A ruthenium (II) photosensitizer, [Ru(bpy)₂(phen)][PF₆]₂ (RuPS), was synthesized and its structure was confirmed by UV–Vis and ¹H NMR spectroscopy. Under visible light, RuPS could efficiently promote the degradation of tetracycline hydrochloride (TC·HCl) in the presence of oxygen (O₂). Its degradation rate could reach 94.6% in 5 h under 20°C, 50 mW/cm² of radiation intensity, 20 mg/L of TC·HCl, 5 mg/L of RuPS, and pH 10.0. Its degradation pathways were complex and involved both direct and indirect photolysis. For both pathways, the degradation rate of TC increased with the increase of pH value. In acidic environment, the degradation of TC mainly depended on the sensitization of photosensitizer. Under alkaline conditions, the photodegradation of TC itself played a major role as well. For the indirect photolysis, it involved the oxidative degradation of exited TC (TC*) by triplet oxygen (³O₂) and the oxidative degradation of TC by singlet oxygen (¹O₂). ¹O₂ was mainly generated by RuPS under light. In conclusion, aerobic photodegradation under alkaline conditions was a feasible and convenient method to remove TC from water.

中文翻译：

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钌光敏剂存在下可见光驱动的盐酸四环素降解

合成了一种钌 (II) 光敏剂 [Ru(bpy) ₂ (phen)][PF ₆ ] ₂ (RuPS)，并通过 UV-Vis 和¹ H NMR 光谱证实了其结构。在可见光下，RuPS 可在氧气（O ₂）存在下有效促进四环素盐酸盐（TC·HCl）的降解。在20℃、50 mW/cm ^{2条件下，5 h降解率可达94.6%}辐射强度，20 mg/L TC·HCl，5 mg/L RuPS，pH 10.0。其降解途径复杂，涉及直接和间接光解。对于这两种途径，TC 的降解率都随着 pH 值的增加而增加。在酸性环境中，TC的降解主要依赖于光敏剂的敏化作用。在碱性条件下，TC 本身的光降解也起着主要作用。对于间接光解，它涉及三线态氧（³ O ₂ ）对退出的TC（TC *）的氧化降解和单线态氧（¹ O ₂）对TC的氧化降解。¹欧₂主要由 RuPS 在光照下产生。总之，碱性条件下的好氧光降解是去除水中TC的一种可行且方便的方法。