煤/聚乙烯亚胺交联复合螯合吸附剂制备及其对重金属离子的协同作用机制研究

Coal is a kind of organic mineral rock and contains rich active functional groups and pore structure.According to the physical and chemical characteristics of coal, this project adopts the high-energy ball milling process preparing superfine pulverized coal to increase its surface activity.In order to increase the chelating properties for heavy metal ions,polyethyleneimine（PEI）was grafted on the coal macromolecular structure.The active function group of coal and grafted group reacted with cross-linking agent to prepare coal/PEI composite chelation adsorption material,which has excellent chelation and adsorption properties,good mechanical properties and chemical stability.Effects of different grafting, crosslinking methods and processes on the structure and characteristic of product were discussed. The mechanisim of chemical grafting and crosslinking of coal with PEI and crosslink agent was illustrated.The physical and chemical structure of composite material was confirmed and the structure model was established.The properties of crosslinked coal/polyethyleneimine composite chelation and adsorption material for aqueous solution of Pb2+, Co2+, Ni2+, Cd2+, Cr6+ and the selective rule were investigated through static experiment.The chelation and adsorption synergism mechanism of coal/PEI crosslinked composite chelating adsorption material for heavy metal ions were confirmed.This project willexplore a new way for coal high efficiency utilization and controlling of heavy metal pollution.

煤是一种有机矿物岩石，含有丰富的活性官能团和孔隙结构。本项目根据煤的物理化学结构特点，采用高能球磨制备超微煤粉以增加其表面活性。通过化学接枝将聚乙烯亚胺（PEI）引入煤的大分子结构中以增加其对重金属离子的螯合性能。将煤表面的接枝基团与交联剂进行化学交联成型制备既具优异螯合吸附性能和良好机械性能及化学稳定性的煤/聚乙烯亚胺交联复合螯合吸附剂。考察不同接枝、交联方法和工艺对产品结构和性能的影响并对其进行表征。探明煤化学接枝聚乙烯亚胺及其化学交联成型的化学反应机制，明确煤/聚乙烯亚胺交联复合螯合吸附剂的物理化学结构并建立结构模型。通过静态实验考察煤/聚乙烯亚胺交联复合螯合吸附剂对水溶液中Pb2+、Co2+、Ni2+、Cd2+、Cr6+等的吸附螯合性能及选择性规律，阐明煤/聚乙烯亚胺复合螯合吸附剂对重金属离子的吸附、螯合协同作用机制，探索煤高附加值利用和重金属污染治理新途经。

本项目选择三种不同变质程度的煤样为原料，采用高能球磨偶联改性制备超微煤粉，通过化学接枝将聚乙烯亚胺（PEI）引入煤的大分子结构，将煤表面接枝基团与交联剂环氧氯丙烷进行化学交联成型制备了具有优异螯合性能和良好吸附性能的煤基复合螯合吸附剂。考察了制备方法、制备工艺等对产品性能的影响，表征了产品的物理化学结构，考察了其对模拟废水和实际废水中重金属离子的去除效果，建立了煤基复合螯合吸附剂物理化学结构模型和螯合吸附协同作用机理。. 研究表明，所研究的三种不同变质程度的煤样中，以褐煤为基体所制产品的性能最好。通过机械力化学KH550偶联改性、化学接枝PEI后采用环氧氯丙烷交联成型，成功制备煤/聚乙烯亚胺交联复合螯合吸附剂。KH550/煤粉=1.5%，球磨4h。改性煤粉与PEI接枝反应温度40℃，时间3h，煤粉:PEI=35:1。交联温度40℃，交联时间3h，煤粉:交联剂=5:1。. 通过静态实验考察了煤/聚乙烯亚胺交联复合螯合吸附剂对模拟废水和冶炼、化学镀镍等实际废水中Cu2+、Pb2+、Ni2+、Cd2+和Cr6+等的吸附螯合性能及选择性规律，阐明煤/聚乙烯亚胺交联复合螯合吸附剂对重金属离子的吸附、螯合协同作用机制。煤/PEI交联复合螯合吸附剂对5种重金属离子的吸附符合二级吸附动力学模型和Freundlich等温模型。实验条件下，交联复合螯合吸附剂对Cu2+、Pb2+、Ni2+、Cd2+、Cr6+的饱和吸附量分别为79.26、74.44、65.28、63.77和30.44mg/g，吸附去除效果好且具有一定的选择性。考察了酸、碱溶液和超声波等不同方法对吸附饱和复合螯合吸附剂的脱附再生方法，HCl溶液脱附效果最好。. 通过对煤/聚乙烯亚胺交联复合螯合吸附剂制备过程和吸附前后FTIR、SEM、元素组成、孔结构等分析对比，提出了煤/聚乙烯亚胺交联复合螯合吸附剂与重金属离子作用的机制。煤/PEI交联复合螯合吸附剂具有丰富的孔隙结构和丰富的螯合功能团，吸附和螯合可以起到协同作用。项目研究煤的高附加值利用和重金属污染治理提供新的途径。