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.

Reductive degradation of perfluorinated compounds in water using Mg-aminoclay coated nanoscale zero valent iron

“…On the contrary, with the exception of PFOA, further increase of nZVI concentration from 100 to 1000 mg L -1 did not significantly affect PFCs removal. A similar trend was also observed in a previous study [36], where Wu et al observed no significant difference on removal of other anions (phosphate) with increase of nZVI concentration from 400 to 600 mg L -1 . …”

Phosphate removal and recovery from water using nanocomposite of immobilized magnetite nanoparticles on cationic polymer

“…Compared with chemical precipitation, adsorption does not produce large volumes of chemical sludge. Various types of phosphorus adsorbents made from zeolites [46], lanthanum and yttrium compounds [47,48], aluminum compounds [49, 50,51,52,53], zero-valent iron [54], amine-functionalize, Pr(OH)3 [55], magnesium amorphous calcium carbonate [56], zirconium compounds [57,58], and iron(III) oxide compounds [12,30,31,38,40,51,59,60,61] were studied.…”

Evaluation of phosphate removal capacity of Fe3O4–ZVINPs from aqueous solution: optimization using response surface analysis

“…Therefore, providing a surface coating of a thin layer of Fe 3 O 4 [22], could alleviate this problem, thereby enhancing the reactivity of ZVINPs. The removal of PO 4 3-from aqueous solution by ZVINPs takes place by simultaneous adsorption and chemical precipitation [23]. Initial pH of solution and point of zero charge (PZC) of adsorbent are very important parameters that affect the adsorption of cationic and anionic species on a solid-liquid interface.…”