In response to the fact that the presence of manganese dithionate(MnS_(2)O_(6))leads to a series of adverse impacts,especially lower purity of manganese sulfate(MnSO_(4))and disruption of its recovery,advanced oxidati...In response to the fact that the presence of manganese dithionate(MnS_(2)O_(6))leads to a series of adverse impacts,especially lower purity of manganese sulfate(MnSO_(4))and disruption of its recovery,advanced oxidation methods such as ozonation system are used to manage MnS_(2)O_(6)in the leaching solution,replacing conventional methods.To ascertain the conversion rate and kinetics of MnS_(2)O_(6)during the ozonation process,we explored the factors influencing its removal rate,including ozone dosage,manganese dithionate concentration,sulfuric acid concentration,and reaction temperature.Batch experiments were conducted to determine the reaction rate constant of ozone(k)and activation energy(Ea)obtained from intermittent experimental data fitting,revealing a least-squares exponential conversion relationship between k and the MnS_(2)O_(6)removal amount,wherein an increase in the aforementioned factors led to an enhanced MnS_(2)O_(6)conversion rate,exceeding 99.3%.The formation mechanism of the ozone products proposed during the experiment was summarized and proposed as follows:1)Mn^(2+)was directly oxidized to MnO_(2),and 2)SO_(4)2−was obtained by the catalytic oxidation of S_(2)O_(6)^(2−)with HO•from O3 decomposition.According to the kinetics analysis,the pre-exponential factor and total activation energy of the ozonation kinetics equation were 1.0×10^(23) s^(−1) and 177.28 kJ/mol,respectively.Overall,the present study demonstrates that O_(3) as an oxidizing agent can effectively facilitate MnS_(2)O_(6)disproportionation while preventing the release of the secondary pollutant,SO_(2)gas.展开更多
基金Project(2022M710619)supported by the Postdoctoral Science Foundation of ChinaProjects(2020YFH0213,2020YFG0039)supported by the Sichuan Science and Technology Program,China+1 种基金Projects(XJ2024001501,KCXTD2023-4)supported by the Basic Scientific Foundation and Innovation Team Funds of China West Normal UniversityProject(CSPC202403)supported by the Open Project Program of Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province,China。
文摘In response to the fact that the presence of manganese dithionate(MnS_(2)O_(6))leads to a series of adverse impacts,especially lower purity of manganese sulfate(MnSO_(4))and disruption of its recovery,advanced oxidation methods such as ozonation system are used to manage MnS_(2)O_(6)in the leaching solution,replacing conventional methods.To ascertain the conversion rate and kinetics of MnS_(2)O_(6)during the ozonation process,we explored the factors influencing its removal rate,including ozone dosage,manganese dithionate concentration,sulfuric acid concentration,and reaction temperature.Batch experiments were conducted to determine the reaction rate constant of ozone(k)and activation energy(Ea)obtained from intermittent experimental data fitting,revealing a least-squares exponential conversion relationship between k and the MnS_(2)O_(6)removal amount,wherein an increase in the aforementioned factors led to an enhanced MnS_(2)O_(6)conversion rate,exceeding 99.3%.The formation mechanism of the ozone products proposed during the experiment was summarized and proposed as follows:1)Mn^(2+)was directly oxidized to MnO_(2),and 2)SO_(4)2−was obtained by the catalytic oxidation of S_(2)O_(6)^(2−)with HO•from O3 decomposition.According to the kinetics analysis,the pre-exponential factor and total activation energy of the ozonation kinetics equation were 1.0×10^(23) s^(−1) and 177.28 kJ/mol,respectively.Overall,the present study demonstrates that O_(3) as an oxidizing agent can effectively facilitate MnS_(2)O_(6)disproportionation while preventing the release of the secondary pollutant,SO_(2)gas.
