Search

Herein, we demonstrate the preparation and application of NiCo2O4 decorated over a g-C3N4-based novel nanocomposite (NiCo2O4@g-C3N4). The prepared material was well characterized through several physicochemical techniques, including FT-IR, XRD, SEM, and TEM. The electrochemical characterizations via electrochemical impedance spectroscopy show the low electron transfer resistance of NiCo2O4@g-C3N4 owing to the successful incorporation of NiCo2O4 nanoparticles on the sheets of g-C3N4. NiCo2O4@g-C3N4 nanocomposite was employed in the fabrication of a screen-printed carbon electrode-based innovative electrochemical sensing platform and the adsorptive removal of a food dye, i.e., fast green FCF dye (FGD). The electrochemical oxidation of FGD at the developed NiCo2O4@g-C3N4 nanocomposite modified screen-printed carbon electrode (NiCo2O4@g-C3N4/SPCE) was observed at an oxidation potential of 0.65 V. A wide dual calibration range for electrochemical determination of FGD was successfully established at the prepared sensing platform, showing an excellent LOD of 0.13 µM and sensitivity of 0.6912 µA.µM−1.cm−2 through differential pulse voltammetry. Further, adsorbent dose, pH, contact time, and temperature were optimized to study the adsorption phenomena. The adsorption thermodynamics, isotherm, and kinetics were also investigated for efficient removal of FGD at NiCo2O4@g-C3N4-based adsorbents. The adsorption phenomenon of FGD on NiCo2O4@g-C3N4 was best fitted (R2 = 0.99) with the Langmuir and Henry model, and the corresponding value of Langmuir adsorption efficiency (qm) was 3.72 mg/g for the removal of FGD. The reaction kinetics for adsorption phenomenon were observed to be pseudo-second order. The sensitive analysis of FGD in a real sample was also studied. [ABSTRACT FROM AUTHOR]

Present work demonstrates the synthesis, characterisation and application of a novel hybrid nanocomposite GO@Fe3O4-MnO2 for adsorption and catalytic degradation of dyestuff malachite green and tartrazine from wastewater. The nanocomposite GO@Fe3O4-MnO2 was characterised by FT-IR, XRD, SEM-EDS and pHzpc. Effects of various optimising parameters such as contact time, solution pH, surfactants, light, adsorbent dose, ultrasonication and coexisting ions were investigated. The removal efficiencies of malachite green and tartrazine were observed as high as 99.9% and 98% under direct sunlight, respectively. The adsorption kinetics follows the pseudo-second order model (R2 = 0.99) where k2 for malachite green and tartrazine were 0.0097 and 0.0011 g mg−1 min−1, respectively, that means adsorption was controlled by chemisorption. Equilibrium adsorption isotherm of these dyes was analysed in the context of Langmuir and Freundlich models, and the maximum adsorption capacity for Langmuir isotherm was found to be 8.0 and 5.1 mg g−1 for malachite green and tartrazine, respectively. The percentage removal was initially low, but when the ultrasound was irradiated, the removal percentage (96% for malachite green and 98% for tartrazine) was drastically increased because of the formation of highly active •H and •OH radicals in the water through the decomposition of water molecules by the formation of hot spots. On treatment with H2O2, advance oxidation processes were observed with high remediation percentage (99.5% for malachite green and 98% for tartrazine) of dye. The synthesised GO@Fe3O4-MnO2 was finally used for the treatment of dyes from real water samples. The used nanocomposite was separated using an external magnet and recycled with 0.1 N HCl or 0.1 N NaOH as desired. [ABSTRACT FROM AUTHOR]