Organic Pollutants Research Articles

Impact of Cathodic Scaling on Electrocatalytic Degradation of Organic Pollutants

Impact of Cathodic Scaling on Electrocatalytic Degradation of Organic Pollutants

Impact of tetracycline on mixotrophic denitrification process under different sulfur to nitrogen ratios

The sulfur-based autotrophic-heterotrophic denitrification, i.e., mixotrophic denitrification, is suitable for the nitrate and antibiotics removal in aquaculture tailwater at a low COD to nitrogen (C/N) ratio. This study focused on the effect of tetracycline (TC) on mixotrophic denitrification under different S/N ratios. Two bioreactors were simultaneously operated with or without dosing tetracycline under different sulfur to nitrogen (S/N) ratios of 3.94, 4.64 and 5.94. The results showed that the removal rate of total inorganic nitrogen (TIN) increased from 0.25 to 0.69 mg N L−1 min−1 with the rise of S/N ratio, while TC dosage significantly declined the removal efficiency of TIN. Dissimilatory nitrogen reduction to ammonia (DNRA) bacteria was detected when exposing to TC, indicating that DNRA presented more resistance to TC. The removal efficiency of TC in the denitrification system reached the maximum of 22.87 % at S/N of 4.64. Meanwhile the genus Marinicella was detected at this phase, which was conducive to the degradation of organic pollutants. This study found that TC promoted the accumulation of ammonia nitrogen, and had a great effect on sulfur autotrophic bacteria at S/N of 5.94. The removal of TC mainly depended on microbial co-metabolism, and there was a significant correlation between the reduction of TC concentration and the decrease of sulfur compounds (p < 0.05). 4.64 is the best S/N ratio for the mixotrophic denitrification process, which revealed maximum nitrate and TC removal rates.

Activation of peroxymonosulfate by MnOOH/g-C3N5: Study on highly selective removal of phenolic pollutants and its non-radical pathway

In this research, the MnOOH/g-C3N5 material was successfully synthesized, demonstrating its efficacy in selectively removing phenolic organic pollutants. This material outperformed traditional free radical pathways, exhibiting higher selectivity, enhanced persulfate utilization efficiency, and strong resistance to background anions and complex organic matter. Using phenol as the target pollutant, the MnOOH/g-C3N5/PMS system achieved 81 % mineralization, a PMS utilization efficiency of 88 %, and a 75 % process unit energy consumption value in degrading phenol. This efficient degradation is attributed to the synergistic effects of high-valence metal oxides (MnV(O)/MnIV(O)), singlet oxygen (1O2), and electron transfer complexes, as confirmed by electrochemical analysis and In-situ EPR. Additionally, Transmission Electron Microscopy observations disclosed the development of an amorphous shell on the MnOOH/g-C3N5 surface post-reaction. Electrochemical Impedance Spectroscopy analysis suggested an enhanced charge transfer resistance, further affirming the role of MnOOH/g-C3N5 as an "electron transfer station" in the electron transfer process, accompanied by the formation of electron transfer complexes. This study provides crucial scientific insights and theoretical guidance for applying MnOOH/g-C3N5 materials in environmental engineering.

Current levels of inorganic and organic pollutants in Romanian marine waters: Implications for ecosystem health

Human activities continue to impact the Romanian Black Sea, with implications for the marine ecosystem. This study presents new data (2023) on the spatial distribution of heavy metals, persistent organic pollutants, and nutrients in Romanian Black Sea waters. Our findings reveal the influence of various pollution sources, including the Danube River, municipal and industrial discharges, and maritime activities. Nutrient loads, primarily from the Danube and diffuse sources, exert pressure on the pelagic habitat. While there has been some improvement in nutrient conditions, the potential for increased eutrophication due to climate change remains a concern. Understanding the spatial distribution of pollutants and identifying their sources is crucial for developing effective management strategies to protect the marine environment.

