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The zero valence iron (ZVI) Fenton-like catalyst has two main defects: one defect is that the surface passivation impairs the reusability of catalysts, and the other defect is the deactivation under neutral working pH. To overcome these problems, we synthesized a dendrite-like ZVI@Fe 3 O 4 composite modified with carbon quantum dots (CQDs) and oxygen vacancies (OVs) by electrodeposition and solvothermal treatments. The results showed that the CQDs (approximately 5 nm) with polar C-groups on the surface of the composites were derived from the carbonization of glucose during thermal treatment, and the OVs (atomic scale) at the junction of Fe 3 O 4 and the CQDs were induced by the reduction of the CQDs. The synthesized composite possessed excellent catalytic activity and reusability. Under the condition of 6 mmol/L H 2 O 2 , the synthesized composite catalyst with the dose of 0.10 g/L completely removed 35 ppm phenol within 10 min at pH 4.0 and within 60 min at neutral pH. Furthermore, the catalytic mechanism was proposed. The reducing effect of CQDs accelerated the Fe3+/ Fe2+ cycle, and the surface polar C-groups promoted the adsorption of phenol molecules; the OVs induced the formation of acidic micro regions and facilitated the dissociation of the O O bonds in H 2 O 2 into OH, extending the application range of pH from ~4.0 to the neutral condition during the Fenton-like process. Unlabelled Image • Dendritic Fe@Fe 3 O 4 /OVs@CQDs were multiscale-designed and green-synthesized. • Abundant CQDs and OVs were formed by the carbonization effect of glucose. • CQDs promote the transform of Fe3+/Fe2+ and attract phenol molecules. • OVs provide acid micro-regions and reduce the activation energy of H 2 O 2 into OH. [ABSTRACT FROM AUTHOR]

A series of EDTA-metal complexes was prepared for the Fenton oxidation catalysts and Fe(II)L exhibits high catalytic performance for degradation of hydroxypropyl guar gum in a wide pH range 7.0-13.0. The viscosity of hydroxypropyl guar gum can be reduced with the 10.0% H2O2 and 5.0% Fe(II)L. The viscosity average molecular weight of hydroxypropyl guar gum was decreased from almost 2 million to 3,199. Most important of all, the chemical oxygen demand (COD) value can be decreased to 104 mg/L from 8,080 mg/L with enough H2O2, and Fe(II)L also shows great catalytic ability in the degradation of various polymers by H2O2. The proposed mechanism of the activation of H2O2 by the complex was studied. [ABSTRACT FROM AUTHOR]

This paper is built on the Fenton-like oxidation of p-hydroxybenzoic acid (p-HBZ) in the presence of H2O2 and 3%Fe supported on CeO2-TiO2 aerogels under mild conditions. These catalysts were deeply characterized by X-ray diffraction (XRD), hydrogen temperature programmed reduction (H2-TPR), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and X-ray photoelectron spectroscopy (XPS). The effect of thermal treatment, pH (2-3, 5, 7), H2O2/p-HBZ molar ratio (5, 15, 20, 25) and reaction temperature (25 °C, 40 °C and 60 °C) on the catalytic properties of supported Fe catalysts are studied. Our results highlight the role of CeO2 and the calcination of the catalyst to obtain the highest catalytic properties after 10 min: 73% of p-HBZ conversion and 52% of total organic carbon (TOC) abatement. [ABSTRACT FROM AUTHOR]

Abstract Porphyrin-based chemistry has reached an unprecedented period of rapid development after decades of study. Due to attractive multifunctional properties, porphyrins and their analogues have emerged as multifunctional organometals for environmental and energy purposes. In particular, pioneer works have been conducted to explore their application in pollution abatement, energy conversion and storage and molecule recognition. This review summarizes recent advances of porphyrins chemistry, focusing on elucidating the nature of catalytic process. The Fenton-like redox chemistry and photo-excitability of porphyrins and their analogues are discussed, highlighting the generation of high-valent iron oxo porphyrin species. Finally, challenges in current research are identified and perspectives for future development in this area are presented. Graphical abstract Highlights • Comprehensive study of porphyrin species in environmental and energy applications. • Mechanism of the generation of high-valent iron oxo porphyrin species. • Photoexcitability of porphyrins as efficient photocatalysts to produce 1O 2 or O 2 −. • Challenges and future prospects in current researches. [ABSTRACT FROM AUTHOR]

[Display omitted] • CaO 2 @Cu-MOF was designed for integrated detection and degradation of TC. • Dual signal amplification endows the sensor with excellent detection sensitivity. • Cu+ mediated Fenton oxidation and O 2 activation accelerate TC degradation. • H 2 O 2 self-suppling ensures reaction systems do not require additional H 2 O 2. Simultaneous accomplishment of sensitive detection and efficient degradation of antibiotics residues exposed in the aqueous environments has proved to be a difficult endeavor. Here, multifunctional composite CaO 2 -loaded Cu-MOF nanosheets (CaO 2 @Cu-MOF NSs) was elaborately designed and synthesized. Triggered by H+, the composite is not only capable of producing Ca2+ as the signal factor for tetracycline (TC) detection by activating the fluorescence emission of calcein, but also capable of self-supplying H 2 O 2 and Cu2+ to construct a novel Fenton-like oxidation and O 2 activation system for TC degradation based on Cu2+/Cu+ cycle. Under the synergy of target cycling and nano-enhancement, the sensing system exhibited great TC detection performance with a linear range of 0.001 to 100 ng mL−1 and detection limit of 11.8 fg mL−1. At the same time, the degradation system exhibited favorable degradation performance under the systematic action of Fenton-like and O 2 -activated oxidation. Nearly 80 % of the TC residues could be degraded within 10 min, and more than 95 % within 60 min. The constructed system was successfully applied to detect and degrade exposed TC in actual water samples in an integrated manner, demonstrating great promise for practical applications. [ABSTRACT FROM AUTHOR]

Large amounts of wastewater containing hydroxypropyl guar gum (HPGG), polyacrylamide (PAM) and carboxymethyl cellulose (CMC) are produced in the process of fracturing. In the work, a Fentonlike system in the presence of H2O2 was employed to degrade wastewater. The effects of oxidant concentration, catalyst dosage, the temperature and pH on the degradation efficiency of the polymer were studied in detail. Results showed that the prepared complex (Cu(II)L) exhibited a great catalytic effects in the range of pH 7-12. It was also found that under the conditions of 45℃ and pH=10, when the amount of H2O2 was 5.0% (mass ratio to hydroxypropyl guar gum) and the amount of Cu (II)L complex was 10%, HPGG had a great reduction rate, and its viscosity value can be reduced from 18 to 6.47.

