Nanoscale Zero-Valent Iron Supported on Graphene Novel Adsorbent for the Removal of Diazo Direct Red ۸۱ from Aqueous Solution: Isotherm, Kinetics, and Thermodynamic Studies

In this study, a nanoscale Zero-Valent Iron-Graphene (nZVI-G) composite was synthesized and applied for the removal of diazo Direct Red ۸۱ from an aqueous solution. The prepared nanocomposite was characterized using Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray Spectroscopy (EDS), X-Ray Diffraction (XRD)analysis, and Fourier-Transform InfraRred (FT-IR) spectroscopy. The particle size was in the range of ۲۰ to ۳۵ nm. The effect of influential experimental variables on dye removal such as contact time, pH, adsorbent dosage, initial dye concentration, and the temperature was investigated. In optimum conditions, including contact time of ۱۰ min, pH = ۳, the adsorbent dosage of ۰.۰۵ g, and initial dye concentration=۱۰ mg/L, dye removal was achieved ۹۲%. Different adsorption isotherm models (Langmuir and Freundlich) were used and adsorption followed Langmuir isotherm well (R۲= ۰.۹۷۷۳). The maximum Langmuir adsorption capacity of nZVI-G was obtained ۲۹.۰۷ mg/g. The pseudo-first-order kinetic model with R۲=۰.۹۸۳۸ fitted well with the experimental data. The thermodynamic parameters (  were calculated and the results revealed that the adsorption of dye was spontaneous and exothermic. The nZVI-G composite was found to be a low-cost potential candidate with high adsorption capability to be applied as an adsorbent for the removal of Direct Red ۸۱ from the aqueous media. Reduction degradation reaction which rapidly produces radicals has a major effect on reaction time. This nano adsorbent has the ability to adsorb, reduce, and degradation of pollutants, so the dye was removed efficiently.

کلیدواژه ها:

Nanoscale zero-valent iron ، Graphene ، Direct Red ۸۱ ، Removal ، Isotherm ، Kinetics