Removal Of Environmental Pollutants Research Articles

Bimetallic biochar-MOFs composites catalyzing peroxydisulfate in sulfadiazine removal

Sunflower seed husk is a common oil crop by-product. In this study, the husk was used as a base material for preparing a new catalyst, referred to as Fe-Cu-biochar-MOFs. The new material was characterized by multiple nanoscale metal clusters with rough surfaces and irregular shapes, thus providing abundant reactive surface area and sites. The catalytic reactivity was tested using sulfadiazine (SDZ) through batch kinetic experiments, where Fe-Cu-biochar-MOFs were used to activate peroxydisulfate (PDS). The results indicate that the system was able to degrade 95.9% of SDZ within 60 minutes. Mechanistic investigations revealed that the presence of PDS converted Fe0 to Fe2+ and Cu0 to Cu+ in the Fe-Cu-biochar-MOFs, and the resulting Fe(Ⅱ) and Cu(I) ions facilitated the activation of PDS, resulting in abundant reactive oxygen species (1O2, SO4∙− and ∙OH). This work provides a new approach of using waste agricultural by-products for the removal of environmental pollutants.

New magnetic nanocomposites based on hexafrite and keggin-type -type heteropolyanions: Synthesized and characterized for removal of environmental pollutants

This research paper details the creation of innovative nanocomposites using the sol-gel technique, incorporating polyoxometalates SiW9Ba3 to stabilize ceramic particles of strontium ferrite (SrFe12O19) polymer and Chitosan (CS). The identification and confirmation of the nanocomposites obtained at each stage were carried out through the use of FT-IR, EDX, XRD, and FESEM analyses. To evaluate their ability to remove organic dyes, we analyzed the catalytic activity of these nanocomposites during photocatalytic detoxification procedures. With its exceptional photocatalytic properties, the nanocomposite (SiW9Ba3@SrFe12O19@Cs) was able to remove estamipride poison at an impressive rate of 85 % and xylene dye solution at an even higher rate of 98 %. In addition, an extensive examination was undertaken to explore the primary variables that influence process efficiency. The study suggests that ceramic nanocomposites incorporating heteropolyoxometalate may offer a viable approach to effectively eradicate pollutants from the environment.

The Using of Plain PAC and PAC Impregnated with MgO and Fe2O3 as Catalysts for the Degradation of Cationic Dyes: Homogenous and Heterogeneous Ozonation

This study presented the removal of methylene blue in the batch system based on catalytic ozonation (heterogeneous and homogenous). The effect of variables such as initial MB (methylene blue)concentration, initial pH of solution (3-11), contact time (5-40 min), and catalyst dosage on homogeneous and heterogeneous ozonation systems was examined. The findings of the research showed that dye removal was better in alkaline conditions. The amount of dye removed in acidic conditions was slightly better than in neutral conditions (approximately 10% to 15%). In addition, the removal efficiency of dye was decreased by increasing of concentration. Besides, as the amount of catalyst (dosage) increased, the removal efficiency of MB had been increased by 40%. Due to the use of catalyst, the significant difference was between the use of two processes of single ozonation processes (SOP) and catalytic ozonation processes (COPs). The results indicated thatMB degradation in COPs was several times faster (approximately 4.7 times). It was due to the numerous advantages of these processes in the removal of environmental pollutants, they can be widely used in the removal of various pollutants if their cost can be reduced.

Efficient removal of environmental pollutants by green synthesized metal nanoparticles of Clitoria ternatea

