湿式氧化再生饱和片状活性炭及机理研究

Wet air oxidation regeneration process of flake activated carbon and the mechanism

采用湿式氧化装置再生吸附间甲酚饱和片状活性炭,采用标准再吸附实验法测定饱和活性炭的再生效率,确定湿式氧化再生的最佳反应时间和温度.通过总有机碳测定仪和高效液相色谱测得再生过程中总有机碳和间甲酚浓度变化,其中间甲酚浓度由脱附过程和降解过程综合影响.通过高效液相色谱和气相色谱-质谱联用确定活性炭再生过程产物包括:间甲酚降解产物乙酸、丙烯酸以及部分稳定的大分子物质,其中乙酸浓度变化是导致总有机碳变化的主要因素.通过氮气吸附脱附测试可知,再生过程中活性炭表面有部分塌陷.通过程序升温脱附-质谱联用技术得出经过再生处理的活性炭表面氧化官能团的数量有显著增加,其中以羧酸酐类和内酯的增加最为显著,表明再生过程中活性炭表面部分被氧化.通过溶液分析以及表征结果,推测再生过程的反应机理.

A wet air oxidation (WAO) device was used to regenerate the flack activated carbon (AC) saturated by m-cresol. The regeneration efficiency of saturated AC was measured by adsorption method, and the optimum reaction time and temperature of WAO process were determined through this method. The changes of total organic carbon(TOC) and m-cresol concentration in the regeneration process were measured by total organic carbon tester and high performance liquid chromatography(HPLC),m-cresol concentration was influenced by the desorption and degradation process. The degradation products of m-cresol were determined by HPLC and gas chromatography-mass spectrometry(GC-MS),which include acetic acid,acrylic acid and some stable macromolecule. The concentration of acetic acid is the main factor that caused the change of TOC. During the regeneration process,the surface of AC was partially collapsed,which was determined by the nitrogen adsorption and desorption tests. The number of surface function groups of AC especially the carboxylic acid anhydride and lactone increased significantly after regeneration process,which was measured by the temperature programmed desorption-mass spectrometry techniques,indicating that part of the AC surface was oxidized in the regeneration process. Combining the analysis of solution with characterization results, a possible mechanism of regeneration process was proposed.