j.jhazmat.2010.05.085. Epub 2010 May 25.
The further development of Fe(0)-based remediation technology depends on the profound understanding of the mechanisms involved in the process of aqueous contaminant removal. The view that adsorption and co-precipitation are the fundamental contaminant removal mechanisms is currently facing a harsh scepticism. Results from electrochemical cementation are used to bring new insights in the process of contaminant removal in Fe(0)/H(2)O systems. The common feature of hydrometallurgical cementation and metal-based remediation is the heterogeneous nature of the processes which inevitably occurs in the presence of a surface scale. The major difference between both processes is that the surface of remediation metals is covered by layers of own oxide(s) while the surface of the reducing metal in covered by porous layers of the cemented metal. The porous cemented metal is necessarily electronic conductive and favours further dissolution of the reducing metal. For the remediation metal, neither a porous layer nor a conductive layer could be warrant. Therefore, the continuation of the remediation process depends on the long-term porosity of oxide scales on the metal surfaces. These considerations rationalized the superiority of Fe(0) as remediation agent compared to thermodynamically more favourable Al(0) and Zn(0). The validity of the adsorption/co-precipitation concept is corroborated.
铁基修复技术的进一步发展取决于对水相污染物去除过程中涉及的机制的深刻理解。目前，吸附和共沉淀被认为是基本的污染物去除机制，这一观点正面临着严峻的质疑。电化学胶结的结果为铁/水系统中污染物去除过程带来了新的认识。水冶胶结和基于金属的修复的共同特点是，在表面结垢的存在下，不可避免地会发生多相过程。这两个过程的主要区别在于，修复金属的表面被自身氧化物层覆盖，而还原金属的表面被胶结金属的多孔层覆盖。多孔胶结金属必然具有导电性，并有利于还原金属的进一步溶解。对于修复金属，既不可能有多孔层，也不可能有导电层。因此，修复过程的持续取决于金属表面氧化层的长期多孔性。这些考虑合理化了铁作为修复剂相对于热力学上更有利的铝和锌的优势。吸附/共沉淀概念的有效性得到了证实。
