Degradation of diethyl phthalate (DEP) by ultraviolet/persulfate (UV/PS) process at different reaction conditions was evaluated. DEP can be degraded effectively via this process. Both tert-butyl (TBA) and methanol (MeOH) inhibited the degradation of DEP with MeOH having a stronger impact than TBA, suggesting sulfate radical () and hydroxyl radical (HO

) both existed in the reaction systems studied. The second-order rate constants of DEP reacting with and HO were calculated to be $(6.4\pm 0.3)\times {10}^7$ M⁻¹s⁻¹ and $(3.7\pm 0.1)\times {10}^9$ M⁻¹s⁻¹, respectively. To further access the potential degradation mechanism in this system, the pseudo-first-order rate constants (k_o) and the radical contributions were modeled using a simple steady-state kinetic model involving and HO. Generally, HO had a greater contribution to DEP degradation than . The k_o of DEP increased as PS dosages increased when PS dosages were below 1.9 mM. However, it decreased with increasing initial DEP concentrations, which might be due to the radical scavenging effect of DEP. The k_o values in acidic conditions were higher than those in alkaline solutions, which was probably caused by the increasing concentration of hydrogen phosphate (with higher scavenging effects than dihydrogen phosphate) from the phosphate buffer as pH values rose. Natural organic matter and bicarbonate dramatically suppressed the degradation of DEP by scavenging and HO. Additionally, the presence of chloride ion (Cl⁻) promoted the degradation of DEP at low Cl⁻ concentrations (0.25–1 mM). Finally, the proposed degradation pathways were illustrated.

中文翻译：

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紫外线/过硫酸盐降解邻苯二甲酸二乙酯（DEP）：羟基和硫酸根自由基贡献的实验和模拟研究

评价了在不同反应条件下通过紫外线/过硫酸盐（UV / PS）工艺对邻苯二甲酸二乙酯（DEP）的降解。通过此过程可以有效地降低DEP。叔丁基（TBA）和甲醇（MeOH）都抑制了DEP的降解，而MeOH的影响比TBA强，这表明硫酸根（）和羟基（HO

）都存在于所研究的反应体系中。DEP的二阶速率常数与 和何 被计算为 $（6.4\pm 0.3）\times {10}^7$M ^-1 s ^-1和$（3.7\pm 0.1）\times {10}^9$M ^-1 s ^-1。为了进一步访问该系统中的可能的降解机理，伪一级速率常数（K _Ò）和自由基贡献使用涉及一个简单的稳态动力学模型进行建模 和何。通常情况下，HO 对DEP降解的贡献大于 。当PS剂量低于1.9 mM时，DEP的k _o随着PS剂量的增加而增加。但是，它随着初始DEP浓度的增加而降低，这可能是由于DEP的自由基清除作用所致。酸性条件下的k _o值高于碱性溶液中的k _o值，这可能是由于随着pH值的升高，磷酸盐缓冲液中磷酸氢盐浓度的增加（清除效果比磷酸二氢盐高）。天然有机物和碳酸氢盐通过清除而极大地抑制了DEP的降解 和何。此外，氯离子（CL的存在^- ）促进DEP在低氯的降解^-浓度（0.25-1毫米）。最后，说明了拟议的降解途径。