新型树脂基水合氧化铁对水体中微量砷的吸附性能研究

将水合氧化铁固载于凝胶型强碱阴离子树脂N201上并合成出新型除砷吸附剂N201-Fe.研究了不同实验条件下N201-Fe对去除水溶液As(V)的影响.实验结果表明,N201-Fe对砷的吸附受pH值的影响较小;N201-Fe对As(V)具有很高选择性,在Cl-、HCO3-、SO42-等竞争离子共存时,N201对As(V)的去除率不到2%,而N201-Fe却高达90%.N201-Fe对As(V)的高选择性归因于N201-Fe中水合氧化铁与As(V)之间的络合配位能力及树脂表面的Donnan膜效应.静态吸附实验表明N201-Fe吸附As(V)的等温线符合Freundlich模型,热力学结果显示,该吸附过程为吸热过程.动态穿透实验表明,模拟水中的As(V)经N201-Fe处理后可达到中国和美国的饮用水标准,且N201-Fe的吸附处理量较N201提高30多倍.

ARSENATE SORPTION BY A NEWLY-DEVELOPED POLYMER-SUPPORTED HYDRATED IRON OXIDE

Hydrated iron oxide was loaded successfully onto gel-type strong-base anion exchanger N201 to obtain a new sorbent named N201-Fe. The revomal of As(V) by N201-Fe under different experiment conditions was studied. The results indicated that As(V) sorption on N201-Fe was less pH-dependent than N201. N-201 was can hardly remove As(V) in the presence of competing anions such as Cl-, HCO3-and SO42-, but the removal ratio of N201-Fe can achieve 90% in the identical condition. Moreover, N201-Fe exhibited the high selective sorption toward As(V), which was mainly due to the coordinate bonding between Fe(III) and As(V) and the Donnan membrane effect in the exchanger surface. The static experiment data also demonstrated that the sorption isotherm presented a good fit to Freundlich model, and the thermodynamic results showed that As(V) sorption onto N201-Fe was an endothermic process. The adsorption and stripping curves of As(V) onto N201 and N201-Fe were explored in fixed-bed column experiments, which represented that the concentration of As (V) in effluent solution was lower than the maximum contaminant level for As in drinking water in China and USA. And also, the dynamic adsorption capacity of N201-Fe was more than 30 times than N201.