用于海水脱硫恢复系统的电化学-化学复合氧化方法探讨

Study on Integrated Electrochemical-Chemical Oxidation Used in Seawater Desulfurization Recovery System

本文将聚丙烯腈基碳纤维（PAN-CF）刷电极用于海水脱硫电化学辅助恢复系统,研究不同初始pH、不同刷电极组合方式、一次海水掺混量、停留时间和二次海水掺混量等参数,在电化学-化学复合氧化和单独化学曝气处理时对SO2-3氧化效率和排水pH值的影响。结果表明,PAN-CF刷电极对SO2-3具有显著的电催化活性,电化学氧化效率与初始pH（3--6）值无关,而化学氧化则在pH增加时氧化效率升高。在一次掺混比2∶1时,相比于单独化学氧化处理4 min的结果（SO2-3氧化效率仅为88%）,采用电化学-化学复合氧化处理2min后SO2-3氧化效率已达91.2%,而后再化学曝气处理2min可使SO2-3氧化效率达到95%,海水的pH值提升到6.04。因此,复合氧化比单独化学曝气处理更易形成有利的二次掺混条件,使二次掺混比低至0.5∶1时,pH、溶解氧和SO2-3浓度就可达到排放标准。

High energy consumption exists in seawater desulfurization recovery system in order to meet the requirement of pH and COD of drainage.Polyacrylonitrile carbon fiber（PAN-CF）brush electrode was used in seawater desulfurization recovery system assisted by electrochemical method.The effects of different initial pH,the combination of brush electrode,the first mixing ratio,the residence time and the secondary mixing ratio on oxidation efficiency of SO2-3and drainage pH were studied by integrated electrochemical-chemical oxidation method and chemical oxidation treatment.It showed that PAN-CF brush electrode had a significant electrocatalytic activity towards the oxidation of SO2-3,and its oxidation efficiency was independent of the initial pH（3~6）,while the oxidation efficiency of chemical oxidation increased with the increase of pH.Under the condition of the first mixing ratio of 2∶1,compared with the results of the chemical oxidation treatment alone for 4 min（SO2-3oxidation efficiency was only88%）,the oxidation efficiency of SO2-3by integrated electrochemical-chemical oxidation for 2min was above 91.2%,and then pH of seawater was up to 6.04 and the oxidation efficiency of SO2-3reached 95%by chemical oxidation treatment for another 2 min.Moreover,compared with the chemical oxidation,integrated electrochemical-chemical oxidation method was more likely to form the more favorable secondary mixing conditions.When the secondary mixing ratio was 0.5∶1,pH and the concentration of dissolved oxygen and SO2-3almost reached discharge standards.