Organic Pollutants In Industrial Wastewater Research Articles

One-step eco-friendly synthesis of Ag nanoparticles on bentonite-g-C₃N₄ for the reduction of hazardous organic pollutants in industrial wastewater.

Silver nanoparticles (Ag NPs) supported on natural materials have garnered significant attention due to their wide applicability across various research fields. This study presents an eco-friendly, scalable, and one-step approach to synthesizing high-purity Ag NPs supported by bentonite-graphitic carbon nitride (Bt-g-C3N4) nanocomposites via thermal reduction. The successful integration of Ag NPs into the Bt-g-C3N4 matrix was confirmed through several characterization techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDX). XRF analysis identified the clay as beidellite-rich (Si/Al molar ratio less than 2), while EDX spectra and XRD patterns confirmed the presence of Ag NPs, with characteristic peaks at 38.04° and 44.24°. SEM and TEM images showed uniform Ag NP distribution with an average particle size of 4.75 nm and a spherical morphology. Acid-activated bentonite preserved its layered structure and exhibited a significant surface area increase, reaching 113.77 m²/g after hydrochloric acid treatment, thereby enhancing its capacity for supporting nanoparticle-based catalysts. The synthesized nanocomposites demonstrated exceptional catalytic performance, achieving reduction efficiencies of approximately 99 % for various organic pollutants, including nitrophenols (within 7 min for 4-nitrophenol), cationic dyes (within 12 min for Rhodamine B), and anionic dyes (within 5 min for methyl orange), using sodium borohydride (NaBH4) as the reducing agent. The reduction followed first-order kinetics, with activity factors (k′) calculated as 134 s−1.g−1, 260 s−1.g−1, and 92 s−1.g−1 for 4-NP, MO, and RhB, respectively. Furthermore, the Ag NPs/Bt-g-C3N4 nanocomposites exhibited remarkable recyclability, maintaining high catalytic efficiency across multiple cycles.

Activation mechanism of persulfate by Fe3C-based materials for efficient benzo-a-pyrene abatement in wastewater: The reversed direct electron transfer from persulfate to contaminants

Herein, an unusual reserved direct electron transfer (r-DET) process from persulfate (PS) to contaminants was observed on the surface of Fe3C with N-doped C shell supported on carbon nanotubes (Fe3C@CN-CNTs). The Fe3C-based materials were synthesized via a facile sol–gel method employing melamine, glucose, FeCl3, and commercial multi-walled CNTs. The activation mechanisms were fully explored with a comparison of Fe3C@CN-CNTs and other Fe3C-based materials for the effective abatement of benzo-a-pyrene (BaP), a typical persistent organic pollutant in industrial wastewater. Electrochemical measurements, zeta potential monitoring, and Mössbauer spectroscopy indicated that the lack of CN shell result the relatively large particle size of Fe3C on Fe3C-CNTs, leading to more negatively charged surface and abundant OH during PS activation. Nevertheless, the superparamagnetic fraction with a fine particle size on the surface of Fe3C@CN and Fe3C@CN-CNTs potentially leads to a more positively charged surface, enhancing the zeta potential of surface adsorbed BaP and benefiting the r-DET. Through r-DET, oxidized PS and reduced BaP formed as intermediates, accelerating the overall degradation of BaP in Fe3C@CN-CNTs/PS. The degradation pathways, cytotoxicity, and operation conditions of BaP degradation by Fe3C@CN-CNTs/PS were thoroughly investigated. Additionally, Fe3C@CN-CNTs were found to promote the nucleophilic reaction between Cl− and PS, producing free chlorine and enhancing BaP degradation efficiency in chloride-containing wastewater. Overall, this study presents a new insight for the PS-based r-DET process and offers a promising approach for treating organically-contaminated wastewater.

Enhanced photocatalytic degradation activity of titanium dioxide by adsorbing aromatic amines through N-bonding

Narrowing the wide band gap of TiO2 (∼3.2 eV) to enhance its visible light efficiency is crucial for advancing photocatalytic degradation of organic pollutants in industrial wastewater. In this study, we achieved band gap reduction and slowed recombination rates by adsorbing some aromatic amines, like aniline and its electron-donating derivatives, onto TiO2. The predominantly present N-bonded amine species reduced the band gap and decelerated charge carriers’ recombination, enhancing photocatalytic degradation under visible light. In contrast, the amine with electron-withdrawing group is adsorbed as only H-bonded species, which showed no improvement in photocatalytic activity, performing similarly to pristine TiO2. This surface modification strategy offers potential for creating visible light-driven photocatalysts for effective degradation of organic pollutants in water.

