| Ferrous chelates can complex and absorb NO efficiently,but they are easily oxidized and lose their complexing performance.Therefore,the regeneration method of the absorption liquid is the research focus of this process.Electrochemical reduction has the advantage of not using reducing agents,but it still has low current efficiency and high energy consumption,which limits the application of ferrous complexes to absorb NO.Improving electrode performance is a way to improve the above shortcomings.This study investigated the performance of graphite felt electrodes and modified graphite felt electrodes in the process of electrochemical reduction and regeneration,explored the suitable modification conditions of graphite felt electrodes,and conducted simultaneous absorption-reduction experiments.Medium contrast NO absorption effect.The thesis is divided into the following three parts:1.Compared with the performance of stainless steel,titanium sheet,graphite sheet and graphite felt electro-reducing regenerative absorption liquid,the reduction performance of stainless steel and titanium sheet is not as good as graphite sheet and graphite felt.The performance of graphite felt electrode to reduce Fe3+ in Fe3+EDTA is twice that of graphite sheet electrode,while the reduction performance of complexed NO in reducing Fe2+ EDTA-NO is equivalent.2.The performance of CeO2 modified and KOH-modified graphite felt electroreduction and reduction from Fe3+EDTA and Fe2+EDTA-NO was studied.The results show that for the current efficiency of Fe3+EDTA reduction experiment,KOH modified graphite felt Compared with CeO2 modification,it is improved by 7.4%.For the reduction current efficiency of Fe2+EDTA-NO,KOH modified graphite felt improved by 11%compared to CeO2 modification.The optimal KOH modification conditions were explored.The results showed that after 6 mol·L-1 KOH was immersed in graphite felt,the KOH modified graphite felt electrode produced the best reduction and regeneration performance when calcined at 800? for 4hours.3.The performance of KOH/ammonia composite modified graphite felt electroreduction regeneration absorbent was studied.For the reduction current efficiency of Fe3+EDTA,KOH/ammonia modification improved 14%,KOH modification increased 10.8%,and ammonia modification increased 3.2%.For the reduction current efficiency of Fe2+EDTA-NO,KOH/ammonia modification improved 17.8%,while KOH modification improved 12.9%,and ammonia modification improved 5.4%.At the same time,the optimal KOH/ammonia modification conditions were also explored.The composite modified graphite felt prepared by using 9 mol·L-1 ammonia water and 6 mol·L-1 KOH to immerse the graphite felt and calcining at 800? for 4hours showed The best restoration performance.The different modified graphite felt materials were analyzed by FT-IR test,XPS test and BET test characterization methods.The results show that both ammonia modification and KOH/ammonia modification can make graphite felt doped with nitrogen-containing functional groups.After modification with KOH/ammonia,the specific surface area is further increased compared to the single modification.The synchronous absorption reduction experiment compared the NO removal rates using different modified electrodes.The results show that the KOH/ammonia modified graphite felt electrode maintains the highest NO removal rate,which also shows that the KOH/ammonia modified graphite felt electrode reduces Fe3+ EDTA and Fe2+EDTA-NO have the best performance.4.Explore the feasibility of using modified graphite felt electrode for anodic oxidation absorption of NH4+.Comparing the modified anodic oxidation performance of the modified graphite felt electrode to the NH4+produced by the reduction of the absorption liquid,it was found that the KOH/ammonia modified electrode corresponding to the NH4+ oxidation rate and N2 selectivity were the highest,reaching 71.2%and 86.6%,respectively,KOH/ammonia modified Graphite felt may be suitable for anodizing NH4+. |
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