氮氧双掺杂中空多孔碳微球对四环素的电吸附特性及机理

Electro-adsorption characteristics and mechanism of tetracycline on nitrogen and oxygen co-doped hollow porous carbon microspheres

多孔碳吸附剂去除水体中四环素(tetracycline, TC)时存在选择性低、吸附容量和吸附速率有限等问题,且吸附效果容易受到水体环境的影响.针对上述问题,本文提出采用水蒸气辅助碱活化法将回收的聚酰亚胺纤维制备成具有高氧掺杂量(15.20%)和氮掺杂量(4.04%)的多孔结构中空碳微球(HKCPI).通过电容去离子技术(CDI)对TC进行吸附实验,发现HKCPI电极在200 mg·L^(-1)的TC溶液中的电吸附容量高达985.7 mg·g^(-1),是自吸附的2.05倍(460.2 mg·g^(-1)).经过100次吸-脱附循环后,HKCPI对TC的吸附容量仍可保持80%以上,展示了优异的再生性和循环稳定性.通过结构表征、动力学模拟和电容去离子特性等研究发现,CDI技术的特殊电场作用充分加速了四环素分子在体系中的孔隙填充与扩散、静电吸附、π-π相互作用、氢键吸附和化学吸附等多种吸附机制,实现了协同增强HKCPI吸附四环素的速率和效率.

The removal of tetracycline(TC)from water using porous carbon adsorbents suffers from drawbacks such as low selectivity,limited adsorption capacity,and slow adsorption rate.Additionally,the adsorption efficiency is readily influenced by the water environment.To address these challenges,this study proposes the utilization of steam-assisted alkali activation to prepare recovered polyimide fibers into hollow-porous carbon microspheres(HKCPI)with high levels of oxygen doping(15.20%)and nitrogen doping(4.04%).Applied with capacitive deionization(CDI)technology,it is revealed that the HKCPI electrode achieved an exceptional adsorption capacity of 985.7 mg·g^(-1) in a TC solution of 200 mg·L^(-1),which is 2.05 times higher than self-adsorption(460.2 mg·g^(-1)).Even after 100 adsorption-desorption cycles,the HKCPI maintained an adsorption capacity of over 80%,demonstrating excellent regeneration and cycling stability.Structural characterization,kinetics simulation,and CDI analysis revealed that the electric field of CDI significantly accelerated the filling,diffusion,electrostatic adsorption,π-πinteraction,hydrogen bonding adsorption,and chemical adsorption of TC molecules in the system,thus synergistically enhanced the rate and efficiency of TC adsorption by HKCPI.