Fe(Ⅱ)-H_2O_2不同温度浸润改性活性炭吸附去除水中砷(Ⅴ)

Fe(Ⅱ)-H2O2不同温度浸润改性活性炭是采用FeSO4·7H2O添加H2O2在温度100℃下纯浸润24 h(Fe(Ⅱ)-24 h)和高温蒸发15 min(Fe(Ⅱ)-15 min)制备.对2类材料进行SEM表征并对其吸附1.1 mg/L砷(Ⅴ)的性能进行比较.SEM显示Fe(Ⅱ)(0.485%)-24 h(0.485%为Fe(Ⅱ)-24 h的铁含量,下同)表面覆盖厚的棒状纳米羟基铁,Fe(Ⅱ)(1.35%)-15 min表面覆盖薄而烧结扭曲羟基铁;高温蒸发15 min有利于铁负载;Fe(Ⅱ)-24 h(108~142 mg/gFe)对砷(Ⅴ)吸附的铁效率是Fe(Ⅱ)-15 min(57~63 mg/gFe)的2倍;Fe(Ⅱ)(0.485%)-24 h在2pH3.5或9pH12时对砷(Ⅴ)的吸附平衡容量高于Fe(Ⅱ)(1.35%)-15 min,同时Fe(Ⅱ)(0.485%)-24 h在不同pH值的条件下铁的溶出量低于Fe(Ⅱ)(1.35%)-15 min;SO42-、NO3-、ClO4-、PO43-抑制Fe(Ⅱ)(0.485%)-24 h对砷(Ⅴ)的去除,PO43-抑制效果更为明显,Cl-(100 mg/L)和BrO3-促进其对砷(Ⅴ)的去除.

Preparation of Fe（Ⅱ）-H2O2-impregnated granular activated carbon at different temperatures for arsenate removal from water

Granular activated carbon（GAC） modified by Fe（Ⅱ）-H2O2 incipient wetness impregnation at different temperatures are prepared by FeSO4·7H2O and hydrogen peroxide（H2O2） via the incipient wetness for 24 h at100 ℃（Fe（Ⅱ）-24 h） and the high temperature evaporation for 15 min（Fe（Ⅱ）-15 min）.Fe（Ⅱ）-24 h and Fe（Ⅱ）-15 min are characterized by SEM and are compared for the adsorption behavior of the arsenate（1.1 mg/L）.The SEM has shown that nano-iron hydroxides are formed on the surface of Fe（Ⅱ）（0.485 %）-24 h（0.485 % is the iron content of Fe（Ⅱ）-24 h,the same below） and that sintering distorted hydroxides are formed on the surface of Fe（Ⅱ）（1.35 %）-15 min.The high temperature evaporation for 15 min is favorable for iron to load on GAC.The iron use efficiency of Fe（Ⅱ）-24 h（108～142 mg/gFe） is two fold of that of Fe（Ⅱ）-15 min（57～63 mg/gFe）.The arsenate equilibrium adsorption capacity of Fe（Ⅱ）（0.485 %）-24 h is better than the Fe（Ⅱ）（1.35 %）-15 min at pH 2～3.5 or 9～12,at the same time,the soluble iron at any particular pH released from the Fe（Ⅱ）（0.485 %）-24 h is less than that released from the Fe（Ⅱ）（1.35 %）-15 min.The presence of SO42-, NO3-, ClO4-, or PO43-inhibit the adsorption of arsenate, especially for phosphate,while the existence of Cl-（100 mg/L）and BrO3-promote the adsorption of arsenate.