Under microwave solvent free conditions, bare iron magnetic nanoparticles (Fe₃O₄-MNPs) have been silica coated, amine functionalized and gallic acid grafted, in presence and absence of tetraethylorthosilicate (TEOS). The synthesized adsorbents in both cases have been followed up by Fourier transform infrared, scan electron microscopy and transmission electron microscopy analyses to verify and compare the progress of surface modification. The effects of various parameters on the adsorption efficiency of Fe(III) such as pH of solution, amount of adsorbent and contact time have been studied and optimized. The adsorbents Fe₃O₄-MNPs-SiO₂-CPTMS-1,2-EDA-GA and MNPs-CPTMS-1,2-EDA-GA exhibit higher Fe(III) capacities (4.980 and 4.700 mmol/g) than their analogous Fe₃O₄-MNPs-SiO₂-APTMS-GA and Fe₃O₄-MNPs-APTMS-GA (4.324 and 4.230 mmol/g). The studies of sorption kinetics showed rapid sorption dynamics by a second-order kinetic model, suggesting chemisorption mechanism. Fe(III) adsorption equilibrium data have been fitted well to the Langmuir isotherm. The results of medium stability as criteria for potential coating and values of metal uptake capacity support the possibility of the direct use of alkoxysilanes as an alternative to TEOS not only for coating but also for amine functionalization. This is strengthened by almost equal capability of gallic acid anchored adsorbents for extraction of trace concentrations of Fe(III) spiked natural water samples.

中文翻译：

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微波辐射下两种途径合成的没食子酸锚固铁磁性纳米吸附剂对Fe（III）的吸附去除

在无微波溶剂的条件下，在存在和不存在原硅酸四乙酯（TEOS）的情况下，已对裸铁磁性纳米粒子（Fe ₃ O ₄ -MNP）进行了二氧化硅涂层，胺官能化和没食子酸的接枝。两种情况下合成的吸附剂都进行了傅里叶变换红外光谱，扫描电子显微镜和透射电子显微镜分析，以验证和比较表面改性的进展。研究和优化了各种参数对Fe（III）吸附效率的影响，例如溶液的pH值，吸附剂的量和接触时间。吸附剂Fe ₃ O ₄ -MNPs-SiO ₂-CPTMS-1,2-EDA-GA和MNPs-CPTMS-1,2-EDA-GA比其类似的Fe ₃ O ₄ -MNPs-SiO _2-具有更高的Fe（III）容量（4.980和4.700 mmol / g）。 APTMS-GA和Fe ₃ O ₄-MNPs-APTMS-GA（4.324和4.230 mmol / g）。吸附动力学的研究表明通过二级动力学模型快速吸附动力学，表明化学吸附机理。Fe（III）吸附平衡数据已经很好地拟合到Langmuir等温线。中等稳定性的结果作为潜在涂层的标准和金属吸收能力的值，证明了不仅可用于涂层而且还可用于胺官能化，直接使用烷氧基硅烷作为TEOS的替代品。没食子酸锚定的吸附剂对痕量的Fe（III）加标的天然水样品的萃取几乎具有相同的功能，从而加强了这一点。