ABSTRACT We report the effect of the synthesis route of starch-functionalized magnetite nanoparticles (NPs) on their adsorption properties of As(V) and As(III) from aqueous solutions. NP synthesis was achieved by two different routes implying the alkaline precipitation of either a mixed Fe2+/Fe3+ salt solution (MC samples) or a Fe2+ salt solution in oxidative conditions (MOP samples). Syntheses were carried out with starch to Fe mass ratio (R) ranging from 0 to 10. The crystallites of starch-free MC NPs (14 nm) are smaller than the corresponding MOP (67 nm), which leads to higher As(V) sorption capacity of 0.3 mmol gFe−1 to compare with respect to 0.1 mmol gFe−1 for MOP at pH = 6. MC and MOP starch-functionalized NPs exhibit higher sorption capacities than a pristine one and the difference in sorption capacities between MOP and MC samples decreases with increasing R values. Functionalization tends to reduce the size of the magnetite crystallites and to prevent their agglomeration. Size reduction is more pronounced for MOP samples (67 nm (R0) to 12 nm (R10)) than for MC samples (14 nm (R0) to 9 nm (R10)). Therefore, due to close crystallite size, both MC and MOP samples, when prepared at R = 10, display similar As(V) (respectively, As(III)) sorption capacities close to 1.3 mmol gFe−1 (respectively, 1.0 mmol gFe−1). Additionally, according to the effect of pH on arsenic trapping, the electrostatic interactions appear as a major factor controlling As(V) adsorption while surface complexation may control As(III) adsorption.

中文翻译：

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淀粉官能化磁铁矿纳米粒子对 As(V) 和 As(III) 的螯合：合成路线对捕集效率的影响

摘要 我们报告了淀粉官能化磁铁矿纳米颗粒 (NPs) 的合成路线对其从水溶液中吸附 As(V) 和 As(III) 性能的影响。NP 合成是通过两种不同的途径实现的，这意味着混合 Fe2+/Fe3+ 盐溶液（MC 样品）或氧化条件下的 Fe2+ 盐溶液（MOP 样品）的碱性沉淀。合成是在淀粉与铁的质量比 (R) 范围从 0 到 10 的情况下进行的。无淀粉 MC NPs (14 nm) 的微晶小于相应的 MOP (67 nm)，这导致更高的 As(V) 0.3 mmol gFe-1 的吸附能力与 pH = 6 时 MOP 的 0.1 mmol gFe-1 相比。MC 和 MOP 淀粉官能化的 NPs 表现出比原始的更高的吸附能力，并且 MOP 和 MC 样品之间的吸附能力差异随着 R 值的增加而减小。官能化倾向于减小磁铁矿微晶的尺寸并防止它们团聚。MOP 样品（67 nm (R0) 至 12 nm (R10)）的尺寸减小比 MC 样品（14 nm (R0) 至 9 nm (R10)）更明显。因此，由于微晶尺寸相近，当在 R = 10 下制备时，MC 和 MOP 样品显示出相似的 As(V)（分别为 As(III)）吸附容量，接近 1.3 mmol gFe-1（分别为 1.0 mmol gFe -1). 此外，根据 pH 值对砷捕获的影响，静电相互作用是控制 As(V) 吸附的主要因素，而表面络合可能控制 As(III) 吸附。