{"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. 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":8,"journal":{"name":"ACS Biomaterials Science & Engineering","volume":null,"pages":null},"PeriodicalIF":5.4000,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Biomaterials Science & Engineering","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.1016/j.scitotenv.2024.175998","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/9/2 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"MATERIALS SCIENCE, BIOMATERIALS","Score":null,"Total":0}
引用次数: 0
Abstract
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：
ACS Biomaterials Science & Engineering is the leading journal in the field of biomaterials, serving as an international forum for publishing cutting-edge research and innovative ideas on a broad range of topics:
Applications and Health – implantable tissues and devices, prosthesis, health risks, toxicology
Bio-interactions and Bio-compatibility – material-biology interactions, chemical/morphological/structural communication, mechanobiology, signaling and biological responses, immuno-engineering, calcification, coatings, corrosion and degradation of biomaterials and devices, biophysical regulation of cell functions
Characterization, Synthesis, and Modification – new biomaterials, bioinspired and biomimetic approaches to biomaterials, exploiting structural hierarchy and architectural control, combinatorial strategies for biomaterials discovery, genetic biomaterials design, synthetic biology, new composite systems, bionics, polymer synthesis
Controlled Release and Delivery Systems – biomaterial-based drug and gene delivery, bio-responsive delivery of regulatory molecules, pharmaceutical engineering
Healthcare Advances – clinical translation, regulatory issues, patient safety, emerging trends
Imaging and Diagnostics – imaging agents and probes, theranostics, biosensors, monitoring
Manufacturing and Technology – 3D printing, inks, organ-on-a-chip, bioreactor/perfusion systems, microdevices, BioMEMS, optics and electronics interfaces with biomaterials, systems integration
Modeling and Informatics Tools – scaling methods to guide biomaterial design, predictive algorithms for structure-function, biomechanics, integrating bioinformatics with biomaterials discovery, metabolomics in the context of biomaterials
Tissue Engineering and Regenerative Medicine – basic and applied studies, cell therapies, scaffolds, vascularization, bioartificial organs, transplantation and functionality, cellular agriculture
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