Environmental Remediation Technologies Research Articles

Nano-resolutions for Environmental Salvation: Leaping to Sustainability

Abstract: Nanoparticles have emerged as a transformative technology in environmental remediation, addressing the pressing challenges of pollution across air, water, and soil. Nanoparticles, particularly metal oxides, carbon-based materials, and polymers, demonstrate remarkable capabilities in addressing water, air, and soil contamination. Their high surface area to volume ratio enhances their efficiency in pollutant removal while minimizing toxicity, making them suitable alternatives to conventional methods. As traditional remediation methods often carry their environmental risks, there is a pressing need for innovative and sustainable solutions. This review delves into the mechanisms and applications of nanoparticles in various remediation techniques, including photocatalysis, Nanoadsorption, and nanomembranes for water treatment, as well as their effectiveness in soil and air purification. The findings underscore the potential of nanomaterials to enhance remediation efficiency while reducing environmental toxicity. By integrating these innovative solutions into existing environmental management frameworks, nanoparticles can play a crucial role in achieving sustainable environmental practices and mitigating contamination. This review advocates for continued research, development, and application of nanotechnology as a promising avenue for fostering a cleaner, healthier environment and contributing to global sustainability goals.

Synthesis of SrTiO3 nanoparticles for photocatalytic applications

Due to the heightened emphasis on environmental protection and the escalating demand for renewable energy sources, the potential applications of strontium titanate (SrTiO3) nanoparticles in photocatalysis have shown remarkable promise. With rapid advancements in technological capabilities, the standards for SrTiO3 photocatalytic materials have soared. Researchers have relentlessly delved into and innovated techniques for preparing strontium titanate powders, striving to yield nanocrystalline SrTiO3 that exhibits specific morphologies, high purity, superior dispersibility, and exceptional photocatalytic efficiency, while continually refining the properties of these powders. The paper encapsulates the advancements in preparation methodologies and photocatalytic attributes of perovskite SrTiO3 nanoparticles, encompassing diverse synthetic routes such as hydrothermal synthesis, sol-gel process, chemical precipitation, solid-state reaction, sonochemical technique, and composite modification strategies. The characteristics, merits, demerits, and prevailing challenges associated with each synthesis technique are thoroughly and analyzed. Ultimately, this review serves as a valuable reference and foundation for the synthesis, modification, and application of SrTiO3 nanoparticle photocatalysts, fostering their development and practical implementation in environmental remediation and renewable energy technologies.

Rational design of Z-scheme configured polymeric carbon nitride-decorated ZnWO4 nanofibers for enhanced visible-light-driven photodegradation of antibiotics

In this study, a Z-scheme heterostructure was meticulously engineered between zinc tungstate (ZnWO4) nanofibers and polymeric carbon nitride (PCN) nanosheets to augment the photocatalytic degradation of tetracycline (TC) under visible light irradiation. A cohesively integrated PCN/ZnWO4 photocatalyst structure was synthesized through an in-situ gas-solid reaction. The quantity and spatial distribution of PCN nanosheets were modulated by fine-tuning the gas precursor and reaction parameters. Relative to pristine ZnWO4 nanofibers and PCN photocatalysts, the distinct three-dimensional PCN/ZnWO4 heterostructure manifests a notable enhancement in photocatalytic performance, attributed to its plethora of active sites and a Z-scheme configuration that bolsters charge separation efficiency, achieving a tetracycline degradation rate of 95.4% upon exposure to simulated sunlight for 160 minutes. The employment of gas-solid reaction as a design paradigm pioneers a fresh paradigm in the strategic assembly of Z-scheme heterostructured photocatalysts, thereby illuminating a promising pathway for advancements in environmental remediation technologies.

