污泥基活性炭催化臭氧氧化对氯苯甲酸效能

以城市污水处理厂剩余污泥和玉米芯为原料,用氯化锌活化法制备出污泥基活性炭(SCAC),研究了其催化臭氧氧化去除水中对氯苯甲酸(p-CBA)的效能和机理,同时,考察了臭氧浓度、SCAC投量、p-CBA初始浓度以及自由基抑制剂叔丁醇的加入对SCAC催化活性的影响。实验结果表明,SCAC的加入可以显著提高臭氧对p-CBA的氧化去除效果,在反应初期尤为明显,反应1.0 min时p-CBA的去除率由单独臭氧氧化的26.1%提高到SCAC催化臭氧氧化的60.2%。SCAC催化臭氧氧化对p-CBA的去除率随臭氧浓度的增加和p-CBA初始浓度的减小而增加。此外,在一定范围内增加催化剂的投量可以增加p-CBA的去除率。叔丁醇的加入显著减弱了SCAC催化臭氧氧化降解p-CBA的效能,表明SCAC催化臭氧氧化反应的主要活性物种为羟基自由基(·OH)。

Ozonation degradation of para-chlorobenzoic acid by sludge-corncob activated carbon

Sludge-corncob activated carbon (SCAC) was prepared from sewage sludge and corncob with ZnCl₂ as an activation regent. The removal efficiency of para-chlorobenzoic acid (p-CBA) by SCAC catalytic ozonation and its mechanism were discussed. The influences of ozone concentration, SCAC dosage, initial concentration of p-CBA and a radical scavenger tert-butyl alcohol (TBA) on the removal of p-CBA were also studied. The results showed that SCAC/O₃ process, compared with sole ozonation, significantly increased the removal efficiency of p-CBA, especially in the early period of reaction. The removal efficiency of p-CBA by SCAC/O₃ process reached 60.2% within the first 1 min, while only 26.1% by sole ozonation. Under the experimental conditions of the present study, the removal efficiency of p-CBA by SCAC/O₃ treatment increased with the ozone concentration increasing and the initial concentration of p-CBA decreasing. Through the result, it is proved that increased SCAC dosage in a certain range can improve the removal efficiency of p-CBA. The presence of TBA greatly inhibited the degradation of p-CBA, indicating that hydroxyl radical (·OH) was the major active species during the SCAC induced catalytic ozonation.