Abstract：
Nitrogen-doped biochar as Fenton-like catalysts has been widely used to remove emerging pollutants in wastewater. However, the effect of in-situ and ex-situ nitrogen doping on the Fenton-like catalytic activity of biochar is unclear. In this study, the nitrogen-doped biochar was prepared by in-situ (NBC) and ex-situ (BC-N) nitrogen doping, and the Fenton-like catalytic activity of NBC and BC-N was compared for activating hydrogen peroxide (H2O2), peroxydisulfate (PDS) and peroxymonosulfate (PMS). The results showed that NBC had higher Fenton-like catalytic activity than BC-N, because the formation of carbon quantum dots (CQDs) significantly increased the adsorption capacity to H2O2, PDS and PMS. NBC could activate H2O2, PDS and PMS for degradation of sulfamethoxazole (SMX), but showed different catalytic activity and degradation mechanism. In the systems of NBC/H2O2 and NBC/PDS, CQDs played a key role in the activation of H2O2 and PDS, and surface-bound reactive species were mainly responsible for SMX degradation. In the system of NBC/PMS, NBC acted as both electron mediator and activator, direct electron transfer between PMS and SMX and surface-bound reactive species contributed to SMX degradation. This study provides an insight into the catalytic activity of NBC for H2O2, PDS and PMS.
摘要：
氮掺杂生物炭作为类Fenton催化剂已被广泛用于去除废水中的新兴污染物。然而,原位和非原位氮掺杂对生物炭类Fenton催化活性的影响尚不清楚。在这项研究中,通过原位(NBC)和非原位(BC-N)氮掺杂制备了氮掺杂生物炭，并比较了NBC和BC-N对活化过氧化氢（H2O2）的类Fenton催化活性，过氧二硫酸盐(PDS)和过氧单硫酸盐(PMS)。结果表明,NBC比BC-N具有更高的类Fenton催化活性,因为碳量子点（CQDs）的形成显着增加了对H2O2，PDS和PMS的吸附能力。NBC可以激活H2O2，PDS和PMS降解磺胺甲恶唑（SMX），但表现出不同的催化活性和降解机理。在NBC/H2O2和NBC/PDS系统中，CQDs在H2O2和PDS的活化中起着关键作用，表面结合的反应性物种是SMX降解的主要原因。在NBC/PMS系统中，NBC既充当电子介体又充当激活剂，PMS和SMX之间的直接电子转移以及表面结合的反应性物种有助于SMX降解。这项研究提供了深入了解NBC对H2O2，PDS和PMS的催化活性。
