利用过热蒸汽再生不同吸附饱和度的活性炭

Regeneration of different adsorption saturated-activated carbon with superheated steam

利用活性炭进一步处理城镇污水处理厂二级出水,对于城镇污水达标排放具有重要意义。为提高此工艺中活性炭的再生效率,采用过热蒸汽冲洗的方式,对不同吸附饱和度的活性炭进行再生实验。考察了再生温度、再生时间、多次再生对不同吸附饱和度活性炭再生效率和得率的影响。结果表明:在温度为400℃的条件下,再生6 h,对不同吸附饱和度的活性炭均能取得最佳的再生效率和较高的得率;经过3次吸附-再生循环后,吸附饱和度为60%活性炭的再生效率与得率损失最少,对二级出水COD的吸附符合伪二级动力学方程,活性炭表面酸性官能团减少,pHpzc增加;比较再生前后的扫描电镜,再生后的活性炭孔结构更加清晰,炭化与解吸较好。基于上述结果,选取吸附饱和度为60%的活性炭,在再生温度400℃、再生时间6 h时,多次再生后,可获得最佳的再生效果和较低的得率损失。

It is significant to meet the requirement of discharge standards for the municipal sewage when activated carbon is used to further treat secondary effluent from the urban wastewater treatment plant.In order to improve the regeneration efficiency of the used activated carbon,the superheated steam was used to regenerate different adsorption saturated-activated carbon.The effects of regeneration temperature,regeneration time and multiple regeneration on the regeneration efficiency and yield of different adsorption saturated-activated carbon were investigated.The results showed that the best regeneration efficiency and high yield occurred for different adsorption saturated-activated carbon after 6 h regeneration at 400℃.After three times of adsorption-regeneration cycles,the losses on the regeneration efficiency and yield of 60%adsorption saturated-activated carbon were the least.The adsorption of COD from secondary effluent conformed to the pseudo second-order kinetic equation.The acid functional groups on the surface of activated carbon decreased and its pHpzc increased.Through comparison of the scanning electron microscope images before and after regeneration,the pore structure of the regenerated activated carbon was clearer,indicating better carbonization and desorption.Therefore,the best regeneration efficiency and lower yield loss can be obtained by multiple regeneration of 60%adsorption saturated-activated carbon after 6 h regeneration at 400℃.