Abstract:
Water pollution is one of the biggest problems in the world nowadays. Among various
contaminants at about 20% of the water pollution is caused by organic dyes. Organic dye
removal from different sources has never been easy and is becoming a major concern for
environmental and societal health. Among these organic dyes, cationic methylene blue is highly
toxic and can cause great environmental pollution and health effects. In this work, the effect of
temperature on sulfur doped copper selenide for degradation of methylene blue was studied.
Initially, Cu (Se, S) was synthesized by the hydrothermal method, then the synthesized materials
were characterized using X-Ray Diffraction, Scanning Electron Microscopy, Fourier
Transform-Infra Red Spectroscopy, Photoluminescence spectroscopy, and UV-Vis Diffuse
Reflectance Spectroscopy to determine phase purity, the particles morphology, functional
groups, photon recombination, and the degradation efficiency respectively. From the
diffraction pattern, it is confirmed the synthesized CuSe was crystalline klomannite hexagonal
with no other impurities peaks and Scanning Electron Microscope reveals that synthesized
pristine CuSe with smooth surface and relatively symmetrical hexagonal shapes. The optical
bandgap of the synthesized samples CuSe, 3% S CuSe, and 5% S CuSe estimated from Diffuse
Reflectance Spectroscopy and Photoluminescence spectroscopy measurement were becoming
2.33eV,2.3eV, 2.32eV respectively. 3% S CuSe exhibited a better degradation efficiency of
about 46.5% at the initial MB concentration of 10 mgL-1
and with a catalyst dose of 0.05g. This
sample was subsequently selected for further temperature studies. The effect of temperature
was investigated for the present material ranging from room temperature to 90℃. At a
temperature of 70℃, the degradation efficiency is maximum, with the corresponding results of
70% removal of MB, and decrease at 90℃. The kinetic behavior obeyed the Pseudo-first-order
degradation kinetics. Finally, the reusability of the present synthesized material was studied
for up to 4 cycles and showed suitable reusability towards the MB removal. Therefore, the
results of this study indicate that system temperature has a great effect on the photocatalytic
activity of CuSe for the removal of methylene blue organic dye.
