A preparation method of Fe(II/III)Loaded Attapulgite-Biochar to passivate Cd(II) in Soil

In this study, various kinds of attapulgite and biochar were selected as the raw material. Attapulgite, being an inorganic carrier, was used to prepare the mineral materials of the modified composite-clay, and iron of Fe (II/III) and biochar was loaded on the surface of the attapulgite through chemical precipitation. Both attapulgite and biochar samples loaded with Fe2+/3+ were characterized using the FTIR, FESEM, XRD, surface area analysis and zeta potentials. A soil culture pot experiment was also carried out. The results showed that APT5 and BAC5 were selected as the best raw materials for the preparation of Fe2+/3+ loaded attapulgite and biochar. The composite had the highest adsorption rate, while the ratio of BAC5 to ATP5 was 1:10. The crystal structure of attapulgite was changed significantly after surface modification, being converted into montmorillonite, as being illustrated by the analysis of FESEM, XRD and FTIR. XRD, FTIR and Zeta potential biocarbon and Fe2+/3+ were successfully loaded on the surface of attapulgite, while Cd2+ was mainly bonded with Fe on the surface of the composite to form stable chemical covalent bonds. Combining with the results of soil culture pot experiment, we further indicate that under the material of proportion of 3%, Cd2+ passivation effect in the soil was the best. Moreover, plant Cd content in plants decreased by 89.3%, fresh weight of plants increased by 514% and height increased by 34.6%. Fe(II/III) loaded attapulgite-biochar can provide a potential remedy for Cd-contamination in soil environment.