Kinetic Insights into Solar-Assisted Fabrication and Photocatalytic Performance of CoWO4/NCW Heterostructure

This work studies the kinetic model for the solar-driven fabrication of CoWO4/NCW heterostructure photocatalysts and investigates their enhanced photocatalytic degradation activity. The synthesis of CoWO4/NCW, its characterization, and the kinetic aspects of photocatalytic degradation under solar light. New nanocomposite prepared from Nano cellulose (NCW) by hydrolysis cotton waste (CW) by nitric acid and cobalt tungstate (CoWO4) prepared from sodium tungstate and cobalt chloride by wet chemical method and characterized through XRD, FTIR, EDX, and FE-SEM analyses. The composite's performance in organic oxidation from refinery wastewater (RWW) was evaluated under solar light. The high removal ratio was 97.4% for organic pollutants (OP) in refinery wastewater. The results indicate that the heterostructure exhibits improved photocatalytic performance compared to individual components, which kinetics model was the best to represent the photocatalytic degradation of organic pollutants from oily wastewater over the heterostructure CoWO4/NCW catalyst. Add future applications of this finding in the relevant industries. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Promotion of Single-Electron Transfer by Low-Coordinated Co Single Atoms to Facilitate Advanced Oxidation Processes in Wastewater Treatment.

Heterogeneous catalysts are fascinating for advanced oxidation processes (AOPs) in wastewater treatment to reduce cost, metal contamination, and pH operation limitations. However, they usually encounter low catalytic efficiency because of the difficult single-electron-transfer (SET) pathway during AOPs. Herein, an efficient heterogeneous catalyst for AOPs is realized through the rational regulation of N coordination around Co single-atom (SA) centers in favor of SET. As guided by calculations, low N coordination enables a high density of electronic states at the Fermi energy level of SA Co to facilitate SET activation of peroxomonosulfate (PMS). A special oxide-compounding method is further applied to decrease the N coordination of SA Co on the carbon carriers from common Co1-N3/4 to the desired Co1-N2. Co1-N2 shows a delightful activity for AOP degradation of various organic pollutants with kinetic rate and turnover frequency values up to 0.862 min-1 and 389 h-1, respectively, greatly outperforming those of Co1-N3/4. It is also superior in a wide pH operation range and has strong resistance to environmental disturbances. Detailed mechanistic investigations confirm the generation of singlet oxygen (1O2) instead of common radical O species from the SET between PMS and Co1-N2, corroborating the calculated results and accounting for the enhanced AOP activity.

Antibacterial and Methylene Blue Dye Degradation Activity of hibiscus rosa sinensis Synthesized CoFe2O4 Nanocomposites

AbstractCo‐precipitated biotic CoFe2O4 nanoparticles from the leaves of the Hibiscus rosa sinensis plant were used to produce bio‐reductant nanoparticles. The CoFe2O4 biomolecules were analyzed using EDX analysis to identify their structure through XRD, FTIR, UV, VSM, and SEM characterization. The cubic phase and crystallite size of biotic CoFe2O4 nanoparticles were determined using XRD analysis. The FTIR spectroscopy was used to confirm Cation migration and Co−Fe−O interaction. Using SEM, TEM, and EDX, it was confirmed that spherical biosynthesized CoFe2O4 nanoparticles and the material they were made were present. VSM analysis confirmed the super‐paramagnetic nature of the CoFe2O4 nanoparticles and magnetic pulse. Biosynthetic CoFe2O4 nanoparticles were used to eliminate organic(MB dye) and bacterial(S. aureus, B.Substils, and E. coli bacterial strains) pollutants. Spinel ferrite biosynthetic CoFe2O4 nanoparticles are capable of generating radical superoxide ions.

Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (Fe2O3-CoO@NC) derived from cobalt/iron solid complex as peroxymonosulfate (PMS) activator for efficient bensulfuron-methyl degradation

Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (Fe2O3-CoO@NC) was synthesized by convenient solid phase coordination combined with calcination method to activate PMS for the degradation of BSM. A series of Co/Fe bimetallic oxides with different metal ratios were designed and prepared to select the most efficient catalyst and Fe2O3-CoO@NC(Co:Fe = 1:1) demonstrated the highest catalytic activity and the lowest ions leaching. The reasons for high catalytic activity of Fe2O3-CoO@NC(Co:Fe = 1:1) were evaluated by a range of characterization techniques and the results showed it stemmed from higher mental content and larger current density. Complete (100%) degradation of 10 g L−1 BSM was achieved within 10 min under the conditions of 0.05 g L−1 catalyst and 0.3 mmol/L PMS dosage at 25 °C. Moreover, Fe2O3-CoO@NC(Co:Fe = 1:1) showed more excellent catalytic activity and lower ions leaching than Fe2O3, CoO and Fe2O3-CoO, indicating superior bimetallic synergy and carbon encapsulation effect. Furtherly, radical experiments and XPS analysis revealed the main active species and catalytic mechanism of the Fe2O3-CoO@NC/PMS system, respectively. Finally, the degradation pathway of BSM by Fe2O3-CoO@NC/PMS system was deduced by LC-TOF-MS. This paper is aimed to provide a new insight into the convenient preparation method for the construction of catalysts which could reach efficient removal of complex organic pollutants.

