摘要
通过水杨醛(salicylideimine,SA)与四乙烯五胺(tetraethylenepentamine,TEPA)缩合反应合成了四乙烯五胺水杨醛亚胺席夫碱配体ST [ST=N, N’-tetraethylenepentaminebis(salicylideimine)],进一步与铁(Ⅲ)配位得到双核铁(Ⅲ)配合物[Fe_2(ST)(H_2O)_4]Cl_4[简写为Fe_2(ST)]。通过元素分析(EA)、红外光谱(FTIR)、紫外可见光谱(UV-Vis)等手段对其进行了表征。以其为催化剂,考察了在双氧水作用下,可见光降解水中新型环境污染物酞酸丁酯(DBP)的性能。结果表明,pH在3.5~8.0范围内,Fe_2(ST)的浓度大于5.5 mmol/L,H_2O_2的浓度大于8.2 mmol/L,10 min内催化体系可以实现对浓度小于20.0 mg/L的DBP 99%以上的降解。监测了加入H_2O_2前后的反应体系电子光谱随时间的变化,结果表明催化剂的活性位点可能为μ-N桥联的双核Fe(Ⅲ)活性中心,形成了有利于H_2O_2活化的过渡态。催化体系在循环使用10次后,对DBP的降解率仍可达95%。Fe2(ST)是具有优异潜力的水中酞酸丁酯污染物的绿色催化剂。
Schiff base ligand(ST = N, N'-tetraethylene pentaminebis(salicylideimine) was prepared by condensation reaction of salicylaldehyde(SA) and tetraethylenepentamine(TEPA), and further coordinated with iron(Ⅲ) via coordination reaction to form a binuclear iron(Ⅲ) complex, [Fe_2(ST)(H_2 O)_4]Cl_4(abbreviated as Fe_2(ST)). It was characterized by elemental analysis(EA), Fourier transform infrared spectrometer(FTIR), and ultraviolet-visible spectroscopy(UV-vis), etc. It was used as catalyst for the degradation of emerging contaminants, e. g., dibutyl phthalate(DBP) under visible light with hydrogen peroxide solution as oxidant. The results show that at pH 3.5~8.0,with the initial concentration of Fe_2(ST) complex larger than 5.5 mmol/L, and that of H_2O_2 larger than 8.2 mmol/L,the degradation of DBP at initial concentration less than 20.0 mg/L can be reached to almost 99% within 10 minutes. The catalytic reaction system has been monitored by electronic spectrum before or after adding H_2O_2 at different time intervals. The results show the catalytic activity site may be a μ-N-bridged binuclear Fe(Ⅲ) center and a di-Fe(Ⅲ)-H_2O_2 transition-state might be formed. The Fe_2(ST) can be reused after regeneration for at least 10 times with degradation percentage of DBP over 95%. The Fe_2(ST) is a potentially effective and green catalyst for the degradation of DBP.
引文
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