纳米二氧化锰的制备及其对Cd~(2+)的吸附研究

采用微乳液还原法,用甲苯还原KMnO4制备了纳米MnO2。采用傅立叶红外光谱(FTIR)、X射线衍射(XRD)、扫描电镜(SEM)等方法对所制纳米MnO2进行了表征。研究表明:所得纳米MnO2为球型颗粒,其粒径范围为50～70 nm,比表面积大,表面存在大量活性-OH基团,高温煅烧使纳米MnO2从无定型向α晶型转变。以水体中Cd2+为目标污染物,通过吸附实验,研究表明溶液pH、煅烧温度、初始浓度对吸附效果有显著影响。pH=6时,300℃煅烧的MnO2吸附Cd2+效果较好,去除率达99.36%。,符合Langmuir模型。

Preparation of Nano-MnO2 and Adsorption of Cd2+

Spherical nano-MnO2 was prepared with KMnO4 reduced by toluene in microemulsion.The product was characterized by Fourier transform infrared(FTIR),X-ray diffraction(XRD) and scanning electron microscopy(SEM).Results showed that the nano-MnO2 with sizes range of 50~70 nm possess large specific surface area and lots of active-OH group.The structures of nano-MnO2 transform from amorphous to α-MnO2 under high temperature calcination.The adsorption capacity was affected by pH value,calcination temperature and initial concentration.Under the selected conditions of pH 6.0,the adsorption efficiency of Cd2+ reaches 99.36% by nano-MnO2 which was calcined by 300 ℃.The adsorption data fit well in Langmuir isotherm equation.