Prevention and management of water pollution are becoming a great challenge in the present scenario. Different conventional methods like carbon adsorption, ion exchange, chemical precipitation, evaporation, and biological treatments remove water pollutants. Nowadays, the requirement for effective, non-toxic and safe waste management strategies is very high. Nanomaterials have been explored in various fields due to their unique characteristics. Green synthesis of nanomaterial is becoming more popular due to their safety, non-toxicity, and ease of scale-up technology. Metal nanoparticles can be synthesized using a green synthesis method using biological sources provided by eco-friendly, non-hazardous nanomaterials with superior properties to bulk metals. Hence, this study has designed a green synthesis of magnetic (cobalt oxide) and noble (gold) nanoparticles from the fresh flowers of Clitoria ternatea. The flavonoids and polyphenols in the extract decreased the energy band gap of cobalt oxide and gold nanoparticles; hence, the capping of the natural constituents in Clitoria ternatea helped form stable metal nanoparticles. The cobalt oxide and gold nanoparticles are evaluated for their potential for eliminating organic pollutants from industrial effluent. The novelty of this present work represents the application of cobalt oxide nanoparticles in the removal of organic pollutants and a comparative study of the catalytic behaviour of both metal nanoparticles. The degradation of bromophenol blue, bromocresol green, and 4–nitrophenol in the presence of gold nanoparticles was completed in 120, 45, and 20 min with rate constants of 3.7 × 10−3/min, 6.9 × 10−3/min, and 16.5 × 10−3/min, respectively. Similarly, the photocatalysis of bromophenol blue, bromocresol green, and 4–nitrophenol in the presence of cobalt oxide nanoparticles was achieved in 60, 90, and 40 min with rate constants of 2.3 × 10−3/min, 1.8 × 10−3/min, and 1.7 × 10−3/min, respectively. The coefficient of correlation (R2) values justify that the degradation of organic pollutants follows first-order kinetics. The significance of the study is to develop green nanomaterials that can be used efficiently to remove organic pollutants in wastewater using a cost-effective method with minimal toxicity to aquatic animals. It has proved to be useful in environmental pollution management.

Preparation of porous carbon fibres : A review

Porous carbon fibres(PCF) was extensively applied to energy storage, environment pollution control and healthcare due to their superior electrical conductivity, diverse aperture,high specific surface area and super electrochemical stability.This paper reviewed the methods of preparing porous carbon fibres.The preparing PCF technology mainly included template methods( hard templates,soft templates, dual-templates), electrospinning technology and polymer blend technology. The working principles of different pore-forming techniques were summarized.The contributions of different preparation techniques to improve material properties such as electrochemical properties,adsorption performance,drug sustained-release materials and catalitic activity in practical applications were described.The different preparation methods had their superiorities and places needed improving.It was proposed that develop more advanced template methods to prepare PCF with reasonable cost, zero environmental pollution, high efficiency and easy removal.

Metabolic cross-feeding between the competent degrader Rhodococcus sp. strain p52 and an incompetent partner during catabolism of dibenzofuran: Understanding the leading and supporting roles

Microbial interactions, particularly metabolic cross-feeding, play important roles in removing recalcitrant environmental pollutants; however, the underlying mechanisms involved in this process remain unclear. Thus, this study aimed to elucidate the mechanism by which metabolic cross-feeding occurs during synergistic dibenzofuran degradation between a highly efficient degrader, Rhodococcus sp. strain p52, and a partner incapable of utilizing dibenzofuran. A bottom-up approach combined with pairwise coculturing was used to examine metabolic cross-feeding between strain p52 and Arthrobacter sp. W06 or Achromobacter sp. D10. Pairwise coculture not only promoted bacterial pair growth but also facilitated dibenzofuran degradation. Specifically, strain p52, acting as a donor, released dibenzofuran metabolic intermediates, including salicylic acid and gentisic acid, for utilization and growth, respectively, by the partner strains W06 and D10. Both salicylic acid and gentisic acid exhibited biotoxicity, and their accumulation inhibited dibenzofuran degradation. The transcriptional activity of the genes responsible for the catabolism of dibenzofuran and its metabolic intermediates was coordinately regulated in strain p52 and its cocultivated partners, thus achieving synergistic dibenzofuran degradation. This study provides insights into microbial metabolic cross-feeding during recalcitrant environmental pollutant removal.

Efficient adsorption of fluorescein sodium by diatomite-loaded Co-doped MIL-125Ti

The removal of environmental pollutants by green and efficient means has always been a hot issue in research. However, adsorption has been proved to be an important means to remove organic pollutants in water. In this work, a diatomite-loaded Co-doped MIL-125Ti composite adsorbent was synthesized by a simple and mild solvothermal method. The structure and morphology of the materials were characterized by SEM, FT-IR and XRD. The results show that the obtained Co@MIL-125Ti@DE has better void structure and thermal stability than MIL-125Ti. The maximum adsorption capacity of Co@MIL-125Ti@DE for fluorescein sodium is as high as 622.84 mg/g, which is better than MIL-125Ti (401.55 mg/g). The adsorption process conforms to Langmuir isotherm and pseudo-second-order kinetic model. In summary, this study provides a new idea for the construction of bimetallic MOFs materials to efficiently remove organic pollutants in water.

