title: Phosphate removal from aqueous solutions by nanoscale zero-valent iron.
abstract: In this study, nanoscale zero-valent iron (NZVI) was synthesized by conventional liquid-phase chemical reduction methods without a support material and then characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of NZVI particles on phosphate removal from aqueous solutions was examined. The results showed that the phosphate removal efficiency increased from 34.49% to 87.01% as the dosage of nanoscale iron particles increased from 100 to 600 mg L(-1) with an initial phosphate concentration of 10 mg L(-1), and the phosphate removal efficiency decreased from 72.89% to 51.39% as the initial phosphate concentration increased from 10 to 90 mg L(-1), with 400 mg L(-1) NZVI. Phosphate removal efficiencies of 99.41% and 95.09% were achieved at pH values of 2 and 4, respectively, with an initial phosphate concentration of 20 mg L(-1) and 400mg L(-1) NZVI. The use of NZVI particles synthesized in a carboxymethyl cellulose (CMC)-water solution significantly enhanced phosphate removal from an aqueous solution compared with the use of NZVI synthesized in an ethanol-water solution. NZVI particles achieved 71.34% phosphate removal, which was remarkably higher than that of microscale zero-valent iron (MZVI) particles (16.35%) with 10 mg L(-1) of phosphate and 400mg L(-1) iron. Based on the removal mechanism analysis performed in this study, we recommend that phosphate removal be accomplished by simultaneous adsorption and chemical precipitation. The XRD patterns of the NZVI before and after the reactions indicated the formation of crystalline vivianite (Fe3(PO4)2 x 8H2O) during the procedure.
authors: College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China. wudl@zju.edu.cn
authors: Donglei
authors: D
authors: Wu
authors: College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors: Yanhong
authors: Y
authors: Shen
authors: College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors: Aqiang
authors: A
authors: Ding
authors: College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors: Mengyu
authors: M
authors: Qiu
authors: College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors: Qi
authors: Q
authors: Yang
authors: College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
authors: Shuangshuang
authors: S
authors: Zheng
mesh_terms: D000327:Adsorption; D011232:Chemical Precipitation; D007501:Iron / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D010710:Phosphates / Q000302:isolation & purification*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D007501:Iron