改性凹凸棒土对尾菜废水中磷的吸附性能研究

Study on the Adsorption Performance of Modified Attapulgite for Phosphorus in Vegetable Wastewater

摘要: 尾菜废水中含大量磷元素，随意排放容易导致水体富营养化，导致一系列环境问题的产生。本文以天然凹凸棒土(ATP)为原料，利用AlCl3∙6H2O对其进行处理制得改性凹凸棒土(AL-ATP)，用于尾菜废水中磷的吸附研究。考察了改性剂浓度、不同pH、吸附时间、吸附温度及不同投加量对改性凹凸棒土除磷效果的影响。并通过扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)等测试手段进行表征，分析改性凹凸棒土的吸附机制。结果表明，AL-ATP对磷的去除效率高于ATP，当AlCl3∙6H2O浓度为2 mol/L时AL-ATP对磷的去除效果最好，最大理论吸附量可达1.09 mg/g。AL-ATP的吸附符合Freundlich等温方程和准二级动力学方程。AL-ATP对磷的吸附性能提升的主要原因在于AlCl3∙6H2O改变了凹凸棒土的孔隙结构并增加吸附点位。

Abstract: The vegetable wastewater contains a large amount of phosphorus, which can easily lead to eutrophication of water body and a series of environmental problems. In this paper, natural attapulgite (ATP) was used as raw material, and modified attapulgite (AL-ATP) was prepared by treating it with AlCl3·6H2O, which was used for the adsorption of phosphorus in vegetable wastewater. The effects of modifier concentration, different pH, adsorption time, adsorption temperature and different dosage on phosphorus removal efficiency of modified attapulgite were investigated. The adsorption mechanism of modified attapulgite was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results show that the phosphorus removal efficiency of AL-ATP is higher than that of ATP. When the concentration of AlCl3∙6H2O is 2 mol/L, the phosphorus removal efficiency of AL-ATP is the best, and the maximum theoretical adsorption amount can reach 1.09 mg/g. The adsorption of AL-ATP conforms to the Freundlich isotherm equation and the quasi-second order kinetic equation. The main reason for the improvement of phosphorus adsorption performance of AL-ATP is that AlCl3·6H2O changes the pore structure of attapulgite and increases the adsorption point.