Preparation Of Hierarchical Micro/Nano Materials And Their Application In Swage Treatment

With the rapid development of industry,water pollution has become increasingly serious recent years.The sweage included heavy metal ions and organic pollutants threats the survival of human through the food chain.It is necessary to remove these pollutants from water.The hydrothermal method was adopted to synthesize Fe3O4@MnO2 hollow spheres for the removal of U(VI)from aqueous solution.The effects of contact time,pH,ionic strength,solid content and temperature were investigated by using a batch technique.The experimental results show Fe3O4@MnO2 hollow sphere surface area is 247.9m2/g and the average diameter is 3.7nm.The adsorption equilibrium process is very fast.The temperature,pH and ion concentration are the main factors affecting the adsorption.Typical sorption isotherms(Langmuir,Freundlich,Dubinin-Raduskevich)were determined for the mechanism of sorption process.The thermo-dynamic parameters were calculated from the temperature isotherms,and the results suggested that U(VI)sorption on Fe3O4@MnO2 hollow spheres was a spontaneous and endothermic process.In this paper,three-dimensional(3D)hierarchical flower-like metal silicate,including magnesium silicate,zinc silicate,nickel silicate and cobalt silicate,were prepared by using rice husks as a sustainable silicon source for the first time.The flower-like morphology,interconnected ultrathin nanosheets structure and high specific surface area endowed them with versatile applications.Magnesium silicate was used as an adsorbent with the maximum adsorption capacities of 557.9,381.3,and 482.8mg/g for Pb2+,tetracycline(TC),and U(VI),respectively.Ni nanoparticles/silica(Ni NPs/SiO2)exhibited high catalytic activity and good stability for 4-nitrophenol(4-NP)reduction within only ~160 s,which can be attributed to the ultra-small particle size(~6.8 nm),good dispersion and high loading capacity of Ni NPs.Considering the abundance and renewability of rice husks,metal silicate with complex architecture can be easily produced at a large scale.