Bowen Yang,Longhui Zheng,Zhiwen Cheng,Maohong Fan,Jiming Hao,Qiang Ma
Phenol-polluted water poses significant risks, inflicting serious harm on both aquatic and terrestrial organisms. While Fenton and Fenton-like processes have been widely employed in wastewater treatment, their effectiveness is hindered by a major limitation: the sluggish cycle of Fe(III)/Fe(II). This slow cycle has become the Achilles' Heel of these methods, preventing their broader application. In this study, graphene oxide (GO) was introduced to facilitate the generation of Fe(II) from Fe(III), enhancing peroxydisulfate (PDS) activation for pollutant degradation. The Fe(III)/GO/PDS system demonstrated effective pollutant degradation capability with 100 % treatment efficiency (phenol = 10 mg L −1 , GO = 50 mg L −1 , Fe(III) = 0.2 mM, PDS = 1 mM, and initial pH of 3). The radical-mediated oxidation mechanism was proposed based on radical scavenger effects, oxidation products, and electron paramagnetic resonance spectra. The conversion of methyl phenyl sulfoxide (PMSO) to methyl phenyl sulfone (PMSO 2 ) indicated the formation of Fe(IV) in Fe(III)/GO/PDS system. To reveal degradation rules for multiple substrates, eighteen molecular descriptors were calculated using density functional theory (DFT) and correlated them with degradation rate constants ( k ). BO n , E B3LYP , and F (−) x emerged as significant parameters in this relationship. The Fe(III)/GO/PDS system demonstrated excellent reusability during the first five runs, effectively treating contaminants. However, its performance was hindered by kinetic retardation when certain anions, such as phosphate and bicarbonate, were present. These findings contribute to both scientific understanding and technical development of persulfate activation via the Fe(III)/Fe(II) cycle using carbonaceous materials, particularly for environmental remediation applications.
Slow iron cycling is an important factor limiting the reactivity of zero-valent iron (ZVI). Developing novel strategies to facilitate iron cycling is vital for the ZVI practical application. This study reports a novel interfacial slow-release reduction strategy for synthesizing L-ZVI with excellent performance by adding L-ascorbic acid 2-phosphate sesquimagnesium salt hydrate (AAPS). Experiments revealed that AAPS slowly released ascorbic acid via acid-catalyzed hydrolysis, thereby using reduction to promote Fe(III)/Fe(II) cycling, a process that regulates iron cycling while preventing low utilization by direct adding reductants. The enhanced content of Fe(II) and self-corrosion of L-ZVI facilitated the release of Fe(II) into the solution. Electrochemical experimental and comparisons of hydrogen production demonstrated that L-ZVI exhibited exceptional electron transfer and selectivity capacity. The strategy alters the electronic structure of L-ZVI, lowers work function, and shifts the band center upward. Cr (VI) was chosen as the model contaminant to investigate the reactivity of L-ZVI. L-ZVI can remove Cr (VI) within 7 min completely, exhibiting a reaction rate constant ( k obs ) of 0.6809 min⁻¹ , which was 154.75-fold higher than that of ZVI (0.0044 min⁻¹) and significantly surpassing the performance of other reported water treatment materials. This article presents a novel strategy for developing efficient iron-based materials.
Hao Xu,Qian Ye,Jing Zhang,Qiansong Li,Meijing Wang,Peng Zhou,Guanyu Zhou,Qingguo Wang
In response to the inherent restriction of low Fe(II) regeneration in the Fenton process, this study demonstrated a mutual-promoting configuration, where oxygen functionalized g-C 3 N 4 (OCN) was applied in Fe(III)/H 2 O 2 system to utilize mild natural solar light (SL) for persistent Fe(II) generation. The constructed OCN/Fe(III)/H 2 O 2 /SL system exhibited strong adaptability to various pollutants, and it well outperformed the g-C 3 N 4 (GCN) modified system and the traditional Fenton system in pollutants degradation efficiency. Compared with GCN, OCN could significantly promote the Fe(II) generation under solar light (SL), leading to more efficient H 2 O 2 activation. The characterization analyses revealed the larger surface area and enhanced charge separation of OCN, which were considered to take main responsibility for its enhanced photoactivity. The complexation of Fe(III) with the carboxyl groups of OCN also benefited the Fe(II) generation. ·OH was detected as the dominant radical responsible for metronidazole (MNZ) degradation, and its production in the OCN modified system was about twice that in the GCN modified system and the Fenton system. Moreover, the precipitation of FeO x on the OCN surface benefited the charge separation of the OCN, so that the improved OCN enabled a slight enhancement of MNZ degradation in the reuse experiments. The intermediates of MNZ degradation were analyzed based on the results of LC-MS, which provided insight into MNZ degradation pathways. This work highlighted the concept of self-improving photocatalyst, the ingenious combination of photocatalysis and Fenton-like system formed a mutual-promoting situation where the OCN and the Fenton-like system could both be improved, which endowed the configuration great potential for green and economical oxidation in environmental remediation.
危险品化学品经营许可证（带存储）