Synthesis and characterization of manganese oxide nanoparticles for organic dye removal
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Date
2016-06
Authors
Low Jiong Xiong
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Abstract
Increasing in water pollution from textile industries had become a health concern across the globe. Advanced Oxidation Process (AOP) and adsorption techniques are techniques available for the application in dye removal. The AOP approach utilizes the reaction on the semiconductor’s surface in the presence of UV or visible light irradiation. Besides, adsorption method utilizes the surface of adsorbent to absorb the adsorbate from the water. The use of manganese oxide semiconductor has not been widely studied on the removal of organic dye due to the complexity of phase behaviour. In this project, MnO2 nanoparticles were synthesized using sol-gel method by using KMnO4 and MnSO4 as precursor and the Mn3O4 nanoparticles were synthesized using sol-gel method by using MnCl2 and NaOH as precursor. Under UV irradiation, MnO2 has the highest photodegradation efficiency of 87% after 15 min and rate constant of 0.06943 ± 0.00532 min-1. Mn3O4 nanoparticles in dark room with infrared filter shows the highest degradation efficiency and rate constant of 91% at 15 min and 0.05281 ± 0.00714 min-1 respectively. MnO2 nanoparticles did not show sign of RhB desorption under various desorption agents. Whereas, the Mn3O4 shows positive sign of desorption under hydrochloric acid. In the repeatability test, MnO2 nanoparticles lost its effectiveness to remove RhB dye from solution after 3rd run and Mn3O4 nanoparticles failed to remove the RhB dye after the 2nd run of removal tests. Therefore, the proposed MnO2 RhB dye removal mechanism was carried out via adsorption and photodegradation. Whereas, the removal of RhB dye by Mn3O4 nanoparticles was carried out by adsorption.