Highlights • Industrial container and drum cleaning (ICDC) wastewater characterization was done. • The concentrations of pollutants in ICDC wastewater have very variable structure. • Fenton-like process and combined coagulation/oxidation processes have been studied. • All methods were suitable for the removal of COD, BOD, TOC, TP, and of some metals. • Fenton-like process is a favorable system for modification of existing system. Abstract Industrial container and drum cleaning (ICDC) facilities generated complex wastewater which have organic/inorganic compounds, acids, alkalis, metals, dyes, asbestos, PCBs, chemical cleaning solutions or textile auxiliary chemicals. Treatment of such these wastewaters containing all these pollutants is also very difficult. It is required that the wastewater chemical oxygen demand (COD) is below 1500 mg/L to treat in a centralized wastewater treatment facility in Thrace Region, Turkey. In this study the characterization of ICDC industrial wastewater and treatment alternatives of this wastewater using Fenton-like (FL) process, acidic coagulation-flocculation + H 2 O 2 /UV-C (CF + H 2 O 2 /UV-C) and acidic coagulation-flocculation + S 2 O 8 2− (CF + S 2 O 8 2−) processes have been studied. The existing treatment system already has a biological treatment system after coagulation-flocculation system and couldn't be operated effectively in spite of all the efforts. We have studied processes that can be integrated into the coagulation-flocculation (CF) process used in the existing wastewater treatment plant. According to characterization study, COD values were in the range of 4584–18125 mg/L. The COD of the wastewater used in treatment experiments were 11,853 mg/L. According to the results FL and CF + S 2 O 8 2− systems were suitable for the COD discharge standards specified for the centralized wastewater treatment plant. The optimum conditions of FL process were 0.8 g/L for FeCl 3 and 45 g/L for H 2 O 2 and COD was measured as about 1500 mg/L at these doses. The optimum conditions of CF + S 2 O 8 2− system were determined as 0.64 g/L FeCl 3 for CF and 15 g/L H 2 O 2 doses. At these dosages the highest COD removal efficiency was achieved to 68% after 5 h. All methods used were suitable for the removal of COD, biochemical oxygen demand (BOD), total organic carbon (TOC), total phosphorus (TP) and of some metals. Considering the integration into the existing treatment system and applicability, it is concluded that the FL process is most favorable. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • First study to assess performance of the Cu NPs/HDPC-H 2 O 2 system for OC degradation. • High surface area and pore volume of HDPC are beneficial to the dispersion of Cu NPs. • Functional groups in HDPC could activate H 2 O 2 to produce OH. • Transformation pathways of OC are proposed based on 7 identified metabolites. Abstract The technical applicability of hydrochar-derived pyrolysis char-supported Cu nanoparticles composite (Cu NPs/HDPC) to the degradation of octocrylene (OC) was investigated in aqueous solutions in the presence of H 2 O 2. The physico-chemical properties of the Cu NPs/HDPC composite before and after degradation reaction were described. The role of OH in this H 2 O 2 -led degradation was examined using electron spin resonance (EPR) technique. The possible degradation mechanisms of OC by the Cu NPs/HDPC-H 2 O 2 system and its degradation pathways were investigated. A relatively large surface area and pore volume of the HDPC (191.4 m2 g−1 and 0.11 cm3 g−1, respectively) resulted in well-dispersed Cu NPs loading on the surface. The degradation efficiency of OC (50 μM) was 97.0% in the presence of Cu NPs/HDPC composite (0.5 g L−1) and H 2 O 2 (20 mM) at pH 5.6 in 4 h, which was significantly higher than in Cu NPs/biochar and the integrated HDPC-Cu NPs, i.e., 62.4% and 79.7%, respectively, under the same conditions (ANOVA test; p ≤ 0.05). Several oxidation by-products of the OC included benzophenone, 3,3-diphenylacrylonitrile, and others. The OH, which resulted from the Fenton-like oxidation between the Cu species and H 2 O 2 on the HDPC surface, was the predominant factor responsible for the OC degradation in the solution. The OH formation was facilitated by a single-electron transfer process from the HDPC surface, in which the Cu NPs/HDPC composite with its C OH functional group promoted the decomposition of H 2 O 2. These findings contribute to a novel approach of cost-effective wastewater treatment by adding value to unused waste materials from agricultural industries. [ABSTRACT FROM AUTHOR]

In this paper, iron-based nanoparticles (Fe NPs) synthesized by Euphorbia cochinchensis leaf extract were used to remove 2,4-dichlorophenol (2,4-DCP). The possible mechanism for removing the adsorption and heterogeneous Fenton-like oxidation of 2,4-DCP was investigated. Various parameters affecting removal efficiency were tested, and the results showed that more than 83.5% of 2,4-DCP was removed with the addition of 10 mM H 2 O 2 and the initial concentration of 2,4-DCP of 30 mg/L at pH 6.26 under 303 K. To understand the suggested removal mechanism, SEM and FTIR were used to characterize the surface change of Fe NPs before and after the adsorption and oxidation. This process confirmed that the removal of 2,4-DCP by Fe NPs was based on pre-adsorption and Fenton-like oxidation. Furthermore, GC-MS served to identify the intermediate and final products of 2,4-DCP to understand the possible pathway. Finally, Fe NPs were used in the treatment of wastewater and the removal efficiency of 2,4-DCP reached as high as 67.5%. Subsequently, a potentially efficient option for in situ organic pollutants remediation was demonstrated. [ABSTRACT FROM AUTHOR]

In this work, a hierarchical dendritic Fe 3 O 4 @Fe 0 composite modified with polar C-groups was obtained by electrodeposition and post-solvothermal methods. SEM, EDS, TEM, XRD, Zeta analysis and ESR were employed to study the structure and composition of catalyst, and the catalytic capability was evaluated by phenol degradation experiments. With the increase of water ratio in thermal solution, the composition of prepared catalyst changes into Fe 3 O 4 /Fe 2 O 3 from Fe/Fe 3 O 4 , and the dendritic structure turns into particle-like structure. The phenol degradation experiments indicate the catalyst prepared in pure-ethanol solution possesses the optimal catalytic capability, which has a Fe@Fe 3 O 4 core-shell structure with some polar C-groups on Fe 3 O 4 outer layer. Under the condition of 0.18 g/L of catalyst dosage, 6 mmol/L H 2 O 2 and pH = 4.0, the composite catalyst prepared in pure ethanol could remove 98% phenol for 5 min, greatly higher than dendritic bare Fe o under the same condition. The enhancement of degradation efficiency by Fenton-like reaction might be ascribed to polar groups that facilitate the adsorption of H 2 O 2 , phenol and hydroxyl radicals and promote the transformation of Fe III to Fe II on the catalyst surface. This work provides a new insight into the design and application of high-efficient Fe 0 -based Fenton-like composite catalysts for wastewater purification. [ABSTRACT FROM AUTHOR]

Abstract: Two Fenton‐like catalysts of iron oxide (Fe2O3) or Fe2O3 doped with silver oxide (Ag2O) and supported on acidified multi‐walled carbon nanotubes (a‐MWCNTs) were successfully prepared by wet impregnation and calcined at 200 °C and noted as Fe2O3/MWCNTs and Ag2O‐Fe2O3/MWCNTs, respectively. These samples were characterized using techniques such as TEM, FTIR, N2 adsorption at ‐196 °C, and XRD. Their catalytic performances were determined through Fenton oxidation process of maxilon red dye (MR) at 25 °C. Fenton degradation results disclosed that the Ag2O‐Fe2O3/MWCNTs nanocomposite has the superior and the faster catalytic degradation rate of dye. This result was due to the synergistic effect that established from the combination of tiny amount of Ag2O with Fe2O3 over a‐MWCNTs support, which prevents the agglomeration of catalyst nanoparticles and enhances the adsorption of dye molecules. A full degradation of dye was obtained within 10 min at 25 °C and the Fenton oxidation capability of Fe2O3/MWCNTs catalyst increased by about 10% after loading ~1wt.% of Ag2O. The catalytic performance was considerably based on pH of solution, H2O2 concentration, and dye concentration. The reusability tests confirmed that Ag2O‐Fe2O3/MWCNTs nanocomposite offers high stability over three consecutive cycles, where over 90% degradation of MR dye was obtained. Finally, Ag2O‐Fe2O3/MWCNTs nanocomposite showed excellent Fenton catalytic oxidation and reusability as compared with Fe2O3/MWCNTs composite in Fenton‐like processes. [ABSTRACT FROM AUTHOR]

