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Adsorption and mechanistic study for phosphate removal by magnetic Fe3O4-doped spent FCC catalysts adsorbent

Yuan, Ling, Qiu, Zhaofu, Yuan, Lin, Tariq, Muhammad, Lu, Yunqing, Yang, Ji, Li, Zhen, Lyu, Shuguang
Chemosphere 2019 v.219 pp. 183-190
active sites, adsorbents, adsorption, anions, carbonates, catalysts, catalytic cracking, iron, iron oxides, ligands, magnetism, phosphates, wastes
The waste materials utilization has attained increasing attention due to the generation of a large number of spent materials. In the current study, a practical magnetic adsorbent (Fe3O4-doped spent Fluid Catalytic Cracking catalysts, abbreviated as FCCx@(Fe)y-O) was prepared, liable to be separated. The batch experiments were employed to investigate the phosphate removal behavior. The findings of this study demonstrated that FCC4@(Fe)1-O exhibited the best phosphate removal performance among the adsorbents (FCCx@(Fe)y-O), attributed to rough surface layer, i.e., composed of active sites. The various characterizations results revealed that the adsorption behavior of FCC4@(Fe)1-O followed the inner-sphere adsorption based on ligand exchanges mechanism. Furthermore, OH− played an important role in the adsorption process. Minor effects were showed on the phosphate removal in the experiments of commonly coexisting anions, except CO32− and SiO32−. The above findings affirmed that FCC4@(Fe)1-O was a suitable adsorbent for phosphate removal in the practical application.