改性沸石负载纳米β-FeOOH对溶液中Cr(Ⅵ)的吸附性能

采用恒温水浴法制得纳米β-Fe OOH,将其负载在改性沸石(SMZ)上制得复合材料β-Fe OOH/SMZ。用β-Fe OOH/SMZ吸附溶液中的Cr(Ⅵ)。考察了吸附时间、溶液p H、初始Cr(Ⅵ)质量浓度等因素对其吸附Cr(Ⅵ)效果的影响。实验结果表明:β-Fe OOH/SMZ对Cr(Ⅵ)的最佳吸附时间为5 h,适宜的溶液p H为6.0;随着初始Cr(Ⅵ)质量浓度的增加,β-Fe OOH/SMZ对Cr(Ⅵ)的吸附量逐渐增加;在β-Fe OOH/SMZ加入量为5.0 g/L、溶液p H为6.0、初始Cr(Ⅵ)质量浓度为250 mg/L、吸附温度为25℃的条件下,吸附量最高(为22.1 mg/g)。准二级动力学方程适用于描述β-Fe OOH/SMZ对Cr(Ⅵ)的吸附过程。该吸附由多个过程共同控制,颗粒内扩散并非唯一控速步骤。Freundlich等温方程比D-R等温方程更适于描述Cr(Ⅵ)在β-Fe OOH/SMZ上的吸附行为,β-Fe OOH/SMZ对Cr(Ⅵ)的吸附为多层吸附。

Adsorption Capability of Modified Zeolite Supported Nano β-FeOOH to Cr (Ⅵ) in Water

Nano β-FeOOH was synthesized by water bath heating method at constant temperature,and then was loaded on the surfactant-modified zeolite （SMZ） to prepare the composite material β-FeOOH/SMZ. The β-FeOOH/SMZ was used to adsorb Cr（Ⅵ） from water. The factors affecting Cr（Ⅵ） adsorption were studied. The experimental results show that：The optimum adsorption time is 5 h and the suitable solution pH is 6.0;The adsorption capacity of β-FeOOH/SMZ to Cr（Ⅵ） is increased with the increase of initial Cr（Ⅵ） mass concentration;The highest adsorption capacity is 22.1 mg/g under the conditions of β-FeOOH/SMZ dosage 5.0 g/L,solution pH 6.0,initial Cr（Ⅵ） mass concentration 250 mg/L and adsorption temperature 25 ℃. The adsorption of Cr（Ⅵ） onto β-FeOOH/SMZ meets the pseudo-second-order kinetics equation, and is controlled by several adsorption mechanisms,one of which is intra-particle diffusion. The Freundlich isothermal equation is more suitable for describing the adsorption process than the D-R isothermal equation, which indicates that multilayer adsorption occurs.