Recently, polyaniline (PANI) has received widespread attention for the free volume, optical transmittance and electrical conductivity. In this study, a chemical vapor deposition method was developed to synthesize the conductive PANI-clay composite catalyzed by Fe(III)-saturated attapulgite (Fe(III)-ATTP). The reaction is initiated by the electron transfer from aniline (ANI) to Fe(III), subsequently generating ANI radical cation. The radical could further polymerize and form PANI in the constrained micropore structure of ATTP. The Raman, Fourier transform infrared and X-ray photoelectron spectra confirmed the formation of PANI on Fe(III)-ATTP surface by comparison with the PANI standard. The newly synthesized Fe(III)-ATTP-PANI composite exhibited superior reactivity as indicated by the efficient dissipation of atrazine in the presence of hydrogen peroxide (H 2 O 2 ), and the degradation rate increased up to almost 150 times compared to Fe(III)-ATTP. The higher reactivity of Fe(III)-ATTP-PANI/H 2 O 2 system was attributed to the accelerated electron transfer, the formation of ferrous ions, and the enhanced adsorption of atrazine onto attapulgite. Furthermore, our experimental results demonstrated that Fe(III)-ATTP-PANI showed good stability and it could be reused for several reaction cycles with high reactivity. This new material could act as an environmental-friendly catalyst in Fenton-like reaction system and show promising potential to effectively eliminate many persistent organic contaminants. [ABSTRACT FROM AUTHOR]

Methylene Blue which has a wide usage area in various sectors including the medicine, pharmaceutics, chemistry and textile is one of the common pollutants found in industrial wastewaters. In this study, the catalytic performance of LaFeO3 perovskite type of catalyst under different reaction conditions in Fentonlike oxidation of the target micropollutant, Methylene Blue was compared. In the parametric study the initial H2O2 concentration was fixed at 1 ppm (1000 μg/L). The aromatic degradation and the decolorization efficiencies were evaluated as 74.5% and 94.6%, respectively, under the optimum reaction conditions which were determined as 0.05 g/L of catalyst loading, 3.5 of pH, 0.1 mM of the initial H2O2 concentration and 45°C. The iron leaching under the optimum conditions was 0.63 ppm. The toxicity tests were performed by the comparison of the Lepidium sativum root lengths growing in the treated dye solution and the distilled water. The toxicity was evaluated as 1.2% in terms of root growth inhibition. In the kinetic study a reaction mechanism was proposed and the reaction rate equation was derived. The decolorization reaction followed pseudo first order reaction kinetics. The activation energy and the pre-exponential factor were calculated as 130.8 kJ/mole and 1.2 ×1020 min-1, respectively. [ABSTRACT FROM AUTHOR]

Effluent arising from kraft or soda pulping section of a pulp and paper mill is difficult to treat due to the presence of recalcitrant organics such as lignin. In this study, FeCl3 pretreated pulping effluent was subjected to Fenton-like oxidation. Residual dissolved iron from pretreatment step and H2O2 were utilized as catalyst and oxidant, respectively while the initial wastewater pH was 4.0 (unadjusted). The maximum lignin and total organic carbon (TOC) removals of 85% and 48% could be achieved within 2 h of reaction. The oxidation reaction was mediated by hydroxyl radicals (HO) which were detected by electron spin resonance (ESR) spectroscopy. Moreover, the addition of tertiary butyl alcohol and chloroform (both radical scavengers) as well hydroxyl amine (a ferrous ion recycler) affected TOC removal significantly. The TOC degradation data could adequately be fit in a lumped kinetic model (LKM) and the activation energy was calculated as 50.85 kJ/mol. The nature of chemical compounds in treated wastewater was also predicted using Fourier transforms infrared (FTIR) spectroscopy. [ABSTRACT FROM AUTHOR]

This study makes a comparison between the pyrite/H 2 O 2 and pyrite/persulfate (PS) Fenton systems to investigate the degradation of Rhodamine B (RhB). The most relevant findings revealed that a significantly negative effect of carbonate and a narrow pH range of 2–4 were found in the pyrite/H 2 O 2 system, whereas a relatively less negative effect of carbonate and a broad pH range of 2–11 were observed in the pyrite/PS system. It was demonstrated that the pyrite catalyst in the pyrite/PS system exhibited better structural stability and showed a relatively limited loss in performance upon reuse as compared to pyrite in the pyrite/H 2 O 2 system. Experiments with different scavengers indicated that HO radicals were the major reactive species responsible for RhB degradation by pyrite/H 2 O 2 . In this case the contribution of radical was in the order of HOHO >O 2 − , whereas the SO 4 − radicals prevailed over HO in the pyrite/PS system. The role of O 2 − in the recycling of Fe(III) to Fe(II) was very important. The possible mechanism for RhB degradation by pyrite/H 2 O 2 mainly involves the reaction of the dissolved Fe 2+ released by the surface of the pyrite with added H 2 O 2 , whereas the reaction of the dissolved Fe 2+ formed in the pyrite with PS triggers degradation in the pyrite/PS system. The degradation of RhB is initiated in both cases by N-de-ethylation, chromophore cleavage and ring opening processes, which leads to the production of a series of oxidation products with smaller molecular sizes. The pyrite/PS system is here proven to be a superior heterogeneous Fenton-like oxidant process for the removal of dyes from wastewater. [ABSTRACT FROM AUTHOR]

Surfactant is one of the most important compounds widely used in the formulation and structure of detergents all over the world. In this study, we investigated the combined Fenton-like oxidation and aerobic moving bed biofilm reactor (MBBR) biological processes for treatment of the wastewater of detergent industries. The average chemical oxygen demand (COD) and linear alkylbenzene sulfonate (LAS) in the raw wastewater were 24,039 and 210 mg/L, respectively. The maximum removal efficiencies of the pretreatment and Fenton-like oxidation process for COD and LAS were 95% and 90%, respectively, and the effluent concentrations of COD and LAS were about 1,250 and 100 mg/L, respectively. For MBBR process, in reactor 1 (with lower LAS concentrations) with 36 h hydraulic retention time (HRT), the maximum removal efficiencies were found to be 94.20% and 99.99% for the influent COD and LAS, respectively (R² = 0.93 and p < 0.05 and R² = 0.92 and p < 0.05). Also, for reactor 2 (with higher LAS concentrations), in the same condition with 36 h HRT, the maximum removal efficiencies were 93.41% and 95% for the influent COD and LAS, respectively (R² = 0.92 and p < 0.05 and R² = 0.84 and p < 0.05). This investigation shows that Fenton-like oxidation process, in combination with MBBR process, can provide the local effluent discharge standard for detergent industries. [ABSTRACT FROM AUTHOR]

