Review of the hydrolysis of iron(III) and the crystallization of amorphous iron(III) hydroxide hydrate
Review of the hydrolysis of iron(III) and the crystallization of amorphous iron(III) hydroxide hydrate
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DOI：
10.1002/jctb.280460204
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发表时间：
2007-04
影响因子：
3.4
通讯作者：
R. M. Cornell;R. Giovanoli;W. Schneider
中科院分区：
文献类型：
--
作者：
R. M. Cornell;R. Giovanoli;W. Schneider
三价铁溶液的水解最初导致单核和双核物种，其相互作用以产生更高核性的进一步物种。这些多核物质最终老化为结晶化合物或无定形沉淀物（无定形氢氧化铁（III）水合物）。无定形氢氧化铁（III）水合物是化学不稳定的，并逐渐转化为α-FeO（OH）和α-Fe 2 O3。这些结晶产物通过竞争机制形成，并且每种在最终产物中的比例取决于形成的相对速率。控制这些化合物形成速率的主要变量是pH值。其他重要因素是温度和添加剂的存在。大多数添加剂延缓转变，并通过抑制α-FeO（OH）的形成导致产物中α-Fe 2 O3的量增加;某些添加剂还直接促进后者化合物的形成。在α-FeO（OH）和α-Fe_2O_3晶格中，金属离子可以取代一定比例的Fe。在足够高的浓度下，它们可以诱导形成额外的相。添加剂也可以改变结晶产物的形态。
Hydrolysis of ferric solutions leads initially to mono- and dinuclear species which interact to produce further species of higher nuclearity. These polynuclear species age eventually to either crystalline compounds or to an amorphous precipitate (amorphous iron(III) hydroxide hydrate). Amorphous iron(III) hydroxide hydrate is thermodynamically unstable and gradually transforms to α-FeO(OH) and α-Fe2O3. These crystalline products form by competing mechanisms and the proportion of each in the final product depends on the relative rates of formation. The master variable governing the rates at which these compounds form is pH. Other important factors are temperature and the presence of additives. Most additives retard the transformation and by suppressing formation of α-FeO(OH) lead to an increase in the amount of α-Fe2O3 in the product; some additives also directly promote formation of the latter compound. Metal ions can oftxen replace a proportion of Fe in the α-FeO(OH) and α-Fe2O3 lattices. At high enough concentrations they can induce formation of additional phases. Additives may also modify the morphology of the crystalline products.