| Abstract: Using natural hydromagnesite as raw material, mesoporous reticular MgO with high specific surface area was prepared by the simple method of "calcination-hydration-calcination", and no reagent was added in the experimental process. The effects of MgO dosage, adsorption time, adsorption temperature and pH on the adsorption of lead ions in simulated wastewater by MgO were systematically studied, the adsorption mechanism was revealed, and the adsorption effect of MgO on various ions was investigated. The results showed that the MgO adsorbent had a high specific surface area of 188 m2·g-1 and a high pore volume of 0.85 cm3·g-1, with an average pore diameter of 12.33 nm. The adsorption kinetics and isotherm data are highly consistent with the pseudo-second-order model and Langmuir model, indicating the monolayer chemisorption of heavy metal ions. MgO mesoporous reticular structure exhibited high adsorption performance for Pb(Ⅱ), and the maximum adsorption capacity was up to 7 431.5 mg·g-1, which was far higher than other reported values based on MgO adsorbent, and the removal rate of Pb(Ⅱ) was over 99.8%. The adsorption mechanism is mainly due to hydroxyl functional groups and ion exchange between Mg and heavy metal ions on MgO surface. In addition, the MgO can adsorb various ions simultaneously, and has excellent adsorption performance on Cd, Cr, Ni, As, Co, P, Se, Be, Bi, Cu, Fe, Mn, V, Zn and Al ions. |
