高剂量亚铁Fenton反应及形成次生铁矿物的特性

Characteristics of the Fenton process and formation of secondary iron minerals with the high dosage of Fe^(2+)

通过测定pH值、氧化还原电位(ORP)、溶解态铁离子和H2O2浓度等在Fenton反应中(初始Fe2+浓度为10~200mM)的变化,考察了葡萄糖、苯酚等对Fenton反应过程的影响,分析了生成的次生铁矿物组成.结果表明:初始Fe2+浓度≥50mM条件下的瞬时ORP和pH值随n(H2O2):n(Fe2+)摩尔比的增加呈先递增后快速降低的变化过程.初始葡萄糖和苯酚浓度为4.17mM、初始葡萄糖浓度为8.33mM时的H2O2基本耗尽时间分别约为15,10,2min;初始苯酚浓度为8.33mM、初始葡萄糖和苯酚浓度为16.66mM时的Fe2+浓度至60min末分别为7.40,27.40,58.83mM.初始pH值为3.3时Fenton反应形成的次生铁矿物经XRD分析初步鉴定为施氏矿物,其中添加葡萄糖或苯酚的Fenton反应生成的球形次生铁矿物其表面形成刺突.

The effects of glucose and phenol dosage on Fenton process were investigated by analysis of pH,ORP,dissolved iron ion and H2O2 levels during Fenton oxidation with[Fe2+]0of 10—200mM.The identification of secondary iron mineral was carried by XRD,SEM and BET.The results show that the instantaneous pH and ORP values at the end of 1 min increased gradually and then decreased rapidly with the increasing of n(H2O2)/n(Fe2+)molar ratio as[Fe2+]0≥50mM.At the initial conditions of[Fe2+]0of 200 mM,[H2O2]0of 200 mM and pH of 3.3,the addition of 4.17 mM glucose,4.17 mM phenol and 8.33 mM glucose resulted in the exhaustion of H2O2 after 15,10 and 2min,respectively,while the dosage of 8.33 mM phenol,16.66 mM glucose and 16.66 mM phenol lead to Fe2+concentration of 7.40,27.40 and 58.83 mM,respectively,after 60 min.The secondary iron minerals formed from Fenton reaction at the initial pH of 3.3 were identified as schwertmannite by XRD,among which the particles formed with addition of glucose or phenol were composed of spheroids with surface spikes.