磁性水滑石复合材料的制备及其对曙红Y的吸附性能

In order to solve the problem of difficult recovery of hydrotalcite (LDH) adsorbent in sewage treatment, Fe₃O₄@Ni-Mg-Al-LDH magnetic hydrotalcite composite adsorption material was synthesized by combining magnetic Fe₃O₄ particles with Ni-Mg-Al-LDH hydrotalcite via double-drop precipitation method. The morphology and structure of the as-prepared Fe₃O₄@Ni-Mg-Al-LDH samples were characterized by SEM, XRD, FT-IR and N₂ adsorption-desorption technologies. And it was used as adsorbent to simulate the wastewater treatment performance of Eosin Y dye. The results show that the adsorption of Eosin Y dye on Fe₃O₄@Ni-Mg-Al-LDH is very quickly within 20 min, while the adsorption tends to balance after 120 min. In addition, with the increase of the initial concentration of Eosin Y dye, the adsorption capacity of Fe₃O₄@Ni-Mg-Al-LDH sample for Eosin Y dye increases gradually and the maximum adsorption capacity is 108.6 mg·g⁻¹. Meanwhile, the adsorption process of Eosin Y dye on Fe₃O₄@Ni-Mg-Al-LDH conforms to the Langmuir isothermal model and pseudo second-order kinetic equation, indicating that the adsorption process is dominated by the chemisorption of molecular layer, and the adsorption rate is controlled by surface diffusion and intra particle diffusion. After five cycles, the removal rate of Eosin Y dye still keeps above 80%, and the adsorbent is easy to be separated by magnetic field, implying that Fe₃O₄@Ni-Mg-Al-LDH magnetic hydrotalcite composite is a good adsorbent for dye wastewater.