Facile fabrication of Cu/kaolin nanocomposite as highly efficient heterogeneous catalyst for 4-nitrophenol reduction in aqueous solution

Hazardous organic pollutants in industrial wastewaters are becoming a major global challenge that threatens life on earth and particularly poses a serious health risk to human beings. 4-Nitrophenol (4-NP) is a highly hazardous organic contaminant that has been extensively utilized across multiple industries, and their wastewater disposal into water streams leads to a higher accumulation of 4-NP. It is therefore important for both academia and industry to make catalysts that are cheap, very effective, good for the environment, easy to recover, and can be used more than once for reducing 4-NP in normal conditions. This paper reports the synthesis, characterization, and application of Cu/kaolin nanocomposite (NC) as an efficient heterogeneous catalyst for decomposing 4-NP, a model organic molecule. The catalyst was synthesized by incorporating a copper precursor into layered kaolin clay and directly reducing the metal precursor using sodium borohydride (NaBH4). The morphology, structure, surface property, and interaction of the resulting Cu/kaolin NC were characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron spectroscopy/energy-dispersive X-ray spectroscopy, selected area electron diffraction, X-ray diffraction, and N2 adsorption/desorption, and the results clearly demonstrated the growth of copper nanoparticles on the kaolin surface. It was discovered that the Cu nanoparticles (NPs) on the kaolin surface had a crystallite size of about 23.6 nm. The significance of Cu NPs and the high catalytic activity of the synthesized Cu/kaolin NC toward 4-NP reduction by NaBH4 were evaluated by the catalytic reduction experiments. Among the different nanocomposites synthesized, 30-Cu/kaolin showed the highest catalytic activity for 4-NP reduction, with a reduction efficiency of over 99 % within 4 min with a pseudo-first-order rate constant, kapp, of 1.23 min−1. Furthermore, the reusability test indicated that Cu/kaolin NC can be reused for up to six runs efficiently without significant decrease in its catalytic performance, indicating the nanocomposite has excellent stability and great potential applications in industrial and agricultural wastewater treatment.

Sustainable Solutions for Industrial Wastewater Remediation by KBiFe2O5 Under Visible‐Light Irradiation

AbstractIndustrial wastewater poses a serious threat to human health and the environment. The rising demand for an easy, efficient, environment‐friendly, and cost‐effective method for wastewater treatment has paved the way for the photocatalytic degradation of wastewater. Organic dyes, which comprise a major portion of organic pollutants in industrial wastewater, are highly toxic and carcinogenic. The hydrothermal method, being economical, easily available, and environmentally friendly, is used to prepare the time‐varying KBiFe2O5 samples. KBiFe2O5 is a lead‐free (nonhazardous), low‐bandgap brownmillerite‐structured crystalline material that can use a wide range of solar spectrum. Their phase purity is also confirmed by powder X‐ray diffraction (XRD), UV–Vis diffuse reflectance spectrophotometer (UV–Vis DRS) is done to confirm the bandgap value and Fourier transform infrared (FTIR) spectroscopy is performed to identify the chemical bonds in the material. Degrading textile organic effluent methylene blue (MB) dye under visible light and comparing its photodegradation performance are conducted to investigate the synthesized samples’ photocatalytic properties. The photocatalytic activity is relatively enhanced by adding H2O2 in a precise amount. So, the synthesized samples effectively demonstrate photocatalytic behavior, which has been used for wastewater remediation purposes.

