基于氮掺杂碳负载铁催化剂的硫代硫酸盐催化空气氧化

Catalytic air oxidation of thiosulfate by nitrogen-doped carbon supported iron catalyst

焦化脱硫废液中硫代硫酸盐严重制约高品质硫氰酸盐产品提取。利用马铃薯薯渣为碳源,通过热处理技术制备氮掺杂碳负载铁催化剂(Fe-NCNT/PC),采用N_(2)物理吸附仪、扫描电子显微镜、X射线光电子能谱对催化剂的表面积、微观形貌和表面结构特征进行了表征,考察了其对HB、LN 2种脱硫废液中硫代硫酸盐的催化空气氧化性能。结果表明,Fe-NCNT/PC具有微-介孔结构和FeNx限域结构,焙烧温度的升高会降低催化剂活性和稳定性,最适焙烧温度为700℃;当Fe-NCNT/PC-700用量1.5 g、氧化时间6 h时,HB、LN脱硫废液中硫代硫酸盐的去除率可达95%;脱硫废液氧化后pH显著降至酸性,Fe-NCNT/PC-700的限域结构能够防止活性组分铁流失。此外,Fe较其他过渡金属(Mn、Cu、Co、Ni)对硫代硫酸盐催化空气氧化活性更佳。

Thiosulfate in coking desulfurization waste liquid(CDWL)seriously restricts extraction of high-quality thiocyanate products.In this study,potato residue was taken as carbon source,nitrogen-doped carbon supported iron catalyst(Fe-NCNT/PC)was prepared by heat treatment technology.The specific surface area,morphology and surface structure of the catalyst were characterized by N_(2) physical adsorption instrument,scanning electron microscope and X-ray photoelectron spectroscopy.The catalytic air oxidation of thiosulfate in two kinds of CDWL:HB and LN,was investigated.The results showed that Fe-NCNT/PC had micro-mesoporous structure and FeNx confined structure,the activity and stability of the catalyst decreased with the increase of calcination temperature,and the optimum calcination temperature was 700℃.When the dosage of Fe-NCNT/PC-700 was 1.5 g and the oxidation time was 6 h,the removal rates of thiosulfate in the above two kinds of CDWL could reach 95%.After oxidation,the pH of CDWL decreased significantly to acidity,and the confined structure of Fe-NCNT/PC-700 could prevent the loss of active component iron.Besides,Fe showed a better catalytic activity for air oxidation of thiosulfate than other transition metals(Mn,Cu,Co,Ni).