Effect of Silicon on Phosphorus Adsorption of Two Synthetic Iron Oxides

Abstract:

Iron oxides play an important role in controlling P activity and availability in environmental systems. Two iron oxides (goethite and ferrihydrite) were synthesized characterized by X-ray diffraction, transmission electron microscopy and N₂ adsorption method. To investigate the effect of silicon on phosphorus adsorption of them, batch equilibration method was used. Attempts were made to explore the mechanisms involved by eliminating effects of pH and accompany ions. Results reveal that the ability of two kinds of iron oxides adsorbed phosphorus were as follows: ferrihydrite > goethite. Compared with the control, silicon inhibited the adsorption of phosphorus on two iron oxides, and this effect increased with the increasing of silicon content. Langmuir, Freundlich and Temkin equations could be used to describe the adsorption characteristics of phosphorus on iron oxides well, but the Langmuir model was optimal. With silicon addition, the adsorption equilibrium constants (K) decreased of the phosphorus absorbed on iron oxide, the free energy(ΔG)dropping degree increased, the maximum adsorption capacity(X_m)and maximum buffering capacity (MBC) reduced.

• Periodical: Advanced Materials Research (Volumes 726-731)
• Pages: 325-330
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.726-731.325
• Online since: August 2013
• Authors: Ming Da Liu, Feng Jiang, Hui Sun, Dan Yang, Yu Long Zhang, Yao Jing Wang
• Keywords: Adsorption, Ferrihydrite, Goethite, Phosphorus, Silicon

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