Iron-based nanoparticles (Fe NPs) synthesized by Euphorbia cochinchensis leaves extracts and used for degradation of 2,4-dichlorophenol (2,4-DCP) were investigated. The TEM image indicated Fe NPs were spherical and uniformly dispersed particles with a diameter of about 100 nm. The XPS results indicated Fe NPs consisted mainly of Fe(III), Fe(II), iron oxide and hydroxide. Results confirmed that the efficiency to remove 2,4-DCP was 20.6% by adsorption. The efficiency increased to 51.9% when Fe NPs were used as Fenton-like catalyst in the presence of H 2 O 2 . However, the removal efficiency of 2,4-DCP reached up to 64.0% when adsorption and Fenton-like oxidation were integrated. The kinetic data fitted well with the pseudo - second-order kinetic model of adsorption, while the Fenton-like process fitted the pseudo-first-order oxidation model. Furthermore, the degraded products were detected by gas chromatography mass spectrometry (GC–MS) to verify the mechanisms of degradation. It is concluded that removal of 2,4-DCP via adsorption/Fenton-like oxidation. [ABSTRACT FROM AUTHOR]

Manganese oxide nanorods with different crystal phases ( α -, β -, γ -, and δ -MnO 2 ) were prepared via a mild hydrothermal method, and examined as heterogeneous catalysts for the decomposition of H 2 O 2 into active radicals and concomitant degradation of methylene blue (MB) dye at neutral pH. The catalytic activity of MnO 2 nanorods was highly dependent upon their crystal structures, following the order of γ -MnO 2 > β -MnO 2 > α -MnO 2 > δ -MnO 2 . Complete degradation of MB was achieved with γ -MnO 2 in a short duration of 20 min. Furthermore, γ -MnO 2 exhibited much higher activity compared to iron-containing nanoparticles (Fe° and Fe 3 O 4 ) and several reported catalysts in the literature. The observed trend in catalyst performance was discussed in terms of surface area, degree of crystallinity, and exposed facets. It was found that γ -MnO 2 showed considerable activity over a broad range of pH and temperature as well as desired reusability for four consecutive cycles. Quenching studies indicated that hydroxyl radicals ( OH) played a major role in the degradation of MB. These results provide important insight into the design of more efficient manganese oxide catalysts for wastewater treatment. [ABSTRACT FROM AUTHOR]

Low-valent transition metal catalysts have shown great application potential in boosting the Fenton-like catalytic performance. The dispersity and particle size are closely related to catalytic performance. However, it is still a challenge to develop a simple and effective strategy to synthesize well-dispersed low-valent transition metal catalysts with small particle size. Herein, Cu/Cu 2 O nanoparticles with the size of about 42 nm are successfully in-situ synthesized during the carbonization process of surfactants, and evenly dispersed on petaloid SiO 2 (x-CS catalysts). The ratio of Cu/Cu 2 O can be easily adjusted by changing the adding amount of Cu(NO 3) 2. 6-CS catalyst exhibits the optimal catalytic performance for the degradation of high concentration tetracycline hydrochloride (TC, 100 mg/L). About 89.4 % of TC is degraded within 40 min of reaction. The excellent catalytic ability is mainly attributed to the plenty of exposed highly reactive metal sites, accelerating the activation of H 2 O 2. The experimental results show that Cu species are the catalytic active centers, in which low-valent Cu(0)/Cu(Ⅰ) plays the critical role in boosting the catalytic performance. Interestingly, the leaching concentration of Cu ions in solution is reduced to some extent, which is attributed to the adsorption by functional groups on SiO 2. ∙OH, 1O 2 and ∙O 2 – are confirmed to contribute to the degradation of TC. In addition, a catalytic mechanism is proposed in the Cu/Cu 2 O/SiO 2 /H 2 O 2 system. [Display omitted] • Cu/Cu 2 O nanoparticles were in-situ synthesized during the carbonization process of surfactants. • 6-CS catalyst exhibited excellent catalytic ability to degrade high concentration TC. • Excellent catalytic ability was attributed to the plenty of exposed highly reactive sites. • Cu(0) and Cu(Ⅰ) played the critical role in boosting the catalytic performance. • A part of leached copper ions could be re-absorbed on the surface of catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • MILs(Al)-Fe with different carboxyl group amounts were used for Fenton-like catalysis. • Surface and free HO are postulated to be the main active species for decontamination. • Free/surface HO formation ratio was positively correlated with carboxyl group amount. • Mechanims of regulation was proposed as steric hindrance and charge density. • Surface HO favored positively charged organic oxidation while free HO did not. Iron based Fenton-like processes have been widely investigated, while how to regulate active species generation still is a problem of concern. In this study, MILs(Al) with various carboxyl group amounts were used as research tools, loading iron for Fenton-like oxidation, to investigate the effect of free carboxyl group on surface or free HO generation. Active species identification indicates that surface and free HO were main active species for carbamazepine removal. Moreover, it was concluded that contribution of free HO for the decontamination was positively correlated with carboxyl group amounts on MILs(Al). With free carboxyl group amounts increasing from 3.07 to 5.09 mmol/g on MILs(Al)-Fe, concentration of free HO for carbamazepine removal increased from 47.4% to 62.5%. The mechanisms of carboxyl group amounts impact the chemical state of HO was proposed as steric hindrance effect and charge density near iron sites. The destruction of carbamazepine was proposed in different systems by intermediates determination, and the results indicate that the existing form of HO mainly influenced the efficiency of pollutant degradation, rather than oxidation mechanisms of it. Various pollutants degradation in different MILs(Al)-Fe catalyzed Fenton-like systems were investigated as well, to understand the superiority of different HO for decontamination. MILs(Al)-Fe with various carboxyl group amounts catalyzed Fenton-like processes could remove 34.2%–73.0% carbamazepine, 56.7%–93.8% sulfamethoxazole, 36.4%–75.6% bisphenol S and 43.8–79.7% salicylic acid. This study understood the regulation of active species by carboxyl group in MILs(Al)-Fe/H 2 O 2 systems, and sheds new light on active species precise regulation in Fenton-like systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bimetallic catalyst of Fe 7 Cu 3 /CN was fabricated for Fenton-like catalysis. • The new catalyst showed high catalytic and good reusability. • Synergistic effect of Fe and Cu mainly contributed to the superiority of Fe 7 Cu 3 /CN. • Oxidation mechanisms were proposed by active species and pathways analysis. • Superiority remained for different pollutants and real wastewater treatment. In this study, a new Fenton-like catalyst was developed through incorporating iron and copper in polymeric graphitic carbon nitride (FeCu/CN) for catalytic activity and reusability enhancement. With theoretical Fe/Cu ratio of 7:3 (Fe 7 Cu 3 /CN) and pH of 5, the bimetallic catalyst system showed a pseudo-first-order rate constant of 0.07294 min−1 for bisphenol S (BPS) degradation, which was near double the sum of values in monometallic catalyst systems. Moreover, the new catalyst showed much better performance for reuse, BPS removal of which catalyzed system decreased from 98.0 % to 87.3 % after five cycles used. Comparatively, BPS removal declined from 69.5 % to 45.0 % in Fe/CN catalyzed system. Characterization results indicate the superiority of Fe 7 Cu 3 /CN for Fenton-like catalysis is mainly attributed to the intrinsic advantage of CN support, Fe(II) formation, copper catalysis, and synergistic effect between iron and copper. Furthermore, hydroxyl radicals were determined as the main species for pollutant degradation, and their accumulation was monitored. The destruction pathways of BPS were analyzed by detection of degradation intermediates, and the results further confirm the main active species of hydroxyl radicals. Moreover, the new Fenton-like system also exhibited good performance for different pollutant removal and real wastewater treatment. This study provided a new catalyst with superior catalytic activity and favorable reusability, and also sheds new light on supported bimetallic catalyst development. [ABSTRACT FROM AUTHOR]