Nanofiber aerogel with layered array with structure coupled photothermal/magnetothermal effect for continuous seawater desalination

The solar evaporation is susceptible to intermittent solar irradiation as well as salt crystallization deposition on the surface severely limits the evaporation efficiency. In this work, subject to inspiration of the transpiration, groove array structure and antifouling performance of banana leaves, a multifunctional photothermal/ magnetothermal coupled three-dimensional(3D) aerogel evaporator with layer-by-layer array structure was prepared by blow-spun technology which can achieve mass produced. The unique super hydrophilic vertical array structure has multi-scale high-efficiency water transport channels and the SnSe-Fe3O4 evaporation layer realizes super hydrophobic self-cleaning and excellent photothermal and magnetothermal conversion performance, which can achieve all-weather seawater desalination. The vertical array structures facilitate the reflection and refraction of light and promote the seawater convection and salt crystals absorption coupling. It could improve the photothermal conversion efficiency and salt resistance of the evaporator. Which resulted in an evaporation rate of 2.53 kg m−2h−1 under 1 sun, with solar energy conversion efficiency of 105 % and the evaporation rate is about 4.54 kg m−2h−1 at a magnetic field. Furthermore, it could purify organic pollutants in industrial wastewater and use waste heat to generate electricity. This evaporator provides a new economical and environmentally friendly solution for seawater desalination and sewage treatment.

Trace silver doping improved the efficiency of copper-based Fenton-like catalysts cathode for wastewater treatment

The treatment of highly concentrated and recalcitrant organic pollutants in industrial wastewater has garnered significant attention, with Fenton oxidation emerging as a promising approach. However, traditional iron-based Fenton reagents present certain limitations, and copper-based Fenton systems are often less efficient. Thus, it is necessary to develop innovative copper-based Fenton catalytic materials. In this study, Cu₂O and Ag-modified activated carbon fibers (Cu₂O-Ag@ACF) were synthesized via liquid-phase reduction. The composition, structure, and morphology of Cu₂O-Ag@ACF were systematically characterized. The Cu₂O-Ag@ACF was employed as a functionalized cathode in the electro-Fenton process to degrade a highly concentrated organic pollutant solution, with methylene blue serving as a model contaminant. The loading of Cu₂O and Ag not only enhances the electrochemical performance of ACF but also improves its Fenton oxidation efficiency. Cu₂O-Ag@ACF exhibited less than 1 % performance degradation after five cycles of use, highlighting its potential for industrial applications under simulated realistic conditions. Moreover, the electro-Fenton system parameters, including current density, pH, electrode spacing, and solution temperature, were optimized. Under the optimal conditions, the degradation rate of methylene blue by Cu₂O-Ag@ACF reached 92.8 % within 120 minutes. Kinetic analysis indicated that the reaction followed a first-order kinetic model, with a rate constant of 0.253 min⁻¹. Furthermore, this study revealed that trace silver doping significantly accelerated the generation of reactive oxygen species, thereby enhancing the efficiency of the Cu-based Fenton-like catalysts. In conclusion, this work presents a convenient strategy for the sustainable and efficient purification of industrial wastewater, contributing to the improvement of human life quality.

Atomically dispersed ternary FeCoNb active sites anchored on N-doped honeycomb-like mesoporous carbon for highly catalytic degradation of 4-nitrophenol

In the last decades, 4-nitrophenol is regarded as one of highly toxic organic pollutants in industrial wastewater, which attracts great concern to earth sustainability. Herein, atomically dispersed ternary FeCoNb active sites were incorporated into nitrogen-doped honeycomb-like mesoporous carbon (termed FeCoNb/NHC) by a two-step pyrolysis strategy, whose morphology, structure and size were characterized by a set of techniques. Further, the catalytic activity and reusability of the as-prepared FeCoNb/NHC were rigorously examined by using 4-NP catalytic hydrogenation as a proof-of-concept model. The influence of the secondary pyrolysis temperature on the catalytic performance was investigated, combined by illuminating the catalytic mechanism. The resultant catalyst exhibited significantly enhanced catalytic features with a normalized rate constant (kapp) of 1.2 × 104 min-1g−1 and superior stability, surpassing the home-made catalysts in the control groups and earlier research. This study provides some constructive insights for preparation of high-efficiency and cost-effectiveness single-atom nanocatalysts in organic pollutants environmental remediation.

Coupled treatment of aniline and phenol in water by electrochemical copolymerization

ABSTRACT Anilines and phenols are recognized as challenging organic pollutants in industrial wastewater. Herein, the coupled treatment of aniline and phenol in water was achieved through electrochemical oxidation-induced copolymerization. After the electrolysis (1,300 mA for 10 h) in the solution of aniline and phenol (200 mL, each at a concentration of 5 g/L), the organic compounds were efficiently precipitated from their mixed solution by copolymerization. These insoluble copolymers could be easily separated by filtration and collected as brown powders, and the average removal rate of aniline and phenol was calculated as 0.6 mol/h m2 in this coupled electrolysis. The chemical oxygen demand (COD) test of the filtrates showed that it reached up to 98% of the COD removal ratio. Moreover, mixed solutions containing multiple aniline and phenol derivatives were also applicable for this coupled treatment strategy, and they were efficiently removed together after electrolysis.