Biogenic Iron Oxide Nanoparticles Based on Algal Biofilm Formed in the Wastewater Treatment Plant and Their Dye Removal Performance

In the field of environmental pollution removal, bioremediation plays a crucial role in removing or converting toxic substances from the environment. Bacteria, yeasts, molds, algae, and plants are widely used in bioremediation events. Recently, green-synthesized nanoparticles have also been employed in bioremediation applications. In this study, iron oxide nanoparticles (FeONPs) were synthesized from algal biofilms that are naturally formed in the settling ponds of the Gümüşhane Municipality Wastewater Treatment Plant. These biological nanoparticles were utilized to investigate their adsorption efficiency for water-polluting dyes such as methylene blue (MB), malachite green (MG), and phenol red (PR). The synthesized FeONPs were characterized using Fourier transform infrared spectroscopy (FTIR) scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD). To test their efficacy, MB, MG, and PR dye solutions were treated with 5.0, 10.0, and 20 g/L FeONP concentrations. The remaining dye concentrations were quantified with a UV-VIS spectrophotometer after filtration. The results showed that FeONPs obtained from algal biofilms effectively removed MB, MG, and PR, with the highest efficiency observed for PR.

Pattern identification in data about unmodified waste eggshell application as an adsorbent for metal ion removal from aqueous media

Abstract In recent years, a significant increase in the amount of research published about the application of eggshells for the removal of metal ions from aqueous solutions has been observed. The paper presents different aspects of metal adsorption from aqueous solutions on untreated eggshells. Pretreatment procedures and tested parameters for the adsorption differ significantly across all the reviewed data, providing a source of variance for the results. For untreated eggshells, the range of the reported BET surface area is from 0.07 m2/g to 8.941 m2/g. Correlation between particle size and BET surface area has been highlighted. Reported removal efficiencies for the untreated eggshell have been compared. Reported results show that eggshell is most employed for the removal of Pb(II), Cd(II), and Cu(II) from aqueous solutions. Eggshell capacity to remove metal ions from the main group elements has also been demonstrated. While results look promising, not enough data are present to make reliable conclusions about its efficiency with other (mainly transition) metal ions – which makes it a possible research direction. Based on the reported data, multiple removal pathways are involved. Several eggshell modification methods and possibilities of creating new adsorbents using eggshells only as a part of the raw material have been assessed. Finally reported eggshell modification methods have been assessed and it is clear that to compare different material’s effectiveness as an adsorbent, comparing only materials adsorption capacities is insufficient. Certain environmental water pollution removal studies using adsorption demand further study, such as metal ion specification in aqueous solution, in different processing water, and even in wastewater.

Iron Molybdenum Sulfide‐Supported Ultrafine Ru Nanoclusters for Robust Sulfion Degradation‐Assisted Hydrogen Production

AbstractElectrocatalytic hydrogen evolution and (S2−) recycling present promising strategies for cost‐effective hydrogen production and simultaneous removal of environmental pollutants. However, the advancement of this technology is hindered by the limited availability of affordable, efficient, and stable catalysts. Herein, the study synthesizes ultrafine ruthenium (Ru) nanoclusters on a substrate of iron molybdenum sulfide (FeMo‐S) nanosheets, creating a new heterointerface catalyst (FeMo‐S/Ru) for the hydrogen evolution reaction (HER) and sulfion oxidation reaction (SOR). Experimental and theoretical calculations suggest that strong electron interactions between Ru nanoclusters and FeMo‐S substrate, optimizing *H adsorption and promoting HER activity on one side while facilitating the production and adsorption of sulfur intermediates on the other side, effectively catalyzing SOR. Additionally, the assembled electrocatalytic coupling system with FeMo‐S/Ru displays an ultralow cell voltage of 0.57 V at 100 mA cm−2, achieving high Faradaic efficiencies (>96%) for H2 production, while also exhibiting remarkable durability over 1 month (838 h). This work paves the way for the development of highly efficient and durable supported catalysts, enabling energy‐saving hydrogen production and environmentally friendly sulfion recycling.

