三维花状结构α-FeOOH纳米材料的制备与表征

以硫酸亚铁、尿素及乙醇为原料,采用低温常压一步回流法制备了具有三维花状结构的α-FeOOH纳米材料.考察了反应时间、反应温度、尿素浓度和乙醇用量对其结构和形貌的影响及α-FeOOH纳米材料对双氯芬酸钠的吸附性能.实验结果表明,当反应温度为90℃、反应时间为6 h、尿素浓度为0.1 mol/L、乙醇的体积分数为20%时,所得α-FeOOH纳米材料具有规整的三维花状结构,对双氯芬酸钠的吸附量达199.2mg/g.基于扫描电子显微镜(SEM)和X射线衍射(XRD)分析,推断三维花状结构α-FeOOH的生长机制包括定向聚集和外延生长2个过程,反应初期生成的高活性晶核快速形成不规则橄榄状颗粒并定向聚集成短簇状结构,再沿z轴方向外延生长,形成长簇的三维花状结构.

Synthesis and Characterization of 3D Flower-like α-FeOOH Nanostructures

3D flower-like α-FeOOH nanoparticles were synthesized by means of mild-temperature reflux method, and the samples were characterized via X-ray diffraction(XRD) and scanning electron microscopy(SEM). The influencing factors such as the reaction time, the reaction temperature, the concentration of urea, and the amount of ethanol were systematically investigated. The adsorption capacity of the α-FeOOH nanoparticles for diclofenac sodium was also tested. The results show that the sample prepared with 0.1 mol/L urea and 20%(volume fraction) ethanol at 90 ℃ for 6 h is in high structural uniformity with good crystal quality and has the best adsorption capactity of 199.2 mg/g for diclofenac sodium. The formation mechanism of the flower-like α-FeOOH nanostructures is involved with a combination of oriented attachment and epitaxial overgrowth. The fresh nanonuclei are formed in solution at the early reaction stage with high surface energy, then aggregate together to minimize the interfacial energy. The olive-like agglomerates orient into short clusters, continue to grow along z axis till the complete flower-like structures are formed.