Investigation of the Adsorption Process of Chromium (VI) Ions from Petrochemical Wastewater Using Nanomagnetic Carbon Materials

Abstract

Magnetic mesoporous carbon (MMC) and magnetic activated carbon (MAC) are good functionalized carbon materials to use when applying environmental techniques. In this work, a series of efficient magnetic composite adsorbents containing Fe3O4 and carbon were prepared successfully and used for the adsorption of Cr(VI) ions in petrochemical wastewater. The morphology and structure of these magnetic adsorbents were characterized with FTIR, TG, XRD, VSM, BET, and SEM technologies. The effect of different factors, such as pH, adsorption time, initial Cr(VI) ions’ concentration, Fe3O4 loading, and adsorption time, on the adsorption behavior were discussed. The results showed that the 8%Fe3O4@MMC adsorbent exhibited a high removal rate, reutilization, and large adsorption capacity. The corresponding adsorption capacity and removal rate could reach 132.80 mg·g−1 and 99.60% when the pH value, adsorption time, and initial Cr(VI) ions’ concentration were 2, 180 min, and 80 mg·L−1 at 298 K. Four kinds of adsorption isotherm models were used for fitting the experimental data by the 8%Fe3O4@MMC adsorbent at different temperatures in detail, and a kinetic model and thermodynamic analysis also were performed carefully. The reutilization performance was investigated, and the Fe3O4@MMC adsorbent exhibited greater advantage in the adsorption of Cr(VI) ions. These good performances can be attributed to a unique uniform pore structure, different crystalline phases of Fe3O4 particles, and adsorption potential rule. Hence, the 8%Fe3O4@MMC adsorbent can be used in industrial petrochemical wastewater treatment.