几种铁（氢）氧化物对溶液中磷的吸附作用对比研究

铁(氢)氧化物不仅是土壤中广泛存在的矿物,也是重要的矿物资源。表生地质作用形成的针铁矿、赤铁矿和无定形氢氧化铁都具有纳米尺度,具有很高的表面积,表现出对磷的专性吸附,是低浓度磷的潜在吸附材料。本文通过铁(氢)氧化物对水溶液中磷酸根的等温吸附实验,初步对比研究了针铁矿、合成氧化铁黄、赤铁矿和无定形氢氧化铁对水中低浓度磷的吸附作用。结果表明,无定形氢氧化铁对水溶液中磷酸根的吸附能力最强(对低浓度磷的吸附达到5.5mg/g),其次是氧化铁黄和针铁矿,赤铁矿的吸附能力最差。几种铁(氢)氧化物对磷吸附容量的差别主要受比表面积控制。无定形氢氧化铁、合成氧化铁黄、针铁矿、赤铁矿对磷的吸附符合Freundlich等温方程。针铁矿和赤铁矿对磷的吸附动力学符合双常数速率方程。

A comparison of phosphate adsorption capacity between different iron hydroxides/oxides

Iron hydroxides/oxides widely existent in soil can serve as important mineral resources.Goethite,hematite and amorphous ferrihydrite generated in surface of the earth all assume nanometer particle size,have high specific surface area and perform specific adsorption capacity for phosphate,thus being potential adsorbents for low concentration phosphate in water.The adsorption of goethite,hematite and amorphous ferrihydrite for phosphate was studied through the isothermal adsorption experiment.The results indicate that amorphous ferrihydrite performs the strongest adsorption capacity for phosphate(5.5 mg/g minerals),followed by goethite,and hematite has the smallest adsorption capacity.Isothermal adsorption of phosphate on goethite,hematite and amorphous ferrihydrite is in accordance with the Freundlich equation.The time-dependent phosphate adsorption data are consistent with the Bangham equation.