Removal of phosphate from water by amine-functionalized copper ferrite chelated with La(III)

• Published in: The Science of the total environment 2018-04, Vol.619-620, p.42-48
• Main Authors: Gu, Wei, Li, Xiaodi, Xing, Mingchao, Fang, Wenkan, Wu, Deyi
• Format: Article
• Language: English
• Subjects: Adsorption; Copper ferrite; Eutrophication; Lanthanum; Magnetic nanoparticle; Phosphate
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2017.11.098

•La ion was chelated to amine-functionalized CuFe2O4 to create a new adsorbent.•It had a saturation magnetization of 31.32emu/g, enabling magnetic separation.•The maximum adsorption capacity of the material for phosphate attained 32.59mg/g.•It showed good selectivity for phosphate in the presence of common anions.•The adsorbed phosphate could be desorbed through NaOH treatment. [Display omitted] Eutrophication has become a worldwide environmental problem and removing phosphorus from water/wastewater before discharge is essential. The purpose of our present study was to develop an efficient material in terms of both phosphate adsorption capacity and magnetic separability. To this end, we first compared the performances of four spinel ferrites, including magnesium, zinc, nickel and copper ferrites. Then we developed a copper ferrite–based novel magnetic adsorbent, by synthesizing 1,6-hexamethylenediamine–functionalized copper ferrite(CuFe2O4) via a single solvothermal synthesis process followed by LaCl3 treatment. The materials were characterized with X-ray diffraction, transmission electron microscope, vibrating sample magnetometer, Fourier transform infrared spectra and N2 adsorption–desorption. The maximum adsorption capacity of our material, calculated from the Langmuir adsorption isotherm model, attained 32.59mg/g with a saturation magnetization of 31.32emu/g. Data of adsorption kinetics were fitted well to the psuedo–second-order model. Effects of solution pH and coexisting anions (Cl−, NO3−, SO42−) on phosphate adsorption were also investigated, showing that our material had good selectivity for phosphate. But OH– competed efficiently with phosphate for adsorption sites. Furthermore, increasing both NaOH concentration and temperature resulted in an enhancement of desorption efficiency. Thus NaOH solution could be used to desorb phosphate adsorbed on the material for reuse, by adopting a high NaOH concentration and/or a high temperature.