作　　者： ; ; ; ;

机构地区： 南京农业大学资源与环境科学学院环境工程系

出　　处： 《环境科学学报》 2011年第3期460-467,共8页

摘　　要： 羟基硫酸铁矿物Schwertmannite(简称施氏矿物)作为一种新型环境矿物材料对重金属的迁移和钝化有重要作用.借助X射线衍射(XRD)、电镜扫描(SEM)、离子色谱(Ic)及比表面积测定仪(BET)等方法对H2O2氧化亚铁(化学法)和氧化亚铁硫杆菌氧化亚铁(生物法)合成的矿物成分、结构和比表面积进行了分析与表征,同时对As(Ⅲ)吸附性能进行了研究.结果表明,两种方法合成矿物均为纯施氏矿物.化学法合成的黄棕色矿物产量在24h达到稳定,总铁沉淀率为43.1%;生物法合成的红棕色矿物产量在48～60h达到稳定,总铁沉淀率为36.7%,对应化学式为Fe8O8(OH)3.78(SO4)2.11和Fe8O8(OH)4.06(SO4)1.97.生物合成施氏矿物颗粒均匀、分散性好、且矿物比表面积(45.63m2.g-1)远远高于化学合成(3.17m.2g-1).吸附试验表明,在本试验条件下(pH=7,25℃),生物合成矿物吸附As(Ⅲ)的效果明显优于化学合成矿物,当As(Ⅲ)浓度为1、10和30mg·L-1时,生物合成矿物对As的去除率分别为97.83%、85.96%与61.49%,而化学合成矿物的去除率为95%、62.96%与41.97%. An amorphous ferric hydroxysulfate named schwertmannite,as a novel material,has played an important role in transference and passivation of toxic heavy metals. In this study,schwertmannite was synthesized by two different procedures：chemical oxidation of ferrous iron by H2O2 and bacterial oxidation of ferrous iron by resting Acidithiobacillusferrooxidans cells in ferrous sulfate solution. The components,structures and surface areas of the minerals were analyzed and characterized by XRD,SEM,Ic and BET. In addition,the adsorption of As（Ⅲ） by schwertmannite was also studied at pH=7 and 25 ℃. The results showed that the synthetic minerals made through both methods were pure schwertmannites. In the chemosynthesis system,about 43.1% of the ferrous iron was transformed into a yellow-brown precipitate after 24 h of reaction,while in the biosynthesis system,it took 48~60 h for 36.7% of the ferrous ions to transform into a red-brown precipitate. Their chemical formulas could be expressed as Fe8O8（OH）3.78（SO4）2.11 for the chemosynthetic schwertmannite and Fe8O8（OH）4.06（SO4）1.97 for the biosynthetic schwertmannite. Although bacterial oxidation required more time to synthesize precipitates,the physiochemical properties of the precipitate were better than that formed by chemosynthesis. For example,the specific surface area was 45.63 m2·g-1 for the biosynthetic schwertmannite,while only 3.17 m2·g-1 for the chemosynthetic one. Adsorption experiments indicated that at pH=7.0 and 25 ℃,schwertmannite synthesized by the biological procedure exhibited a larger adsorption capacity for As（Ⅲ） than that produced by chemosynthesis. When As （Ⅲ） concentrations in water were 1,10 and 30 mg·L-1,their removal efficiencies through adsorption by schwertmannite reached 97.83%,85.96%,and 61.49% for biosynthetic schwertmannite,respectively and 95%,62.96%,and 41.97% for the chemosynthetic mineral,respectively.

关 键 词： 施氏矿物 生物成因 化学成因 表征 吸附

领　　域： [环境科学与工程]