School of Chemistry and Chemical Engineering, YuLin University, Yulin, 719000, PR China; Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization, Yulin, 719000, PR China; Yulin Engineering Research Center of Coal Chemical Wastewater, Yulin, 719000, PR China.
School of Chemistry and Chemical Engineering, YuLin University, Yulin, 719000, PR China; Yulin Engineering Research Center of Coal Chemical Wastewater, Yulin, 719000, PR China.
Chemosphere. 2024 Sep;364:143141. doi: 10.1016/j.chemosphere.2024.143141. Epub 2024 Aug 24.
The CoO-Ti electrodes were successfully prepared via calcination method to degrade nitrogen-containing (TNP) simulate wastewater in this reaserch. SEM and EDS were employed to analyze the morphology and element composition on CoO-Ti electrode, revealing the successful load of cobalt element. Then the electrochemical performance was evaluated by CV and indicated a better redox performance of electrode. Furthermore, five factors as processing time (A), electrolyte concentration (B), pH (C), initial concentration of TNP (D), and current density (E) were systematic studied in electrical treatment process. The removal rate of TN could be 77%. After the optimization work by RSM, the removal rate of TN raised up to 81% with the condition as: A of 180 min, B of 0.05 M, C of 3, D of 400 mg L, and E of 20 mA cm. The sequence of significants is: C > D > A > E > B. Mechanism analysis revealed that the entire process could be divided into two stages. In the first stage, organic nitrogen compounds were converted into inorganic nitrogen species, such as NO-N. The oxidation and reduction would react owing to the generating of ·OH at second stage in order to turn the NO-N into NO-N, NH-N or N The activation of ·OH on the surface of CoO-Ti electrode possesses the exothermic nature with transition theory. The energy calculation of 1.168 eV indicated these reactions could occur spontaneously.
本研究采用煅烧法成功制备了 CoO-Ti 电极，用于降解含氮（TNP）模拟废水。通过 SEM 和 EDS 分析 CoO-Ti 电极的形貌和元素组成，表明钴元素成功负载。然后通过 CV 评估了电化学性能，表明电极具有更好的氧化还原性能。此外，系统研究了电处理过程中的五个因素，即处理时间 (A)、电解质浓度 (B)、pH 值 (C)、TNP 初始浓度 (D) 和电流密度 (E)。TN 的去除率可达 77%。通过 RSM 进行优化后，TN 的去除率提高到 81%，条件为：A 为 180 min，B 为 0.05 M，C 为 3，D 为 400 mg/L，E 为 20 mA/cm。显著顺序为：C>D>A>E>B。机理分析表明，整个过程可以分为两个阶段。在第一阶段，有机氮化合物转化为无机氮化合物，如 NO-N。在第二阶段，由于生成·OH，会发生氧化还原反应，将 NO-N 转化为 NO-N、NH-N 或 N。CoO-Ti 电极表面·OH 的活化具有过渡理论的放热性质。计算出的 1.168 eV 的能量表明这些反应可以自发发生。
