No abstract

Here, CeO2 was used as the sole oxidant for pyrrole polymerization via in-situ chemical oxidation, and polypyrrole (PPy) was grown on the CeO2 surface to form CeO2-PPy nanocomposites. The morphology of CeO2-PPy nanocomposites was observed using SEM. The electrochemical corrosion behavior of the coatings in 3.5 wt% NaCl solution was investigated through electrochemical impedance spectroscopy (EIS) measurements. After 40 days of immersion, the coating with CeO2-PPy nanocomposite fillers exhibited outstanding anti-corrosion performance, and the |Z|0.01 Hz value exceeded 108 Ω·cm2, which was one order of magnitude higher than of the pure epoxy coating. The enhanced corrosion protection was attributed to the complex passive film produced by the synergistic effect of PPy and cerium(Ⅲ) ions. The results showed that CeO2-PPy nanocomposites can be used as fillers for the corrosion protection of steel substrates.

Pesticide wastewater is difficult to treat, and it is necessary to develop a new anode material electrochemical oxidation to efficiently degrade pesticide wastewater. DIL-PbO2-Ti/BDD electrodes with better electrocatalytic oxidation performance were obtained by using dicationic ionic liquid (DIL) for assisted electrodeposition of PbO2 modified boron-doped diamond (BDD) electrodes. At a current density of 100 mA cm−2 and a temperature of 25 °C using the DIL-PbO2-Ti/BDD electrode as anode and titanium plate as cathode. The electrochemical window and Oxygen evolution potential (OEP) of the DIL-PbO2-Ti/BDD electrode obtained by CV testing at a scan rate of 50 mV s−1 in 1 M H2SO4 were 4.12 V and 3.29 V, respectively. Under the conditions of current density of 100 mA cm−2, 25 °C, pH 12, salt content of 8%, chemical oxygen demand (COD) of 24,280.98 mg L−1, and total nitrogen (TN) content of 5,268 mg L−1, after electrification for 12 h, the removal efficiency of COD and TN reached 64.88% and 67.77%, respectively, indicating that the DIL-PbO2-Ti/BDD electrode has excellent electrocatalytic performance. In order to further understand the mechanism of electrochemical degradation of pesticide wastewater, HPLC-MS was used to detect the intermediates in the degradation process, and the possible degradation pathways were proposed in turn.