Oh Wen-Da, Ho Yeek-Chia, Mohamad Mardawani, Ho Chii-Dong, Ravi Rajiv, Lim Jun-Wei
School of Chemical Sciences, Universiti Sains Malaysia, Gelugor 11800, Penang, Malaysia.
Civil and Environmental Engineering Department, Centre for Urban Resource Sustainability, Institute of Self-Sustainable Building, Universiti Teknologi PETRONAS, Seri Iskandar 32610, Perak Darul Ridzuan, Malaysia.
Materials (Basel). 2021 Sep 14;14(18):5284. doi: 10.3390/ma14185284.
Activated zero-valent iron (Ac-ZVI) coupled with Fe was employed to activate peroxymonosulfate (PMS) and peroxydisulfate (PDS) for acid orange 7 (AO7) removal. Fe was used to promote Fe liberation from Ac-ZVI as an active species for reactive oxygen species (ROS) generation. The factors affecting AO7 degradation, namely, the Ac-ZVI:Fe ratio, PMS/PDS dosage, and pH, were compared. In both PMS and PDS systems, the AO7 degradation rate increased gradually with increasing Fe concentration at fixed Ac-ZVI loading due to the Fe-promoted liberation of Fe from Ac-ZVI. The AO7 degradation rate increased with increasing PMS/PDS dosage due to the greater amount of ROS generated. The degradation rate in the PDS system decreased while the degradation rate in the PMS system increased with increasing pH due to the difference in the PDS and PMS activation mechanisms. On the basis of the radical scavenging study, sulfate radical was identified as the dominant ROS in both systems. The physicochemical properties of pristine and used Ac-ZVI were characterized, indicating that the used Ac-ZVI had an increased BET specific surface area due to the formation of FeO nanoparticles during PMS/PDS activation. Nevertheless, both systems displayed good reusability and stability for at least three cycles, indicating that the systems are promising for pollutant removal.
采用负载铁的活化零价铁（Ac-ZVI）来活化过一硫酸盐（PMS）和过二硫酸盐（PDS）以去除酸性橙7（AO7）。铁作为活性物种用于促进从Ac-ZVI中释放铁以产生活性氧（ROS）。比较了影响AO7降解的因素，即Ac-ZVI与铁的比例、PMS/PDS投加量和pH值。在PMS和PDS体系中，在固定的Ac-ZVI负载量下，由于铁促进了铁从Ac-ZVI中的释放，AO7降解率随铁浓度的增加而逐渐升高。由于产生的ROS量增加，AO7降解率随PMS/PDS投加量的增加而升高。由于PDS和PMS活化机制的差异，随着pH值升高，PDS体系中的降解率降低，而PMS体系中的降解率升高。基于自由基清除研究，硫酸根自由基被确定为两个体系中的主要ROS。对原始和使用后的Ac-ZVI的物理化学性质进行了表征，表明在PMS/PDS活化过程中由于形成了FeO纳米颗粒，使用后的Ac-ZVI的BET比表面积增加。然而，两个体系在至少三个循环中均表现出良好的可重复使用性和稳定性，表明该体系在去除污染物方面具有前景。
