Ankamwar Balaprasad G, Kamble Vaishali B, Annsi Jose I, Sarma Loka S, Mahajan Chandrashekhar M
J Nanosci Nanotechnol. 2017 Feb;17(2):1185-192. doi: 10.1166/jnn.2017.12579.
The scalable and economical synthesis approach of ZnO has always been demanded, since it is very useful material in the degradation of hazardous dyes. Herein, a scalable synthesis approach for ZnO nanoparticles by precipitating the precursors such as zinc sulphate heptahydrate and ammonium hydroxide has been proposed. Calcinations at suitable temperatures can improve crystalline nature of materials. Therefore as-synthesized ZnO nanoparticles were calcinated at different temperatures 400 °C, 650 °C, 900 °C, 1150 °C, and subsequently their physical and morphological properties were characterized. The TEM analysis revealed the morphology, whereas XRD and SAED confirmed the purity and crystalline nature of ZnO. Moreover, photo catalytic degradation/adsorption results for methylene blue dye of lower (2.5 ppm) and higher concentrations (5 ppm) in the presence and absence of sunlight and ZnO nanoparticles are also reported. Addition of ZnO nanoparticles to methylene blue resulted in enhanced rate of photo degradation in the presence of sunlight. The complete photodegradation of 2.5 and 5 ppm methylene blue in sunlight occurred in 90 min and 165 min, respectively in presence of ZnO nanoparticles. In general many photocatalytic degradation studies had been reported using an artificial light source; however in the present work direct sunlight has been utilized.
由于ZnO在有害染料降解中是非常有用的材料，因此一直需要可扩展且经济的合成方法。在此，提出了一种通过沉淀七水硫酸锌和氢氧化铵等前驱体来可扩展合成ZnO纳米颗粒的方法。在合适的温度下煅烧可以改善材料的结晶性质。因此，将合成的ZnO纳米颗粒在400℃、650℃、900℃、1150℃等不同温度下煅烧，随后对其物理和形态性质进行表征。透射电子显微镜（TEM）分析揭示了其形态，而X射线衍射（XRD）和选区电子衍射（SAED）证实了ZnO的纯度和结晶性质。此外，还报道了在有阳光和无阳光以及有ZnO纳米颗粒存在的情况下，亚甲基蓝染料在较低浓度（2.5 ppm）和较高浓度（5 ppm）下的光催化降解/吸附结果。在阳光存在下，向亚甲基蓝中添加ZnO纳米颗粒导致光降解速率提高。在有ZnO纳米颗粒存在的情况下，2.5 ppm和5 ppm亚甲基蓝在阳光中的完全光降解分别在90分钟和165分钟内发生。一般来说，许多光催化降解研究是使用人工光源进行报道的；然而在本工作中使用的是直射阳光。