PbO2 /graphite and graphene/carbon fiber as an electrochemical cell for oxidation of organic contaminants in refinery wastewater by electrofenton process; electrodes preparation, characterization and performance

The electro-Fenton oxidation process was used to treat organic pollutants in industrial wastewater as it is one of the most efficient advanced oxidation processes. The novel cell in this process consists of a prepared PbO2 electrode by electrodeposition on graphite substrate and carbon fiber modified with graphene as a cathode. X-ray diffraction, fluorescence, analysis system, atomic force microscopy, and scan electron microscopy were used to characterize the prepared anode and cathode. XRD patterns clearly show the characteristic reflection of the mixture of  - and β phases of PbO2 on graphite and carbon fiber, and AFM results for cathode and anode present that PbO2 on graphite substrate and graphene on carbon fiber surface are on a nanoscale. Contact angle measurement was determined for the carbon fiber cathode before and after modification. The anodic polarization curve showed a higher anodic current when utilizing the PbO2 anode than the graphite anode. Phenol in simulated wastewater was removed by electro-Fenton oxidation at 8 mA/cm2 current density, 0.4 mM of ferrous ion concentration at 35 °C up to 6 h of electrolysis. Chemical oxygen demand for the treated solution was removed by 94.02 % using the cell consisting of modified anode and cathode compared with 81.23% using modified anode and unmodified cathode and 79.87 % when using unmodified anode and modified cathode.

Influence of aeration-induced air–water interfaces on pollutant degradation in water treatment: A theoretical and experimental study

Advanced oxidation processes (AOPs) based on hydroxyl radicals (OH)-dominant pathway are the most important technologies for the removal of bio-recalcitrant organic pollutants in industrial wastewater. Air–water interface formed by aeration is one of the factors that affect the removal efficiency of pollutants in AOPs. In this work, the mechanistic and kinetic insights into the roles of air–water interface on the hydroxylation of three chlorophenols (CPs) in UV/H2O2 process have been investigated via theoretical calculation and experimental methods. Results show that CPs is more prone to accumulate at the air–water interface as the number of chlorine substituents increases. Consequently, the hydration reaction of CPs occurring at the interfacial influence the electron transfer associated with OH, leading to the non-oxidative consumption of OH. This interfacial reaction diminishes degradation efficiency, resulting in the formation of persistent organic pollutants. Herein, in UV/H2O2 degradation of 2,4,6-TCPs, persistent free radical (PFRs), as well as 1,3,7,9-TCDD and 2,3,6-Trichloro-4-(2,4,6-trichlorophenoxy)phenol, were identified using EPR spectroscopy and LC-Q-TOF-MS mass spectrometry, respectively. Altogether, this work provides a comprehensive understanding of the roles of aeration on OH-initiated degradation behavior of chlorinated phenol pollutants.

Effective visible light-driven binary ZnO catalyst decorated on layered double hydroxides for simultaneous photocatalytic degradation of Ciprofloxacin and Ampicillin

BackgroundThe direct use of clean solar energy to convert organic pollutants in industrial wastewater into harmful products is a viable tactic and a hot topic to save water bodies and avoid water pollution. Pharmaceutical wastewater is complicated and contains a variety of contaminants, making its treatment difficult. MethodThis study focuses on the simultaneous degradation of an aqueous solution containing a combination of contaminants, Ampicillin (AMP) and Ciprofloxacin (CIP). Using hydrothermal process, we successfully fabricated a ZnO-NiCoMn layered double hydroxide (LDH) sheet. The prepared catalyst was examined using a range of surface analytical optical techniques. Significant findingsThe ZnO-NiCoMn LDH demonstrates exceptional photocatalytic performance, as demonstrated by the maximal CIP and AMP degradation rates of 96 % and 94 % in 100 min under visible light, respectively, according to the data. ZnO-adorned NiCoMn LDH sheets exhibited a rod-like structure, as demonstrated by FE-SEM and HR-TEM. Because of the highest charge separation and superior electron (e−) transport between ZnO and NiCoMn LDH material, the binary catalyst degraded CIP and AMP by 96 % and 94 % in 100 min, respectively, more than the bare catalyst. The binary ZnO-NiCoMn LDH catalyst could withstand up to five CIP and AMP degradation cycles.

