Efektifitasnanokomposit Zink Oksida Carbon Dots Sebagaifotokatalis Padafotodegradasi Metilen Biru Dibawahradiasi Sinar UV

Abstract

In this study, several stages of work have been carried out, that is the synthesis of nitrogen doped carbon dots (CDs), nitrogen doped zink oksida (N-ZnO) and N-ZnO /CDs as photocatalysts in photodegradation of organic pollutants methylene blue (MB). In the first stage, the synthesis of CDs was carried out using soybean as a precursor and ethylenediamine as nitrogen doping using the hydrothermal method at a temperature of 180oC for 8 hours. In the second stage, N-ZnO synthesis was carried out using urea as a nitrogen dopant with a calcination method at a temperature of 500oC for 2 hours in air (N2) condition and heating rate of 5 oC/min. The calcination temperature is determined from the results of the TGA analysis. In the third stage, the synthesis process of N-ZnO/CDs nanocomposites was carried out using a simple one method with concentration ratio of 2: 1. The results of this study show that CDs have been successfully synthesized which is confirmed from the results of HR-TEM, which shows that CDs are spherical with a particle size of 4,249 nm. Based on the caharacterization results of XRD and HR-TEM, N-ZnO and N-ZnO/CDs nanocomposites have a hexagonal wurtzite structure. The materials N-ZnO and N ZnO/CDs nanocomposites also experienced an increase in photocatalyst characteristics such as adsorption in the visible beam region, having a mikroporous structure, with a small Eg value of N-ZnO (2.78eV), N-ZnO/CDs (2.45 eV) and surface area (SBET) N-ZnO (3.827 m2 /g), N-ZnO/CDs (3.757 m2 /g). In the fourth stage photocatalyst CDs, N-ZnO and N-ZnO/CDs were used in methylene blue photodegradation under UV B light radiation for 60 min. Photocatalysts of nanocomposites N-ZnO/CDs showed the highest photodegrading effectivity of 83.4% with a degradation rate k= 0.0202 min-1 . This is evidenced from UV-Vis and PL data which explains that N dopant in ZnO forms p-type semiconductors, as well as the addition of CDs which act as energy transfer and photosensitizers so as to reduce and prevent electron-hole recombination. From this study, it was concluded that N ZnO/CDs nanocomposites can be an ideal photocatalyst material for the degradation of methylene blue organic liquid waste.