Nanostructured spinel ferrites: A comprehensive study on the synthesis, characterization, and magnetic properties of Zn and Mn substituted magnetite nanoparticles produced through the co-precipitation method

Seven cubic spinel ferrite nanoparticles were successfully synthesized through the co-precipitation method. These nanoparticles include Fe3O4, Zn0.4Fe0.62+Fe23+O4, Mn0.4Fe0.62+Fe23+O4, Zn0.6Mn0.4Fe0.42+Fe1.63+O4, Zn0.4Mn0.6Fe0.42+Fe1.63+O4, Zn0.4Mn0.4Fe0.22+Fe23+O4, and Zn0.4Mn0.4Fe0.42+Fe1.83+O4. The Rietveld method was used to analyze X-ray diffraction data, confirming that all samples have a single-phase cubic spinel structure. The presence of zinc and manganese ions in magnetite lattice leads to changes in lattice parameters and crystallite size, resulting in a range of 7–12 nm crystallite sizes. Fourier transform infrared spectroscopy (FT-IR) analysis of nanoparticles reveals two significant adsorption peaks at 560-576 cm−1 and 437-449 cm−1, corresponding to metal ion stretching vibrations at tetrahedral and octahedral sites. The X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of iron, zinc, and manganese in various oxidation states. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) images showed spherical, agglomerated nanoparticles. The study confirmed the elemental composition and mapping images of prepared samples using energy-dispersive X-ray spectroscopy (EDS). The magnetic properties of the synthesized nanoparticles were meticulously examined utilizing a vibrating sample magnetometer (VSM) at room temperature. A direct correlation is established between the structural alterations induced by Zn2+/Mn2+ and their subsequent effects on magnetic characteristics, specifically through the reallocation of cations and the mechanisms of electron hopping occurring at the B-sites. The structural modifications result in enhanced superparamagnetic behavior, exhibiting saturation magnetization values between 46.01 and 69.38 emu/g. The sustainable characteristics of these materials render them highly viable options for applications in environmental remediation and green technology.

Analysis of the potential of the electroactive biofilm growth in a microbial fuel cell type H

Microbial fuel cells (MFC) constitute an attractive alternative as an environmental remediation technology since they can generate electrical current using organic waste as a substrate. Since the performance of MFCs depends on the characteristics of the biofilm on the anode surface, it is important to assess the genetic information of the microorganisms that grow on the electrode. For this purpose, a sewage sludge sample was obtained from a wastewater treatment plant and used to inoculate a type H MFC. Electrochemical characterization, on one hand, indicates that while the biofilm has a typical electrochemical performance reflected by the generated voltage (near 0.4 V) and by the electroactivity observed in cyclic voltammetry experiments, and on the other hand, the metagenomic analysis shows that the most abundant genera are Pseudomonacea, Nitrosomonas, Hyphomonas, and Opitutus. The study also indicates that the biofilm’s electroactive microorganisms can metabolize amino acids, lipids, and carbohydrates and possess genetic tools for ionic transport and energy production. Regarding the electron acceptor/donator capabilities, several oxidases, reductases, and complexes were identified, mainly terminal cytochrome C oxidase and respiratory complex I, which could be associated with the exoelectrogenic capacity of the microorganisms. Finally, the metagenomic information indicates that the biofilm can synthesize rhamnose, sialic acid, and alginate molecules, which could possibly be associated with the formation and consolidation of the microbial biofilm.

Removing multiple refractory organic pollutants in wastewater by cell bioaugmentation and genetic bioaugmentation with Rhodococcus sp. strain p52

Bioaugmentation is an appealing remediation strategy to treat refractory organic pollutants in contaminated environments. In this study, activated sludge was bioaugmented with Rhodococcus sp. strain p52 to treat synthetic wastewater containing multiple refractory organic pollutants (dibenzofuran, dibenzo-p-dioxin, and phenanthrene). Bioaugmentation of activated sludge reactors with strain p52 alleviated the adverse effects of refractory pollutants on the chemical oxygen demand and ammonia nitrogen removal capacity of the reactors and enhanced the removal of the refractory organic pollutants, especially highly refractory compound dibenzo-p-dioxin. Toxicity of the refractory pollutants to activated sludge bacteria was attenuated due to contaminant degradation by strain p52. Genetic bioaugmentation mediated by catabolic plasmid transfer from strain p52 to activated sludge bacteria and cell bioaugmentation occurred along with successful colonization and proliferation of strain p52. In addition, a potential metabolically mutualistic relationship existed between strain p52 and activated sludge bacteria for refractory pollutants degradation. Both refractory organic pollutants input and strain p52 bioaugmentation profoundly influenced the structure of the activated sludge bacterial community and drove bacterial community shifts in different directions. This study provides insights into the activities of bioaugmented bacteria and bioaugmentation technology for environmental contaminant remediation.

