With the copper/iron cinder as the starting material,ferrous ions were obtained through maturing,acid leaching,reducing and purifying processes,and then iron nanoparticles were prepared by reacting with sodium borohyd...With the copper/iron cinder as the starting material,ferrous ions were obtained through maturing,acid leaching,reducing and purifying processes,and then iron nanoparticles were prepared by reacting with sodium borohydride in the system of ethanol-water.The nano Fe/SiO2 core-shell composite particles were synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS).The products were characterized by X-ray diffraction (XRD),transmission electron microscope (TEM) and reflectance absorption infrared spectroscopy (RA-IR).The particles were randomly dispersed in paraffin at a mass ratio of 5.5∶4.5 for microwave electromagnetic parameters detection in the frequency range of 2.0—18.0 GHz by vector network analyzer.The results showed that there were two characteristic absorption peaks of Si—O and Si—O—Fe bond appearing at 1389 cm-1 and 878 cm-1,which indicated that the nano iron was successfully coated by SiO2.Through measuring and calculation,the minimal reflection loss was-39.0 dB at 17.2 GHz when the sample thickness was 4.5 mm.So nano Fe/SiO2 core-shell composite particles can be prepared from copper/iron cider to be used as an effective microwave absorbing material.展开更多
文摘运用共沉淀低温水热技术制备软铋矿铁酸铋(sillenite bismuth ferrite,S-BFO),构建S-BFO非均相活化过一硫酸盐(peroxymonosulfate,PMS)降解环丙沙星(ciprofloxacin,CIP)体系。实验结果表明:在初始pH值为(6.5±0.1)和反应温度为(25±1)℃条件下,向反应溶液中加入0.675 mmol/L PMS、1000 mg/L的催化剂,反应60 min后,溶液中84.8%的CIP被去除(初始浓度为5.0 mg/L);在相同反应条件下,S-BFO活化PMS降解CIP效率高于SBFO活化过二硫酸盐(persulfate,PS)。采用场发射电子显微镜(scanning electron microscope,SEM)和X射线衍射仪(X-ray diffraction,XRD)分别对S-BFO的微观形貌特征和晶型结构进行了分析。探究了PMS浓度和初始反应pH值对S-BFO活化PMS降解CIP的影响,评估了S-BFO/PMS体系在实际水体条件下处理污染物的应用潜能。通过活性物质淬灭实验,发现体系中对CIP起主要降解作用的活性物质是单线态氧(^(1)O_(2)),而不是硫酸根自由基(·SO_(4)^(-))和羟基自由基(·OH),并提出了S-BFO活化PMS降解CIP的机理。采用三重四级杆串联液相色谱质谱仪(liquid chromatography tandem mass spectrometry,LC/MS/MS)技术检测到了9种CIP降解过程中的主要中间产物,并确定了CIP被氧化去除的主要降解路径是通过羟基加成反应(路径Ⅰ)及脱羧反应(路径Ⅱ)。本研究为基于过硫酸盐的高级氧化技术在污水处理领域的应用提供了重要的理论支撑。
文摘With the copper/iron cinder as the starting material,ferrous ions were obtained through maturing,acid leaching,reducing and purifying processes,and then iron nanoparticles were prepared by reacting with sodium borohydride in the system of ethanol-water.The nano Fe/SiO2 core-shell composite particles were synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS).The products were characterized by X-ray diffraction (XRD),transmission electron microscope (TEM) and reflectance absorption infrared spectroscopy (RA-IR).The particles were randomly dispersed in paraffin at a mass ratio of 5.5∶4.5 for microwave electromagnetic parameters detection in the frequency range of 2.0—18.0 GHz by vector network analyzer.The results showed that there were two characteristic absorption peaks of Si—O and Si—O—Fe bond appearing at 1389 cm-1 and 878 cm-1,which indicated that the nano iron was successfully coated by SiO2.Through measuring and calculation,the minimal reflection loss was-39.0 dB at 17.2 GHz when the sample thickness was 4.5 mm.So nano Fe/SiO2 core-shell composite particles can be prepared from copper/iron cider to be used as an effective microwave absorbing material.
