(59g) Synthesis and Characterization of Magnetite Nps Decorated Onto ACF, Heat-Treated g-C3N4, Pure CS and OSCS Nps for the Efficient Removal of MB and CV Dyes from Aqueous Solution

Industrial activities lead to the release of toxic dye compounds into the water bodies on a regular basis. Toxic dyes are known to create health hazards to the mankind and the aquatic ecosystems. This current study describes the novel synthesis of magnetite (Fe₃O₄) nanoparticles (NPs) decorated onto various carbonaceous materials, viz., pure activated carbon fiber (ACF), heat-treated graphitic carbon nitride (g-C₃N₄-HT), candle soot (CS) particles, and onion shaped candle soot (OSCS) particles using coprecipitation technique. The physicochemical properties of the synthesized materials are extensively investigated using various analytical and spectroscopic techniques such as SEM, TEM, VSM, EDAX, FTIR, XRD, XPS, and BET. Characterization data confirm that magnetite NPs are successfully incorporated onto pure ACF, g-C₃N₄-HT, CS, and OSCS surfaces. The synthesized materials are tested for their efficacy towards the removal of two industrially relevant dyes, namely, methylene blue (MB) and crystal violet (CV) dyes from aqueous solutions. The experimental data show that all four materials are capable of removing both the dyes. The adsorption performance of all four materials satisfy the following trend:

Fe₃O₄-ACF > Fe₃O₄-OSCS > Fe₃O₄-CS > Fe₃O₄/g-C₃N₄-HT

The batch adsorption kinetic data for all four adsorbents agreed well with the pseudo-second order kinetic model. Besides, Langmuir model is the best fitted isotherm model for all the adsorbents. Owing to the magnetic property, the adsorbents are efficiently separated from the aqueous solution with the help of an external magnet. This obviates the requirement of time consuming centrifugation and filtration steps. Additionally, the spent adsorbents are further characterized using FTIR, XRD, and SEM analyses. The characterization data reveal that no structural deterioration /chemical transformation of adsorbents occur post adsorption studies. With adequate optimization, the materials may be utilized to remove recalcitrant pollutants from water.