TAGRA 2024

Abstract
In this research, a graphene oxide/MnO₂ quantum dot (GO/MnO₂-QDs) nanocomposite was utilized as a solid-phase adsorbent to remove Ni²⁺ and Cr⁶⁺ metal ions from water and wastewater samples. This approach leverages the adsorption capabilities of the nanocomposite to effectively capture and eliminate these heavy metal contaminants, offering a potential solution for purifying water sources. All measurements of Ni²⁺ and Cr⁶⁺ were conducted through their complexation with 1,5-diphenylcarbazide (DPC) at their maximum absorbance wavelengths of 284 nm and 540 nm, respectively. 1,5-Diphenylcarbazide is an organic compound commonly used as a chemical reagent, particularly in analytical chemistry. This compound is a derivative of carbazide with two phenyl groups attached to its molecular structure. MnO₂ quantum dots (MnO₂-QDs) were synthesized via the reduction of potassium permanganate in the presence of wheat extract, and Graphite powder was used for the synthesis of graphene oxide.
The synthesized nanocomposite was characterized using UV-Vis spectrophotometry, flourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy and X-ray diffraction (XRD). The surface morphology and particle size of the nanocomposite were analyzed using. High-resolution transmission electron microscopy (HR-TEM) and field-emission scanning electron microscopy (FE-SEM). The influence of parameters such as temperature, time of removal, pH values, dosage of the analyte and adsorbent, and initial metal ion concentration was investigated and optimized. The present approach was successfully applied to solid-phase extraction (SPE) for the removal of heavy metal ions from real samples, and under optimal conditions, the removal percentage was 98% to 99%.