title: Influence of moderate pre-oxidation treatment on the physical, chemical and phosphate adsorption properties of iron-containing activated carbon.
abstract: A novel adsorbent based on iron oxide dispersed over activated carbon (AC) were prepared, and used for phosphate removal from aqueous solutions. The influence of pre-oxidation treatment on the physical, chemical and phosphate adsorption properties of iron-containing AC were determined. Two series of ACs, non-oxidized and oxidized carbon modified by iron (denoted as AC-Fe and AC/O-Fe), resulted in a maximum impregnated iron of 4.03% and 7.56%, respectively. AC/O-Fe showed 34.0%-46.6% higher phosphate removal efficiency than the AC-Fe did. This was first attributed to the moderate pre-oxidation of raw AC by nitric acid, achieved by dosing Fe(II) after a pre-oxidation, to obtain higher iron loading, which is favorable for phosphate adsorption. Additionally, the in-situ formed active site on the surface of carbon, which was derived from the oxidation of Fe(II) by nitric acid dominated the remarkably high efficiency with respect to the removal of phosphate. The activation energy for adsorption was calculated to be 10.53 and 18.88 kJ/mol for AC-Fe and AC/O-Fe, respectively. The results showed that the surface mass transfer and intra-particle diffusion were simultaneously occurring during the process and contribute to the adsorption mechanism.
authors: Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China.
authors: Zhengfang
authors: Z
authors: Wang
authors: Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China.
authors: Mo
authors: M
authors: Shi
authors: Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China.
authors: Jihua
authors: J
authors: Li
authors: Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China. Electronic address: zzhenghj@fudan.edu.cn.
authors: Zheng
authors: Z
authors: Zheng
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D009584:Nitrogen; D010084:Oxidation-Reduction; D010710:Phosphates / Q000302:isolation & purification; D016062:Porosity; D017550:Spectroscopy, Fourier Transform Infrared; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D014961:X-Ray Diffraction
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D002244:Carbon; D007501:Iron; D009584:Nitrogen
keywords: Adsorption; iron-containing activated carbon; mechanism; per-oxidation; phosphate