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Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Acid-modified natural magnetite shows excellent arsenic removal properties due to its change in specific surface area and internal structure. It is essential to study further its adsorption to arsenic in water， in order to provide data for practical engineering applications. The feature of arsenic adsorption by modified magnetite immersed in 0.5 mol/L hydrochloric acid and ignited for 10 minutes at 150°C, and the construction of its adsorption rate curve chart is described in this paper. Results of the experiment on adsorption influencing factors indicate that when initial pH value are 6 - 9, magnetite shows strong adsorption property. Ions such as Cl-, Ca2+, Mg2+, HCO3-, CO32- do not have competitive adsorption with As( III ) and As( V ) , but PO43- , NO3-, and SO42- have competitive adsorption with As ( III ), in the order of PO43- > SO42- > NO3-. PO43- and NO3- have competitive adsorption with As ( V ). In combination with XRD, SEM, and preliminarily studies show the arsenic removal mechanism of modified magnetite, and conclude that modified magnetite shows an obviously increased specific surface area and that Fe( II ) and Fe( III ) contained in its surface products are the main cause for improving arsenic adsorption ability. Experimental results natural magnetite is a de-arsenic material for water, which deserves further study and practical application. [ABSTRACT FROM AUTHOR]

Iron oxides and their complex oxides such as siderite and ferrihydrite have high surface charge and specific surface area, which have strong binding capacity and affinity for arsenite and arsenate under specific conditions. Natural magnetite, mainly consisting of Fe3O4, has low activity itself, and is not efficient for direct treatment of high arsenic water. Reported in this paper, natural magnetite is modified by acidification, alkalization, and calcined at different temperatures for different periods, in order to enhance arsenic removal from water. Experimental results show that the modified magnetite acidified in 0.5 mol/L hydrochloric acid and calcined at 150℃ for 10 min, has high removal efficiencies for both As(Ⅲ) and As(Ⅴ). Removal efficiency was 98% for As(Ⅴ), whereas the removal efficiency was 75% for As(Ⅲ) with concentration decreases from 1000 μg/L to 250 μg/L (in Fig. 2). The modified natural magnetite has stronger adsorption capacity for As than natural magnetite, and is identical to other modified iron minerals. In addition, the modification method is simple and convenient. Therefore, the modified natural magnetite would be a potential adsorbent for controlling arsenic content in high arsenic water. [ABSTRACT FROM AUTHOR]