Synthesis and characterization of iron oxide nano-minerals

• Main Authors: Fu-AnLi, 李馥安
• Other Authors: Yen-Hua Chen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/47281992798072992103

碩士 === 國立成功大學 === 地球科學系碩博士班 === 98 === In this study, the iron oxide nano-minerials ( magnetite、maghemite、hematite、ilmenite and goethite）are synthesized using a sol-gel and co-precipitation method. We want to synthesize different particle sizes of iron oxide nano-minerials to investigate the effect of particle size on the photocatalytic activity and heavy metal adsorption. From the XRD pattern, it is observed that we can successfully synthesize different particle sizes of nano-minerals, and they have a pure crystalline phase except nano-ilmenite. TEM images also show the particle sizes of all the nano-minerals are in the nano-scale, and they are a little aggregated except nano-hematite. The BET results exhibit a higher specific surface area with a smaller particle size of nano-minerals. The SQUID result shows the coercivity field, and the ratio of remnants of magnetic moment and saturated magnetic moment would be affected by the particle size. It is also found that the band gap of nano-minerals belongs to the range of visible light. It is observed that the Cu2+ adsorption seems favorable for a higher pH condition, and the surface area is the key factor to influence the adsorption activity. Furthermore, the Cu2+ adsorption behavior of all the nano-minerals are well fitted to the pseudo-second order equation and it belongs to Langmuir isotherm. The photocatalytic activity under UV-light irradiation suggests that a higher surface area and higher absorbance of nano-minerals would own a higher photocatalytic efficiency. The photodegradation under Vis-light irradiation is dependent on the factors of surface area and absorbance of vis-light. Therefore, these findings indicate that iron oxide nano-minerials are effective materials for Cu2+ removal and, together with its photocatalytic activity, may be applied in the environmental treatment. Keywords: magnetite、maghemite、hematite、ilmenite、goethite、adsorption、photocatalysis.