SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Xianni Song,Xinhua Xu,Donglei Wu,Haijiao Xie
Sulfoxides are widely recognized as probes for identifying and evaluating the generation and contribution of high-valent metals in advanced oxidation processes. However, this paper was surprising to find that the presence of sulfoxides selectively enhanced the degradation of specific pollutants in the Fe(II)/PS system. Represented by methyl phenyl sulfoxide (PMSO), scavenging experiments for active species showed that the presence of PMSO transformed the mechanism from radical dominated (55.60 %) to nonradical dominated (60.91 %), greatly improving the anti-interference ability of the system. Determining the concentration of Fe(Ⅱ) and total iron (Fe tot ) in solution revealed that the presence of PMSO improved the utilization efficiency of Fe(II) and PS by enhancing the redox reaction between Fe(II) and PS, and resulted in the generation of Fe(IV) more favorably than the generation of SO 4 ·− and ·OH. Additionally, comparing the proven high-valent iron dominated Fe(II)/PI system with the free radical dominated Fe(II)/PS system of this paper, it was revealed that the selectively enhanced oxidation of PMSO specifically targets the free radical dominated system. Experiments have shown that the degradation of acetaminophen, ibuprofen, phenol, and p-chlorophenol was enhanced by PMSO, while the degradation of norfloxacin, primidone, chloramphenicol, sulfamethoxazole, p-nitrophenol, benzoic acid, and nitrobenzene was inhibited. Based on density functional theory (DFT) calculations, PMSO has a selectively enhanced degradation effect for organic pollutants with ionization potential (IP) below 8.66 eV, and vice versa, it has an inhibitory effect. The present study provides new insights into the contribution of sulfoxide to the assessment of high-valent metals and sheds new light on the mechanism of active species.
研究领域:
环境科学
·
化学
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JOURNAL OF HAZARDOUS MATERIALS
·
2015
·
IF 4.529
Zhouwei Miao,Xiaogang Gu,Shuguang Lu,Mark L. Brusseau,Ni Yan,Zhaofu Qiu,Qian Sui
In this study, the effects of reducing agents on the degradation of tetrachloroethene (PCE) were investigated in the Fe(II)/Fe(III) catalyzed sodium percarbonate (SPC) system. The addition of reducing agents, including hydroxylamine hydrochloride, sodium sulfite, ascorbic acid and sodium ascorbate, accelerated the Fe(III)/Fe(II) redox cycle, leading to a relatively steady Fe(II) concentration and higher production of free radicals. This, in turn, resulted in enhanced PCE oxidation by SPC, with almost complete PCE removal obtained for appropriate Fe and SPC concentrations. The chemical probe tests, using nitrobenzene and carbon tetrachloride, demonstrated that HO was the predominant radical in the system and that O 2 − played a minor role, which was further confirmed by the results of electron spin resonance measurements. PCE degradation decreased significantly with the addition of isopropanol, a HO scavenger, supporting the hypothesis that HO was primarily responsible for PCE degradation. It is noteworthy that Cl − release was slightly delayed in the first 20 min, indicating that intermediate products were produced. However, these intermediates were further degraded, resulting in the complete conversion of PCE to CO 2 . In conclusion, the use of reducing agents to enhance Fe(II)/Fe(III) catalyzed SPC oxidation appears to be a promising approach for the rapid degradation of organic contaminants in groundwater.
研究领域:
环境化学
·
水处理
·
修复技术
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Chemical Engineering Journal Advances
·
2021
·
IF 0
Kai Wei,Xiufan Liu,Shiyu Cao,Huijuan Cui,Yu Zhang,Zhihui Ai
In this study, we fabricated a micro-nano structured Fe 2 O 3 @FeB composites by treating commercial Fe 2 O 3 with sodium borohydride. The outside amorphous FeB alloy shell endowed the Fe 2 O 3 @FeB with remarkable Fenton-like performance in organic pollutants oxidation by efficient Fe(III)/Fe(II) cycle. For instance, the pseudo first-order rate constants of RhB degradation using Fe 2 O 3 @FeB as Fenton reagent was 74.6 times that of the Fe 2 O 3 counterpart, the hydroxyl radical generation rate of Fe 2 O 3 @FeB was 1-3 orders of magnitude larger than that of other heterogeneous Fenton reagent. Further mechanistic study unveiled that FeB was oxidized accompanying with Fe(0) and B(0) continuously donated electrons to Fe(III) to secure the efficient generation of surface Fe(II), which could generate additional H 2 O 2 by consecutive single-electron molecular oxygen activation (O 2 →•O 2 − →H 2 O 2 ), leading to enhance •OH production and Fenton-degradation toward typical pollutants. This study provides a facile route for efficient heterogeneous Fenton and strengthens the vital role of molecular oxygen activation on Fenton-like process.
