La-Fe改性蛭石对水中磷酸盐的高效去除:吸附行为及内在机制

Performance and mechanism of La-Fe modified vermiculite adsorbent for efficient phosphorus removal

蛭石(VE)作为吸附剂具有很强的吸附性及离子交换能力,价格低廉、丰富易得,对环境无害。近年来,许多关于蛭石吸附的研究获得报道,但由于疏水性弱且缺乏活性位点使其在磷酸盐吸附方面表现不佳。本文制备了Le-Fe双金属改性蛭石提升对磷酸盐的吸附性能。结果表明:La、Fe原子比为1∶2时改性蛭石(La-Fe/VE-2)具有优异的磷吸附能力,最大吸附容量为185.09 mg P/g,且在pH=3~9的范围内能实现高效吸附。La-Fe/VE-2具有较强的抗阴离子干扰性能,在中低浓度磷酸盐溶液(50~100 mg P/L)条件下仍然保持较高的吸附率(>90%)。材料表征结果显示,La和Fe成功负载在蛭石上,静电吸附和配体交换是主要吸附机制。综上所述,双金属改性蛭石对磷酸盐亲和力强,是一种很有前途的除磷吸附剂。

Vermiculite(VE)as an adsorbent had strong adsorption and the capability of ion exchange,which was inexpensive,abundant,available and environmental friendly.In recent years,many studies on vermiculite adsorption have been reported,but the weak hydrophobicity and lack of active sites made it perform poorly in phosphate adsorption.In this paper,Le-Fe bimetallic modified vermiculite(La-Fe/VE)was prepared to enhance the adsorption performance of phosphate.The results shows that vermiculite at the atomic ratio of La and Fe of 1∶2(La-Fe/VE-2)has excellent phosphorus adsorption capacity with a maximum adsorption capacity of 185.09 mg P/g and it can achieve highly efficient adsorption in the pH range of 3 to 9.La-Fe/VE-2 has highly resistant to interference from anions,and maintains high adsorption rate(>90%)at low and medium concentrations of phosphates(50-100 mg P/L).Characterization analyses of the materials conclusively establishes the successful deposition of La and Fe onto the vermiculite substrate.The primary adsorption mechanisms are identifies as electrostatic attraction and ligand exchange.In summary,bimetallic-modified vermiculite has a pronounced affinity for phosphate and is a promising adsorbent for phosphorus removal.