School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Rd., Shanghai 200240, China.
School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Rd., Shanghai 200240, China.
Sci Total Environ. 2018 Apr 1;619-620:42-48. doi: 10.1016/j.scitotenv.2017.11.098. Epub 2017 Nov 11.
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(CuFeO) via a single solvothermal synthesis process followed by LaCl treatment. The materials were characterized with X-ray diffraction, transmission electron microscope, vibrating sample magnetometer, Fourier transform infrared spectra and N 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, NO, SO) 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.
富营养化已成为全球性环境问题，在排放前从水中/废水中去除磷至关重要。我们目前的研究目的是开发一种在吸附磷容量和磁分离性能方面都高效的材料。为此，我们首先比较了四种尖晶石铁氧体（包括镁、锌、镍和铜铁氧体）的性能。然后，我们通过单溶剂热合成工艺合成了 1,6-己二胺功能化的铜铁氧体（CuFeO），随后进行了 LaCl 处理，开发了一种基于铜铁氧体的新型磁性吸附剂。采用 X 射线衍射、透射电子显微镜、振动样品磁强计、傅里叶变换红外光谱和 N 吸附-脱附对材料进行了表征。根据 Langmuir 吸附等温线模型计算出的我们材料的最大吸附容量为 32.59mg/g，饱和磁化强度为 31.32emu/g。吸附动力学数据很好地符合伪二级模型。还研究了溶液 pH 和共存阴离子（Cl、NO、SO）对磷酸盐吸附的影响，结果表明我们的材料对磷酸盐具有良好的选择性。但 OH 与磷酸盐竞争吸附位点的能力很强。此外，增加 NaOH 浓度和温度都导致解吸效率提高。因此，NaOH 溶液可用于解吸吸附在材料上的磷酸盐，以便重复使用，可采用高浓度 NaOH 和/或高温。
