聚苯胺/改性凹凸棒的制备及其对亚甲基蓝的吸附性能

Preparation of Polyaniline/modified Attapulgite Composites and its Adsorption Properties of Methylene Blue

采用原位氧化法以不同浓度硫酸改性的凹凸棒(ATP)和掺杂的聚苯胺(PANI)为原料制备了聚苯胺/改性凹凸棒(PANI/mATP)复合材料,采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、红外光谱仪(FT-IR)和比表面测定仪(BET)分别对PANI/mATP进行分析表征,并研究了PANI/mATP对阳离子染料亚甲基蓝(MB)的吸附性能,系统考察了pH值、吸附剂用量、温度、初始浓度和吸附时间的影响及吸附过程的热力学与动力学性能,探讨了PANI/mATP对MB的吸附机理。结果表明,吸附在180 min内达到吸附平衡,当温度为338 K,pH值为12时,4.0mol/L硫酸改性的ATP与掺杂4.0 mol/L硫酸的PANI制备的复合材料对MB的吸附性能最佳,其吸附率可达96.2%,吸附量为240.5 mg/g,且吸附过程符合Langmuir模型和准二级动力学模型;吸附热力学结果表明,PANI/mATP对MB的吸附是吸热过程,其吸附作用力主要为氢键、π-π共轭与静电作用。

PANI/mATP composites were prepared via in-situ oxidation by using acid-doped polyaniline and attapulgite modified by different concentrations of sulfuric acid.PANI/mATP was characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),infrared spectroscopy(FT-IR)and Brunauer-emmett-teller(BET)surface area measurement.And the adsorption of cationic dye methylene blue(MB)onto PANI/mATP was also studied.The parameters,such as pH value,adsorbent dosage,temperature,initial concentration and adsorption time,were carefully investigated.In addition,the adsorption thermodynamics and kinetics of MB onto PANI/mATP was studied.Finally,the adsorption mechanism of MB onto PANI/mATP was discussed.The results show that the adsorption performance is the optimum when ATP is modified and PANI is doped by using 4.0 mol/L sulfuric acid,respectively.The adsorption ratio and amount are 96.2%and 240.5 mg/g at the temperature of 338 K and pH of 12.0 in 180 min.And the adsorption process is endothermic.The data are fitted well by using Langmuir adsorption isotherm and the pseudo-second-order kinetics.Meanwhile,the main adsorption forces in the adsorption of MB onto PANI/mATP are the hydrogen,π-πconjugate and electrostatic interaction.