The development of a pH-tolerant Fenton-like catalyst is a active and challenging project in the field of environmental catalysis. In this work, an efficient Fenton-like catalytic fibers (Cit-Fe@ACFs) with pH-tolerance has been prepared by an extremely simple impregnation method. First, activated carbon fibers (ACFs) were impregnated into a nitric acid solution at 25 ℃ for 24 h to obtain acidified ACFs, and then immersed in a sodium citrate solution at 25 ℃ for 2 h, which was taken out to put into ferric chloride solution at 25 ℃ for 2 h. The treated ACFs were rinsed with distilled water and dried at room temperature to obtain the Cit-Fe@ACFs. Cit-Fe@ACFs exhibited efficient catalytic activity for the activation of hydrogen peroxide at neutral pH to degrade dyes, including reactive, acid, and basic dyes, etc. The UV-vis spectroscopy showed that reactive brilliant red M-3BE (RR M-3BE) was eliminated completely in 15 min (Cit-Fe@ACFs: 12 g/L; H2O2: 60 mmol/L; RR M-3BE: 5×10-5 mol/L; pH 7; T=50 ℃). Moreover, the catalyst presented excellent regeneration capability and sustained catalytic ability in these experiments. Importantly, the Cit-Fe@ACFs/H2O2 catalytic system exhibited remarkable catalytic activity across a wider pH range (2～10) and the values of apparent rate constant (kapp) were greater than 0.320 min-1, which was efficient to expand the pH range for the traditional Fenton reaction. Various scavengers and probe compounds (n-butanol, benzoquinone) combined with electron paramagnetic resonance (EPR) spectroscopy were used to identify the active species involved in the catalytic system. The results revealed that the hydroxyl radicals (·OH) and superoxide radical (HO2·) may be responsible for the degradation of dyes. This paper discusses a possible catalytic oxidation mechanism in the Cit-Fe@ACFs/H2O2 system, which may be a feasible approach for the elimination of widely existing pollutants.
王列, 姚玉元, 孙利杰, 吕汪洋, 陈文兴. 活性炭纤维耦合柠檬酸铁在中性pH条件下活化双氧水降解染料[J]. 化学学报, 2013, 71(12): 1633-1638.
Wang Lie, Yao Yuyuan, Sun Lijie, Lü Wangyang, Chen Wenxing. Activation of Hydrogen Peroxide by Activated Carbon Fibers Coupled with Fe(Ⅲ)-Citrate for Degradation of Dyes at Neutral pH. Acta Chimica Sinica, 2013, 71(12): 1633-1638.