| This study prepared different types of nano-crystal manganese dioxidesα-MnO2,β-MnO2 andδ-MnO2, and the adsorption of Arsenite (As (Ⅲ)), Arsenate (As(Ⅴ)), Monomethylarsonous acid (MMA), Dimethylarsinic acid (DMA) byα-MnO2,β-MnO2 andδ-MnO2 was studied. Based on analysis of the existing methods of arsenic removal, this research presented an arsenic removal method classified as pre-oxidation and adsorption technology. The study prepared a new adsorbent with potassium permanganate, manganese sulfate, and ammonium persulfate as main raw materials, and this adsorbent can function as pre-oxidation and adsorption at the same time and remove various forms of arsenic from water. The experiments investigated the conditions of arsenic removal by this new arsenic removal adsorbent. The experiments of arsenic removal by static adsorption were conducted, and the effect and influence factors of the arsenic removal were discussed. The results showed that water of 1.0mg/L As can be effectively reduced to below 0.01mg/L by nano-manganese dioxide, which is the drinking water health standard in China. The adsorption process is affected by pH, temperature, initial arsenic concentration and time period. Compared with other arsenic removal adsorbents, the nano-crystal manganese dioxides achieve good removal effect. Adsorption kinetics study shows that:the absorption of various forms of arsenic byα-MnO2,β-MnO2 andδ-MnO2 is in accordance with Langmuir Adsorption Isotherm.α-MnO2 is the best in various forms of arsenic removal, andα-MnO2 can reduce water of 2.0mg/L As to below 0.01mg/L. The maximum adsorption capacity of As (Ⅲ), As (Ⅴ), MMA, DMA respectively are 103.09mg/g,106.38mg/g,92.59mg/g and 95.24mg/g.The experimental studies have shown that nano-manganese dioxide method for arsenic removal has the advantages of high removal efficiency, easy-to-prepare reactants, and rapid removal process. Nano-manganese dioxide method for arsenic removal is a prospective removal method of arsenic in drinking water.
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