The cobalt ferrite Fenton catalysts were obtained by the flow co-precipitation method. FTIR, XRD, and Mössbauer spectroscopy confirmed the spinel structure. The crystallite size of the as-synthesized sample is 12 nm, while the samples annealed at 400 and 600 °C have crystallite sizes of 16 and 18 nm, respectively. The as-synthesized sample has a grain size of 0.1–5.0 μm in size, while the annealed samples have grain sizes of 0.5 μm–15 μm. The degree of structure inversion ranges from 0.87 to 0.97. The catalytic activity of cobalt ferrites has been tested in the decomposition of hydrogen peroxide and the oxidation of caffeine. The annealing of the CoFe 2 O 4 increases its catalytic activity in both model reactions, with the optimal annealing temperature being 400 °C. The reaction order has been found to increase with increasing H 2 O 2 concentration. Electromagnetic heating accelerates the catalytic reaction more than 2 times. As a result, the degree of caffeine decomposition increases from 40% to 85%. The used catalysts have insignificant changes in crystallite size and distribution of cations. Thus, the electromagnetically heated cobalt ferrite can be a controlled catalyst in water purification technology. [Display omitted] • Electromagnetic heating is used to boost the catalytic activity of cobalt ferrite. • The reaction order increases with increasing H 2 O 2 concentration. • Induction heating accelerates the catalytic decomposition of H 2 O 2 up to 2 times. • Induction heating accelerates the Fenton-like oxidation of caffeine more than 2 times. • Electromagnetically heated CoFe 2 O 4 can be a controlled catalyst in water purification. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and properties of CuFeS 2 chalcogenides, which were prepared using a heat precipitation method. The effect of synthetic temperature on the catalytic activity of CuFeS 2 was also investigated. The study found that CuFeS 2 prepared at 250 °C (CuFeS 2 –250) had higher crystallinity, a higher concentration of Fe2+ on its surface, and a higher catalytic activity in the decolorization of rhodamine B (RhB) using a Fenton-like oxidation process with Na 2 S 2 O 8 (99.0% RhB decolorization efficiency within 7 min). The iron sites of CuFeS 2 were found to be the catalytic active sites through density-functional theory calculations. The study also determined that •SO 4 − and •OH radicals were the reactive species responsible for the decolorization of RhB. In addition, the study demonstrated that CuFeS 2 –250 had the ability to decolorize different dyestuffs (methylene blue, methyl orange, and acridine orange) in environmental water samples (river and seawater). Furthermore, CuFeS 2 –250/Na 2 S 2 O 8 possessed excellent antibacterial activity (>90.4% eradication rate within 120 min) against pathogen (Escherichia coli , Staphylococcus aureus , and methicillin-susceptible S. aureus). In conclusion, this study highlights the enhanced catalytic activity of CuFeS 2 –250 and its potential for industrial applications related to the decomposition of organics from wastewater. Enhanced catalytic of CuFeS 2 -250/Na 2 S 2 O 8 for decolorization and disinfection of organics in wastewater. [Display omitted] • CuFeS 2 was prepared by a heat precipitation method. • The iron site was the catalytic active site. • Decolorization efficiency was 99.0%. • Excellent recycling runs and stability. • Antibacterial activity of 90.4% was found. [ABSTRACT FROM AUTHOR]

The catalytic activities of the iron catalysts over activated carbon supports prepared by different activation methods in the heterogeneous Fenton-like oxidation of Procion Red MX-5B were investigated. The activated carbons were prepared from walnut shells by applying physical and three chemical activation methods, including HNO3, ZnCl2, and KOH activations to obtain various catalyst supports. KOH-activated carbon catalyst was assessed to be the most efficient one. Under the optimum reaction conditions, 47.5% COD removal, 51.6% degradation, and 91.6% decolorization efficiencies were achieved in the presence of this catalyst. In the kinetic study, the activation energy was evaluated as 47.36 kJ/mol. [ABSTRACT FROM PUBLISHER]

A family of copper oxide catalysts with loadings spanning 1–5 wt% were dispersed on a three dimensional, mesoporous TUD-1 silica through a hydrothermal, surfactant-free route employing tetraethylene glycol as a structure-directing agent. Their bulk and surface properties were characterized by N 2 physisorption, XRD, DRUVS, EPR, TEM and Raman spectroscopy, confirming the expected mesoporous wormhole/foam support morphology and presence of well-dispersed CuO nanoparticles (∼5–20 nm). The catalytic performance of Cu/TUD-1 was evaluated as heterogeneous Fenton-like catalysts for Bisphenol A (BPA) oxidative degradation in the presence of H 2 O 2 as a function of [H 2 O 2 ], and CuO loading. Up to 90.4% of 100 ppm BPA removal was achieved over 2.5 wt% Cu/TUD-1 within 180 min, with negligible Cu leaching into the treated water. [ABSTRACT FROM AUTHOR]

The degradation of spent radioactive resin by Fenton-like process with Cu2+ as catalyst was optimized using response surface methodology (RSM) based on Box-Behnken design (BBD) method. The influence of three independent variables like catalyst concentration, H2O2 dosage, and initial pH value on resin degradation was investigated. The weight loss percentage of resin was evaluated using the quadratic model. Analysis of variance showed that correlation coefficient (R2) of the model was 0.9786, providing a satisfactory approximation of quadratic model with the experimental data. Out of three factors, especially pH value had significant influence on the weight loss percentage of resin. The weight loss percentage increased as pH decreased from 2.25 to 0.75. The conditions for resin degradation were optimized as follows: pH = 0.75, H2O2 = 20 mL, and catalyst concentration was 0.25 M. The confirmation experiment carried out at optimal conditions using RSM. The weight loss percentage was 95.80%. The predicted weight loss percentage was 96.19%, indicating that RSM based on BBD was a reliable method to optimize the operational conditions for resin degradation by Fenton-like process. Finally, the intermediates of resin degradation were analyzed by ion chromatograph and GC-MS. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1590-1596, 2016 [ABSTRACT FROM AUTHOR]

This study investigates the effect of humic acid, oxalate and phosphate on the heterogeneous Fenton-like oxidation efficiency of microcystin-LR (MC-LR) using zero-valent iron nanoparticles (nZVI) as a catalyst at neutral pH. The degradation efficiency of MC-LR in the Fenton-like system increases significantly from 59.1% to 78%, and 59.1% to 72.1% in the presence of humic acid and oxalate, respectively. These mean that humic acid and oxalate are able to form complexes with iron and iron oxide, thus promote the Fenton-like oxidation of MC-LR. However, the degradation efficiency reduces from 59.1% to 47.8% in the existence of phosphate, because phosphate adsorbs competitively with MC-LR to the nZVI surface, consequently inhibits the heterogeneous Fenton-like oxidation of MC-LR. The oxidation kinetics of MC-LR fits well with the pseudo first-order kinetic model. The results illustrate that humic acid was more effective than oxalate and phosphate to generate hydroxyl radicals. The surface changes of nZVI before and after reaction were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR).Magnetite, maghemite, lepidocrocite and other iron complexes were detected at nZVI surfaces after reaction with MC-LR. [ABSTRACT FROM AUTHOR]

