摘要
以4A分子筛粉末和凹凸棒土粉末为原材料制备了4A分子筛-凹凸棒土颗粒,采用扫描电子显微镜和X射线衍射仪等对其形貌和结构进行了表征,并研究了不同p H、不同Cd(Ⅱ)含量时4A-凹土颗粒对Cd(Ⅱ)的吸附行为。结果表明,4A-凹土颗粒疏松多孔,表面及内部有许多孔径较均匀的孔道;当p H=3.9~12.9、Cd(Ⅱ)的质量浓度为100mg/L、反应时间1 h、投加量1 g/L时,4A-凹土对Cd(Ⅱ)的去除率为80%~100%;吸附过程符合准2级速率方程和Langmuir等温线,表明4A-凹土对Cd(Ⅱ)的吸附为快速的单分子层化学吸附,计算得到最大吸附容量可达212.8 mg/g;交换出来的Na^+与吸附的Cd^(2+)摩尔比约为理论值2倍,因而Cd(Ⅱ)的去除机理主要是离子交换吸附。
A granular 4A molecular sieve/attapulgite adsorbent for Cd（Ⅱ） was synthesized, and the morphology and structure was characterized by scanning electron microscope （SEM） and powder X-ray diffxaction （XRD） etc. The effect of pH and initial content on the Cd（Ⅱ） adsorption by 4A/attapulgite were investigated.. The results showed that, granular 4A/attapulgite had large spaces and homogeneous pore canals in the interlayers and surface. When pH, mass concentration of Cd（Ⅱ）, reaction time and granular 4A/attapulgite dosage was 3.9~ 12.9, 100 rag/L, 1 b and 1 g/L, the removal rate of Cd（Ⅱ） was 80%~ 100%. The adsorption process followed the pseudo second-order model and Langmuir isotherm, which showed that Cd（Ⅱ） adsorption by granular 4A/attapulgite was monomolecular layer chemisorption, and the maximum sorption capacity of Cd（Ⅱ） was 212.8 mg/L. Additionally, The molar ratio of exchanged Na＋ and adsorbed Cd2＋ at equilibrium was close to the ideal value 2, indicating that the main adsorption mechanism could be explained to the ion exchange.
出处
《水处理技术》
CAS
CSCD
北大核心
2017年第9期62-66,共5页
Technology of Water Treatment
基金
国家自然科学基金项目(50904047)
湖北省环保厅项目(2015HB05)
