多功能棉纤维的制备及其识别并吸附水体重金属镉的机理研究

Cadmium (Cd), as one of the heavy metal ions in water, is a toxic and persistent pollutant to the environment and human health. It needs to be detected and simultaneously removed with the integrated technology. This project will prepare a multi-functional material with cotton fiber as the substrate, from which two different polymer chains are grafted through the Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP) technology, and subsequently chemically modified by amine groups to obtain two functions - detection and adsorption of cadmium. The main research contents will include the optimization of the multi-functional cotton fiber (MFCF)'s preparation, the characterization of MFCF, performance and mechanism of Cd detection / adsorption with MFCF, and dynamic Cd detection / adsorption experiments. The analytical methods including X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Fine Structure (XAFS) will be used to illustrate the detection and adsorption mechanism, including the explanation of the coordination, electrostatic force, and physical adsorption that may possibly exist between Cd and MFCF, and discussion of the changes for the coordination structure during Cd detection and adsorption. The multi-functional cotton fiber of this project would have a great prospect of application in the fast detection and efficient adsorption of Cd. In addition, the research work for the demonstration of the detection and adsorption mechanism would provide theoretical bases for the structural design of other multi-functional materials.

水体中的重金属镉是一种毒性极强的累积型环境污染物，严重危害人类健康，迫切需要可及时发现并将其快速去除的一体化处理。本项目将采用棉纤维作为基质材料，利用两阶段SI-ATRP（表面引发原子转移自由基聚合）方法在其表面接枝两种高分子的共聚链段，并对其进行胺基改性，制备对镉兼备识别及吸附功能的多功能材料。本项目主要研究内容包括多功能棉纤维的制备条件及优化，性能表征，识别及吸附镉的特性及机理研究，以及动态识别/吸附实验。本项目拟采用X-射线光电子能谱（XPS）、X-射线吸收精细光谱（XAFS）等分析手段深入阐明其识别及吸附机理，对镉与多功能棉纤维之间可能存在的络合、静电、物理吸附等作用予以阐明，对识别及吸附过程中镉与识别、吸附基团之间络合结构的变化规律进行深入探讨。该项目研究的多功能棉纤维对快速识别及高效吸附重金属镉具有很好的应用前景，其识别与吸附机理研究将为其他多功能材料的结构设计提供理论基础。

随着政府和公众对加大环保力度的强烈要求，水体被重金属污染后“第一时间发现，第一时间治理”的处理模式对重金属的有效治理有着重要的意义。本项目采用棉纤维作为基质材料，主要利用SI-ATRP（表面引发原子转移自由基聚合）方法在其表面接枝聚合物刷，并对其进行胺化、卟啉化改性，制备对重金属镉污染兼备预警（识别）以及修复（吸附）功能的多功能棉纤维，开展了多功能棉纤维的制备条件及优化、性能表征、识别及吸附重金属镉的特性以及识别吸附机理等一系列的研究。主要结果包括：（1）利用SI-ATRP技术及表面改性技术，成功制备了接枝双功能聚合物刷的多功能棉纤维，并优化了制备方法；（2）对多功能棉纤维进行了SEM、FTIR、XPS等仪器表征，阐明了其表面形貌、基团组成以及表面元素构成等参数；（3）研究了多功能棉纤维对重金属镉的吸附性能，对吸附动力学、吸附等温线以及影响因素的作用做出阐述。研究了多功能棉纤维通过颜色变化识别重金属镉的特性，确立了颜色变化与重金属镉浓度的关系曲线；（4）探讨并阐明了多功能棉纤维吸附和识别重金属镉的络合机理。该项目所研制的多功能棉纤维将在环境应急监测与治理方面具有实际意义和潜在应用，其制备研究将为其它多功能吸附剂的制备提供实验依据，其对重金属镉识别和吸附的研究将为针对其它重金属的多功能吸附剂的设计与应用提供理论基础。