改性海泡石对水体中砷的吸附研究

Study on Adsorption of Modified Sepiolite to Arsenic in Water

采用FeSO_(4)溶液对海泡石改性,制备出一种简单高效的吸附剂。利用X射线荧光光谱分析(XRF)、X射线衍射分析(XRD)、傅里叶红外光谱分析(FTIR)以及扫描电镜(SEM)对海泡石进行表征。研究该材料对As(V)和As(Ⅲ)的吸附和影响因素。结果表明:在溶液初始浓度为200μg/L时,pH为6、接触时间为120min、投加量为1g/L时,对As(V)和As(Ⅲ)去除率分别为97%和90%。6种阴离子对砷吸附的抑制强度为:PO_(4)^(3-)>HPO_(4)^(2-)>H_(2)PO_(4)^(-)>CO_(3)^(2-)>HCO_(3)^(-)>Cl^(-)。对吸附过程进行拟合,改性海泡石对As(V)和As(Ⅲ)动力学更符合二级动力学方程,Langmuir和Freundlich吸附等温方程均能很好地描述改性海泡石对砷的吸附过程,由Langmuir吸附模型计算出As(V)和As(Ⅲ)的吸附量分别为2.0mg/g和1.43mg/g,是原始海泡石的25倍和30倍。

Sepiolite was modified with FeSO_(4) solution to prepare a simple and efficient adsorbent.X-ray fluorescence spectroscopy(XRF),X-ray diffraction analysis(XRD),Fourier infrared spectroscopy(FTIR)and scanning electron microscopy(SEM)were used to characterize sepiolite.And the material's adsorption of As(Ⅴ)and As(Ⅲ)and influencing factors were studied.The experimental results show that when the initial concentration of the solution is 200μg/L,the pH is 6,the contact time is 120min,and the dosage is 1g/L,the removal rates of As(V)and As(III)are 97%and 90%,respectively.The inhibition strength of six anions on arsenic adsorption is:PO_(4)^(3-)>HPO_(4)^(2-)>H_(2)PO_(4)^(-)>CO_(3)^(2-)>HCO_(3)^(-)>Cl^(-).Fitting of adsorption kinetics reveals that the kinetics of As(Ⅴ)and As(Ⅲ)in modified sepiolite are more in line with the second-order kinetic equation.Both Langmuir and Freundlich adsorption isotherm equations can describe the adsorption process of modified sepiolite to arsenic,the adsorption amount of As(Ⅴ)and As(Ⅲ)calculated by the Langmuir adsorption model is 2.0mg/g and 1.43mg/g,which are 25times and 30times of the original sepiolite.