Marín Zenydia, Rojas Diana, Pérez Isabel Fernández, Santaballa J Arturo, Canle Moisés
Departamento de Química, Facultade de Ciencias & CICA, Universidade da Coruña, A Coruña E-15071, Spain.
Ind Eng Chem Res. 2025 Jun 3;64(24):11624-11629. doi: 10.1021/acs.iecr.4c04696. eCollection 2025 Jun 18.
This study focuses on the degradation of the postharvest fungicide thiabendazole (), which is widely used in citrus production and veterinary medicine. Although is effective in controlling fungal infections, its residues have been detected in agricultural runoff, industrial wastewater, and surface and groundwater, demonstrating its resistance to conventional water treatment methods. Additionally, is highly toxic to aquatic organisms and has been classified as a possible carcinogen at high doses. To address this issue, advanced oxidation processes (AOPs), particularly heterogeneous photocatalysis, have emerged as promising solutions. Titanium dioxide (TiO) is one of the most effective photocatalysts due to its chemical stability, low cost, and strong oxidizing ability when exposed to UV radiation. This study examines the phototransformation of using TiO P25, evaluating its degradation products and proposing a set of reaction pathways. The phototransformation of aqueous thiabendazole (), using commercial TiO-P25 as a photocatalyst and UV irradiation (mainly 365 nm), is much faster than using UV irradiation (254 nm) alone. All kinetic runs were carried out at natural pH (ca. 6.1) and 298 K. The rate constant for photocatalyzed disappearance was ca. (4.8 ± 0.5)·10 s ( ca. 3.5 min), with a mineralization of ca. 67% after 2 h, relative to the initial concentration of fungicide. Aqueous also underwent 254 nm induced phototransformation, with a rate constant of disappearance ca. (5.0 ± 0.1)·10 s ( ca. 221 min), and just 3% of mineralization after 340 min. The quantum yield for direct phototransformation was Φ = 0.05, and the reactive species was identified as the singlet excited state of , as the concentration of dissolved O does not affect the phototransformation process. Up to 11 photoproducts were identified by HPLC-MS, the main one being benzimidazole. A suitable set of reaction pathways that may explain these products are proposed.
本研究聚焦于采后杀菌剂噻菌灵（）的降解，噻菌灵在柑橘生产和兽医学中广泛使用。尽管噻菌灵在控制真菌感染方面有效，但其残留物已在农业径流、工业废水以及地表水和地下水中被检测到，这表明它对传统水处理方法具有抗性。此外，噻菌灵对水生生物具有高毒性，在高剂量时已被归类为可能的致癌物。为解决这一问题，高级氧化工艺（AOPs），特别是多相光催化，已成为有前景的解决方案。二氧化钛（TiO₂）因其化学稳定性、低成本以及在紫外辐射下具有强氧化能力，是最有效的光催化剂之一。本研究考察了使用TiO₂ P25时噻菌灵的光转化，评估其降解产物并提出了一组反应途径。以商业TiO₂-P25作为光催化剂并进行紫外辐射（主要为365 nm）时，水相噻菌灵（）的光转化比单独使用紫外辐射（254 nm）快得多。所有动力学实验均在自然pH（约6.1）和298 K下进行。光催化噻菌灵消失的速率常数约为(4.8 ± 0.5)·10⁻⁴ s⁻¹（t₁/₂约为3.5 min），相对于杀菌剂的初始浓度，2 h后矿化率约为67%。水相噻菌灵也经历了254 nm诱导的光转化，消失速率常数约为(5.0 ± 0.1)·10⁻⁵ s⁻¹（t₁/₂约为221 min），340 min后矿化率仅为3%。直接光转化的量子产率为Φ = 0.05，且由于溶解氧的浓度不影响光转化过程，反应活性物种被确定为噻菌灵的单重激发态。通过高效液相色谱-质谱法鉴定出多达11种光产物，主要产物为苯并咪唑。提出了一组可能解释这些产物的合适反应途径。
