In this work, γ-Fe2O3/CNTs composite was facile synthesized by simple hydrothermal method and hydrazine hydrate treatment at low temperature (CNTs = carbon nanotubes). The result of VSM shows that the saturation magnetization of Fe2O3/CNTs composites increase from 0 to 1.29 emu g−1 after hydrazine hydrate treatment, indicating that the Fe2O3 in the composite transforms from α phase to γ phase. Moreover, the electrochemical properties of both α-Fe2O3/CNTs and γ-Fe2O3/CNTs was studied. Compared with α-Fe2O3/CNTs, γ-Fe2O3/CNTs shows enhanced electrochemical performance toward paracetamol determination. Under optimum condition, the γ-Fe2O3/CNTs modified electrode exhibits two linear ranges of 2.5 μM−385 μM and 593 μM−1550 μM and a low detection limit of 0.046 μM. In addition, the constructed sensor can be successfully utilized for detecting paracetamol in different water bodies. This work provides a new clue for the design and construction of excellent electrochemical sensor for paracetamol determination.
Yuanchuan Ren,Jun Wang,Guangfei Qu,Nanqi Ren,Ping Lu,Xiuping Chen,Zuoliang Wang,Yuyi Yang,Yan Hu
Three-dimensional electrochemical reactor (3DER) is an efficient technology for the treatment of printing and dyeing wastewater. The particle electrode between anode and cathode is the core unit of 3DER, which determines the treatment efficiency of wastewater. However, the deactivation of the particle electrode caused by the coverage of the catalytic sites seriously hindered the continuous operation of 3DER. In this work, γ-Fe 2 O 3 @CNTs particle electrode was prepared by immersion calcination , and its performance was evaluated by degradation of Rhodamine B (RhB) wastewater in 3DER. The study showed that in γ-Fe 2 O 3 @CNTs/Mn@FNE-3DER, the removal rate of RhB reached the best of 99.16% within 7 min under the conditions of γ-Fe 2 O 3 @CNTs dosage of 1.00 g·L -1 , initial RhB concentration of 100 mg·L -1 , pH 7.0, and current density of 20 mA·cm −2 . The superior catalytic activity of the system is mainly due to the charge transfer channel in γ-Fe 2 O 3 @CNTs structure, which improves the mass transfer efficiency of electrons. According to LC-MS analysis, the degradation process of RhB can be divided into five stages: deethylation, chromophore cracking, debenzylation and deamination, ring opening and mineralization. Hydroxyl radicals play an important role in this process. After the reaction, most RhB is converted into CO 2 and H 2 O. In addition, the study also showed that the Fe 3+ /Fe 2+ circulating system formed between the anode and cathode was the important reason for the high degradation efficiency of RhB. After five cycles of experiments, the degradation efficiency of 92.55% was still maintained, indicating that the particle electrode has significant stability and reusability in the catalytic process. To sum up, the excellent performance of γ-Fe 2 O 3 @CNTs particle electrode in three-dimensional electrochemical system provides a promising idea for the actual treatment of printing and dyeing wastewater.
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