| The iron and manganese concentrations are excess in our country's many water sources, especially in the groundwater of the key cities and regions in northeast, southwest, south china. The high content of iron and manganese in water is harmful to people's health, and may have adverse impacts on people's daily lives, water distribution system, industrial production and so on. Since the 50s of last century, a meaningful task for society and economy, about removal of iron and manganese from groundwater, had been established in our country. Its theories and applications had been developed from natural oxidation and contact catalytic oxidation to biological oxidation. However, it's one of the common water treatment technical problems to search a more economic and effective method for the removal of iron and manganese from water so far. Therefore, the removal of iron and manganese has been further discussed in this paper.Contact catalytic oxidation technology for removal of iron and manganese was primarily studied in the first section. The method tested successfully by academician Guibai Li in the 60s of 20th century, had been widely applied in engineering practices in our country. The practical results showed that it was effective for iron removal, while there were some problems on manganese removal. For example, when there were both iron and manganese in water, fast iron oxidation could interfere with manganese oxidation. Besides, it could take a long time to form the manganese oxides attached to the filtering media, and it had unstable effect of manganese removal owing to its easily interfering with outside factors. Based on previous studies, aerial contact catalytic oxidation for removing iron and manganese in aqueous and its influencing factors had been studied by model experiments about filtering. Quartz sand and manganese sand were chose as filter media, and their performances had been further tested through static experiments. Results indicate that some iron and manganese oxides that play an important role for removing iron and manganese in aqueous, could strongly attach to the surface of quartz sand and manganese sand by the operation increasing the hydraulic loadings and iron and manganese concentrations gradually. When the filtering velocity reaches a high value, iron and manganese concentrations at the filter outlet will increase with the increase of filtering velocity. Neutral and slightly acid or alkaline conditions are appropriate for contact catalytic oxidation. Organic substance in a certain range of concentration(TOC:1.39～4.93 mg/L) hardly affect the removal of iron and manganese. The removal rate of iron and manganese increases with the increase of dissolved oxygen in a certain range of concentration(3.84～7.88 mg/L). The Lagergren Second-order equation and the Langmuir adsorption isotherm could well describe the adsorption of Fe2+ and Mn2+ ions in aqueous by quartz sand and manganese sand attached with iron and manganese oxides. The percentages of adsorbed Fe2+ and Mn2+ ions increase with the increase of temperature, and are influenced with the competitive adsorption between Fe2+ and Mn2+ ions.The adsorption of Fe2+ and M2+ ions in aqueous by titanate nanowires was studied in the second section. Titanate nanowires were synthesized via a simple hydrothermal method using tetrabutyl titanate as the titanium source. The as-prepared products were characterized by scanning electron microscopy(SEM), powder X-ray diffraction(XRD) and transmission electron microscope(TEM). The adsorption behavior of Fe2+ and Mn2+ in aqueous by titanate nanowires was tested in a static system. The results indicate that titanate nanowires have a diameter of about 50-400nm and a length up to a few micrometers. The adsorption capacities of Fe(Ⅱ) and Mn(Ⅱ) by titanate nanowires in aqueous are 39.89 and 34.67 mg/g respectively (298 K, pH=6.68). The experimental data obtained are in good agreement with the Freundlich adsorption isotherm. The adsorption kinetics is well described by the Lagergren First-order equation. Besides, the adsorption percentages of Fe(Ⅱ) and Mn(Ⅱ) increase with the increase of the value of pH (during the experimental range of 4.05 to 8.45) and the dosage of titanate nanowires.
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