两种纳米颗粒对沸石吸附环丙沙星的影响

Effect of Two Types of Nanoparticles on the Adsorption of Ciprofloxacin on Zeolite

为了探明纳米颗粒(NPs)共存对抗生素在黏土矿物上的吸附的影响,以沸石为供试黏土矿物,环丙沙星(CIP)为目标污染物,研究了不同温度、pH值和离子强度条件下,纳米氧化锌(ZnO NPs)和纳米二氧化钛(TiO_(2) NPs)这2种NPs对沸石吸附CIP的影响,并结合沸石的表面特征探讨不同类型NPs对CIP吸附的影响机制.结果表明,除5 mg·L^(-1)ZnO NPs共存时,轻微促进了CIP的吸附,其他NPs浓度均对CIP产生不同程度的抑制,抑制程度表现出TiO_(2) NPs>ZnO NPs的顺序;随温度升高,NPs的存在增强了沸石对CIP吸附的增温正效应;当离子强度由0.001 mol·L^(-1)增加到0.01 mol·L^(-1)时,CIP的吸附量下降,但2种NPs的存在均减弱了离子强度的负效应;溶液pH会影响CIP的存在形态和NPs的性质,进而影响CIP的吸附.沸石对单一CIP的吸附存在静电引力、氢键和孔径填充作用,ZnO NPs主要通过静电引力竞争吸附位点对CIP吸附产生影响,而TiO_(2) NPs主要通过孔径填充和氢键作用来竞争吸附位点,二者因自身性质差异造成了影响机制的不同.

In order to explore the influence of the coexistence of nanoparticles(NPs)on the adsorption of antibiotics on clay minerals,zeolite was used as the test clay mineral,and ciprofloxacin(CIP)was used as the target pollutant.Under different temperatures,pH values,and ionic strength conditions,the effects of ZnO nanoparticles(ZnO NPs)and TiO_(2) nanoparticles(TiO_(2) NPs)on the adsorption of CIP by zeolite was studied,and the mechanism of different types of NPs on CIP adsorption was analyzed and discussed in combination with the surface properties of zeolite.The results showed that,except for that under the coexistence of 5 mg·L^(-1) ZnO NPs,the adsorption of CIP was slightly promoted,and the concentration of other NPs inhibited CIP to varying degrees.The degree of inhibition showed the order of TiO_(2) NPs>ZnO NPs.With the increase in temperature,the presence of NPs enhanced the positive effect of zeolite on CIP adsorption.When the ionic strength increased from 0.001 mol·L^(-1) to 0.01 mol·L^(-1),the adsorption capacity of CIP decreased,but the presence of both NPs weakened the negative effect of ionic strength.The pH of the solution could affect the existence of CIP and the properties of NPs and in turn affect the adsorption of CIP.The adsorption of zeolite on a single CIP exhibited electrostatic attraction,hydrogen bonding,and pore filling.ZnO NPs mainly competed for adsorption sites through electrostatic attraction to affect CIP adsorption,whereas TiO_(2) NPs mainly competed for adsorption sites through pore filling and hydrogen bonding.Their differences in nature resulted in different influence mechanisms.