Graphite rod surface by potential cycling. No interference effect of the most common ions such as sodium, potassium, chloride, nitrate, iodide, calcium, zinc, aluminum, sulfate and sorbitol was observed during electrochemical determination of fluoride. The graphite felt was oxidized at a positive electrode potential in sulfuric acid solution. The electrochemical performance of the treated graphite felt served as electrode for vanadium redox battery was investigated with FT-IR, On the other hand, the PAPBA/GR electrode showed not only good sensitivity and selectivity, but also relatively rapid response to changes of analyte concentrations in the range of 20s.
The PAPBA-modified graphite rod (PAPBA/GR) electrode prepared in this way was used for potentiometric fluoride determination. The linear calibration range was from 5x10(-4) to 5x10(-2)M with the slope of the linear part of the calibration curve of 42.5mV/logC. SEM, XPS, BET, cyclic voltammetry and testing VRB system, respectively. The results show that the molar ratio of O to C increases from 0.085 to 0.15 due to the increase of —COOH functional groups during electrochemical oxidation treatment, and the GF surface is eroded by electrochemical oxidation, resulting in the surface area increase from 0.33 m2/g to 0.49 m2/g. The VRB with modified GF electrode exhibits excellent performance under a current density of 30 mA/cm2. The average current efficiency reaches 94% and average voltage efficiency reaches 85%. The improvement of electrochemical activity for the electrode is ascribed to the increase of the number of —COOH group and the special surface of GF.
