Study on the preparation of magnetic attapulgite and its mercury removal performance

The attapulgite (Atp) widely existed in nature could be modified by magnetism, and a magnetic attapulgite (MAtp) modified by magnetic iron oxide was prepared by deposition-precipitation method. The physical and chemical properties of the magnetic attapulgite were analyzed by BET, VSM, XRD and SEM, and the effects of iron oxide content, reaction temperature and flue gas composition on the mercury removal capacity were studied. The results show that the removal ability for Hg⁰ is enhanced by the combination of Atp and magnetic materials, and the removal ability of MAtp is gradually improved with the increase in iron oxide content. Moreover, the removal ability of Hg⁰ is enhanced with the increase of temperature in the test temperature range, and the chemical adsorption of Hg⁰ is a main factor for MAtp. The addition of O₂ and NO is beneficial to the removal of Hg⁰, but the Hg⁰ penetration rate does not change significantly with the concentration; while SO₂ inhibits the removal of mercury, and the inhibition effect is more obvious with the increase of concentration. However, when NO and SO₂ coexist, NO can greatly weaken the inhibition effect of SO₂ on mercury removal.