活性炭的表面性质对CeOx/AC催化臭氧氧化水中苯甲酸的影响机制

实验对活性炭(activated carbon,AC)进行了氧改性、氮改性、硫改性和氮-硫共改性,考查AC的表面性质对CeO_x/AC催化臭氧氧化苯甲酸性能的影响.结果表明,相比氧改性活性炭ACO、硫改性活性炭ACS和氮改性活性炭ACN,氮-硫共改性活性炭ACNS由于含氮官能团和含硫官能团的引入,提高了对苯甲酸的吸附性能和催化臭氧氧化性能.采用氮-硫共改性活性炭为载体制备的CeO_x/ACNS催化剂表面Ce~(3+)含量最高,因而具有最高的催化活性,反应30 min,苯甲酸的去除率由单独臭氧氧化的22%提高到88%,TOC的去除率单独臭氧氧化的7%提高到55%.CeO_x/ACNS催化剂具有良好的稳定性,循环使用6次,苯甲酸的去除率仅从88%降低到82%,整个过程中活性组分Ce的流失只占负载量的0.32%,是一种很有应用潜力的臭氧氧化催化剂.

Effect of activated carbon surface properties on catalytic ozonation of benzoic acid in water with CeOx/AC catalysts

To investigate the effect of surface property of AC on catalytic ozonation of benzoic acid, activated carbon was modified to obtain O-(ACO), N-(ACN), S-(ACS) and N, S-doped activated carbon (ACNS). The results show that ACNS enhanced the adsorption and catalytic ozonation of benzoic acid compared to ACO, ACN and ACS, owing to the introduction of N-containing and S-containing functional groups. CeO_x/ACNS exhibits the highest Ce³⁺ content on catalyst surface and thus presents the optimal catalytic performance. The removal rate of benzoic acid and TOC were 22% and 7% by ozonation alone, while 88% and 55% by catalytic ozonation with CeO_x/ACNS.The stability of CeO_x/ACNS catalyst was good. A slight leaching of Ce took place, accounting for 0.32% of the total Ce supported on AC. CeO_x/ACNS is a promising catalyst for catalytic ozonation.