Studies on oxidation kinetics of sulfadiazine (SDZ) using δ-MnO2 (birnessite) and natural MnO2 are limited. Reaction order at different SDZ speciation was determined based on the effects of initial H+, MnO2 and SDZ concentrations using initial rate method, which would be useful to determine the optimum pH and MnO2 concentration. Birnessite and natural MnO2 with different physico-chemical properties such as BET surface area, pHPZC, d-spacing, and crystal size similarly showed good efficiencies in oxidizing neutral SDZ (pH 5) and anionic SDZ (pH 8). Activation energy (Ea) and thermodynamic parameters indicated the similar oxidation efficiencies in the temperature range of 10 to 40°C. The SO42- was produced from the SDZ oxidation coupled to the reduction of MnO2 to Mn2+. The effect of co-solute ciprofloxacin (CIP) on the oxidation kinetics of SDZ was also studied. The rates of SDZ oxidation by both birnessite and natural MnO2 were reduced by the presence of CIP due to competition in oxidation between SDZ and CIP. The SDZ was more rapidly oxidized than CIP in both single- and bi-solute systems, as indicated by the presence of CIP intermediate, whereas the intermediate of SDZ was not detected.

中文翻译：

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使用合成和天然二氧化锰氧化去除磺胺嘧啶

使用 δ-MnO2（水钠锰矿）和天然 MnO2 对磺胺嘧啶 (SDZ) 的氧化动力学进行研究是有限的。根据初始 H+、MnO2 和 SDZ 浓度的影响，使用初始速率法确定不同 SDZ 形态下的反应顺序，这将有助于确定最佳 pH 值和 MnO2 浓度。具有不同物理化学性质（如 BET 表面积、pHPZC、d-间距和晶体尺寸）的水钠锰矿和天然 MnO2 在氧化中性 SDZ（pH 5）和阴离子 SDZ（pH 8）方面同样表现出良好的氧化效率。活化能 (Ea) 和热力学参数表明在 10 至 40°C 的温度范围内具有相似的氧化效率。SO42- 是由 SDZ 氧化与 MnO2 还原为 Mn2+ 相结合产生的。还研究了共溶质环丙沙星 (CIP) 对 SDZ 氧化动力学的影响。由于 SDZ 和 CIP 之间的氧化竞争，CIP 的存在降低了水钠锰矿和天然 MnO2 对 SDZ 的氧化速率。在单溶质和双溶质系统中，SDZ 比 CIP 氧化得更快，如 CIP 中间体的存在所示，而 SDZ 中间体未检测到。