Bi-functional CoCr2O4 hollow-sphere for enhanced oxygen evolution reaction and photocatalyst for harmful environmental pollutants removal

The development of a high-performance, cost-effective, and durable multifunctional semiconductor is crucial for clean energy and environmental remediation applications such as oxygen evolution reaction (OER) and photocatalysts. In this research, we have developed a hollow sphere-based spinel-structured CoCr2O4 (HS.CCO) for bi-functional applications. These hollow spheres exhibit excellent electrocatalytic OER performance under an alkaline (1 M potassium hydroxide (KOH)) medium, which displays a higher electrocatalytic ability. The spinel hollow spheres demonstrate favorable overpotentials and Tafel potentials of 180 mV and 162 mV/dec, respectively towards OER activity. On the other hand, as a photocatalysis, they portrayed outstanding degradation efficiency under visible light irradiation towards Congo red (CR) dye degradation. Within the short treatment time higher CR degradation efficiency is achieved. These photo-electroactive spinel hollow spheres accelerate efficient OER and visible-light-driven photocatalysis with remarkable stability. They serve as an excellent example of a multifunctional heterogeneous catalyst. Finally, the obtained results indicate the current needs and future demands for enhancing the prospects of multifunctional semiconductor catalysts.

Synthesis, characterization and application of tangerine peel-derived Fe3C/Fe-encapsulated biochar for electrochemical removal of environmental pollutant

Conforming to the principles of green chemistry and sustainable environmental progress, this work demonstrated the concept of “treating waste with waste”, i.e. treating atmospheric pollutant sulfur dioxide (SO2) with agricultural waste of tangerine peel. SO2 electro-catalytic oxidation is the key technique in this endeavor, which utilizes SO2 as reaction raw material in the anode to remove it. The anodic SO2 electro-catalytic oxidation could be coupled to the cathodic hydrogen evolution to achieve the simultaneous SO2 removal and hydrogen production. Anodic catalyst plays a vital role in this SO2 transformation. In this work, tangerine peel has been re-utilized to afford tangerine peel-derived biochar (TPB) to prepare TPB/CNT-derived Fe3C/Fe/C (N-doped) as a capable anodic catalyst to achieve this goal. With help of various characterization techniques and electrochemical testing, the optimal iron mass fraction and pyrolysis temperature were found to be 16 wt% Fe under 800 °C, with carboxylated carbon nanotube as carbon additive. Transmission electron microscopy (TEM) image showed that the as-prepared TPB/CNT-derived Fe3C/Fe/C (N-doped) featured a unique morphology to encapsulate Fe3C/Fe with a layer of protecting carbon, which should contribute to the enhanced electro-catalytic performances. A flow electrolyzer was also assembled to illustrate practical application of the anodic catalyst in the real scenario. Owing to its lower cost, the as-prepared TPB/CNT-derived Fe3C/Fe/C (N-doped) will be advantageous to replace precious metals to mediate SO2 electro-catalytic oxidation as one of promising environmental treatment techniques in the future.

Preliminary Results of Spadns Treatment by Electroflocculation With Iron Electrodes

Objective: The objective of this work is to present the results obtained from the removal of color from SPADNS effluent by electroflocculation treatment. Theoretical framework: The dyes used for analysis methods such as SPADNS are released into nature without any treatment, even in low concentrations affecting the aesthetics of rivers. Dyes are considered common pollutants in effluents and color removal is a major challenge for the industry. Method: Iron nails (Fe) were used as cathode and anode, dipped in a sodium chloride solution with the SPADNS effluent, connected to an ATX (advanced technology extended) computer source at a voltage of 12 volts (v) with maximum current of 15 amps (a). Mass balance of the nails used was carried out to determine the mass dissolved in the effluent. After dissolving the iron, the pH is corrected. Results and conclusion: It was determined that the samples achieved 98% color removal. The results indicate a slight increase in turbidity, within the maximum allowed value. The use of Fe as an electrode is economically viable. The use of sodium chloride to pass current did not prove to be satisfactory. Implications of the research: The use of simple processes such as electroflocculation can use renewable energy sources, low-cost materials, greater automation in the removal of environmental pollutants. Originality/value: The use of chemicals is drastically reduced compared to the conventional process. The gases generated in the treatment help to drag the particles to the surface just like a floater using dissolved air.