研究领域:
环境科学
·
材料科学
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DOI
DYES AND PIGMENTS
·
2021
·
IF 4.889
Yu Kuai,Tao Yang,Feiya Yuan,Yujie Dong,Qingbao Song,Cheng Zhang,Wai-Yeung Wong
A new metallo-supramolecular film was prepared by a liquid–liquid interface self-assembly method based on the metal ion Fe(II) in water solution and a star-shaped ligand of triphenylamine-substituted alkyl terpyridine in organic solvents . The film obtained exhibited excellent flexibility due to the presence of flexible alkyl arms, and could tightly adhere to the surface of ITO glass with very smooth surface morphology via SEM characterization. Spectroelectrochemical experiments demonstrated that the film displayed the electrochromism with purplish color in the neutralized state at 0 V vs Ag/AgCl turning to yellow-green color in the oxidized state at 1.2 V vs Ag/AgCl. This work further indicates that the liquid–liquid interfaciad self-assembly method is a promising strategy to prepare the metallo-supramolecular film towards electrochromic applications.
研究领域:
材料科学
·
电化学
·
超分子化学
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Lan Liang,Guanyi Chen,Jianhui Zhao,Penghui Shao,Ning Li,Mengting He,Qinglong Fu,Beibei Yan,Li-an Hou
The peroxymonosulfate (PMS) process may be hindered severely due to natural organic matter (NOM) conversion in the treatment of emerging pollutants from river water, becoming a critical engineering and technical issue. In this study, a Fe(II)-induced river water (RW)/PMS catalytic system was constructed for investigating molecular transformation of NOM and related influence mechanism to sulfamethoxazole (SMX) degradation. Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) analysis indicated that NOM molecules containing no more than one heteroatom in river may be attacked by hydroxyl radicals ( OH) and then polymerized, converting into molecules with two or three heteroatoms during PMS oxidation. Based on the correlation analysis, CHONP-NOM, CHOSP-NOM and CHONSP-NOM showed a significant inhibition against SMX degradation, while CHONS-NOM exhibited a moderate inhibitory effect. Besides, more condensed aromatic structures, carbohydrates and tannins were generated via reactive species ( OH and sulfate radicals (SO 4 − )) oxidation, radical addition and polymerization reactions. Notably, condensed aromatic structures, carbohydrates and tannins presented weak, modest and strong inhibition to SMX degradation, respectively. Based on the current results, the inhibition of target pollutants degradation would be mitigated via regulation of NOM molecules in a Fe(II)-induced PMS activation system, providing valuable information to reduce NOM impact. In addition, this study paves the way to achieve efficient removal of emerging pollutants from river water.
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高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Zhengheng Yang,Xiaoming Ma,Hongbo Zhou,Jinxing Ma,Yuxin Ding,Di He
For more than a century, coagulation-precipitation using Fe(II) and Fe(III) are ubiquitous in wastewater treatment , however, a systematic understanding of the underlying mechanism and their performance toward chelated heavy metals (e.g. Cu II -EDTA) is still lacking. In this study, we therefore investigate the efficiency of Fe(II) and Fe(III) salts coagulation-precipitation, the properties (coagulation and crystallization behavior) of in-situ formed iron (oxy)hydroxides and explore the reaction mechanism using a suite of characterization techniques. Our results reveal that no matter Fe(II) and Fe(III) exhibited an exceptional removal performance for Cu(II) in terms of kinetics and iron dosage along with pH. Impressively, under optimal condition, over 95 % of chelated Cu(II) was removed within 10 min from Fe(II) while about 85 % from Fe(III) dosing. The highly reductive structural Fe(II) existing on mixed-valent iron bearing mineral results in reductive decomplexation of Cu II -EDTA in the Fe(II) coagulation-precipitation process in compare with replacement decomplexation in the Fe(III) coagulation-precipitation process, and then released free metal ions (Cu(I) and Cu(II)) can be removed by adsorption and coprecipitation . In addition, the in-situ formed Fe(III) (oxy)hydroxides were amorphous 2-line ferrihydrite with stable flocs and better sedimentation behavior than crystalline lepidocrocite from Fe(II) dosing, and these factors are crucial to the subsequent retention of heavy metals. The elucidation of this study has highlighted the great potential of using in-situ formed iron (oxy)hydroxides for cost-effective treatment of chelated heavy metal-bearing industrial wastewaters .
