Morphology-controlled Synthesis And Environmental Properties Research Of Nano/Micro-functional Materials

Environmental sustainability represents a major challenge facing our world. Recent advances in synthetic micro/nano-materials have opened new horizons for addressing environmental problems. Opportunities and challenges in translating the remarkable progresses in nano/micro-technology toward practical environmental applications have caused more and more interest in a wide range of the world.Heavy metal ions and cyanide pollutants in wastewater are severely harmful to the ecological system, however, morphology-controlled synthesis of novel micro/nano-functional materials is an efficient way for addressing such challenging environmental problems.In this study, hierarchical MnO2microspheres assembled from nano-films are fabricated through an environmental route and subsequent drying under vacuum. The synthesis process, adsorption kinetics and thermodynamics are investigated in detail. The unique nano-film assembly structure with high BET surface area of252.82m2g-1can allow for higher exposure of adsorption sites to adsorbate molecules than a solid one, and thus results in the high removal efficiency of heavy metal ions. The final removal efficiency of Pb(Ⅱ), Cd(Ⅱ), Cu(Ⅱ) and Cr(Ⅵ) from acid aqueous solutions can reach100%,99.6%,99.1%and95.2%, respectively. Moreover, the relatively large submicrometer particles are easy to recover after adsorption. Therefore, it may serve as an ideal candidate for heavy metal ion removal in water treatment.Core-shell Fe3O4@C hybrid nanoparticle aggregates are successfully fabricated, and characterizations such as BET, SEM, TEM, FTIR, adsorption kinetics as well as thermodynamics were investigated in detail. The synthesis process of precursor was investigated by controlling time parameter. The unique stable configuration with high BET surface area can allow for higher exposure of adsorption sites to adsorbate molecules comparing with the solid one, and thus results in the high removal efficiency of heavy metal ions. The final removal efficiency of Pb(Ⅱ), Cd(Ⅱ), Cu(Ⅱ) and Cr(Ⅵ) from acid aqueous solutions can arrive at100%,99.3%,98.6%and98.2%, respectively. Moreover, the products are easy to be separated from the aqueous solutions after adsorption due to the multi-magnetic functional Fe3O4cores. Also, the carbon shells are attractive because of its low cost, acid and alkali corrosion resistance, high specific surface area and enhanced adsorption capacity. Therefore, it may serve as an ideal candidate for heavy metal ions removal in wastewater treatment.Apart from this, ring-shaped Bi2WO6-CeO2hybrid nanoparticle aggregates are fabricated through an environmental route and subsequent facile calcinations. The synthetic parameters are regulated to control the shape of the as-prepared samples. The photo-catalytic property was investigated in detail by degradation experiment of cyanide and organic dyes. The concentration of the cyanide ion decreased sharply from the initial4.72mM to0.95mM with the exposure time of60min. The intrinsic ring-shaped microstructure results in multiple reflections of light within the chamber, allowing more efficient use of the light source compared with a solid structure. Hybrid character can lead to enhanced charge separation and interfacial charge transfer efficiency due to the existence of an internal electric field. Therefore, it exhibits a remarkable photo-catalytic detoxification of cyanide and some organic dyes under visible light.