Natural Vanadium–Titanium Magnetite Activated Peroxydisulfate and Peroxymonosulfate for Acid Orange II Degradation: Different Activation Mechanisms and Influencing Factors

Persulfate-based advanced oxidation processes have emerged as a promising approach for the degradation of organic pollutants in aqueous environments due to their ability to generate sulfate radicals (SO4−·) within catalytic systems. In this study, peroxydisulfate (PDS) and peroxymonosulfate (PMS) were investigated with the natural vanadium–titanium magnetite (VTM) as the activator for the degradation of acid orange II. The degradation efficiency increased with higher dosages of VTM or persulfate (both PDS and PMS) at lower concentrations (below 10 mM). However, excessive PMS (higher than 10 mM) in the PMS/VTM system led to the self-consumption of free radicals, significantly inhibiting the degradation of acid orange II. The VTM-activated PDS or PMS maintained an effective degradation of acid orange II in a wide pH range (3~11), suggesting remarkable pH stability. The SO4−· was the main active species in the PDS/VTM system, while hydroxyl radical (·OH) also contributed significantly to the PMS/VTM system. In addition, PMS exhibited better thermal stability during VTM activation. Coexisting ions in an aqueous environment such as bicarbonate (HCO3–), carbonate (CO32–), and hydrogen phosphate (HPO42–) had obvious effects on persulfate activation. Our study systematically investigated the different activation processes and influencing factors associated with PDS and PMS when the natural VTM was used as a catalyst, thereby providing new insights into the persulfate-mediated degradation of organic pollutants in aqueous environments.

Preliminary detection of toxic organic pollutants in sediments of the confluence area of Hong river - Bach Hac, Phu Tho, Vietnam

Preliminary detection of toxic organic pollutants in sediments of the confluence area of Hong river - Bach Hac, Phu Tho, Vietnam

Research on the application of catalytic complex between transitional metal ion cobalt (II) and citric acid to treat organic pollutants contained in textile wastewater

Research on the application of catalytic complex between transitional metal ion cobalt (II) and citric acid to treat organic pollutants contained in textile wastewater

Numerical Simulation of Organic Pollution Migration in the Heterogeneous Aquifer and the Application of Chemotactic Bacteria for Remediation: A Case Study of a Chemical Contamination Site in Zhejiang Province, China

Groundwater pollution poses a significant threat to ecosystems and public safety. Traditional remediation methods have limitations, necessitating innovative approaches. This study integrates numerical modeling and bioremediation to address groundwater contamination in an industrial site. It explores the potential of chemotactic bacteria to enhance remediation efficiency. The research establishes groundwater pollutant transport models, analyzes flow fields, and assesses the distribution of various pollutants. The results demonstrate the effectiveness of chemotactic bacteria, particularly chemotactic bacteria that can rapidly adapt as the pollutant concentration decreases, the concentration of chemotactic bacteria in the low-permeability area has increased by 112%. This study provides insights into the practical application of bioremediation and the promising role of bacterial chemotaxis in treating contaminated groundwater.

Accelerated Indirect Photodegradation of Organic Pollutants at the Soil-Water Interface.

Indirect photolysis driven by photochemically produced reactive intermediates (PPRIs) is pivotal for the transformations and fates of pollutants in nature. While well-studied in bulk water, indirect photolysis processes at environmental interfaces remain largely unexplored. This study reveals a significant acceleration of indirect photodegradation of organic pollutants at the soil-water interface of wetlands. Organic pollutants experienced ubiquitously enhanced indirect photodegradation at the soil-water interfaces, with rates 1.41 ± 0.01 to 4.27 ± 0.03-fold higher than those in bulk water. This enhancement was observed across various natural and artificial wetlands, including coastal wetlands and rice paddies. In situ mapping indicated that soil-water interfaces act as hotspots, concentrating both organic pollutants and PPRIs by 9.30- and 4.27-folds, respectively. This synchronized colocation is the primary cause of the accelerated pollutant photolysis. Additionally, the contribution of each PPRI species to pollutant photolysis and a coupled transformation pathway at the soil-water interface significantly differed from those in bulk water. For instance, the contribution of singlet oxygen to metoxuron photolysis increased from 10.1% in bulk water to 44.4% at the soil-water interface. Our study highlights the rapid indirect photolysis of organic pollutants at the soil-water interfaces, offering new insights into the natural purification processes in wetlands as "Earth's kidneys."

