为了提高生物炭对污染物的吸附效率,制备类石墨烯生物炭(GBC)或氮掺杂生物炭是两种常用的方法。然而,氮掺杂(N掺杂)对原始生物炭(PBC)和GBC吸附污染物的影响差异,以及潜在的机制,还不清楚。以四环素(TC)为例,本研究分析了生物炭(PBC,GBC,N-PBC,N-GBC),在不同的溶液性质下,N掺杂对PBC和GBC吸附TCs的影响存在显著差异。具体来说,N掺杂对PBC的吸附性能有不同的影响,均匀地提高了GBC的吸附性能。为了解释这种现象,QSAR模型揭示了吸附时的N掺杂,这表明孔隙填充(VM)和TC与生物炭(Ead-v)之间的相互作用是最重要的两个因素。此外,密度泛函理论(DFT)结果表明,N掺杂对生物炭的化学反应性略有影响。范德华(vdWs)和静电相互作用是TC-生物炭相互作用的主要力量。此外,N掺杂主要增强了TC-生物炭的静电相互作用,但大多数样品的vdWs相互作用基本上不受影响。总的来说,揭示的N掺杂对生物炭吸附TCs的机理将增强我们对抗生素污染修复的认识。
To improve the adsorption efficiency of pollutants by biochar, preparing graphene-like biochar (GBC) or nitrogen-doped biochar are two commonly used methods. However, the difference in the nitrogen doping (N-doping) effects upon the adsorption of pollutants by pristine biochar (PBC) and GBC, as well as the underlying mechanisms, are still unclear. Take the tetracycline (TC) as an example, the present study analyzed the characteristics of the adsorption of TCs on biochars (PBC, GBC, N-PBC, N-GBC), and significant differences in the effects of N-doping on the adsorption of TCs by PBC and GBC were consistently observed at different solution properties. Specifically, N-doping had varied effects on the adsorption performance of PBC, whereas it uniformly improved the adsorption performance of GBC. To interpret the phenomenon, the N-doping upon the adsorption was revealed by the QSAR model, which indicated that the pore filling (VM) and the interactions between TCs with biochars (Ead-v) were found to be the most important two factors. Furthermore, the density functional theory (DFT) results demonstrated that N-doping slightly affects biochar\'s chemical reactivity. The van der Waals (vdWs) and electrostatic interactions are the main forces for TCs-biochars interactions. Moreover, N-doping mostly strengthened the electrostatic interactions of TCs-biochars, but the vdWs interactions of most samples remained largely unaffected. Overall, the revealed mechanism of N-doping on TCs adsorption by biochars will enhance our knowledge of antibiotic pollution remediation.