聚羟基铝柱撑蛭石对废水中Sb(Ⅲ)的去除性能研究

Study on adsorption performance of Al_(30)-pillared vermiculite to Sb(Ⅲ)in wastewater

采用铝的多聚物Al_(30)对蛭石进行柱撑制备聚羟基铝柱撑蛭石(Al-VMT),考察初始pH、Al-VMT投加量、时间、温度等因素对去除Sb(Ⅲ)的影响。利用扫描电子显微镜、能谱仪、X射线衍射、X射线光电子能谱仪和傅里叶红外光谱仪对材料进行表征。该吸附过程符合拟二级动力学和颗粒内扩散模型,Langmuir和Freundlich吸附等温线模型均能很好地描述Al-VMT对Sb(Ⅲ)的吸附行为。结果表明,通过酸预处理以及聚羟基铝柱撑成功对蛭石进行了改性;Al-VMT对Sb(Ⅲ)的吸附机理主要包括静电吸附以及与羟基(—OH)的配位络合等;经过4次吸附-解吸循环后,Sb(Ⅲ)去除率仍达80%以上。

Polyhydroxyaluminum pillared vermiculite(AI-VMT)is prepared through pillaring vermiculite by polymers of aluminum(Al_(30)).The effects of initial pH,dosage of Al-VMT,time and temperature on the removal of Sb(Ⅲ)from wastewater are investigated.The maximum adsorption capacity is 23.82 mg·g-1 under the optimum conditions.AI-VMT is characterized by means of scanning electron microscope,energy spectrometer,X-ray diffraction,X-ray photoelectron spectroscopy,and Fourier transform infrared spectroscopy.It is found that this adsorption process accords with the pseudo-second-order kinetics and intra particle diffusion mode.Both Langmuir and Freundlich adsorption isotherm models can well describe the adsorption behavior of Sb(Ⅲ)by Al-VMT.It is verified that vermiculite is successfully modified by acid pretreatment and Al_(30)pillaring.The adsorption mechanism of Sb(Ⅲ)by Al-VMT mainly includes electrostatic adsorption and coordination complexation with hydroxyl(—OH).After four cycles of adsorption-desorption,the adsorption efficiency of Al-VMT to Sb(Ⅲ)is still over 80%.