氧化锌/纤维素复合材料对镉离子吸附性能的实验与密度泛函理论研究  

Adsorption of zinc oxide /cellulose composite onto cadmium ions: a combined experimental and density functional theory study

作　　者：姚晓冬[1] 王凯悦 孙媛 张继国[1] 郭元茹[1] 潘清江[2] YAO Xiaodong;WANG Kaiyue;SUN Yuan;ZHANG Jiguo;GUO Yuanru;PAN Qingjiang(College of Material Science and Engineering,Northeast Forestry University,Harbin 150040,China;School of Chemistry and Materials Science,Heilongjiang University,Harbin 150080,China)

机构地区：[1]东北林业大学材料科学与工程学院,哈尔滨150040 [2]黑龙江大学化学化工与材料学院,哈尔滨150080

出　　处：《黑龙江大学自然科学学报》2020年第2期206-212,共7页Journal of Natural Science of Heilongjiang University

基　　金：黑龙江省自然科学基金资助项目(C2018006);国家自然科学基金资助项目(21671060)。

摘　　要：采用固液非均匀体系法制备了氧化锌/纤维素(ZnO/cellulose)复合材料。XRD、SEM和FT-IR分析表明,氧化锌均匀分散在纤维素网络结构中,其中ZnO具有六方纤锌矿结构,而纤维素为I型结构。对不同pH值、浓度等条件进行了探索,并考察了所制备的复合材料对重金属镉离子的吸附性能。结果表明,在弱酸及中性(pH=4~7)条件下,复合材料对镉离子有较好的吸附能力。对吸附过程进行了Freundlich和Langmuir模型的拟合处理,结果显示吸附过程符合这两个模型,最大吸附量为43 mg·g^-1。采用密度泛函理论计算探索了复合材料吸附水合镉离子形成的复合体系模型,结构优化发现可采用Outer sphere(OS)和Inner sphere(IS)机制模式,其界面作用分别为氢键和O→Cd配位键。虽然它们具有相似的占据轨道性质,但是界面作用强度与性质差异导致了非占据轨道性质和HOMO-LUMO带隙的不同。ZnO/cellulose composite was prepared by a solid-liquid heterogeneous system method. Characterizations such as XRD, SEM and FT-IR showed that ZnO particles were evenly distributed in the network of cellulose;the ZnO was hexagonal wurtzite phase and cellulose had structure of I-type. Considering effects of different pH values and concentrations, the adsorption properties of the composite on toxic cadmium(II) ions were explored. It was found that the composite exhibited good adsorption performance in the weak acidic and neutral condition(pH=4~7). Data fitting indicated that both Freundlich and Langmuir model were suitable, and the largest adsorption capacity was 43 mg·g^-1. To provide deep insight into the interfacial behavior between the composite and Cd ions, density functional theory calculations were conducted. It showed that the adsorption modes agreed with mechanisms of Outer sphere(OS) and Inner sphere(IS). They utilized weak hydrogen bonds and O→Cd bond to stabilize their respective system. The OS and IS modes displayd similar character for occupied orbitals, but the difference of their interfacial interactions in strength and nature resulted in the difference of character of virtual orbitals and HOMO-LUMO gaps.

关 键 词：氧化锌/纤维素复合材料 吸附 镉离子 OS和IS吸附机制 密度泛函理论计算 

分 类 号：TB332[一般工业技术—材料科学与工程]