The oxidation of 4-chlorophenol (4-CP) was firstly carried out by heterogeneous Fenton-like process in the presence of ferrocene-containing silicotungstate catalyst (denoted as FcSiW). The catalyst was successfully prepared by precipitation method in aqueous solution using ferrocene (Fc, or CpFeCp) and silicotungstic acid (SiW, or H 4 SiW 12 O 40 · x H 2 O) as raw materials and the intrinsic relationship between structure and catalytic activity was fully studied. Under the suitable conditions, the prepared FcSiW exhibited high catalytic activity, especially under irradiation conditions. Moreover, the catalyst showed good reusability without significant performance drop after successive experimental runs and high stability with very low iron leaching. The strong interaction resulting from the close contact between Fc and polyoxometalate (POM) species contributes to the charge-transition from Fc to POM, which is in favor of its photocatalysis. A possible catalytic mechanism revealing the synergistic effect between the Fenton-like reaction of ferricinium and photocatalysis of SiW 12 O 40 4− anions in FcSiW/H 2 O 2 system was proposed on the basis of experiment results and previous reports. This novel highly active heterogeneous catalyst has the potential for wide range of application in wastewater pollutants treatment. [ABSTRACT FROM AUTHOR]

In this study, heterogeneous Fenton-like processes using ferrocene groups immobilized on aluminum-silicate nanoparticles and multi-walled carbon nanotubes (Si/Al@Fe/MWCNT) show a high degradation and decolorization efficiency for methyl orange (MO). The effects of several parameters such as pH, initial H 2 O 2 concentration, reaction time, catalyst loading, and temperature on the oxidative degradation and decolorization of MO have been studied. The seven cycles of the Fenton-like processes utilizing the aforementioned catalyst showed the steady removal of MO, thereby demonstrating the high stability of the Si/Al@Fe/MWCNT system over several Fenton oxidation processes. Scavenging of the HO produced in the reaction media was assessed using n-butanol and KI and confirmed that this radical, which is generated upon decomposition of H 2 O 2 , is mainly responsible for the heterogeneous Fenton-like oxidation of MO. A feasible Fenton-like oxidation pathway for MO in the presence of the Si/Al@Fe/MWCNT nanocatalyst was proposed. Finally, the degradation of various dyes using the Si/Al@Fe/MWCNT system was compared. [ABSTRACT FROM AUTHOR]

A mesoporous sulfur-modified iron oxide (MS-Fe) was prepared as a heterogeneous H 2 O 2 catalyst for degradation of BPA. The physico-chemical properties of MS-Fe and bare M-Fe were characterized by BET surface area measurement, SEM, XRD, FTIR and XPS. Both M-Fe and MS-Fe composites appeared as cubic microparticles with abundant pores and cracks as well as large surface area. As depicted by XRD, EDX and XPS, M-Fe is mainly consisted of hematite while MS-Fe is a kind of S-doped iron oxide with about 5–6% of sulfur element in terms of atomic ratio. In contrast to the poor catalytic activity of bare M-Fe, the MS-Fe composites showed greatly improved efficiencies for H 2 O 2 activation for BPA degradation. The high catalytic activity of this new Fenton-like catalyst can be obtained at different initial pH in range of 3.0–9.0. The time evolution of degradation of BPA followed pseudo-first-order kinetics, and the first-order rate constants showed a linear relationship with parameters of initial pH, catalyst dosage and concentration of BPA. However, the H 2 O 2 dosage showed a dual effect on BPA degradation because excessive H 2 O 2 addition lead to scavenging of hydroxyl radicals ( OH). The investigation of working mechanisms of MS-Fe suggested a synergistic effect of homogeneous and heterogeneous degradation reaction, wherein a strong acidic environment, abundant surface-bonded hydroxyl group and electron-mediating effect of sulfur all contributed to fast activation of H 2 O 2 . Overall, this new material overcomes the limitation of narrow working pH range and shows a fast oxidation of BPA with a low H 2 O 2 and catalyst dosage, would have a good potential for environmental application. [ABSTRACT FROM AUTHOR]

Detoxification by chemical oxidation of polychlorinated biphenyls (PCBs) in contaminated soils is very difficult and inefficient because PCBs typically associate with the solid phase or exist as non-aqueous-phase liquids due to their low solubility and slow desorption rates, and thus, they are difficult to remove from soils by using traditional, water-based elution techniques. Surfactant can enhance washing efficiency of PCBs from contaminated soils. This study used Brij 58, Brij 30, Tween 80, and 2-hydroxypropyl-β-cyclodextrin (HPCD) to solubilize 2,4,4′-trichlorodiphenyl (PCB28) from soil contaminated with capacitor oil into solution. The feasibility of PCB28 oxidation in soil washing wastewater through a Fe-catalyzed Fenton-like reaction was subsequently examined. Washing with 10 g L Brij 58 solution showed the highest extraction efficiency (up to 61.5 %) compared with that of the three other surfactants. The total concentration of PCB28 in contaminated soil at 25 °C after 48-h extraction was 286 mg L. In contrast to conditions in which no washing agent was added, addition of the four washing agents decreased the efficiency of PCB28 degradation by the Fenton-like reaction, with the decrease due to addition of 10 g L Brij 58 solution being the smallest. The optimal concentration of HO for preventing its useless decomposition was found to be 50 mM. The efficiency of PCB28 removal was lower when the initial concentration of PCB28 treated in the Fenton-like reaction was higher. The degradation efficiencies of PCB28 at initial concentrations of 0.1, 10, and 176 mg L in 10 g L Brij 58 solution at 25 °C and pH 3.0 and 9 h of reaction using 50 mM HO were 64.1, 42.0, and 34.6 %, respectively. This result indicates that soil washing combined with Fenton-like oxidation may be a practical approach for the remediation of PCB-contaminated soil. [ABSTRACT FROM AUTHOR]

Highly efficient oxidation, as non-thermal regeneration technology, is a promising method to solve the regeneration problem of spent activated carbon (AC) in wastewater treatment. In this study, FeOCl was confined into activated carbon (FeOCl/AC) for catalytic oxidation of contaminants on AC during the regeneration process. The characterization results of FeOCl/AC showed that amorphous FeOCl was distributed in micropores, mesopores and macropores of AC. The methylene blue (MB)-adsorbed FeOCl/AC had a regeneration efficiency of 93.7 % at neutral pH in the presence of H 2 O 2 , much higher than 46.9 % by Fenton oxidation and 33.7 % by H 2 O 2 oxidation. Meanwhile, the spent FeOCl/AC after the adsorption of atrazine, 2,4-dichlorophenol, and ofloxacin had the regeneration efficiencies of 71.5 %, 86.4 %, and 100 %, respectively. Moreover, the regeneration efficiency still reached 87 % in the fifth adsorption-regeneration cycle, and was linearly decreased with the increase of adsorbed amounts of MB. During 6 h regeneration of spent FeOCl/AC, 97 % of adsorbed MB was degraded. Electron paramagnetic resonance and radical trapping experiments indicated that both superoxide and hydroxyl radicals were involved in MB oxidation during the regeneration process. [Display omitted] • FeOCl is successfully confined into AC for intraparticle Fenton-like regeneration. • FeOCl/AC exhibits Fenton-like regeneration efficiency of 93 % at neutral pH. • ·O 2 - and·OH radicals are responsible for oxidative degradation of pollutants. • The regeneration efficiency of FeOCl/AC reached 87 % in the fifth cycle. [ABSTRACT FROM AUTHOR]