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WATER RESEARCH
·
2022
·
IF 13.4
Dongbo Wang,Chuli Pan,Lisha Chen,Dandan He,Longhu Yuan,Yifu Li,Yanxin Wu
The treatment and disposal of sludge is a complex environmental problem because of the high moisture content. Herein, We reported the process of Fe(II) activating Urea hydrogen peroxide (UHP) to improve waste activated sludge (WAS) dewaterability for the first time. Fe(II)/UHP was proven to significantly improve WAS dewaterability. Specifically, under the optimal conditions with 60/35-Fe(II)/UHP mg/g TSS, the CST, SRF, and WC SC of WAS reduced from 215.3 ± 7.5s, 9.2 ± 0.32 (× 10 12 m/kg), and 92.2 ± 0.7% (control) to 62.3 ± 4.3s, 2.8 ± 0.09 (× 10 12 m/kg), and 70.4 ± 0.4%, respectively. Further analysis revealed that •OH was generated in the Fe(II)/UHP system and played the dominant role in enhancing WAS dewaterability. •OH was found to attack extracellular polymeric substances (EPSs) and cells, causing EPSs fragmentation and decomposition part of EPSs into micro-molecule organics or even inorganics, and leading to cell destruction, thus liberating the EPSs-bound and cells-bound water. •OH also degraded the protein in centrifugal liquor (CL) into micro-molecule organics such as amino acids, which could reduce the viscosity and electronegativity of CL. The above facts ultimately reduced solid-liquid interface interaction but increased hydrophobicity , flocculation , and flowability of WAS. Meanwhile, the broken WAS flocs were then re-flocculated via adsorption bridging and charge neutralization induced by Fe(II) and Fe(III). Moreover, Fe(II)/UHP treatment achieved the reduction and stabilization of heavy metals of dewatered sludge, which further enabled its land application. Finally, the Fe(II)/UHP process was found to be more attractive than the Fe(II)/persulfate, classical Fenton processes, and cPAM in terms of cost savings and practical implementation.
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高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 13
·3251-3258
·
IF 7.779
Chun-Feng Wang,Jin Chuan Wu,Qingxin Li
A new spin crossover-fluorescent compound whose magnetic and fluorescence properties can be simultaneously controlled by multiple external stimuli was prepared. This compound possesses a 2D Hoffman-type structure and its spin crossover transition usually demonstrates high sensitivity toward intriguing effects such as the change of solvent guests. Due to the strong correlations between the spin state and fluorescence emission, the magnetic and fluorescence properties of this material can be synchronously tuned by not only physical thermal treatment, but also the chemical stimuli of solvent guests. Upon desorption or adsorption of the solvent guests, both the temperature-dependent magnetic susceptibility and fluorescence intensity can be reversibly varied between three-, one-, and two-stepped transitions, accompanied by wide thermal hysteresis loops. The synchronous control of magnetic and fluorescence behaviors through multiple external stimuli may give a new perspective to developing novel multifunctional materials.
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Environmental Science-Nano
·
2023
·Vol. 10
·期 10
·2744-2753
·
IF 7.3
Jiaxin Lv,Ruixin Chen,Zhen Wu,Yang Bai,Han Song,Chen Tian,Mengye Wang,Zhang Lin
The enrichment of microplastics in polar ice is a typical phenomenon discovered in recent years. Thus, it is worthwhile to explore the degradation behavior of microplastics in frozen environments, which is crucial to evaluate their impact on polar ecosystems. Here, taking polystyrene (PS) as an example, the degradation behaviors of MPs in frozen anoxic Fe(II)-containing solutions were investigated. The results revealed that PS degradation rate in frozen solution was 14.6-fold higher than that in water. Mechanism study showed that freezing-induced aggregation and extrusion of PS enhanced the generation of environmentally persistent free radicals (EPFRs), which in turn contributed to the formation of H2O2. Moreover, freezing-induced enrichment of Fe(II) further interreacted with H2O2 to form Fe(IV) and OH free radicals at a pH of ∼6.5, and thus accelerated the degradation of PS. Such reaction was accompanied by the formation of Fe(III)-containing products, which would further react with aged PS to produce new EPFRs and Fe(II). Such cycles of aged PS/EPFRs and Fe(III)/Fe(II) continued to accelerate the degradation of PS in the frozen solution. This study provides an overlooked pathway for microplastic degradation in frozen Fe(II)-containing solutions, which would be of key importance to understand the degradation behaviors of microplastics in frozen environments.
