Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing, 210095, China.
Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing, 210095, China; State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, China.
Chemosphere. 2019 Dec;236:124358. doi: 10.1016/j.chemosphere.2019.124358. Epub 2019 Jul 16.
In the present study, the mineralization performance and pathway of uric acid (UA) on boron-doped diamond (BDD) anodes were investigated. The oxidation behavior of UA on BDD surface was firstly tested through cyclic voltammetry measurements. The individual and joint effects of four quantitative parameters (applied current density, NaHCO concentration, NaCl concentration and flow rate) on UA mineralization were then examined with Doehlert experimental design. The results acquired by statistical analysis revealed that NaCl concentration and applied current density displayed the most dominant roles on UA degradation, while the influences of NaHCO concentration and flow rate were statistically insignificant. As a result, the following optimal conditions were reached: applied current density of 7.80 mA cm, NaHCO concentration of 6.0 mM, NaCl concentration of 9.0 mM and flow rate of 600 mL min, which gave a TOC decay of 89.4%, a specific energy consumption of 125.36 KWh kg TOC, a combustion current efficiency of 15.0% and an electrical energy per order of 35.79 KWh m order within 30 min of electrolysis. Further results from LC/MS analysis confirmed the ring rupture of UA during the electrolysis, due to the attack of hydroxyl radicals and active chlorine species. Accordingly, two plausible degradation pathways of UA in bicarbonate and chloride media on BDD anode were proposed respectively.
在本研究中，我们考察了尿酸（UA）在掺硼金刚石（BDD）阳极上的矿化性能和途径。首先通过循环伏安法测试了 UA 在 BDD 表面上的氧化行为。然后，利用 Doehlert 实验设计考察了四个定量参数（施加电流密度、NaHCO浓度、NaCl 浓度和流速）对 UA 矿化的单独和联合影响。通过统计分析获得的结果表明，NaCl 浓度和施加电流密度对 UA 降解的影响最大，而 NaHCO 浓度和流速的影响则无统计学意义。因此，达到了以下最佳条件：施加电流密度为 7.80 mA cm，NaHCO 浓度为 6.0 mM，NaCl 浓度为 9.0 mM，流速为 600 mL min，在此条件下，TOC 衰减率为 89.4%，TOC 比能耗为 125.36 kWh kg，燃烧电流效率为 15.0%，每阶电耗为 35.79 kWh m 阶，电解 30 min 内。进一步的 LC/MS 分析结果证实，由于羟基自由基和活性氯物种的攻击，UA 在电解过程中发生了环破裂。因此，分别提出了 UA 在 BDD 阳极上的碳酸氢盐和氯化物介质中的两种可能的降解途径。
