Photocatalytic Decomposition of Indigo Carmine and Methylene Blue Dyes using Facilely Synthesized Lithium Borate/Copper Oxide Nanocomposite

Efficient Photocatalytic Degradation of Congo Red Dye Using Facilely Synthesized and Characterized MgAl2O4 Nanoparticles

“…However, it was noted that further extension of the ultraviolet exposure time from 80 to 100 min had a minimal impact on the photocatalytic breakdown percentage of congo red dye, suggesting saturation of the active sites. − Consequently, 80 min is considered the optimal duration for achieving the maximum photocatalytic breakdown percentage of congo red dye. Furthermore, the photocatalytic decomposition of congo red dye follows a strong adherence to first-order kinetics, as represented by eq , − and this is depicted in Figure B. ln A normald A normale = K D t …”

“…Figure A exhibits the FT-IR spectrum of the produced MgAl 2 O 4 nanoparticles. The observed peaks at 527 and 696 cm –1 correspond to the stretching vibrations of Al–O and Mg–O bonds, respectively. − , Additionally, the peak at 3567 cm –1 arises from the stretching vibrations of H–O–H, while the peak at 1628 cm –1 results from the bending vibrations of H–O–H. − …”

“…To determine the optical energy gap (denoted as E g ) of the MgAl 2 O 4 nanoparticles, eq was employed. This calculation was based on their UV–vis spectra in a Nujol mull. − ( σ h υ ) Y = K E ( h υ − E normalg ) …”

“…In an acidic medium, these nanoparticles become surrounded by positively charged hydrogen ions, which attract the anionic congo red dye, as shown in Scheme , resulting in an increase in the photocatalytic degradation percentage. − Conversely, in a basic medium, the presence of negatively charged hydroxide ions causes the repulsion of the anionic congo red dye, as shown in Scheme , leading to a decrease in the photocatalytic degradation percentage. − Therefore, a pH value of 3 is considered the optimal condition for achieving the highest photocatalytic degradation percentage of the congo red dye.…”

“…If the quantity of MgAl 2 O 4 nanoparticles is raised from 0.0125 to 0.05 g, the photocatalytic degradation percentage of congo red dye rises from 34.86 to 99.27% due to the enhanced presence of free radicals. Conversely, if the quantity of MgAl 2 O 4 nanoparticles is further increased from 0.05 to 0.20 g, the photocatalytic degradation percentage of congo red dye decreases from 99.27 to 84.92% because of the obstructive turbidity, which hinders the entry of ultraviolet light and reduces the population of generated free radicals. − As a result, the optimal quantity for achieving the maximum photocatalytic decomposition percentage of the congo red dye was determined to be 0.05 g.…”