To investigate the effects of hydroxyl groups on the degradation of tetracycline antibiotics (TCs), three kinds of TCs [tetracycline (TC), oxytetracycline (OTC), and doxycycline (DTC)] were chosen as the target molecules and then degraded in the carbon black (CB)-activated peroxydisulfate (PDS) oxidation process. The degradation ratios of the TC, OTC, and DTC in the CB/PDS oxidation process reached 52%, 60%, and 87% within 40 min, respectively, with the degradation rate following the order of DTC > OTC > TC. According to the density functional theory calculations, these three TCs have different charge distributions, electrostatic potential distributions and average local ionization energy, which are caused by the distinct hydroxyl group position, thus contribute to the different degradation ratios and reaction rate constants. The hydrogenation of TC was slower special degradation pathway relative to those of OTC and DTC, while the decarbonylation of OTC was slower special degradation pathway relative to that of DTC, which adversely resulted in the degradation rate following the order of DTC > OTC > TC. This presentation gives a knowledge that the position and numbers of hydroxyl groups are pivotal to the degradation efficiency toward TCs.

为了研究羟基对四环素抗生素（TCs）降解的影响，选择了三种TCs [四环素（TC），土霉素（OTC）和强力霉素（DTC）]作为目标分子，然后在碳中降解黑色（CB）活化的过二硫酸（PDS）氧化过程。在40分钟内，CB / PDS氧化过程中TC，OTC和DTC的降解率分别达到52％，60％和87％，降解率依次为DTC> OTC> TC。根据密度泛函理论计算，这三个TC具有不同的电荷分布，静电势分布和平均局部电离能，这是由不同的羟基位置引起的，从而导致了不同的降解率和反应速率常数。相对于OTC和DTC而言，TC的氢化是较慢的特殊降解途径，而相对于DTC而言，OTC的脱羰是较慢的特殊降解途径，不利地导致了DTC> OTC> TC的降解速率。该介绍提供了一个知识，即羟基的位置和数量对于TC的降解效率至关重要。