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采用液相沉积的方法将磷酸铁包覆在纳米Fe3O4颗粒表面,成功制备了具有超顺磁性的吸附剂,并用于水中微量Cr(Ⅲ)的富集.通过振动样品磁强计、X射线衍射、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、Zeta电势和激光动态光散射等对Fe3O4磁性纳米粒子进行了形貌表征,研究了该吸附剂在不同的pH值、吸附时间及溶液体积对Cr(Ⅲ)的吸附效率.结果表明在pH=5.3温度为25℃时,0.0200 g吸附剂可使体积为20.0 mL 20.0μg L-1Cr(Ⅲ)定量吸附,吸附等温线符合Freundlich模型,吸附动力学过程符合假二级动力学方程.该吸附剂适合大体积试样中极微量Cr(Ⅲ)的富集,对800 mL浓度为0.5μg L-1的Cr(Ⅲ)吸附率可达80%以上,富集倍数可达1125倍,可以满足痕量分析的要求.该吸附剂可以回收使用,重复使用10次,吸附率仍能达到95%.
The iron phosphate was coated on the surface of nano-Fe3O4 particles by liquid-phase deposition, and the superparamagnetism adsorbent was successfully prepared for the enrichment of trace Cr (Ⅲ) in water.The samples were characterized by X-ray diffraction , Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, Zeta potential and laser light scattering were used to characterize the magnetic properties of Fe3O4 magnetic nanoparticles. The effects of pH, adsorption time and solution volume The adsorption efficiency of Cr (Ⅲ) on Cr (Ⅲ) was investigated.The results showed that the adsorption capacity of 20.0μg L-1Cr (Ⅲ) was adsorbed by 0.0200 g adsorbent at pH = 5.3 and the adsorption isotherm was in accordance with the Freundlich model. The kinetic process accords with the pseudo-second-order kinetic equation. The adsorbent is suitable for the enrichment of trace Cr (Ⅲ) in large volume samples. The adsorption rate of Cr (Ⅲ) to 800 mL 0.5μg L- %, Enrichment factor up to 1125 times, to meet the requirements of trace analysis.The adsorbent can be recycled, reused 10 times, the adsorption rate can still reach 95%.