Compound Similarity Network as a Novel Data Mining Strategy for High-Throughput Investigation of Degradation Pathways of Organic Pollutants in Industrial Wastewater Treatment.

Identification of degradation products and pathways is crucial for investigating emerging pollutants and evaluation of wastewater treatment methods. Nontargeted analysis is a powerful tool to comprehensively investigate the degradation pathways of organic pollutants in real-world wastewater samples but often generates large data sets, making it difficult to effectively locate the exact information on interests. Herein, to efficiently establish the linkages among compounds in the same degradation pathways, we introduce a compound similarity network (CSN) as a novel data mining strategy for LC-MS-based nontargeted analysis of complex wastewater samples. Different from molecular networks that cluster compounds based on MS/MS spectra similarity, our CSN strategy harnesses molecular fingerprints to establish linkages among compounds and thus is spectra-independent. The effectiveness of CSN was demonstrated by nontargeted identification of degradation pathways and products of organic pollutants in leather industrial wastewater that underwent laboratory-scale activated carbon adsorption (ACD) and ozonation treatments. Utilizing CSN in interpreting nontargeted data, we tentatively annotated 4324 compounds in the untreated leather industrial wastewater, 3246 after ACD, and 3777 after ACD/ozonation. We located 145 potential degradation pathways of organic pollutants in the ACD/ozonation process using CSN and validated 7 pathways with 15 chemical standards. CSN also revealed 5 clusters of emerging pollutants, from which 3 compounds were selected for in vitro cytotoxicity study to evaluate their potential biohazards as new pollutants. As CSN offers an efficient way to connect massive compounds and to find multiple degradation pathways in a high-throughput manner, we anticipate that it will find wide applications in nontargeted analysis of diverse environmental samples.

Enhanced Solubilization and Biodegradation of HMW-PAHs in Water with a Pseudomonas mosselii-Released Biosurfactant.

The treatment and reuse of wastewater are crucial for the effective utilization and protection of global water resources. Polycyclic aromatic hydrocarbons (PAHs), as one of the most common organic pollutants in industrial wastewater, are difficult to remove due to their relatively low solubility and bioavailability in the water environment. However, biosurfactants with both hydrophilic and hydrophobic groups are effective in overcoming these difficulties. Therefore, a biosurfactant-producing strain Pseudomonas mosselii MP-6 was isolated in this study to enhance the bioavailability and biodegradation of PAHs, especially high-molecular-weight PAHs (HMW-PAHs). FTIR and LC-MS analysis showed that the MP-6 surfactant belongs to rhamnolipids, a type of biopolymer, which can reduce the water surface tension from 73.20 mN/m to 30.61 mN/m at a critical micelle concentration (CMC = 93.17 mg/L). The enhanced solubilization and biodegradation of PAHs, particularly HMW-PAHs (when MP-6 was introduced), were also demonstrated in experiments. Furthermore, comprehensive environmental stress tolerance tests were conducted to confirm the robustness of the MP-6 biosurfactant, which signifies the potential adaptability and applicability of this biosurfactant in diverse environmental remediation scenarios. The results of this study, therefore, have significant implications for future applications in the treatment of wastewater containing HMW-PAHs, such as coking wastewater.

Metagenomic analysis reveals the distribution, function, and bacterial hosts of degradation genes in activated sludge from industrial wastewater treatment plants

