MnO_(x)@TiO_(2)常压催化湿式空气氧化硫代硫酸钠  

Catalytic wet air oxidation of sodium thiosulfate under atmospheric pressure with MnO_(x)@TiO_(2)

作　　者：朴玮玲 于丹阳 孙承林[1] 孙文静[1] PIAO Weiling;YU Danyang;SUN Chenglin;SUN Wenjing(Dalian Institute of Chemical Physics,Chinese Academy of Science,Dalian 116023,China)

机构地区：[1]中国科学院大连化学物理研究所,大连116023

出　　处：《环境工程学报》2021年第10期3223-3232,共10页Chinese Journal of Environmental Engineering

基　　金：延长石油-大连化物所探索性科研项目(E037550902);辽宁省博士科研启动基金计划项目(2020-BS-012)。

摘　　要：应用MnO_(x)@TiO_(2)催化剂在常压条件下催化湿式空气氧化高浓度硫代硫酸钠,分别考察了空气气量、反应温度和反应时间对高浓度硫代硫酸钠转化率的影响,并采用XRF、XRD、XPS、NH_(3)-/O_(2)-TPD、H_(2)-TPR、BET对使用前后的催化剂进行了分析和表征。结果表明,通入空气中的氧气含量在过量的情况下,气量对硫代硫酸钠的转化影响不大。硫代硫酸钠的转化率随着反应时间的增加而升高;在65~85℃内,硫代硫酸钠的转化率先增大后减小。使用Mn负载质量分数为2%的催化剂,使用硫代硫酸钠为模型底物,当S_(2)O_(3)^(2−)质量浓度为10000 mg·L^(−1)时,最佳反应条件为气量50 mL·min^(−1)、反应时间25 h、反应温度75℃,硫代硫酸钠转化率可达到96%。催化剂表征结果表明,MnO_(x)@TiO_(2)表面存在多种形态的锰氧化物,其中主要活性成分为Mn_(2)O_(3),硫代硫酸钠的氧化过程伴随着催化剂表面Mn^(3+)到Mn^(2+)的电子转移。同时,MnO_(x)@TiO_(2)表面的各种锰氧化物为S_(2)O_(3)^(2−)与O_(2)之间的电子转移提供了更多位点,而这种电子转移也导致催化剂表面氧缺陷的增加。这些结果证明了MnO_(x)@TiO_(2)常压催化湿式空气氧化硫代硫酸钠的可行性,为含硫废碱液高效、经济的预处理技术的开发提供了可能性。This work reported the effects of the airflow,the temperature,the reaction time on sodium thiosulfate conversion.In this process,MnO_(x)@TiO_(2) catalyst was prepared for the catalytic wet air oxidation of sodium thiosulfate in high concentration under atmospheric pressure.X-ray fluorescence(XRF),X-ray diffraction(XRD),X-Ray Photoelectron Spectroscopy(XPS),temperature-programmed desorption(TPD)with NH_(3) and O_(2),temperature-programmed reduction with H2(H2-TPR)and BET were used to characterize the physicochemical properties of MnO_(x)@TiO_(2) catalysts before and after the reactions.The results showed that airflow had an insignificant effect on sodium thiosulfate oxidation under the absolute excess of oxygen.Reaction time and reaction temperature were two important influence factors of the catalytic activities.Reaction time increasing showed a positive influence on the conversion of sodium thiosulfate.The catalytic activities first increased then decreased with the increase of temperature from 65℃to 85℃.The optimal experimental conditions were airflow of 50 mL·min−1,the reaction time of 25 h,and reaction temperature of 75℃,respectively.Under the optimal experimental conditions,the conversion of sodium thiosulfate reached 96%by MnO_(x)@TiO_(2) with Mn loading amount of 2% when the S_(2)O_(3)^(2−)concentration was 10000 mg·L^(−1).The result of MnO_(x)@TiO_(2) characterization showed that there existed various forms of Mn oxides on the surface of the catalyst,of which Mn_(2)O_(3) was the main active component.The sodium thiosulfate oxidation process was accompanied by the valence conversion of Mn^(3+)to Mn^(2+)and electron transfer.At the same time,various Mn oxides on MnO_(x)@TiO_(2) surface provided more active sites for electron exchange between S_(2)O_(3)^(2−)and O_(2),which led to an increase of oxygen defects on the catalyst surface.All these results proved the feasibility of the catalytic wet air oxidation of thiosulfate at atmospheric pressure with MnO_(x)@TiO_(2) as the catalyst.This proce

关 键 词：MnO_(x)@TiO_(2) 硫代硫酸钠 常压 催化湿式空气氧化 

分 类 号：X703.1[环境科学与工程—环境工程]