Fe_(3)O_(4)@PANI-PG硼吸附剂的制备、表征及其吸附性能

Preparation,characterization,adsorption performance and mechanism of Fe_(3)O_(4)@PANI-PG boron adsorbent

基于磁性分离原理,设计并制备了一种磁性多元醇硼吸附剂,有效解决了传统吸附剂与水相分离困难问题。首先,以苯胺为单体,采用原位聚合反应在自制的磁性Fe_(3)O_(4)纳米颗粒表面包裹了一层聚苯胺(PANI),然后通过缩水甘油与聚苯胺末端活性胺基开环反应,制备了一种核壳结构的多元醇硼吸附剂:丙二醇改性聚苯胺复合四氧化三铁(Fe_(3)O_(4)@PANI-PG);采用SEM、TEM、EDS、XRD、XPS和FTIR等表征方法对材料的微观形貌、结构、组成及官能团进行了表征。其次,通过单因素实验考察了吸附时间、硼酸初始浓度、pH等因素对其硼吸附性能的影响,在此基础上采用响应面法优化得到了吸附最佳条件:时间t=10 h,初始浓度C_(0)=1309 mg/L,pH=9.93和相应最佳吸附量Q_(e)=0.1181 mmol/g。此外,通过吸附动力学及吸附等温式拟合,研究发现该吸附剂对硼吸附过程符合准二级吸附动力学和Langmuir等温吸附模型。最后对其吸附机制进行探究,研究发现:该吸附剂末端邻位羟基与水相中的B(OH)_(4)^(-)发生络合反应形成了稳定的五元环螯合物。

In this paper,the traditional difficult problem of separation between adsorbent and water phase was effectively solved by a kind of magnetic polyols boron adsorbent,which were designed and prepared based on the principle of magnetic separation.Firstly,the polyaniline compound Fe_(3)O_(4)(Fe_(3)O_(4)@PANI) composites with coreshell structure were prepared by the in-situ polymerization reaction at the presence of aniline and Fe_(3)O_(4) nanoparticles,which were prepared by ourselves.Then propylene glycol modified polyaniline compound Fe_(3)O_(4)(Fe_(3)O_(4)@PANI-PG) boron adsorbent was successfully prepared by the ring-opening reaction between polyaniline terminal active-NH_(2) and glycidyl.After that,the micro-structure,composition and functional groups were analyzed by the SEM,TEM,EDS,XRD,XPS and FTIR,respectively.The adsorption time,initial concentration of boric acid,pH and other factors of Fe_(3)O_(4)@PANI-PG were investigated by the single factor experiment.On this basis,the optimal adsorption conditions(time t=10 h,initial concentration C0=1 309 mg/L,pH=9.93) were obtained by response surface method,and the corresponding optimal adsorption capacity up to Qe=0.1181 mmol/g.In addition,it was found that the adsorption process was in accordance with the quasi-second-order adsorption kinetics and Langmuir adsorption isotherm based on the adsorption kinetics and adsorption isotherm fitting.Finally,the adsorption mechanism of Fe_(3)O_(4)@PANI-PG was explored and the results indicating the complex reaction between the hydroxyl group at the end of the adsorbent and B(OH)4-in the aqueous phase formed a stable five-membered ring chelate.