Oxidation And Regeneration Of Cu(?) Enhance Desulfurization Rich Liquid Of Iron-based Ionic Liquid

Iron-based ionic liquids(Fe-IL)have the advantages of low vapor pressure,good thermal stability,and designability,as well as have catalytic oxidation properties,are widely used in the removal of H2S and have achieved significant achievements.However,regeneration process during the desulfurization is time-consumed,and the regeneration efficiency and process are poor.In order to realize the recycling of Fe-IL,it is essential to further investigate the regeneration process.In this work,based on the research of H2S removal with complex Fe-IL/organic solvent solutions and the reported regeneration of iron-based rich desulfurization liquid.Adding Fe(?)into Fe-IL to simulate the desulphurization rich liquid of Fe-IL.The effect of NHD and Cu(?)on the regeneration efficiency as well as the optimal regeneration conditions ware investigated.Finally,the regeneration kinetics process of simulated desulfurization rich liquid with and without the addition of NHD and Cu(?)ware studied,combined fourier transform infrared spectroscopy and cyclic voltammetry characterization to analyze the regeneration mechanism.The conclusions were as follow:(1)The desulfurization experiment was carried out under the conditions of T=3030.15K,VFe-IL=30 mL,NH2s=30 mL/min and CH2S=1%for 18h with the use of bubbling desulfurization,and the desulfurization rich liquid with Fe(?)concentration of 1.5 mg/mL was obtained.Meanwhile,BmimCl and FeCl2·4H2O with a molar ratio of 1:0.01 were used to prepare Fe(?)-IL,and Fe(?/?)-IL with a concentration equivalent to Fe(?)and Fe(III)in the desulfurized rich liquid was prepared.The desulfurized rich liquid and Fe(?/?)-IL were characterized by FT-IR Raman spectrum and cyclic voltammetry,the results showed that Fe(?/?)-IL could successfully simulate the desulfurized rich liquid.(2)The effects of the mixture ratio of Fe(?/?)-IL/NHD,Cu(?)concentration,temperature and O2 flow rate on the regeneration efficiency were investigated in a bubbling reactor.The optimal volume ratio of Fe(?/?)-IL/NHD was 3:1,and under the conditions of 5%H2O,CCu(?)=4.36 mg/mL,T=323.15 K and NO2=100 mL/min,the regeneration efficiency can reach 96%after 30min.(3)The regeneration kinetic process of Fe(?/?)-IL/NHD with and without adding Cu(?)ware investigated in a bubbling reactor.The results showed that when the regeneration was carried out at CCu(?)=4.36 mg/mL,NO2=50 mL/min and T=298.15 K for 1h,the regeneration efficiency of the system is more than 2.3 times of the system without Cu(?).The reaction activation energy of the system decreased from 17.97 kJ/mol to 8.64 kJ/mol after adding Cu(?),and the dynamic equation is r=0.8753exp-8.64/RT·CFe((?))2,which showed that Cu(?)can significantly improve the regeneration efficiency.(4)FT-IR spectrum and cyclic voltammetry were used to characterize Fe(?/?)-IL with and without adding NHD and Cu(?),and to infer its regeneration mechanism.Through literature investigation,combined with the characterization results,it was inferred that NHD in Fe(?/?)-IL is physical dissolution.NHD reduced the viscosity of the system,and strengthened the gas-liquid mass transfer process.While Cu(?)coordinated with Cl in the Fe3Cl7-,resulting in the structure changes of the system.Moreover,the addition of NHD and Cu(?)weakened the stability of Fe-Cl bond and improved Fe(?)activity,which promotes the reaction between Fe(?)and O2,thus enhanced the regeneration process of Fe(?/?)-IL.