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Groundwater is an important part of water resources. But the public problem is the high content of iron and manganese in most areas of our country, which seriously affect our living and industrial production. Also the manganese removal has always been a difficult problem in engineering. Recently, the more mature and widely used technology in the project is the contact oxidation process using manganese sand. But there are some shortcomings such as the long mature period, the higher cost of the aeration and higher requirement of temperature and pH value. In this experiment, the Mn2+removal effect, the mechanism and the preliminary application of the new filter, SiC, are studied.Treating the high manganese content water under the same condition, the Mn2+removal effect of the four usual kinds of filters, zeolites, activated carbon, manganese sand and SiC, are comparative analyzed:the Mn2+removal rate of SiC is the highest, reaching93.90%; the activated carbon and manganese sand take the second place, with the rate of45.74%and37.32%separately; the zeolites is the lowest, with the rate of0.10%. Otherwise, in the optimum adsorption conditions, the saturated SiC were regenerated by the acid, the alkali, the salt, the surface active agent and the organic solvent, whose results show that:the regeneration effect of the Na+containing compounds are the best, with the rate of more than114%; for the acid and FeCl3, Al2(SO4)3, the effect is poorer, with the rate of lower than50%; for NH4Cl2, the rate is100%, which is no inhibitory action on SiC regeneration; for HDTMA and alcohol, the rate is67.68%and106.00%, but the cost is higher. Through the SEM picture, the surface character of the four filters before and after saturated and the regenerated SiC by different reagents are analyzed in order to study the Mn2+removal mechanism by SiC. The core structure of activated carbon is most developed, whose adsorption capacity is also the strongest, so its Mn2+removal effect is better; the manganese sand and zeolites are less developed, and the removal effect is poorer; for SiC, the core structure is also less developed, the adsorption capacity is poorer, but its Mn2+removal effect is the best, just for its high ion exchange performance. But regenerated by Na+containing compounds such as NaOH and NaCl, there is no impurities jamming in SiC interior, with homogenous pore-size distribution and increasing porosity. There are more exchangeable groups on the SiC surface, which is favor for Mn2+adsorption.Combined with the test results above, two dynamic ways of back-flushing and soaking with NaOH are used for the saturated SiC regeneration. The results show that:the effect of regenerated by NaOH is obviously better than by back-flushing, with the stable rate in five regenerations and no obvious drop. The rate is still more than100%; but for the latter way, the rate is less than50%, losing Mn2+removal capacity just in the second time. The way of back-flushing alone cannot restore the Mn2+removal capacity of SiC. The Mn2+removal effect by the combination of manganese sand and SiC is compared with the traditional two-stage of manganese sand, which shows that:using manganese sand or SiC alone cannot achieve ideal effect. But the combination of the two filters can guarantee a long time and high efficiency in Mn2+removal. This provides a more economical and effective way for Mn2+and Fe2+removing in groundwater.
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