{"title":"高温生产的生物炭上抗生素的解吸滞后现象:胺基团和酰胺化反应的作用。","authors":"Yizhou Feng, Daohui Lin, Kun Yang, Wenhao Wu","doi":"10.1016/j.scitotenv.2024.175998","DOIUrl":null,"url":null,"abstract":"<p><p>Knowledge of antibiotic desorption from high-temperature biochar is essential for assessing their environmental risks, and for the successful application of biochar to remove antibiotics. In previous studies, irreversible pore deformation, formation of charge-assisted hydrogen bonds or amide bonds were individually proposed to explain the desorption hysteresis of antibiotics on biochars, leading to a debate on hysteresis mechanism. In this study, desorption of sulfamethoxazole (SMX), ciprofloxacin (CFX) and tetracycline (TET) on a wood chip biochar produced at 700 °C (WBC700) and its oxidized product (O-WBC700) was investigated to explore the underlying hysteresis mechanism. Significant desorption hysteresis was observed for SMX, CFX and TET on WBC700 and O-WBC700. Hysteresis index (HI) of each antibiotic was higher on O-WBC700 with more oxygen-containing groups than WBC700, and was higher at lower equilibrium concentration. HI of antibiotics on WBC700 (or O-WBC700) increased in the order of SMX < CFX < TET. The calculated adsorption enthalpy of each antibiotic on WBC700 was positive, indicating an endothermic process. These phenomena together with FTIR, XPS spectra confirmed that the desorption hysteresis mechanism of antibiotics on high-temperature biochar is the formation of amide bonds by amidation reaction, but not the pore deformation or the hydrogen bond. Moreover, antibiotic can form amide bonds with WBC700 only if the amine group with pK<sub>a</sub> > 4.0, and the HI values were positively correlated with their pK<sub>a</sub> values. Amine group of antibiotics with higher pK<sub>a</sub> value show more nucleophilicity and could form stronger amide bonds with carboxyl group of biochar. The obtained results could help to solve the debate on desorption hysteresis mechanism of antibiotics on high-temperature biochars, and provide a new insight into the role of amine groups and amidation reaction on the hysteresis.</p>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":null,"pages":null},"PeriodicalIF":8.2000,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Desorption hysteresis of antibiotics on biochar produced at high temperature: The role of amine groups and amidation reaction.\",\"authors\":\"Yizhou Feng, Daohui Lin, Kun Yang, Wenhao Wu\",\"doi\":\"10.1016/j.scitotenv.2024.175998\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Knowledge of antibiotic desorption from high-temperature biochar is essential for assessing their environmental risks, and for the successful application of biochar to remove antibiotics. In previous studies, irreversible pore deformation, formation of charge-assisted hydrogen bonds or amide bonds were individually proposed to explain the desorption hysteresis of antibiotics on biochars, leading to a debate on hysteresis mechanism. In this study, desorption of sulfamethoxazole (SMX), ciprofloxacin (CFX) and tetracycline (TET) on a wood chip biochar produced at 700 °C (WBC700) and its oxidized product (O-WBC700) was investigated to explore the underlying hysteresis mechanism. Significant desorption hysteresis was observed for SMX, CFX and TET on WBC700 and O-WBC700. Hysteresis index (HI) of each antibiotic was higher on O-WBC700 with more oxygen-containing groups than WBC700, and was higher at lower equilibrium concentration. HI of antibiotics on WBC700 (or O-WBC700) increased in the order of SMX < CFX < TET. The calculated adsorption enthalpy of each antibiotic on WBC700 was positive, indicating an endothermic process. These phenomena together with FTIR, XPS spectra confirmed that the desorption hysteresis mechanism of antibiotics on high-temperature biochar is the formation of amide bonds by amidation reaction, but not the pore deformation or the hydrogen bond. Moreover, antibiotic can form amide bonds with WBC700 only if the amine group with pK<sub>a</sub> > 4.0, and the HI values were positively correlated with their pK<sub>a</sub> values. Amine group of antibiotics with higher pK<sub>a</sub> value show more nucleophilicity and could form stronger amide bonds with carboxyl group of biochar. 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引用次数: 0
