壳聚糖/磁性铁凹凸棒石对四环素的吸附研究

Study of adsorption for tetracyclin with chitosan/magnetic iron attapulgite

将纳米磁性氧化铁负载于改性凹凸棒石,之后利用壳聚糖对其进行包覆,并以戊二醛为交联剂使其充分交联,制备得到壳聚糖/磁性铁改性凹凸棒石复合材料,并利用透射电镜(TEM)、X射线衍射(XRD)、傅里叶红外光谱(FTIR)和X光电子能谱(XPS)对复合材料的结构进行系统表征。将该复合材料应用于对四环素废水的吸附处理,结果发现该材料对水中的四环素具有较高的吸附量,在298 K下可达184.96 mg/g,远高于凹凸棒石和壳聚糖的吸附量,且吸附材料易于与废水分离。对其吸附特性进行研究,发现其在酸性条件下对四环素的吸附量明显高于碱性条件下,当pH=5时达到最高;吸附过程符合准二级动力学方程和Sips模型,说明四环素主要通过化学作用被复合材料吸附,且材料表面均匀;材料对四环素的吸附机理包括螯合、静电吸附、硅酸盐键合、氢键连接及π-π堆积等。

Nano magnetic iron oxide was loaded onto modified attapulgite,which was coated with chitosan and fully crosslinked with glutaraldehyde,to get a chitosan/magnetic iron modified attapulgite composite material.The struc⁃ture of the composite material was systematically characterized by transmission electron microscopy(TEM),X-ray diffraction(XRD),fourier transform infrared spectroscopy(FTIR),and X-ray photoelectron spectroscopy(XPS).The composite was used for removal of tetracycline from wastewater,the results exhibited that the material owned high adsorption capacity of tetracycline from water.When the temperature was 298 K,the maximum could be 184.96 mg/g,which was much higher than that of attpulgite and chitosan.And the adsorbent could be easily sepa⁃rated from wastewater.Studying its adsorption characteristics,it was found that its adsorption capacity for tetracy⁃cline under acidic conditions was significantly higher than that under alkaline conditions and the adsorption capac⁃ity reached its maximum at pH=5.The adsorption process conformed to the quasi second-order kinetic equation and Sips model,indicating that tetracycline was mainly adsorbed by composite materials through chemical reactions,and the material surface was uniform.The adsorption mechanisms of materials for tetracycline included chelation,electrostatic adsorption,silicate bonding,hydrogen bonding,and π-π stacking.