β-Cyclodextrin modified magnetic luffa biochar for efficient removal of Ni(II) from wastewater

In this study, a β-CD modified magnetic loofah biochar adsorbent (LB-MCD) was fabricated and its successful composite was demonstrated using diverse physical and chemical properties. The adsorbent has excellent specific surface area (29.46 m² g⁻¹) and magnetic separation ability (magnetization strength of 18.78 emu g⁻¹) and can rapidly separate ammonia nitrogen from wastewater within 50 s under the action of an applied magnetic field. The adsorption process was well correlated with the quasi-secondary kinetic model and Langmuir model (the Langmuir model fit value was 83.3 mg g⁻¹), and the adsorption reached the equilibrium in about 90 min, which was mainly carried out by monolayer adsorption, and the adsorption process was spontaneous and heat-absorbing. The LB-MCD had an excellent cycling performance, and its initial capacity (the dosage of LB-MCD was 0.06 g, the concentration of Ni(II) was7.65 mg g⁻¹, adsorption time was 100 min, and the pH = 7) was still 80% after 8 cycles of experiments. The LB-MCD showed excellent Ni(II) removal (R% > 90) in various aqueous environments, including deionized water, tap water, lake water, and industrial wastewater. In conclusion, LB-MCD is an eco-friendly and potent adsorbent for the removal of Ni(II) from wastewater.