摘要
了解高温生物炭对抗生素的解吸情况对于评估其环境风险以及成功应用生物炭去除抗生素至关重要。以往的研究分别提出了不可逆孔隙变形、电荷辅助氢键或酰胺键的形成来解释抗生素在生物炭上的解吸滞后现象,从而引发了关于滞后机理的争论。本研究研究了在 700 °C 下生产的木屑生物炭(WBC700)及其氧化产物(O-WBC700)对磺胺甲噁唑(SMX)、环丙沙星(CFX)和四环素(TET)的解吸,以探索其滞后机理。在 WBC700 和 O-WBC700 上观察到了 SMX、CFX 和 TET 的显著解吸滞后现象。在含氧基团较多的 O-WBC700 上,每种抗生素的滞后指数(HI)都高于 WBC700,而且在平衡浓度较低时滞后指数更高。抗生素在 WBC700(或 O-WBC700)上的 HI 值按 SMX a > 4.0 的顺序增加,且 HI 值与它们的 pKa 值呈正相关。pKa 值越高的抗生素胺基团亲核性越强,能与生物炭的羧基形成更强的酰胺键。这些结果有助于解决抗生素在高温生物炭上的解吸滞后机理的争论,并对胺基和酰胺化反应在滞后中的作用有了新的认识。
Desorption hysteresis of antibiotics on biochar produced at high temperature: The role of amine groups and amidation reaction.
Knowledge of antibiotic desorption from high-temperature biochar is essential for assessing their environmental risks, and for the successful application of biochar to remove antibiotics. In previous studies, irreversible pore deformation, formation of charge-assisted hydrogen bonds or amide bonds were individually proposed to explain the desorption hysteresis of antibiotics on biochars, leading to a debate on hysteresis mechanism. In this study, desorption of sulfamethoxazole (SMX), ciprofloxacin (CFX) and tetracycline (TET) on a wood chip biochar produced at 700 °C (WBC700) and its oxidized product (O-WBC700) was investigated to explore the underlying hysteresis mechanism. Significant desorption hysteresis was observed for SMX, CFX and TET on WBC700 and O-WBC700. Hysteresis index (HI) of each antibiotic was higher on O-WBC700 with more oxygen-containing groups than WBC700, and was higher at lower equilibrium concentration. HI of antibiotics on WBC700 (or O-WBC700) increased in the order of SMX < CFX < TET. The calculated adsorption enthalpy of each antibiotic on WBC700 was positive, indicating an endothermic process. These phenomena together with FTIR, XPS spectra confirmed that the desorption hysteresis mechanism of antibiotics on high-temperature biochar is the formation of amide bonds by amidation reaction, but not the pore deformation or the hydrogen bond. Moreover, antibiotic can form amide bonds with WBC700 only if the amine group with pKa > 4.0, and the HI values were positively correlated with their pKa values. Amine group of antibiotics with higher pKa value show more nucleophilicity and could form stronger amide bonds with carboxyl group of biochar. The obtained results could help to solve the debate on desorption hysteresis mechanism of antibiotics on high-temperature biochars, and provide a new insight into the role of amine groups and amidation reaction on the hysteresis.
期刊介绍:
The Science of the Total Environment is an international journal dedicated to scientific research on the environment and its interaction with humanity. It covers a wide range of disciplines and seeks to publish innovative, hypothesis-driven, and impactful research that explores the entire environment, including the atmosphere, lithosphere, hydrosphere, biosphere, and anthroposphere.
The journal's updated Aims & Scope emphasizes the importance of interdisciplinary environmental research with broad impact. Priority is given to studies that advance fundamental understanding and explore the interconnectedness of multiple environmental spheres. Field studies are preferred, while laboratory experiments must demonstrate significant methodological advancements or mechanistic insights with direct relevance to the environment.