Synthesis, Characterization, and Photocatalytic Activity of ZnO Nanomaterials Prepared by a Green, Nonchemical Route

Ngoc Thinh Nguyen,Van Anh Nguyen,Changfa Guo

doi:10.1155/2020/1768371

Ngoc Thinh Nguyen, Van Anh Nguyen + Show 1 more

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https://doi.org/10.1155/2020/1768371

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Abstract

An eco-friendly method for the synthesis of ZnO nanoparticles was studied. Zinc acetate precursor was thermally decomposed without adding any chemical agents. The synthesized materials were thoroughly characterized by various analytical tools. The results indicated that the synthesized ZnO nanomaterials have a wurtzite structure. The estimated crystallite sizes of the materials obtained at 450, 550, 650, and 750°C (named as ZnO-450, ZnO-550, ZnO-650, and ZnO-750) were 33, 36, 38, and 42 nm, respectively. The morphology of the nanomaterials was revealed to be affected by calcination temperature, causing the formation of both nanoparticles and nanorods with different sizes and shapes. The materials were applied as photocatalysts for methylene blue (MB) decomposition under ultraviolet (UV) light. Results showed that the decomposition efficiency strongly depends on UV illumination time, size, and morphology of ZnO nanomaterials. The highest MB decomposition (99.4%) is obtained when using ZnO-750. The photocatalytic decomposition follows the first-order reaction. The reaction rate constants corresponding to the MB decomposition process with the presence of ZnO-450, ZnO-550, ZnO-650, and ZnO-750 are 0.0512, 0.0636, 0.1077, and 0.1286 min-1, respectively.

Highlights

Textile industry annually generates a huge amount of organic dyes, resulting in serious impacts on the environment
The second stage (47.58% of weight loss) within the temperature region from 250 to 350°C is accounted for the decomposition of anhydrous zinc acetate to form ZnO [15]
ZnO nanomaterials were successfully generated by a green method, thermal decomposition of zinc acetate precursor at 450, 550, 650, and 750°C

Summary

Introduction

Textile industry annually generates a huge amount of organic dyes, resulting in serious impacts on the environment. The removal of organic dyes from textile wastewater is considered an essential need. Numerous different technologies have been applied to remove organic dyes in wastewater such as adsorption, coprecipitation, advanced oxidation process (AOP), ozonation, membrane filtration, and biological methods [1, 2]. It is widely known that ZnO is a semiconductor with broad band gap energy (3.3 eV) and n-type conductivity. It is very common in nature and environmentally friendly. Thermal decomposition method is considering as an approach to “green method” that does not consume and/or generate toxic chemicals and/or solvents. On the attempt to minimize generating toxic wastes, this study synthesized ZnO nanoparticles by thermal decomposition of zinc acetate.

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