For comprehensive insights into the bacterial community and its functions during industrial wastewater treatment, with a particular emphasis on its pivotal role in the bioremediation of organic pollutants, this study utilized municipal samples as a control group for metagenomic analysis. This approach allowed us to investigate the distribution, function, and bacterial hosts of biodegradation genes (BDGs) and organic degradation genes (ODGs), as well as the dynamics of bacterial communities during the industrial wastewater bioprocess. The results revealed that BDGs and ODGs associated with the degradation of benzoates, biphenyls, triazines, nitrotoluenes, and chlorinated aromatics were notably more abundant in the industrial samples. Specially, genes like clcD, linC, catE, pcaD, hbaB, hcrC, and badK, involved in the peripheral pathways for the catabolism of aromatic compounds, benzoate transport, and central aromatic intermediates, showed a significantly higher abundance of industrial activated sludge (AS) than municipal AS. Additionally, the BDG/ODG co-occurrence contigs in industrial samples exhibited a higher diversity in terms of degradation gene carrying capacity. Functional analysis of Clusters of Orthologous Groups (COGs) indicated that the primary function of bacterial communities in industrial AS was associated with the category of “metabolism”. Furthermore, the presence of organic pollutants in industrial wastewater induced alterations in the bacterial community, particularly impacting the abundance of key hosts harboring BDGs and ODGs (e.g. Bradyrhizobium, Hydrogenophaga, and Mesorhizobium). The specific hosts of BDG/ODG could explain the distribution characteristics of degradation genes. For example, the prevalence of the Adh1 gene, primarily associated with Mesorhizobium, was notably more prevalent in the industrial AS. Overall, this study provides valuable insights into the development of more effective strategies for the industrial wastewater treatment and the mitigation of organic pollutant contamination.

C, F co-doping Ag/TiO2 with visible light photocatalytic performance toward degrading Rhodamine B

The organic pollutants in industrial wastewater continuously endanger human health. Therefore, effective treatment of organic pollutants is very urgent. Photocatalytic degradation technology is an excellent solution to remove it. TiO2 photocatalysts are easy to prepare and have high catalytic activity, unfortunately, TiO2 only absorbs ultraviolet light limiting its utilization of visible light. In this study, a facile environmentally friendly synthesis of Ag-coated on micro-wrinkled TiO2-based catalysts in order to extend the absorption of Visible light. Firstly, a fluorinated titanium dioxide precursor was prepared by a one-step solvothermal method, and the precursor was calcined at high temperature in a nitrogen atmosphere to form a carbon dopant, and then a surface silver-deposited carbon/fluorine co-doped TiO2 photocatalyst C/F–Ag–TiO2 was prepared by a hydrothermal method The results showed that the Ag was coated on the wrinkled TiO2 layer and C/F–Ag–TiO2 photocatalyst was synthetized successfully. Benefit from the synergistic effect of doped carbon and fluorine atoms in combination with the quantum size effect of the surface silver nanoparticles, the band gap energy of C/F–Ag–TiO2 (2.56 eV) is obviously lower than anatase (3.2eV). The photocatalyst achieved an impressive degradation rate of 84.2% for Rhodamine B in 4 h, with a degradation rate constant of 0.367 h−1, which was 17 times higher than that of P25 under visible light. Therefore, the C/F–Ag–TiO2 composite is a promising candidate as a highly efficient photocatalyst for environmental remediation.

Preparation of an ultra-long-life porous bilayer Ti/Sb-SnO2 electrode modified by nano-TiC for degradation of phenol

Electrochemical advanced oxidation technology produces hydroxyl radicals and has no secondary pollution, making it one of the most promising technologies for treating organic pollutants in industrial wastewater. Nevertheless, low energy efficiency and short lifetime are the key issues hindering the widespread application of electrodes. In this study, TiC nanoparticles were uniformly dispersed in the deposition solution, and the Ti/Sb-SnO2 electrode was prepared by sol electrodeposition, after calcination, a porous double-layer structure was formed, which improved the catalytic performance and effectively delayed the penetration of industrial wastewater into the electrode. Compared with the Ti/Sb-SnO2 electrode, the electrode life is increased by nearly 6 times, the phenol removal rate reaches 90.64 % (2000 mA/cm2, 1 mol/L H2SO4), the oxygen evolution potential of 2.13 V, a current density of 0.096 A/cm2, a charge transfer resistance of 2.245 Ω. The results show that the porous structure is conducive to providing a larger specific surface area and contact area for the reaction, maximizing the utilization of catalytic active sites, shortens the mass transfer distance between the hydroxyl radicals and pollutants, increases the degradation rate, reduces the corrosion rate of the electrode materials, and improves electrode stability. The unique double-layer structure is obviously different from traditional electrodes, adding a layer of protective barrier, which provides a new idea for prolonging the life of electrodes. The electrode prepared in this study has a simple process, a greatly improved lifespan and an excellent energy utilization rate, which is suitable for industrial application.

