水热法制备Mn_3O_4及其对水中刚果红的吸附研究

用水热法制备Mn3O4材料,通过调整反应中Mn（NO3）2与H2O2溶液的体积比,研究H2O2对反应产物的种类和形貌的影响。结果发现,适量H2O2有助于Mn3O4的生成,但是过量的H2O2会导致产物向纳米线状MnO2的生成。用粉末X射线衍射（XRD）、场发射扫描电镜（FE-SEM）、氮气吸附脱附技术对样品进行了表征,并考察了Mn3O4对水中刚果红的吸附性能。结果表明,水热法制备Mn3O4材料,其比表面积（BET）可达119.31 m2/g;Mn3O4对刚果红的吸附符合准二级动力学方程,平衡吸附数据符合Langmuir吸附等温模型;当Mn（NO3）2与H2O2的体积比为2∶1时,在140℃下水热反应15 h合成的Mn3O4对刚果红的吸附效果最佳,最大吸附量可达81.63 mg/g。

The preparation of Mn3O4 by hydrothermal method and adsorption of congo red from aqueous solution

In this paper,Mn3O4 are synthesized via a simple hydrothermal method.Through changing the volume ratio between Mn（NO3）2 and H2O2,it is found that H2O2 can influence on the surface morphology and type of reaction produce.The resulting results shows that H2O2 can help the formation of Mn3O4 and then too much H2O2 can result in the produce of nanowire MnO2.The samples are characterized by X-ray diffraction（XRD）,field emission scanning electron microscopy（FE-SEM） and nitrogen adsorption-desorption isotherms.The adsorption capacity of Mn3O4 for Congo red in aqueous solution is investigated from batch tests.The results show as following： the resulting produces are Mn3O4.The morphology of Mn3O4 looks like octahedron.The surface area of the sample is 119.31 m2/g.The adsorption kinetics follows the pseudo-second order equation quite accurately and the adsorption isotherm is best fitted by Langmuir isothermal model.The Mn3O4 are synthesized using volume ratio between Mn（NO3）2 and H2O2 at 2∶ 1 via hydrothermal treatment at 140 ℃ for 15 h.The as-prepared Mn3O4 have the best adsorption capacity for congo red in aqueous solution,and the maximum adsorption capacity is 81.63 mg/g.