Framework doped iron materials such as Fe-MFI zeolite is an important heterogeneous Fenton-like catalyst for tetracycline degradation. Introduction of mesopore can enhance the tetracycline degradation performance for hollow Fe-MFI zeolite, however its positive effect is extremely limited ascribed to the essence of active sites of confined framework iron species. In this work, highly dispersed copper oxide on the hollow Fe-MFI zeolite CuO/FeS-1 was synthesized via an impregnation procedure and applied as heterogeneous catalyst for the tetracycline degradation. The synthesized CuO/FeS-1 was characterized by Scanning electron microscopy, Transmission electron microscopy, X-ray diffraction, UV–vis absorption spectrometry, Fourier transform infrared spectroscopy, Nitrogen adsorption-desorption and X-ray photoelectron spectroscopy. At pH = 7.0, CuO/FeS-1 revealed the highest tetracycline degradation rate of 99.6 % at experimental conditions: [TCE] = 30 mg/L, [PMS] = 1.0 g/L, [Catalyst] = 1.0 g/L, 333 K, and the largest degradation rate constant of 1.26 min−1, which was 3.4 folds of FeS-1 zeolite and 1.8 folds of CuO. Electron paramagnetic resonance (EPR) technology disclosed that •OH, SO 4 •−, 1O 2 and •O 2 − species were all the active species for CuO/FeS-1 zeolite in the tetracycline degradation. Furthermore, possible intermediates in the degradation of tetracycline over CuO/FeS-1 zeolite were identified with liquid chromatography-mass spectrometry (LC-MS). [Display omitted] [ABSTRACT FROM AUTHOR]

The Fenton-like oxidation of the anionic azo-dye Orange II (100–500 mg/L) was batchwise performed using commercial grade diatomites (3.5% Fe content) thermally treated. Solid samples were thoroughly characterized by several techniques. Peroxidation experiments were performed varying the diatomite calcination temperature (500, 700, 1000 °C), reaction temperature (50, 60, 70, 80 °C), catalyst load (0.47, 0.94, 1.89 and 3.78 g), H 2 O 2 concentration (11.0, 13.7, 20.6 mmol/L) and dosing, pH (2–3.5) and initial dye concentration (0.28, 0.57, 1.43 mmol/L). The influence of NaCl and oxalic acid on the catalytic performance and stability was also addressed. The best results were obtained with samples calcined at 700 °C, with initial pH 3, at 70 °C and using the stoichiometric amount of H 2 O 2 , since complete decoloration, TOC reduction close to 67% and negligible Fe leaching were achieved. The stability of the catalyst maintains after 20 h of usage, with a final Fe loss of 2.25%. An average of 0.88 mg/L of iron leached after each run, which is below the discharge limit. [ABSTRACT FROM AUTHOR]

The treatment and disposal of spent radioactive ion exchange resins produced during the operation of the nuclear facilities is of great importance to minimize their potential hazard to the environments. In this paper, the degradation and disintegration of spent anionic resins was carried out using the Fenton-like oxidation process to reduce their volume and weight. The influencing factors, such as temperature, initial concentration of Cu(II), pH value were determined. The experimental results showed that the degradation efficiency (in term of COD removal rate), weight and volume reduction percentage was 97%, 68%, 75%, respectively, when pH was 3, Cu(II) concentration was 0.5 M and temperature was 95 ± 2 °C. The SEM observation indicated the process of resin disintegration and dissolution. The Raman and FTIR spectrum provided the information of functional groups change of resins during oxidation process, which is useful for further studying the intermediate products of resin degradation. The possible mechanism of anionic resins degradation was proposed to explain why they were difficult to degrade. Fenton-like oxidation process was a potential and promising method for significant volume reduction of spent radioactive resins. [ABSTRACT FROM AUTHOR]

The remediation of toxic persistent organic contaminants in the environment has raised a need for effective cleanup methods. In this study, an integrated remediation technique based on biodegradation of naphthalene using Bacillus fusiformis and Fenton oxidation of their degraded metabolites using nanoscale zero-valent iron (nZVI). A 99.0% naphthalene was biodegraded by B . fusiformis in 96 h, while only 59.4% chemical oxygen demand (COD) was removed, indicating that the degraded metabolites existed in solution. To further degrade the metabolites, nanoscale zero-valent iron (nZVI) was used as heterogeneous catalyst for Fenton-like oxidation of the metabolites after biodegradation lasting 40 h. Results showed that the total the removal COD increased from 36.4% to 91.6% at pH 3.0, 1.0 g L −1 nZVI, 10.0 mM L −1 H 2 O 2 and temperature of 35 °C. Scanning electron microscopy (SEM) showed the aggregation and corrosion of nZVI. X-ray diffraction (XRD) confirmed the existence of Fe 0 and the presence of iron oxide (Fe(II)) and iron oxohydroxide (Fe(III)). A possible degradation pathway was proposed since two naphthalene metabolites (1-Naphthalenol and 1,4-Naphthalenedione) were detected by GC–MS. [ABSTRACT FROM AUTHOR]

The green synthesis of functional iron nanoparticles (Fe NPs) by tea extracts was used as a catalyst for the Fenton-like oxidation of malachite green (MG), where more than 85% of MG was removed. The new findings are that the removal of MG by Fe NPs was based on the adsorption of MG onto iron oxide and degradation of MG by iron nanoparticles. This was confirmed by adsorption and degradation kinetics, indicating that: firstly, the adsorption kinetics follows the pseudo-first-order model; and secondly, degradation kinetics fitted well to the pseudo-second-order model. Morphology, size and changes in the Fe NPs surface were characterized using SEM, XRD, and FTIR techniques, showing that Fe 2 O 3 and Fe 3 O 4 was formed and green tea extract contained a high concentration of caffeine/polyphenols. It acted as both reducing and capping agents in the synthesis of Fe NPs. To further confirm the removal mechanism of MG by the functional Fe NPs, the degraded products were identified by FTIR and GC–MS analysis. Finally the mechanism of Fenton-like oxidation of MG based on both adsorption and degradation was proposed. [ABSTRACT FROM AUTHOR]

