Effective removal of phosphate from aqueous solution using humic acid coated magnetite nanoparticles

WATER RESEARCH

卷:123

Article

Rashid, Mamun¹  Price, Nathaniel T.¹  Gracia Pinilla, Miguel Angel²  O'Shea, Kevin E.¹ 

[1] Florida Int Univ, Dept Chem & Biochem, 11200,SW 8th St, Miami, FL 33199 USA

[2] UANL, Fac Ciencias Fis Matemat, Ciudad Univ, San Nicolas De Los Garza 66455, NL, Mexico

关键词: Humic acid coated magnetite nanoparticles;    Adsorption;    Magnetic separation;    Phosphate;   

DOI  :  10.1016/j.watres.2017.06.085

来源: Elsevier

【 摘 要 】

Effective removal of excess phosphate from water is critical to counteract eutrophication and restore water quality. In this study, low cost, environmentally friendly humic acid coated magnetite nano particles (HA-MNP) were synthesized and applied for the remediation of phosphate from aqueous media. The HA-MNPs, characterized by FTIR, TEM and HAADF-STEM showed the extensive coating of humic acid on the magnetite surface. The magnetic nanoparticles with diameters of 7-12 nm could be easily separated from the reaction mixture by using a simple hand held magnet. Adsorption studies demonstrate the fast and effective separation of phosphate with maximum adsorption capacity of 28.9 mg/g at pH 6.6. The adsorption behavior follows the Freundlich isotherm suggesting the formation of nonuniform multilayers of phosphate on the heterogeneous surface of HA-MNP. The adsorption kinetic fits the pseudo-second order model well with rate constants of 0.206 +/- 0.003, 0.073 +/- 0.002 and 0.061 +/- 0.003 g mg(-1) min(-1) for phosphate (P) concentrations of 2, 5 and 10 mg/L respectively. The removal of phosphate was found higher at acidic and neutral pH compared to basic conditions. The nanoparticles exhibit good selectivity and adsorption efficiency for phosphate in presence of co-existing ions such as Cl-, SO42- and NO3- with some inhibition effect by CO32-. The effect of temperature on the adsorption reveals that the process is endothermic and spontaneous. HA-MNPs are promising, simple, environmentally friendly materials for the removal of phosphate from aqueous media. (C) 2017 Published by Elsevier Ltd.

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