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JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Pengyu Zhang,Xianfa Zhang,Xiaodan Zhao,Guohua Jing,Zuoming Zhou
Peracetic acid (PAA) is an excellent oxidant that can produce multiple carbon-centered radicals (R•C). A novel advanced oxidation process (AOP) that combines PAA and nanoscale zero-valent iron (i.e. nZVI/PAA) is constructed to evaluate its performance toward tetracycline (TC) abatement. The nZVI/PAA process shows excellent abatement efficacy for TC in the pH range of 3.5–7.5. The presence of humic acid , HPO 4 2− and HCO 3 − exerts inhibitory effects on TC abatement, while the presence of Cl − displays negligible influence in the nZVI/PAA process. Nanoscale zero-valent iron (nZVI) exhibits excellent reusability with no apparent variation in crystallinity . CH 3 C(O)OO• is the predominant active radical that contributes to TC abatement, in which leakage of Fe(II) from the nZVI surface is crucial for a radical generation. Due to the strong complexation tendency of TC towards Fe(II), the Fe(II)-TC complexes are formed, which significantly accelerates the PAA decomposition and TC abatement compared to free Fe(II). In addition, the degradation intermediates of TC are identified, and a possible degradation pathway is proposed. These results will be useful for the application of PAA-based AOPs in the treatment of water containing organic micropollutants.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Xingdong Shi,Yitao Li,Zhi Zhang,Lei Sun,Yazhou Peng
The appearance of large amounts of antibiotics in drinking water and wastewater treatment plants has attracted extensive interest because of the potential resultant environmental and biological risks. Although the Fe(II)/peroxymonosulfate (PMS) system provides a feasible method for antibiotic degradation, the narrow pH range in which it operates and the resultant iron precipitation limit its use. In this study, protocatechuic acid (PCA) was introduced into the Fe(II)/PMS system to improve the system performance. Ciprofloxacin (CIP) was used as the probe reagent. Compared with the Fe(II)/PMS system, the Fe(II)/PCA/PMS system performed better for CIP degradation. This enhanced degradation was attributed mainly to the reduction and chelating ability of the PCA, which enhanced radical generation by accelerating the transformation from Fe(III) to Fe(II) and by forming the PCA-Fe chelate. The Fe(II)/PCA/PMS system also showed a superior degradation ability, even under alkaline conditions, because the PCA-Fe chelate protected iron from precipitation and released hydrogen ions continuously in the process. The electron paramagnetic resonance and alcohol-quenching tests indicated that sulfate and hydroxyl radicals existed in this system and two main CIP degradation pathways were proposed from the liquid chromatography-mass spectrometry results. This work aims to provide new ideas for refractory organics treatment.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Lian Zhang,Yue Zhang,Xuyan Gao,Chunhua Xu
Recent studies showed that Fe(II) acts as the major electron donor when sulfidated zero-valent iron (S-ZVI) is used for reductive removal of pollutants. However, few studies have focused on the utilization efficiency and regeneration rate of Fe(II). In this work, the dynamic interaction between pH and S-ZVI for Cr(VI) removal and Fe(II) production was investigated at several pH levels. It was found that the maximum utilization efficiency and regeneration rate of Fe(II) was obtained at pH 5, which is consistent with the Cr(VI) removal by S-ZVI. To further study the role of Fe(II) in Cr(VI) reduction, an innovative binary correlation analysis between aqueous Cr(VI) and Fe(II) was applied with the addition of 1,10-phenanthroline as a way to control Fe(II) availability for Cr(VI) reduction. The analysis revealed that the Cr(VI) sequestration was initially controlled by Fe 0 /FeS and then by Fe(II), which accounts for the majority of the Cr(VI) sequestration. Additionally, the effects of several operational parameters (e.g., S/Fe ratio, S-ZVI dosage and initial concentration of Cr(VI)) on Cr(VI) removal were also evaluated and the results indicated that the removal of Cr(VI) exhibited a bimodal pattern with increasing S/Fe ratio, but followed a unimodal pattern with increase of S-ZVI dosage and chromium concentration. This study sheds additional insight into the dynamic interaction between pH and Fe(II), which is significant for further improving the efficiency of Fe(II) on contaminants.
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