Magnetic metal-organic framework (Fe₃O₄@ZIF-8) nanocomposites for adsorption of anionic dyes from wastewater

Abstract

Since organic dyes are a major category of water contaminants, the processing of dye removal materials focuses on significant environmental significance. A metal organic structure adjusted by Fe₃O₄ nanoparticles (Fe₃O₄@MOF) has been easily synthesized and used as an adsorbent for the adsorption of Acid Red 57 (AR57) and Remazol Red (RR) anionic dyes and is used as a high-performance aqueous solution adsorbent. Fe₃O₄@ZIF-8, using a simple process, was synthesized at room temperature. The SEM, XRD, IR, and BET review described the Fe₃O₄@MOF as prepared. Fe₃O₄@MOF had a large specific area (475.3 m²/g), pore volume and pore size were also measured, X-ray diffraction spectroscopy (XRD), surface modification was measured using electron microscopy (SEM) scanning with a mean particle size of ∼248 nm in diameter, High chemical and thermal stability and high saturation magnetization (56.2 emu/g). Variables such as initial pH, adsorbent dosage, contact time and temperature have been studied in order to find optimal adsorption conditions for the extraction of Acid Red 57 (AR57) and Remazol Red (RR) from aqueous solutions. For the respective AR57 and RR, the optimal pH for extracting the anionic dyes tested from water solutions was 3 and 4. For AR57 and RR dyes, the overall predicted adsorption potential was 888.68 and 808.43 mgg⁻¹, respectively, the effects of the initial solution pH, temperature, and, Initial concentration, contact time, salinity and dosing were systematically analyzed for Fe₃O₄@ZIF-8. These colors were ideal for acidic medium adsorption, where the zero-charge point (pH_PZC) is equal to 4.3. The adsorption results were based on the isotherms of Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich adsorption. For both colors, the adsorption isotherm was found to obey the Lungmuir model. For AR57 and RR, the mean adsorption energy (Ea) is 20.24 and 31.3 kJmol⁻¹, respectively, which indicates a phase of chemisorption. It was found that the kinetics of adsorption followed the pseudo-second-order kinetic model. The adsorption process was verified to be endothermic and random by thermodynamic experiments. The use of ethanol as the solvent was also studied in the method of desorption of the adsorbed anionic dyes.

Keywords:

• Fe₃O₄@ZIF-8
• pH_PZC
• adsorption isotherm
• magnetization
• thermodynamics