Metal‐Organic Framework (Cu@ZIF) for Photocatalytic Reduction of p‐Nitrophenol and its Toxicological Evaluation using Zebrafish (Danio Rerio)

AbstractGlobal food security depends on agricultural development, yet excessive fertilizer and pesticide usage is harmful to the environment. These substances have a role in human health problems, environmental changes, and erosion of the soil. Although p‐nitrophenol, an organic pollutant and other organophosphorous compounds are utilised in agriculture, their usage raises major health and environmental issues. These synthetic pesticides are quite effective at getting rid of pests, but they have also been linked to serious health problems for people and animals, degraded soil, and contaminated water. One typical persistent pollutant present in industrial wastewater is the organic pollutant, which is produced by organophosphorous compounds. The primary objective of this work is to use Cu@ZIF for photoreduction of p‐nitrophenol (PNP). A UV‐visible spectrophotometer test revealed that the deterioration peak after 60 mins. An analyzer for total organic carbon (TOC) was utilised to assess the PNP mineralization. The catalyst remained same and continued in the same behaviour even after four cycles. This study evaluated the acute toxicity of PNP on the development of early‐stage zebrafish, paying particular attention to the embryonic developmental deformities. The technique of photocatalytic decontamination is safe for the environment, financially practical, and technically achievable.

Evaluation of Groundwater Quality Through Identification of Potential Contaminant

Groundwater, is crucial for human consumption and industrial purposes, demands continuous monitoring to assess quality standards. This study conducts a comprehensive evaluation of groundwater quality to assess its overall condition and identify potential contaminants. The research predicts the presence and levels of contaminants such as heavy metals, organic pollutants, and microbial agents using hydrogeological studies, chemical analysis, and statistical modelling. A covariance analysis identified places with low water quality. Analysis shows most samples satisfy drinking water requirements. A consolidated map illustrates a significant expanse suitable for domestic and drinking purposes, particularly in terms of drinking water quality. However, water quality in 2467.09 sq. km is deemed unacceptable. Further analysis, including correlation, ANOVA, and t-tests such as One Sample Test, Bayesian Statistics, and Power Analysis, identifies 836.87 sq. km under the category of maximum permissible water quality and 9.19 sq. km as highly desirable for drinking and domestic use.

Solar Light Elimination of Bacteria, Yeast and Organic Pollutants by Effective Photocatalysts Based on Ag/Cr-TiO2 and Pd/Cr-TiO2.

This study focused on searching for more effective nanomaterials for environmental remediation and health protection; thus, coliform bacteria, yeast and the organic food dye sunset yellow were selected as target pollutants to be eliminated under solar light by Ag/Cr-TiO2 and Pd/Cr-TiO2. Firstly, Cr3+ was in situ incorporated into the anatase crystalline lattice by the sol-gel method; then, Ag or Pd nanoparticles were deposited on Cr-TiO2 by chemical photoreduction. The scientific challenge addressed by the development of these composites was to analyse the recovery of Cr, to be employed in photocatalyst formulation and the enhancement of the TiO2 photocatalytic activity by addition of other noble metals. By extensive characterization, it was found that after TiO2 doping with chromium, the parameters of the crystal lattice slightly increased, due to the incorporation of Cr ions into the lattice. The TiO2 band gap decreased after Cr addition, but an increase in the optical absorptions towards the visible region after noble metals deposition was also observed, which was dependent of the Ag or Pd loading. Generally, it was observed that the noble metals type is a factor that strongly influenced the effectiveness of the photocatalysts concerning each substrate studied. Thus, by using Ag(0.1%)/Cr-TiO2, the complete elimination of E. coli from samples of water coming from a highly polluted river was achieved. Pd(0.5%)/Cr-TiO2 showed the highest efficiency in the elimination of S. cerevisiae from a lab prepared strain. On the other hand, the Pd(0.1%)/Cr-TiO2 sample shows the highest dye degradation rate, achieving 92% of TOC removal after 180 min.