Electrocatalytic degradation of Favipiravir by heteroatom (P and S) doped biomass-derived carbon with high oxygen reduction reaction activity

In this study, a biomass-derived carbon block with heteroatoms (P and S) self-doped graphene structure was successfully synthesized by spent coffee grounds (SCG) directly sintered method. The spent coffee grounds biomass-derived carbon (SCC) block was used as electrocatalytic electrode to effectively degrade the antiviral drug of Favipiravir (FAV) in water, which represented excellent oxygen reduction reaction (ORR) activity with the H2O2 production. The doped heteroatoms in the graphene structure of SCC provided many active sites in the electrocatalytic electrode for ORR as well as more production of reactive OH･. Based on the structural characterization, radical species identification and intermediate products analysis, the reaction mechanism of FAV degradation by the SCC block electrode was proposed. This catalytic system also showed high ecological safety that the ecological toxicity for Vibrio fischeri was significantly reduced with the degradation process of FAV. The degradation of FAV in recycle test and in real sample of lake water, well water, tap water all demonstrated high stability of structure and catalytic activity of SCC. The electrocatalytic system based on SCC block electrode has realized the recycling and utilization of biomass resources and has promising application on the removal of environmental pollutants.

Anatase-Rutile phase transition of Ca@TiO2 nanostructures for the removal of environmental pollutants under visible photon illumination

Regulating the crystalline structure of titanium dioxide is essential granting the potential purposes for oxide. In the present investigation, we employed X-ray diffraction to investigate the significance of calcium doping on the anatase–rutile transition of phase. Preparation of Calcium-doped TiO2 by sonochemical approach, followed by sintering at 700 °C temperatureencompasses a phase transition. The inclusion of calcium into the TiO2 lattice was hampered by the calcium ion's greater radius when contrasted to the titanium ion. Ca@TiO2 nanostructures exhibited a reduced estimated band gap energy compared to pristine TiO2. The Ca2+ substitutesinto the TiO2 surface were demonstrated by the Fourier transform infrared (FT-IR) spectral investigation. By conducting photocatalytic decomposition of persisting Congo red (CR) dye during visible photonradiation exposure, the photocatalytic effectiveness of the produced Ca@TiO2 nanostructures was examined. Ca@TiO2 nanostructures have been discovered to have more catalytic capability than pristine TiO2 nanoparticles. In 4 h of exposure duration with the Ca@TiO2 nanostructures, the maximal degradation of the CR dye, or 88 %, was accomplished with efficient regeneration.

Removal and release of microplastics and other environmental pollutants during the start-up of bioretention filters treating stormwater

Untreated stormwater is a major source of microplastics, organic pollutants, metals, and nutrients in urban water courses. The aim of this study was to improve the knowledge about the start-up periods of bioretention filters. A rain garden pilot facility with 13 bioretention filters was constructed and stormwater from a highway and adjacent impervious surfaces was used for irrigation for ∼12 weeks. Selected plants (Armeria maritima, Hippophae rhamnoides, Juncus effusus, and Festuca rubra) was planted in ten filters. Stormwater percolated through the filters containing waste-to-energy bottom ash, biochar, or Sphagnum peat, mixed with sandy loam. Influent and effluent samples were taken to evaluate removal of the above-mentioned pollutants. All filters efficiently removed microplastics >10 µm, organic pollutants, and most metals. Copper leached from all filters initially but was significantly reduced in the biochar filters at the end of the period, while the other filters showed a declining trend. All filters leached nutrients initially, but concentrations decreased over time, and the biochar filters had efficiently reduced nitrogen after a few weeks. To conclude, all the filters effectively removed pollutants during the start-up period. Before being recommended for full-scale applications, the functionality of the filters after a longer period of operation should be evaluated.

