升温速率对污泥-赤泥炭活化过一硫酸盐的影响

Effect of heating rate on activation of peroxymonosulfate by sewage sludge-red mud char

将污泥-赤泥复配热解制备催化剂可实现大宗固废的资源化利用。活性位点对活性物种的生成具有重要作用。升温速率可调控污泥-赤泥炭基催化剂(RSDBC)表面活性位点的组成,影响过一硫酸盐(PMS)体系中活性物种的生成。使用10℃/min的热解升温速率制备的RSDBC活化PMS,在120 min内磺胺甲唑(SMX)的降解率可达99.6%。通过N_(2)吸附脱附、扫描电子显微镜(SEM)和X射线光电子能谱(XPS)等手段对RSDBC进行表征。结果表明,当升温速率在5~10℃/min范围内增大时,比表面积、Fe(Ⅱ)、C=O、吡啶氮和吡咯氮含量均增大。此外,机理探究表明Fe(Ⅱ)、C=O、吡啶氮和吡咯氮可同时促进羟基自由基(·OH)、硫酸根自由基(SO_(4)^(·-))和单线态氧(~1O_(2))这3种活性物种的生成,有利于SMX的降解。RSDBC-10/PMS体系中~1O_(2)为主要的活性物种。

Conversion of sewage sludge and red mud into catalysts is an effective strategy for resource utilization of solid waste.The active sites play an important role in the generation of active oxidants.Additionally,the heating rate can regulate the active site composition on the surface of the sewage sludge-red mud catalyst carbon-based catalysts(RSDBC),which affects the production of active oxidants in the peroxymonosulfate(PMS)system.It was found that the degradation efficiency of sulfanilamide(SMX)could reach 99.6%within 120 min when PMS was activated using RSDBC prepared at a temperature rise rate of 10℃/min.The RSDBC was characterized by N2 adsorptiondesorption,scanning electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS).Research found that the specific surface area,Fe(Ⅱ),C=O,pyridinic N,and pyrrolic N contents increased as the heating rate increased from 5℃/min to 10℃/min.Furthermore,the mechanistic investigation showed that Fe(Ⅱ),C=O,pyridinic N,and pyrrolic N could simultaneously promote the production of hydroxyl radicals(·OH),sulfate radicals(SO_(4)·-)and single oxygen(^(1)O_(2)),facilitating the degradation of SMX.^(1)O_(2) was the main active oxidant in the RSDBC-10/PMS system.