Influence of iron content in Fe-based amorphous alloy catalysts on degradation of azo dyes by fenton-like process

Degradation of organic pollutants in industrial wastewater has become one of the biggest problems that are threatening the environment, and correspondingly it is a priority for scientists to find a solution. In this work, we study the effect of the iron content in Fe-based amorphous ribbon catalysts (Fe78+xSi9B13-x, x = 0, 1 and 2) in degradation of Direct Blue 6 (DB 6) azo dye by Fenton-like process. We evaluated the catalytic efficiency by changing experimental conditions with the aim to optimize the degradation performance. The amorphous Fe80Si9B11 ribbon showed the highest catalytic activity with its ability to degrade DB 6 by 94.65% within 15 min Fe80Si9B11 ribbon provides more reactive sites than what generates the most hydroxyl radicals (. OH) and thus increases the degradation reaction. Degradation efficiency can be improved by increasing the reaction temperature and ribbons dosage, a correct amount of H2O2 but decreases with increasing initial pH value and concentration of DB 6. Fe80Si9B11 amorphous ribbons can be reused up to 12 times in optimal conditions, which confirms a good reusability. The excellent performance in catalytic activity and reusability of Fe-based amorphous alloy catalysts will contribute to wastewater treatment.

Chemical characterization and source attribution of organic pollutants in industrial wastewaters from a Chinese chemical industrial park

Accelerated urbanization and industrialization have led to an alarming increase in the generation of wastewater with complex chemical contents. Industrial wastewaters are often a primary source of water contamination. The chemical characterization of different industrial wastewater types is an essential task to interpret the chemical fingerprints of wastewater to identify pollution sources and develop efficient water treatment strategies. In this study, we conduct a non-target chemical analysis for the source characterization of different industrial wastewater samples collected from a chemical industrial park (CIP) located in southeast China. The chemical screening identified volatile and semi-volatile organic compounds that included dibutyl phthalate at a maximum concentration of 13.4 μg/L and phthalic anhydride at 35.9 μg/L. Persistent, mobile, and toxic (PMT) substances among the detected organic compounds were identified and prioritized as high-concern contaminants given their impact on drinking water resources. Moreover, a source analysis of the wastewater collected from the wastewater outlet station indicated that the dye production industry contributed the largest quantities of toxic contaminates (62.6%), and this result was consistent with the ordinary least squares and heatmap results. Thus, our study utilized a combined approach of a non-target chemical analysis, a pollution source identification method, and a PMT assessment of different industrial wastewater samples collected from the CIP. The results of the chemical fingerprints of different industrial wastewater types as well as the results of the PMT assessment benefit risk-based wastewater management and source reduction strategies.

Heterogeneous Catalytic and Non-Catalytic Supercritical Water Oxidation of Organic Pollutants in Industrial Wastewaters Effect of Operational Parameters

This work reports supercritical water oxidation (SCWO) of organic pollutants in industrial wastewater in the absence and presence of catalysts. To increase the efficiency of the oxidation process, the SCWO of organic compounds in industrial wastewater was performed in the presence of various iron- and manganese-containing heterogeneous catalysts (Fe-Ac, Fe-OH, and Mn-Al). The catalytic and non-catalytic SCWO of organic compounds in wastewater from PJSC “Nizhnekamskneftekhim”, generated from the epoxidation of propylene with ethylbenzene hydroperoxide in the process of producing propylene oxide and styrene (PO/SM), was performed. The effect of operational parameters (temperature, pressure, residence time, type of catalysts, oxygen excess ratio, etc.) on the efficiency of the process of oxidation of organic compounds in the wastewater was studied. SCWO was studied in a flow reactor with induction heating under different temperatures (between 673.15 and 873.15 K) and at a pressure of 22.5 MPa. The reaction time ranged from 1.8 to 4.83 min. Compressed air was used as an oxidizing agent (oxidant) with an oxidant ratio of two to four. A pseudo-first-order model expressed the kinetics of the SCWO processes, and the rate constants were evaluated. In the present work, in order to optimize the operation parameters of the SCWO process, we used the thermodynamic properties of near- and supercritical water by taking into account the asymmetric behavior of the liquid–vapor coexistence curve.