Polymers with hydroxyl groups may have great influence on the formation process of metal oxides due to complexation. To better study the interaction mechanism between polyhydric polymer and iron (hydr)oxide, herein, without using surfactants or toxic matters, 3D hierarchical iron (hydr)oxide with different nanostructures were obtained with the assistance of polyvinyl alcohol (PVA). The influences of PVA concentration, temperature, and reaction time on the product structure were investigated. Then, the formation mechanisms are discussed. Under different PVA concentrations and temperature, varies products were obtained, such as α-FeOOH, α-Fe₂O₃, and their mixtures. On increasing the PVA concentrations, the material morphology changes from flower-like nanostructures to urchin-like microspheres and finally into nanoplates. Furthermore, an increase in reaction temperature would lead to the formation of microspheres with a smoother surface. The urchin-like α-FeOOH obtained at a moderate PVA condition has the best adsorption performance for Congo red with a maximum adsorption capacity of 287.35 mg g⁻¹, which was a great improvement when compared to that of the sample obtained from pure water (173.01 mg g⁻¹). The results reflect the potential advantages of the polymer applied for the structural improvement of nanomaterials.

中文翻译：

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PVA辅助自组装3D分层氧化铁的结构研究†

带有羟基的聚合物可能由于络合作用而对金属氧化物的形成过程产生重大影响。为了在不使用表面活性剂或有毒物质的情况下更好地研究多元聚合物与氧化铁（氢）的相互作用机理，借助于聚乙烯醇（PVA）获得了具有不同纳米结构的3D分级氧化铁（氢）。研究了聚乙烯醇浓度，温度和反应时间对产物结构的影响。然后，讨论了形成机理。下不同PVA浓度和温度，不同的产品获得，如α-的FeOOH，的α-Fe ₂ ö ₃，以及它们的混合物。随着PVA浓度的增加，材料的形态从花状纳米结构变为海胆状微球，最后变为纳米板。此外，反应温度的升高将导致形成具有更光滑表面的微球。在中等PVA条件下获得的类海胆状α-FeO​​OH对刚果红具有最佳的吸附性能，最大吸附容量为287.35 mg g ^-1，与从纯水制得的样品相比具有很大的改进（ 173.01mg g ^-1）。结果反映了聚合物用于纳米材料结构改进的潜在优势。