Usage of magnetic activated carbon as a potential adsorbent for aniline adsorption from wastewater

Aniline, a hazardous aromatic compound, is a notable contaminant in various industrial wastewater. As a simple and convenient process, adsorption could facilitate aniline adsorption from sewage. Magnetic activated carbon adsorbent (MAC) was produced using the co-precipitation method and applied to the adsorption of aniline from water. The characterization of this adsorbent was surveyed using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and Vibrating-Sample Magnetometer (VSM). Key operational parameters, including adsorbent dosage, initial aniline concentration, and initial pH, have been systematically investigated using the Central Composite Design (CCD) approach in the Response Surface Method (RSM). According to the results, the optimal adsorption percentage was achieved with a 2.9 g/L dosage, pH 7.4, 52.7 mg/L initial concentration, and 300 min of contact time. A study on Langmuir, Freundlich, and Sips isotherms was conducted, alongside evaluating pseudo-first-order and pseudo-second-order kinetics. The Sips isotherm and pseudo-second-order models showed the best fit, with R² values > 0.98 and 0.99, respectively. The thermodynamic study indicated a negative ΔG, confirming that aniline adsorption is spontaneous on both commercial and magnetic activated carbon.