一种新型的类芬顿体系对苯甲酸的降解效果研究

摘要

A novel homogeneous Fenton like system (Fenton-like-HA system ) composed of Fe (Ⅲ),hydrogen peroxide (H2O2),and hydroxylamine (NH2OH) on the benzoic acid (BA) oxidation was studied.Compared to other systems,the Fenton-like-HA system showed notable advantages in both BA conversion and practical application due to the accelerated redox cycles of Fe (Ⅱ)/Fe (Ⅲ) by NH2OH and the widely used of Fe (Ⅲ).Besides,the BA conversion increased with the increase of H2O2,Fe (Ⅲ) and NH2OH dosages and all well fitted pseudo-first-order kinetics during the whole process.The Fenton-like-HA system showed high H2O2 utilization efficiency and HO·generation rates.The concentrations of Fe (Ⅲ) after a few seconds were kept in dynamic equilibrium (almost 5.3 μmol ·L-1) due to the role of NH2OH,which explained the pseudo-first-order kinetics of the system.The novel Fenton-like system could increase the BA oxidation,H2O2 utilization efficiency and save the dosage of iron and H2O2.Accordingly,it has great potential for practical application.%采用由三价铁离子、过氧化氢和羟胺组成的新型均相类芬顿对苯甲酸的去除进行了研究.与芬顿体系、类芬顿体系相比,新型类芬顿体系由于加入了羟胺,而羟胺能够加速三价铁和二价铁的循环,同时不对自由基有明显的抑制.因此,苯甲酸的去除随着过氧化氢,三价铁离子以及羟胺投量的增加而增加,所有反应过程均符合拟一级动力学,拟一级速率常数超过传统芬顿体系的3～4倍.相比于传统体系,新型的类芬顿体系显示出了很高的过氧化氢利用效率以及羟基自由基的产生速度.羟胺的加入使得三价铁离子在整个反应过程中维持一个相对稳定的浓度(5.3 μmol · L-1),从而解释了新型类芬顿体系符合拟一级动力学的原因.这种新型的类芬顿体系可以增加苯甲酸的去除,增加过氧化氢的利用率并且节省三价铁以及过氧化氢的投加量,具有较大的实际应用前景.