In this communication, we investigate the Heterogeneous Fenton-like oxidation of methylene blue in model waste water over ceria based nanocatalysts. Modification of ceria nanoparticles with oxides of Fe, Cu, Zr, La and Dy is carried out via wet impregnation and deposition precipitation methods. The synthesized catalytic systems are well characterized by X-Ray Diffraction technique, Electron microscopy (TEM &SEM), Raman spectral study, FTIR spectroscopy, UV-DR Spectra and BET surface area analysis. Among the prepared catalysts, copper oxide modified ceria system is found to be the most effective for the mineralization of methylene blue. It is concluded that oxygen vacancies and Ce 3+ ions in the catalyst have prominent role in deciding the performance of M/CeO 2 catalysts in Fenton-like oxidation reactions. Besides this, the decisive role of redox potential of the doped metal ions on the efficiency of nanoceria in Fenton-like oxidation has also been examined for the first time in literature. A correlation between redox potential of doped metal ions and the oxidation activity is also established. [ABSTRACT FROM AUTHOR]

Sediments are usually the sinks for many waterborne pollutants, and thus, contaminated sediments need to be remediated to prevent the release of pollutants into the water bodies. The objective of this study was to develop a three-stage system to cleanup total petroleum hydrocarbons (TPH)-contaminated sediments. Sediments were collected from the Kaohsiung harbor with a TPH concentration of 8,105 mg/kg. Results from the sediment analyses show that sediments were mainly fine-grained silts, and the sediment organic matter content was about 19%. Thus, the surfactant washing method became an optimal option for the cleanup of TPH-contaminated sediments at this site. The three-stage scheme included the river water (RW) washing stage followed by the surfactant (Triton X-100) washing and Fenton-like oxidation stages. Batch experiments were conducted to evaluate the TPH removal efficiency by RW washing and surfactants washing with initial Triton X-100 concentrations of 0.5, 1, and 5% (w/w). In these oxidation experiments, three different hydrogen peroxide (H2O2) concentrations (0.6, 1.05, and 6 vol.%) were used to evaluate the TPH oxidation efficiency. Based on the results of the batch experiments, the three-stage operational process was performed using the optimal conditions from the batch experiments. The three-stage process was performed using 10 pore volumes (PVs) of RW washing followed by 30 PVs of Triton X-100 (0.5%) washing and 20 PVs of hydrogen peroxide (6%) oxidation. Results show that approximately 6% of TPH was removed after the RW washing stage. Up to 71% of TPH was removed by surfactant washing through mobilization and solubilization mechanisms. Approximately, 8% of TPH was removed through the Fenton-like oxidation, and a total of 86% of TPH was removed after the three-stage processes. This implies that the Fenton-like oxidation could be used as a polishment method for the TPH-contaminated sediment treatment. Results indicate that the proposed sediment treatment scheme could provide an efficient and cost-effective alternative for TPH-contaminated sediment remediation. [ABSTRACT FROM PUBLISHER]

There is an increasing interest to recycle greywater for meeting non-portable water demand. However, linear alkylbenzene sulphonates (a form of anionic surfactants) that are commonly found in greywater are less biodegradable at moderate to high concentrations. A fenton-like system is a relatively economic advanced oxidation process that can potentially be used for surfactant degradation in greywater treatment. This study investigated the feasibility of zerovalent iron (ZVI)-mediated Fenton's oxidation of sodium dodecylbenzene sulphonate (SDBS) using Fe0/H2O2and Fe2+/Fe0/H2O2systems under a range of operating conditions. For the Fe0/H2O2binary system, the initial pH value and Fe0dosage played important roles in final degradation efficiency. For the Fe2+/Fe0/H2O2ternary systems, a small amount of Fe2+(0.5–1.7 mM) contributed a synergistic effect to promote iron recycling and SDBS degradation. Approximately, 90% of SDBS mineralization efficiency was accomplished within 15 min at a pH range from 3.0 to 6.5, using 18 mM Fe0and 15 mM H2O2. However, the removal kinetics was rate-limited by Fe2+dissolution from the ZVI surfaces. The Fenton-like process of the Fe2+/Fe0/H2O2ternary system also presents a promising treatment method for synthetic greywater, in which 90% TOC removal was achieved within the first 10 min; 78% COD and 91% BOD5were achieved after 120 min of reaction. [ABSTRACT FROM AUTHOR]

Degradation of carbamazepine (CBZ) upon Fenton-like oxidation has been investigated analyzing the effect of H 2 O 2 dose and temperature at a very low catalyst concentration (2 mg L −1 of Fe 3+ ). Fenton-like oxidation allowed complete conversion of CBZ, the oxidation rate depending on the amount of H 2 O 2 used. The addition of the theoretical stoichiometric amount of H 2 O 2 led to the complete conversion of CBZ in 1 h reaction time. The reduction of the H 2 O 2 initial concentration down to 10% of the stoichiometric led to a significant increase of that time up to 3 h. The mineralization efficiency of H 2 O 2 was considerably increased by increasing the temperature (from 21 to 131 mg TOC/g H 2 O 2 at 35 and 50 °C, respectively). Beyond 50 °C no significant effect was observed in the extension of reaction although it proceeded at significantly higher rate. The toxicity and biodegradability of the resulting effluents from Fenton-like oxidation were evaluated by respirometric tests using non-acclimated activated sludge. CBZ strongly inhibits the microbial activity (EC 50 = 1.8 mg L −1 ) being essentially non-biodegradable. Fenton-like oxidation of CBZ (10 mg L −1 ) at 50 °C with the theoretical stoichiometric H 2 O 2 amount for complete mineralization (5.6 mg H 2 O 2 /mg CBZ) allowed obtaining an easily biodegradable effluent. [ABSTRACT FROM AUTHOR]

Thermosetting unsaturated polyester resin (UPR) composites were found widespread industrial applications. However, the numerous stable carbon-carbon bonds in cross-linked networks made them intractable for degradation, causing the large-scale composite wastes. Here a nanoscale Fe0 catalyst in-situ forming strategy was exploited to nondestructively recycle carbon fiber (CF) from UPR composites via Fenton-like reaction. The nano-Fe0 catalyst employed in this strategy activated H 2 O 2 for removing UPR, featuring mild conditions and efficient degradation ability. Aiming at facile growth of the catalyst, a porous UPR was achieved by the hydrolysis of alkalic system. The nanoscale Fe0 catalyst was subsequently formed in-situ on the surface of hydrolyzed resin by borohydride reduction. Benefiting from fast mass transfer, the in-situ grown nano-Fe0 showed more efficient degradation ability than added nano-Fe0 or Fe2+ catalyst during Fenton-like reaction. The experiments indicated that hydrolyzed resin could be degraded more than 90% within 80 min, 80 °C. GC-MS, FT-IR analysis and Density functional theory (DFT) calculation were conducted to explained the fracture processes of carbon skeleton in hydrolyzed resin. Especially, a remarkable recovery process of CF from composites was observed, with a 100 percent elimination of resin. The recycled CF cloth exhibited a 99% strength retention and maintained the textile structure, microtopography, chemical structure, resulting in the nondestructive reclaim of CF. This in-situ formed nanoscale Fe0 catalytic degradation strategy may provide a promising practical application for nondestructively recycle CF from UPR composites. [Display omitted] • More than 90 wt% of thermosetting UPR was degraded under 80 °C. • The mild nano-Fe0 in-situ forming strategy strongly improved degradation efficiency. • The C=O in hydrolyzed resin was more easily attacked by radicals than aromatic ring because of the negative electric field potential. • The CF cloth in UPR composites was nondestructively recycled. [ABSTRACT FROM AUTHOR]