基于蜡烛灰构建的电-Fenton体系中H_(2)O_(2)的生成与磺胺甲恶唑的降解

HO in-situ production and sulfamethoxazole degradation in the electro-Fenton system constructed with candle soots

本文构建了基于蜡烛灰(CS)的电-Fenton体系,研究了体系中H_(2)O_(2)的原位生成和磺胺甲恶唑(SMX)的降解.研究发现,在蜡烛火焰中部收集得到的CS为40—50 nm的疏水性球状颗粒.经过热处理后,样品的比表面积由61.792 m^(2)·g^(-1)(CS)升高到67.098 m^(2)·g^(-1)(CS-200)、102.54 m^(2)·g^(-1)(CS-400)、322.85 m^(2)·g^(-1)(CS-600)和680.69 m^(2)·g^(-1)(CS-800),为氧气还原反应(ORR)提供了更多的反应活性位点.介孔体积由0.1463 cm^(3)·g^(-1)(CS)升高到0.1723 cm^(3)·g^(-1)(CS-200)、0.1740 cm^(3)·g^(-1)(CS-400)、0.2686 cm^(3)·g^(-1)(CS-600)、和0.3570 cm^(3)·g^(-1)(CS-800).除CS-200外,热处理增加了样品表面含氧官能团比例,显著提高了样品的亲水性.旋转圆盘电极(RDE)实验证明,CS,CS-200和CS-400表面ORR为2e-途径,而CS-600和CS-800表面氧气还原涉及4e-途径,并且与其他样品相比,CS-400显示出最高的2e-ORR催化活性,这与其表面存在较高比例的COOH基团(23.15%)和较大的介孔比例(50.39%)有关.在以CS-400空气阴极搭建的电-Fenton体系中,H_(2)O_(2)浓度在60 min内可以积累到1277 mg·L^(-1),产量可达5.11 mg·h^(-1)·cm^(-2).连续5次SMX降解实验中,60 min内SMX的降解率均保持在100%.因此,基于CS构建的电-Fenton体系显示出很高的SMX降解能力和运行稳定性,具有很大的实际应用价值.

In this paper,an electro-Fenton system based on candle soot(CS)was constructed.The in situ production of H_(2)O_(2) and the degradation of sulfamethoxazole(SMX)were studied.Based on the experiments,the pristine CS collected in the middle of the candle flame was hydrophobic spheres.After heating treatment,the specific surface area of the samples increased from 61.792 m^(2)·g^(-1)(CS)to 67.098 m^(2)·g^(-1)(CS-200),102.54 m^(2)·g^(-1)(CS-400),322.85 m^(2)·g^(-1)(CS-600),and 680.69 m^(2)·g^(-1)(CS-800),and the mesopore volumes increased from 0.1463 cm^(3)·g^(-1)(CS)to 0.1723 cm^(3)·g^(-1)(CS-200),0.1740 cm^(3)·g^(-1)(CS-400),0.2686 cm^(3)·g^(-1)(CS-600),and 0.3570 cm^(3)·g^(-1)(CS-800).The increased specific surface area provided more active sites for the reaction of oxygen reduction(ORR).Except CS-200,the content of oxygen-containing functional groups increased after the heating treatment,which significantly improved the hydrophilicity of the samples.Rotating disk electrode(RDE)experiments showed that oxygen was reduced through 2 e-pathway on the surfaces of CS,CS-200,and CS-400,while 4 e-pathway was involved in the oxygen reduction on the surfaces of the CS-600 and CS-800.Compared with other samples,CS-400 exhibited the highest of 2 e-ORR activity,which can be explained by the highest content of COOH groups(23.15%)and mesopores ratio(50.39%).In the electro-Fenton system,H_(2)O_(2) reached its maximum concentration of 1277 mg·L^(-1) with a yield of 5.11 mg·h^(-1)·cm^(-2) in 60 min.In five consecutive degradation experiments,the degradation rates of SMX all remained at 100%within 60 min.Therefore,the electro-Fenton system based on CS exhibited high SMX degradation ability and operating stability,which endowed it with a great potential for practical application.