阴极电场活化过硫酸盐原位再生饱和活性炭纤维

In situ regeneration of saturated activated carbon fibers by cathodic electric field activated persulfate process

摘要:

针对传统电再生活性炭过程中存在的高能耗、再生液二次污染严重等问题,采用阴极电场活化过硫酸盐原位再生苯酚饱和活性炭纤维（ACF）,考察ACF的再生效能以及再生液中污染物的降解效能.通过Langmuir和Freundlich吸附等温模型对ACF吸附的过程进行拟合；探究电流密度、过硫酸盐浓度、再生时间对电阴极/过硫酸盐再生体系的影响；通过ACF的多次吸附饱和-再生循环实验分析该体系应用潜力并阐述再生机理.结果表明:ACF对苯酚的吸附更符合Freundlich吸附等温模型,为非均一吸附；电阴极/过硫酸盐体系的再生效率为62.71%,且再生液中苯酚总量仅为ACF最大吸附容量的3.10%；最优工况为电流密度57.14 mA/cm²,过硫酸盐浓度0.1 mol/L,再生时间6 h.在电阴极/过硫酸盐体系多次再生的过程中,过硫酸盐及其产生的硫酸根自由基会对ACF的孔隙结构和表面形貌产生一定的破坏.3次再生后,再生效率仍能达到40%左右,表明该体系具有较强的应用潜力.

Abstract:

In view of the problems of high energy consumption and serious secondary pollution during traditional electric regeneration of activated carbon, cathodic electric field was adopted to activate persulfate in situ for regenerating phenol saturated activated carbon fiber (ACF), and the regeneration efficiency of ACF and degradation efficiency of pollutants in the regeneration solution were investigated. The adsorption process of ACF was fitted by Langmuir and Freundlich adsorption isotherm models. The effects of current density, persulfate concentration, and regeneration time on the electric cathode/persulfate regeneration process were investigated. Besides, the application potential and regeneration mechanism were analyzed by multiple adsorption–regeneration cycles experiments. Results show that the adsorption of phenol by ACF was more consistent with the Freundlich adsorption isotherm model, indicating heterogeneous adsorption. The regeneration efficiency of the electric cathode/persulfate regeneration process was 62.71%, and the total amount of phenol in the regeneration solution was only 3.10% of the maximum adsorption capacity of ACF. The optimal operating conditions were current density of 57.14 mA/cm², persulfate concentration of 0.1 mol/L, and regeneration time of 6 h. During the multiple regeneration of the electric cathode/persulfate process, the persulfate and the resulting sulfate radical would damage the pore structure and surface morphology of ACF to some extent. After three times of regeneration, the regeneration efficiency could still reach about 40%, which indicates that the process has strong application potential.