Kinetic Study of Organic Dye Degradation Using ZnO Particles with Different Morphologies as a Photocatalyst

Swee-Yong Pung,Azizan Aziz,Wen-Pei Lee

doi:10.1155/2012/608183

Swee-Yong Pung, Azizan Aziz + Show 1 more

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https://doi.org/10.1155/2012/608183

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Abstract

Zinc oxide (ZnO) particles were successfully synthesized via sol-gel approach using zinc acetate dihydrate (Zn(CH3COO)2·2H2O) and ammonia (NH4OH) solution as precursors. By adjusting the reaction parameters such as amount of ammonia and reaction time as well as complexing agent aluminium sulphate Al2(SO4)3, ZnO particles with different morphologies, that is, rodlike, ricelike and disklike could be synthesized. The effectiveness of ZnO particles with different morphologies (rodlike, ricelike and disklike) on the photocatalytic activity has been studied. The results showed that rodlike ZnO particles were the most effective in degrading the Rhodamine B (RhB) solution under the illumination of ultraviolet (UV) light. The rate constant was found to be first order, with rodlike particles the highest (0.06329 min−1), followed by rice-like ZnO particles (0.0431 min−1) and disk-like ZnO particles (0.02448 min−1).

Highlights

Photocatalysis of organic compounds such as methyl green and Rhodamine B (RhB) in water is receiving attention due to the severe ecological impact of various industrial and agricultural pollutants [1, 2]
Different morphologies of Zinc oxide (ZnO) particles were obtained by varying the amount of ammonia, reaction time, and addition of aluminium sulphate as complexing agent
When the absorbance data are plotted as in ln(Ao/A) of the time-dependent normalized dye concentrations in Figure 14, linear plots are obtained. This indicates that the decomposition of RhB follows a first order kinetics regardless the morphology of ZnO particles

Summary

Introduction

Photocatalysis of organic compounds such as methyl green and Rhodamine B (RhB) in water is receiving attention due to the severe ecological impact of various industrial and agricultural pollutants [1, 2]. Concentration of solution, pH, heating duration, and complexing agent, different morphology of ZnO particles such as nanoprisms [14], nanorods [15], nanoflowers [16], nanosheets [17], and nanodisks [18] could be synthesized, respectively. Different morphology of ZnO particles have different exposed crystal planes. The main exposed crystal plane of ZnO nanodisks is (002) with atomic planar density of 1.1 × 1019 atoms/m2. The main exposed crystal plane of ZnO nanorods is {100} with atomic planar density of 5.9 × 1018 atoms/m2. The study of RhB degradation and understanding its reaction kinetics helped to consider actual effluent for the photocatalytic activities, in view of its complexity in containing diverse types of dyes and other chemicals

Experimental Details

Results and Discussion

Conclusions