Investigation of the kinetics and optimization of photocatalytic degradation of methylene blue

ZnO Nanostructures Doped with Various Chloride Ion Concentrations for Efficient Photocatalytic Degradation of Methylene Blue in Alkaline and Acidic Media

In this study, chloride (Cl−) ions were successfully doped into ZnO nanostructures by the solvothermal method. The effect of various Cl− concentrations on the photocatalytic activity of ZnO towards the photodegradation of methylene blue (MB) under the illumination of ultraviolet light was studied. The as-prepared Cl−-doped ZnO nanostructures were analyzed in terms of morphology, structure, composition and optical properties. XRD data revealed an average crystallite size of 23 nm, and the XRD patterns were assigned to the wurtzite structure of ZnO even after doping with Cl−. Importantly, the optical band gap of various Cl ion-doped ZnO nanostructures was successively reduced from 3.42 to 3.16 eV. The photodegradation efficiency of various Cl− ion-doped ZnO nanostructures was studied for MB in aqueous solution, and the relative performance of each Cl ion-doped ZnO sample was as follows: 20% Cl−-doped ZnO > 15% Cl−-doped ZnO > 10% Cl−-doped ZnO > 5% Cl−-doped ZnO > pristine ZnO. Furthermore, the correlation of the pH of the MB solution and each Cl ion dopant concentration was also investigated. The combined results of varying dopant levels and the effect of the pH of the MB solution on the photodegradation process verified the crucial role of Cl− ions in activating the degradation kinetics of MB. Therefore, these newly developed photocatalysts could be considered as alternative materials for practical applications such as wastewater treatment.

An excellent multifunctional photocatalyst cooperated by polyoxometalate-viologen framework for CEES oxidation, Cr(VI) reduction and dyes decolorization under different light regimes

Photocatalytic detoxification of highly toxic agents is a promising approach to protect ecological environment and human health, and the key problem lies in the development of novel efficient photocatalysts. Herein,...

Green synthesis of nickel oxide nanoparticles using Salvia hispanica L. (chia) seeds extract and studies of their photocatalytic activity and cytotoxicity effects

The physical and chemical properties of Nickel oxide nanoparticles (NiO-NPs) have attracted the attention of many and in this regard, this study was performed to produce NiO-NPs by the means of Salvia hispanica L. (chia) seeds extract as the capping agent. Physical and morphological features of the obtained NiO-NPs were examined through the application of TGA, FTIR, UV-Vis, XRD, FESEM/EDAX/PSA, and VSM procedures. According to the FESEM/PSA images, the biosynthesized NiO-NPs contained a spherical shape and a size of about 30 nm, while the results of the EDAX study approved the existence of oxygen and nickel elements in the structure of this product. Furthermore, certain corresponding peaks to the crystal structure of NiO-NPs were observed throughout the XRD pattern. Next to the superparamagnetic behavior that was detected in the results of VSM analysis, the cytotoxicity effect of NiO-NPs was not reported to be dependent on concentration. Considering the high photocatalytic capacity along with the low cytotoxic effects of NiO-NPs, we can suggest the applicability of this product for various applications such as disease control and removal of residual toxins.

Tragacanth-mediate synthesis of NiO nanosheets for cytotoxicity and photocatalytic degradation of organic dyes

In this study, NiO nanosheets have been manufactured using a co-precipitation approach that involved the usage of nickel nitrate (Ni (NO₃)₂.6H₂O) as the raw material and tragacanth in the role of a stabilizing agent. NiO nanosheets have been fabricated through the reduction of nickel nitrate solution that had been obtained by the application of aqueous extract of tragacanth, which is capable of functioning as a reducing and stabilizing agent. In the following, the physical and chemical properties of tragacanth-stabilized NiO nanosheets have been identified via FESEM, EDS, XRD, UV-Vis, and FT-IR techniques. According to the XRD pattern, these particular nanosheets have contained a cubic structure and group space Fm3m, along with the average size of about 18 to 43 nm that had been in agreement with the FESEM measurements. In addition, we have evaluated the photocatalytic activity of tragacanth-stabilized NiO nanosheets on the degradations of methylene blue (MB) and methyl orange (MO) dyes. The performed photocatalytic assessment has displayed that the nanosheets can degrade 82% of MO within 210 min and 60% of MB in 300 min. The cytotoxicity of tragacanth-stabilized NiO nanosheets on human Glioblastoma cancer (U87MG) cell lines has been investigated via the MTT assay, while it has been detected in the obtained results that the inhibitory concentration (IC₅₀) had been 125 µg/mL.