摘要
以凹凸棒土粉末为原料经一定工艺制得凹凸棒土颗粒,采用阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)为改性剂,通过微波改性合成了CTMAB/凹凸棒土颗粒,确定了最佳制备工艺条件为煅烧温度550℃,改性剂浓度80 mmol/L,微波改性时间6 min。考察了Cr(Ⅵ)溶液初始浓度和p H的影响,当Cr(Ⅵ)溶液浓度为20 mg/L,p H=5.6,CTMAB/凹凸棒土颗粒投加量为4 g/L时,在最佳条件下制备的CTMAB/凹凸棒土颗粒对Cr(Ⅵ)的去除率为90.7%。结果表明:改性后CTMAB进入到了凹凸棒土颗粒的表面及孔道,使其所带电性由负转为正,因而对以阴离子重铬酸根存在的Cr(Ⅵ)有更好的吸附性能,且Zeta电位随p H升高而降低,与去除Cr(Ⅵ)效率变化一致。吸附过程符合Langmuir等温线和Lagergren准二级速率方程,表明吸附为一种快速的单分子层化学吸附。
Powder attapulgite as a raw material was used to make the granular attapulgite,then granular attapulgite was modified with the surfactant of cetyltrimethylammonium bromide（CTMAB）by microwave modification to obtain the granular CTMAB/attapulgite,and it was found that the optimal conditions for preparing method were that the calcination temperature550 ℃,the surfactant concentration 80 mmol/L,the time of microwave 6 min. The effects of initial concentration and p H of Cr（Ⅵ）solution were investigated,and it was showed that when the concentration of Cr（Ⅵ）was 20 mg/L,p H was 5.6 and the dosage was 4 g/L,the removal efficiency of Cr（Ⅵ）by granular CTMAB/attapulgite was 90.7%. The results showed that CTMAB had either entered the interlayer or sorbed on the external surface of the granular attapulgite,making the Zeta potential of granular attapulgite become positve from negtive to have better adsorption properties for dichromate. The Zeta potential of granular CTMAB/attapulgite decreased with the increase of p H,consistent with the removal of Cr（Ⅵ）with p H.The adsorption process was found to fit Langmuir isotherm model and pseudo second-order rate equations,indicating that the adsorption model was a faster and monomolecular layer adsorption.
出处
《环境科学与技术》
CAS
CSCD
北大核心
2017年第10期77-81,共5页
Environmental Science & Technology
基金
国家自然科学基金资助项目(50904047)
湖北省环保厅项目(2015HB05)
