Thermal-Induced Effects on the Structural and Photocatalytic Properties of Nickel Oxide Nanoparticles for Indigo Carmine Dye Removal

Abstract

In this study, NiO nanoparticles were formed using the chemical precipitation method, and the calcination process induced structural parameters and optical bandgap. The research was carried out using a variety of techniques such as XRD, FTIR, and SEM. The XRD analysis reveals that the formed NiO crystallized in an fcc crystal structure, and that the calcination process in uences the microstrain, dislocation density, and average surface area. The optical bandgap and crystal structure parameters are signi cantly affected by increasing the calcination temperature and/or time. The formation of a Ni-O stretching vibration mode is revealed by FTIR, and the broadness of the absorption band con rms that the NiO samples are nanocrystals. The morphology of the prepared NiO reveals the formation of spherical nanoparticles for samples calcined at 700 °C and dodecahedron-like shapes for samples calcined at 800 and 900 °C. Depending on the calcination temperature and time, the optical band gap ranged from 3.33 to 3.71 eV. The photocatalytic performance of NiO nanoparticles as catalysts for the degradation of indigo carmine (IC) dye is investigated under UV-visible irradiation for up to 3 h. The best degradation e ciency was found to be 76% for NiO calcined at 800 °C for 4 h, which revealed the smallest crystallite size of 19.13 nm, and the highest surface area of 47.02 m 2 /g. A mechanism for the degradation process was proposed, and the reaction rate constants for various NiO catalysts were estimated, with the maximum value of 4.51×10 -3 /min calculated for NiO calcined at 800 °C for 4 h.

Detection of Indigo Carmine dye in juices via application of photoluminescent europium‐doped carbon dots from tannic acid

“…[5] Nevertheless, Indigo Carmine is regarded as a poisonous indigoid category of dye, and it can produce irritations for eye, skin, and respiratory tract (leading to coughing and shortness of breath) and gastrointestinal tract (leading to vomiting, nausea and diarrhea). [5][6][7] Furthermore, it can produce permanent damage to the conjunctiva and the cornea. [5,7] Additionally, the continuous consumption of Indigo Carmine dye can also lead to death, as the dye is considered a carcinogenic agent and can contribute to neuro, reproductive and developmental toxicity.…”

“…[5][6][7] Furthermore, it can produce permanent damage to the conjunctiva and the cornea. [5,7] Additionally, the continuous consumption of Indigo Carmine dye can also lead to death, as the dye is considered a carcinogenic agent and can contribute to neuro, reproductive and developmental toxicity. [5,8] In recent years, a number of various studies have been performed with the goal of developing methods for the detection of Indigo Carmine, including chromatographic technique, [9] spectrophotometric, [10] resonance Rayleigh scattering, [3] an electrochemical technique [11] and one fluorometric method.…”