酚醛基质苯并咪唑螯合树脂的合成及配位性能

Synthesis,Characterization and Adsorption toward Divalent-ions of Bisbenzimidazole Supported on Phenol-formaldehyde

通过1,4-对苯二酚二缩水甘油醚和2,2'-二苯并咪唑二乙胺反应合成四苯并咪唑单体(TBMZ),经甲醛等缩合生成酚醛聚合物为基质的苯并咪唑螯合树脂(PTBMZs)。新型螯合树脂配基含量达2.1～3.02 mmol/g。新树脂及其单体结构经13 C核磁共振谱、FT-IR红外光谱、元素分析和DSC分析确证。测定了Cu2+、Ni2+、Zn2+、Cd2+和Co2+氯化物在pH值为1.0～6.0的缓冲溶液中的配位容量。实验结果表明,该类螯合树脂对Cu2+有高度的选择性,KCXu≥4.3非竞争条件下,PTBMZ-1的最大配位容量为1.15 mmol/g(pH=5.0,Cu2+),PTBMZ-2的最大配位容量为0.97 mmol/g(pH=5.0,Cu2+),配基占有率分别为35.9%,33.4%。PTBMZ-1树脂对Cu2+吸附较快,t1/2=21 min。电子顺磁共振谱和FT-IR光谱分析结果表明,形成n(金属离子)∶n(配基)=1∶2的螯合物为主。

A couple of new benzimidazole chelating resins, bisbenzimidazole supported on phenol-formaldehyde （PTBMZs）, were synthesized by phenolformaldehyde condensation of tetrabenzimidazole ligand. The PTBMZs have a 2. 06 - 3.02 mmol of ligand content per gram of the resin. Their structures were characterized by solid- state ^13C crossing-polarization and .magic-angle spinning （CP MAS ） NMR, FF-IR spectroscopy. Batch adsorption capacities were determined for the chloride of some divalent metal cations in buffer solutions in the pH rang of 1.0 to 6. 0. The adsorption capacities of the PTBMZ-1 under non-competitive condition are 1.15 mmol/g for Cu2~ at pH = 5 and the ligand occupations are 35.7%. Elemental analysis and electron paramagnetic resonance（EPR） studies suggested that complexes with the metal cation to ligand ratio of mainly 1：2 were formed on the BBEAH modified resins via tridentate chalete structure.