氯化锂插层氮化碳材料的可控制备及吸附性能  

Preparation and Adsorption Properties of Lithium Chloride Intercalation Carbon Nitride

作　　者：位亚茹 马晶[1] 袁婷婷 姜嘉伟 段银利 薛娟琴[1] Wei Yaru;Ma Jing;Yuan Tingting;Jiang Jiawei;Duan Yinli;Xue Juanqin(School of Chemistry and Chemical Engineering,Xi’an University of Architecture and Technology,Xi'an 710055)

机构地区：[1]西安建筑科技大学化学与化工学院,西安710055

出　　处：《化学学报》2022年第4期494-502,共9页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.51874227,51402231);陕西省自然科学基金(Nos.2019JLM-43,2020JQ-677,2022KW-33)资助项目。

摘　　要：近年来,有机废水对环境造成的污染已经引起了广泛的关注.吸附法操作简单,已经被广泛用于处理染料废水.通过在类石墨相氮化碳(g-C_(3)N_(4))上用氯化锂(LiCl)插层制备了一系列 Li/GCN-x 复合材料,并采用 X 射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、N_(2)-吸脱附、场发射扫描电子显微镜(SEM)以及 X 射线光电子能谱(XPS)等对所得吸附剂的形貌和结构进行了表征.测试结果表明,g-C_(3)N_(4)具有明显的层状结构,使得 LiCl 在层间能够稳定地生长.LiCl 的加入使得 g-C_(3)N_(4)晶格膨胀,层间距扩大,表明 LiCl 成功插层.此外,插层后 Li/GCN 的比表面积远大于 g-C_(3)N_(4),扩大的比表面积以及形成的 π 共轭体系使得 Li/GCN 在吸附方面具有较大的潜力.通过控制实验条件,研究了 Li/GCN 对有机染料亚甲基蓝(MB)的吸附性能.结果表明,Li/GCN-5 吸附剂在 p H 为 6 时,5 min 吸附量可达 704 mg·g^(-1).通过动力学拟合,Li/GCN 对 MB 的吸附过程是由准二级动力学模型占主导地位.进一步通过 Weber-Morris 模型探究吸附控制过程,结果表明 MB 的吸附由表面扩散和孔内扩散共同作用,其中表面扩散占主导,且新增官能团与 MB 分子间可形成氢键,并通过 π-π 键相互作用增强吸附能力.采用共混热聚合法所制备的 Li/GCN 吸附剂具有稳定、均一、比表面积大等优点,且简单快速地实现对 MB 的吸附,克服了常用吸附剂动力学缓慢的缺点,为该材料的工业化应用提供一定的借鉴.In recent years,the pollution of organic wastewater to the environment has attracted extensive attention.The adsorption method is simple and has been used for the adsorption of organic dyes in wastewater.In this study,lithium chloride(LiCl) was intercalated on graphite like carbon nitride (g-C_(3)N_(4)),a series of Li intercalated g-C_(3)N_(4) adsorbents (Li/GCN-x)were synthesized.And use X-ray diffraction (XRD),field emission scanning electron microscopy (SEM),N_(2) adsorption-desorption and other methods to comprehensively test and characterize the phase structure,morphology,and surface area of the prepared samples.At the same time,the influence of the amount of LiCl added on the adsorption of methylene blue(MB) on the intercalation material at room temperature was investigated.The optimal Li content in the intercalation g-C_(3)N_(4)was determined.The research results show that compared with pure g-C_(3)N_(4),the prepared Li/GCN-5 can form fibers with uniform diameters between the layers,XRD results show that the addition of LiCl makes the lattice of g-C_(3)N_(4) expand and the layer spacing expand,indicating the successful intercalation of LiCl.The p H and the binding time between the adsorbent and MB were studied.The new functional groups of the adsorbent can form hydrogen bonds with MB molecules and interact through π-π bonds.When only 50 mg of the adsorbent is added,the maximum adsorption capacity can reach 704 mg·g^(-1) in 5min.In addition,adsorption kinetics simulations have been carried out.The results show that the intercalation adsorbent can adsorb MB.The model conforms to the quasi-second-order kinetic equation.The Weber-Morris model was further used to explore the adsorption control process.The results showed that the adsorption of MB was caused by the combined action of surface diffusion and intrapore diffusion,in which surface diffusion was dominant,and the newly added functional groups could form hydrogen bonds with MB molecules,and the interaction enhances the adsorption capacity through π-π

关 键 词：氮化碳 插层 吸附性能 氯化锂 动力学模拟 

分 类 号：O647.33[理学—物理化学] X703[理学—化学]