Joint Research Centre for Protective Infrastructure Technology and Environmental Green Bioprocess, School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China; School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
Joint Research Centre for Protective Infrastructure Technology and Environmental Green Bioprocess, School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia; School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
Sci Total Environ. 2020 May 10;716:137015. doi: 10.1016/j.scitotenv.2020.137015. Epub 2020 Jan 30.
A large amount of spent coffee grounds is produced as a processing waste each year during making the coffee beverage. Sulfonamide antibiotics (SAs) are frequently detected in the environment and cause pollution problems. In this study, biochar (BC) and hydrochar (HC) were derived from spent coffee grounds through pyrolysis and hydrothermal carbonization, respectively. Their characteristics and sulfonamide antibiotics adsorption were investigated and compared with reference to adsorption capacity, adsorption isotherm and kinetics. Results showed BC possessed more carbonization and less oxygen-containing functional groups than HC when checked by Elemental Analysis, X-ray diffraction, X-ray photoelectron spectrometry and Fourier transform infrared. These groups affected the adsorption of sulfonamide antibiotics and adsorption mechanism. The maximum adsorption capacities of BC for sulfadiazine (SDZ) and sulfamethoxazole (SMX) were 121.5 μg/g and 130.1 μg/g at 25 °C with the initial antibiotic concentration of 500 μg/L, respectively. Meanwhile the maximum adsorption capacities of HC were 82.2 μg/g and 85.7 μg/g, respectively. Moreover, the adsorption mechanism for SAs adsorbed onto BC may be dominated by π-π electron donor-acceptor interactions, yet the SAs adsorption to HC may be attributed to hydrogen bonds. Further analysis of the adsorption isotherms and kinetics, found that physical and chemical interactions were involved in the SAs adsorption onto BC and HC. Overall, results suggested that: firstly, pyrolysis was an effective thermochemical conversion of spent coffee grounds; and secondly, BC was the more promising adsorbent for removing sulfonamide antibiotics.
每年生产咖啡饮料时，都会产生大量的咖啡渣作为加工废物。磺酰胺类抗生素（SAs）经常在环境中被检测到，造成污染问题。在本研究中，通过热解和水热碳化分别从废咖啡渣中得到生物炭（BC）和水热炭（HC）。对其特性和磺胺类抗生素吸附进行了研究，并与吸附容量、吸附等温线和动力学进行了比较。结果表明，通过元素分析、X 射线衍射、X 射线光电子能谱和傅里叶变换红外光谱检查，BC 比 HC 具有更多的碳化和较少的含氧官能团。这些基团影响磺胺类抗生素的吸附和吸附机制。BC 对磺胺嘧啶（SDZ）和磺胺甲恶唑（SMX）的最大吸附容量分别为 121.5μg/g 和 130.1μg/g，在 25°C 时，初始抗生素浓度为 500μg/L。同时，HC 的最大吸附容量分别为 82.2μg/g 和 85.7μg/g。此外，磺胺类抗生素在 BC 上的吸附机制可能主要是由π-π电子供体-受体相互作用决定的，而磺胺类抗生素在 HC 上的吸附可能归因于氢键。进一步分析吸附等温线和动力学表明，物理和化学相互作用参与了磺胺类抗生素在 BC 和 HC 上的吸附。总的来说，结果表明：首先，热解是废咖啡渣有效的热化学转化方法；其次，BC 是去除磺胺类抗生素更有前途的吸附剂。
