Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
J Hazard Mater. 2022 Oct 5;439:129655. doi: 10.1016/j.jhazmat.2022.129655. Epub 2022 Jul 21.
Peroxydisulfate (PDS) is a common oxidant for organic contaminant remediation. PDS is typically activated by metal catalysts to generate reactive radicals. Unfortunately, as radicals are non-selective and metal catalysts may cause secondary contamination, alternative selective non-radical pathways and non-metal catalysts need attention. Here we investigated PDS oxidation of commonly detected antibiotic Norfloxacin (NOR) using cyanobacterial nitrogen rich biochars (CBs) as catalysts. NOR was fully degraded by CB pyrolysed at 950 °C (CB950) within 120 min. CB950 caused threefold faster degradation than low pyrolysis temperature (PT) CBs and achieved a maximum surface area normalized rate constant of 4.38 × 10 min m L compared to widely used metal catalysts. CB950 maintained full reactivity after four repeated uses. High defluorination (82%) and mineralization (>82%) were observed for CB950/PDS. CBs were active over a broad pH range (3-10), but with twice as high rates under alkaline compared with neutral conditions. NOR is degraded by organic, OH and SO radicals in low PT CBs/PDS systems, where the presence of Mn promotes radical generation. Electron transfer reactions with radicals supplemented dominate high PT CBs/PDS systems. This study demonstrates high PT biochars from algal bloom biomass may find use as catalysts for organic contaminant oxidation.
过二硫酸盐（PDS）是一种常见的用于有机污染物修复的氧化剂。PDS 通常通过金属催化剂激活以产生反应性自由基。然而，由于自由基是非选择性的，并且金属催化剂可能会引起二次污染，因此需要关注替代的选择性非自由基途径和非金属催化剂。在这里，我们研究了使用富氮蓝藻生物质炭（CB）作为催化剂时，过二硫酸盐（PDS）对常见抗生素诺氟沙星（NOR）的氧化作用。在 120 分钟内，950°C 热解的 CB（CB950）完全降解了 NOR。CB950 的降解速度比低热解温度（PT）CB 快三倍，与广泛使用的金属催化剂相比，其归一化表面积的最大速率常数达到了 4.38×10-2 min m L-1。CB950 在重复使用四次后仍保持完全的反应活性。在 CB950/PDS 体系中，观察到高脱氟（82%）和矿化（>82%）。CBs 在较宽的 pH 范围（3-10）下均具有活性，但在碱性条件下的速率比中性条件下高两倍。在低 PT CBs/PDS 体系中，NOR 是通过有机、OH 和 SO 自由基降解的，其中 Mn 的存在促进了自由基的生成。高 PT CBs/PDS 体系中主要是通过电子转移反应与自由基协同作用。本研究表明，藻类水华生物质衍生的高 PT 生物炭可能可用作有机污染物氧化的催化剂。
