改性沸石对诺氟沙星的吸附行为及机理

Adsorption Behavior and Mechanism of Norfloxacin by Modified Zeolite

利用酸、碱、盐浸泡改性和高温焙烧改性等方法对天然斜发沸石(NZ)进行改性,研究改性后的沸石对诺氟沙星的吸附特性.通过扫描电子显微镜(SEM)、比表面积测定仪(BET)、X射线衍射仪(XRD)对沸石表征,盐酸改性沸石(HAMZ)的比表面积相比NZ的比表面积由6.55 m2/g增大到9.53 m2/g,细孔容积由4.75 mm3/g增大到11.49mm3/g,孔道中原有半径较大的阳离子减少,吸附活性中心增加.HAMZ对诺氟沙星(NX)的最大吸附量提高了41.0%.HAMZ对诺氟沙星的吸附动力学符合拟二级动力学模型,吸附等温线符合Langmuir模型.热力学结果表明:吸附反应为吸热反应,可自发进行,反应向着熵增加的方向进行.吸附作用力表现为静电作用力、氢键作用、电子供体-受体作用和π-π作用.该研究为水中诺氟沙星的去除提供了经济、有效的方法.

Natural zeolite（ NZ） was modified by acid,alkali,salt soaking treatments and calcination. The adsorption properties of the modified zeolite were studied. Natural zeolite and hydrochloric acid modified zeolite（ HAMZ）were characterized by Scanning Electron Microscope（ SEM）,Brunauer-Emmett-Teller（ BET） and X-ray diffraction（ XRD）. Comparing with the NZ,the surface area of HAMZ increased from 6.55 m^2/g to 9.53 m^2/g,the pore volume increased from 4.75 mm^3/g to 11.49 mm^3/g,large radii of cations were reduced in zeolite pores,and the adsorption activity centers were then increased. HAMZ could enhance the maximum adsorption capacity of Norfloxacin（ NX） by 41.0%. The adsorption kinetic of Norfloxacin by HAMZ is followed the pseudo-second-order model,and the adsorption isotherm confirms to the Langmuir model. The thermodynamic study showed that the adsorption reaction is a spontaneous endothermic reaction and the entropy increases. The adsorption forces include electrostatic force,hydrogen bonding,electron donor and acceptor interaction and π-π interaction. The study provides an economical and effective method for the removal of Norfloxacin in water.