Regulable surface hydroxyl group content in disperse ultrafine amorphous SiO2 nanoparticles

AbstractAmorphous silica (SiO2) nanoparticles (NPs) can be applied in environmental pollutant remediation, element removal, and water purification. The content of surface silanol groups in amorphous SiO2 NPs affects the characteristics of SiO2 NPs. However, the regulation of surface silanol group content in amorphous SiO2 NPs below 10 nm remains a challenge. Herein, tunable surface silanol group content was achieved in disperse ultrafine amorphous SiO2 NPs by controlling calcination and rehydroxylation. The surface silanol group content in amorphous SiO2 NPs is low (10 nm) and can be tuned from 0% to 2.5%. The amount of naphthalene adsorbed by the SiO2 NPs increases with increasing surface silanol group content. The surface silanol group content in SiO2 NPs can be an effective means to tune their adsorption performance and applications.

Activation of Z-scheme heterojunction of peroxymonosulfate for augmented visible-light-induced photocatalytic decomposition of tetracycline and enhanced antimicrobial efficacy with O-doped g-C3N4@Co3O4

The widespread use of graphitic carbon nitride (CN) for environmental pollutant removal has been hampered by intrinsic limitations, notably facile electron-hole recombination and a limited surface area. This work successfully synthesized OCN/Co3O4 composite materials. Furthermore, the implementation of a peroxymonosulfate (PMS) reaction system remarkably enhanced the material’s capability to degrade Escherichia coli (E. coli) and tetracycline hydrochloride (TC). Compared with CN, the composite material possessed a notably larger specific surface area, affording it a profusion of reactive sites. Additionally, the replacement of carbon atoms with oxygen atoms in the original CN structure profoundly altered its electronic configuration. The characterization through UV–Vis diffuse reflectance spectra, photoluminescence, transient photocurrent responses, and electrochemical impedance spectroscopy also confirmed the excellent optical and electrochemical attributes of OCN/Co3O4. Experimental results illustrated OCN/Co3O4/Vis/PMS completely degraded E. coli at an initial concentration of 1 × 107 CFU mL−1 within 1 h and reduced TC with the adding concentration of 10 mg/L by 99.2% in only 20 min. An analysis was conducted on reactive oxygen species (ROS) using electron paramagnetic resonance spectroscopy and radical quenching experiments. The test results demonstrated the generation of ROS including •O2−, •OH, h+, and SO4•− within the reaction system. This work explored the degradation mechanism in the OCN/Co3O4/Vis/PMS system, providing innovative insights for the design of eco-friendly, efficient catalysts as well as the enhancement of TC and E. coli degradation through the synergistic activation of photocatalytic PMS.

Crown ether-based porous organic polymers for the removal of environmental pollutants in water

Crown ether-based porous organic polymers for the removal of environmental pollutants in water

Insight into properties and reutilization potential of spent polyaniline adsorbents containing transition metals through DFT calculations

Although adsorption technology is an efficient way for removing heavy metal pollutants from wastewater, its widespread application faces challenges related to the disposal and reutilization of hazardous spent adsorbents. Here, we employ density functional theory (DFT) calculations to investigate the properties and reutilization potential of spent PANI adsorbents containing transition metal ions. Bond strength analysis reveals the high stability of spent PANI adsorbents, which is crucial for their safe reutilization. The interaction region indicator (IRI), localized orbital locator (LOL), and decomposition analysis of Wiberg bond order were employed to understand the nature of the bonds between transition metals and imine N atoms. Fukui function analysis indicates that the presence of reducing groups and reductive metal ions in spent PANI adsorbents enhances their chemical stability. The atomic dipole moment corrected Hirshfeld (ADCH) charge and electron density difference (EDD) analysis reveals electron transfers between transition metals and PANI. Moreover, assessments of electrical conductivity, electronic density under electric fields, excited states, and surface charge demonstrate that spent PANI adsorbents hold significant potential for use in energy storage, electrocatalysis, photocatalysis, and environmental pollutant removal. This study provides a molecular-level understanding of the properties and reutilization potential of spent PANI adsorbents.