WS2-Assisted Electrochemical Activation of Peroxymonosulfate for Eliminating Organic Pollutant in Water

Advanced oxidation process based on heterogeneous activation of peroxymonosulfate (PMS) has received significant attention in wastewater remediation. Herein, a facile and effective electrochemical method was introduced in a tungsten sulfide (WS2)-activated PMS process for the removal of a typical azo dye Acid Orange 7 (AO7) in aqueous solution. It was found that the electrochemical activation could remarkably promote the removal of organic pollutants by coupling with WS2/PMS system. The elimination of AO7 in the electro-assisted WS2-activated PMS (E/WS2/PMS) system achieved 95.8% of AO7 removal in 30 min, with the optimal conditions of 1.0 g/L WS2, 1.0 mM PMS, current density of 1.0 mA/cm2 and initial pH of 6.5. Based on quenching experiments and EPR techniques, mechanistic studies confirmed that hydroxyl radical (•OH) and singlet oxygen (1O2) are the primary reactive oxygen species for the oxidation of pollutants. In addition, the influences of pH, WS2 dosage, PMS concentration, current density, common anions and humic acid on the AO7 removal are also investigated in detail. Furthermore, the system exhibited resistance to aqueous matrices, verifying the accepted applicability in real water (i.e., Yangtze River water and Shahu Lake water). In summary, this study demonstrates a green system for the effective removal of contaminants in water, holding significant implications for practical application.

Role of Charge Density and Surface Area of Tailored Ionic Porous Organic Polymers for Adsorption and Antibacterial Actions.

The development of high-performance adsorbents for environmental remediation is a current need, and ionic porous organic polymers (iPOPs), due to their high physicochemical stability, high surface area, added electrostatic interaction, and easy reusability, have already established themselves as a better adsorbent. However, research on the structural design of high-performance iPOP-based adsorbents is still nascent. This study explored the building blocks' role in optimizing the polymers' charge density and surface area to develop better polymeric adsorbents. Among the three synthesized polymers, iPOP-ZN1, owing to its high surface area and high charge density in its active sites, proved to be the best adsorbent for adsorbing inorganic and organic pollutants in an aqueous medium. The polymers were efficient enough to capture and store iodine vapor in the solid state. Further, this study tried to address using iodine-loaded polymers in antibacterial action. Iodine-loaded iPOPs show impressive antibacterial behavior against E. coli, B. subtilis, and H. pylori.

Copper-doped orange peel biochar activated peroxydisulfate for efficient degrading tetracycline: The critical role of C-OH and Cu

The usage of biomass waste has aroused great concern in water purification. In this study, copper-doped orange peel biochar (Cu-OPB) prepared by one-step carbonization was firstly used to activate peroxydisulfate (PDS) to eliminate tetracycline (TC). The optimized Cu-OPB showed great activation ability for PDS and could degrade 93.7% of TC at pH 9.07. The presence of H2PO4−, Cl−, and HCO3− did not affect the degradation, while HA and SO42− inhibited TC degradation. SO4•−, •OH and 1O2 were confirmed as the primary active oxygen species in the Cu-OPB/PDS system. Moreover, Cu and the C-OH functional groups on the surface of Cu-OPB played a critical role in the activation by accelerating the electronic migration between Cu-OPB and PDS in the catalytic system. 15 possible intermediate products were found and three feasible degradation pathways were proposed. The toxicity of aquatic organisms of TC was reduced. Furthermore, Cu-OPB could be used as an economically efficient and environmentally friendly catalyst for PDS activation to degrade organic pollutants.

Preparation of Loess‐Clay Based Eco‐Friendly Geopolymer for Efficient Removal of Pollutants in Water

AbstractHeavy metals and dyes cause serious harm for water environment, geopolymer materials with the large pores and specific surface area, and easy modification of pore surface have received extensive attention in wastewater treatment. Herein, using loess‐clay (LC) as natural mineral materials, we developed an eco‐friendly geopolymer of loess‐clay (GpLC) with excellent adsorption properties and promotion plant growth was prepared by alkali excitement. Its morphology and structure were exhibited by scanning electron microscopy, Fourier transform infrared spectroscopy, XRD, and Brunauer–Emmett–Teller. Moreover, its adsorption property for removing metal ions and different dyes was measured, and the adsorption kinetics and thermodynamics were investigated. GpLC presented excellent adsorption ability for Pb2+, which the removal rate got to 98.7 %. It had the universality of removing organic pollutants, and the removal rate reached to 98.0 %. It was dominated chemisorption and single‐layer adsorption, which GpLC conformed to quasi‐second‐order adsorption kinetics, and being more consistent with Langmuir isothermal model. Furthermore, it was found that GpLC could promote growth of crops as it contain P and K element with essential element of plants. In summary, it provides insights and strategy for developing a kind of eco‐friendly functional materials with strong adsorption capacity and promoting plant growth, and it is an effective method for reusing loess resources.