镧基改性Fe3O4吸附废水中磷酸盐研究

Investigation on phosphate adsorption in wastewater by lanthanum-modified Fe3O4 nanocomposite

使用镧基改性材料去除废水中磷酸盐已备受关注,然而,如何有效回收镧基吸附剂是有待解决的关键难题。本研究采用水热法合成磁性Fe 3O 4镧基改性复合材料,并以该复合材料作为吸附剂,深入研究了磷酸盐吸附动力学和等温吸附,以及竞争离子、溶液pH值对其吸附效果的影响。研究结果显示,该镧基改性复合材料在吸附磷酸盐120 min后即可达到平衡,吸附过程符合准二级动力学模型。吸附等温线可较好地为Langmuir模型所描述,当温度为25℃时,其最大磷吸附容量可达69.60 mg/g。溶液pH值对复合材料吸附能力有较大影响,在pH值为3~5范围内,其磷吸附能力最高。废水中常见的阴离子对磷酸盐的吸附影响可基本忽略,表明该复合材料对磷酸盐具有较好的选择性。

The use of lanthanum-based materials for the removal of phosphate from water and wastewater has received increasing attention.However,there is still a challenge to enhance phosphate adsorption capacity and recover lanthanum-based sorbents.In this study,magnetic Fe 3O 4 nanocomposites were synthesized by the hydrothermal method.The composite was used as a absorbent to investigate phosphate adsorption kinetics,and the effect of solution pH and competitive ions on phosphate adsorption were also explored through the design of batch experiments.The results indicate that the synthesized nanocomposites reach the adsorption equilibrium after 120 min,and the data are well fitted by pseudo-second-order kinetics equation.The adsorption isotherm can be described by the Langmuir model with a maximum adsorption capacity of 69.60 mg/g.The pH of the solution has a great influence on phosphate adsorption.The highest adsorption capacity can be observed in the range of pH 3~5.The common anions in wastewater have no significant effect on the adsorption of phosphate,indicating that the composite has good selectivity to phosphate.