摘要
采用纤维素/杨梅单宁复合气凝胶(CBT)为载体,用浸渍和原位还原法制备铁负载纤维素/单宁吸附剂(Fe-CBT),使用扫描电镜、傅里叶红外光谱和X射线能谱等手段对其表征,研究了三种典型氟喹诺酮类(FQs)抗生素诺氟沙星(NOR)、盐酸洛美沙星(LOM)和盐酸左氧氟沙星(LVX)的静态吸附性能.结果表明:共存阳离子Na+、K+、Mg2+和Ca2+都对吸附过程有明显的干扰.吸附过程是自发进行的放热反应,主要为单分子层吸附,而化学吸附是主要的限速步骤.准二级和Langmuir模型能很好地拟合这种吸附行为.这种吸附剂在298 K对NOR、LOM和LVX的最大理论吸附量分别达到99.07、74.17和40.14mg/g.NaOH和NaCl对Fe-CBT都表现出较优的洗脱效果,用NaOH和NaCl溶液4次再生后Fe-CBT对NOR的吸附能力仍高于70％.Fe-CBT对FQs的去除,主要是静电引力、表面络合、氢键和π-π堆积间的协同作用造成的.
Abstract
The absorbent of Fe-loaded cellulose/bayberry tannin(Fe-CBT)was prepared via impreg-nation and in-situ reduction process,with cellulose/tannin composite aerogel(CBT)as the carrier,which then was characterized by means of scanning electron microscopy,Fourier infrared spectroscopy and X-ray energy dispersive spectroscopy.Afterwards,the adsorption characteristic of the Fe-CBT was compar-atively assessed for three typical fluoroquinolones(FQs)antibiotics,i.e.,norfloxacin(NOR),lomefloxacin hydrochloride(LOM)and levofloxacin hydrochloride(LVX).The results show that the coexistence of cat-ions Na+,K+,Mg2+and Ca2+all interferes significantly with the adsorption process.Moreover,the adsorp-tion process is an exothermic reaction that proceeds spontaneously,mainly as single-molecule layer ad-sorption,of which chemisorption is the main rate-limiting step.The quasi-secondary and Langmuir mod-els are demonstrated to fit this adsorption behavior,and the maximum theoretical adsorption capacity of 99.07,74.17 and 40.14 mg/g can be achieved for NOR,LOM and LVX at 298 K,respectively.Both NaOH and NaCl show superior elution effect on Fe-CBT,namely,after re-generation for four times with NaOH and NaCl solutions,the adsorption capacity of Fe-CBT on NOR could even be maintained＞70％.In addi-tion,it is found that the removal of FQs by Fe-CBT is caused by the synergy between electrostatic gravita-tion,surface complexation,hydrogen bonding and π-π stacking.
维普
万方数据