NANOPARTICLES UNVEILED: A COMPREHENSIVE REVIEW OF CLASSIFICATION, PROPERTIES, SYNTHESIS, AND APPLICATIONS

Nanoparticles, defined as particles with dimensions ranging from 1 to 100 nm, represent a groundbreaking domain of nanotechnology. NPs have immense importance across various scientific disciplines and industries. NPs can be classified into zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) structures based on their dimensions. NPs are also classified into carbon, semiconductors, ceramics, polymers, and metal NPs based on their materials. NPs exhibit remarkable physicochemical properties, such as high surface area-to-volume ratios, exceptional thermal conductivity, and catalytic activity, making them crucial in fields such as materials science, medicine, and environmental engineering. Nanoparticles can be synthesized through both top-down approaches, where bulk materials are broken down into smaller particles, and bottom-up methods, involving the assembly of atomic or molecular components. Their applications are diverse and include drug delivery systems, advanced catalysts, nanoelectronics, and environmental remediation technologies, demonstrating their pivotal role in shaping our technological landscape.

Green synthesis of Mn3O4@CoO nanocomposites using Rosmarinus officinalis L. extract for enhanced photocatalytic hydrogen production and CO2 conversion

In response to the urgent need for sustainable environmental remediation technologies and clean energy production, this study introduces an eco-friendly synthesized Mn3O4@CoO nanocomposite (MCNC) leveraging the natural reducing capabilities of Rosmarinus officinalis leaves (L.) extract. Focused on the hydrogen evolution reaction (HER) and CO2 methanation, our findings reveal significant enhancements in photocatalytic activity and CO2 methanation efficiency. The MCNC exhibited a promising hydrogen production rate of up to 823 μmol g−1 h−1 and a CO2 conversion efficiency exceeding 84 % under optimal conditions. The investigation highlights the synergistic interfacial effect between Mn3O4 and CoO, contributing to notable performance improvements. Additionally, the study explores the role of catalyst quantity in optimizing reaction efficiencies, presenting a scalable and environmentally benign approach to address global energy and environmental challenges. The apparent quantum efficiency (AQE%) was calculated to be 1.92, 2.39, 2.73, 3.21, 3.44, and 3.56 % for mass values of 15, 25, 35, 45, 55, and 65 mg, respectively. Furthermore, the CO2 methanation also shows a rise with the increase in catalyst quantity. A mass of 0.35 mg achieved a remarkable CO2 conversion efficiency of 71.9 %, while its 0.5 mg counterpart showcased an even more striking CO2 conversion efficiency of 84.4 %. The green synthesis method, characterized by its low energy requirement and the absence of toxic chemicals, aligns with the sustainable practices sought in environmental chemistry and nanotechnology. This work not only opens new avenues for developing efficient photocatalysts but also contributes to the broader application of green synthesized nanomaterials in environmental remediation and clean energy generation.

Three CoS/CoO microspheres and their mixed matrix membranes for the highly efficient photocatalytic degradation of methyl blue.

Photocatalytic degradation technology, as one of the most important advanced oxidation technologies for environmental remediation, has attracted great attention in recent years, but designing photocatalysts with excellent photocatalytic activity and good reusability remains a challenge. Herein, three CoS/CoO microspheres (CoS/CoO-M-1 (1), CoS/CoO-M-2 (2), and CoS/CoO-M-3 (3)) were prepared via a hydrothermal method using cobalt chloride hexahydrate, thiourea, deionized water and polyethylene glycol (PEG) with different polymerization degrees as raw materials, which have a uniform size distribution in the range of 5-24 μm and specific surface areas of 6.1924 m2 g-1 (1), 6.2870 m2 g-1 (2) and 6.6663 m2 g-1 (3). It is worth noting that all the three CoS/CoO microspheres showed a wide optical absorption range from the ultraviolet to the near-infrared (NIR) region and a high photocatalytic activity for degrading methyl blue under visible light (500 W metal halide lamp) irradiation. In order to improve the portability and recyclability of 3, a mixed matrix membrane (MMM) of 3 (3-MMM) was manufactured by coating a mixture dispersion of 3 and polyvinylidene fluoride (PVDF) on a glass substrate, which not only displayed excellent photocatalytic degradation performance, but also showed good portability and reusability (cycles > 12 times). Furthermore, adsorption and photocatalytic kinetics and possible mechanisms were studied.

Characterization, potential valuable metals recovery and remediation of historic wolframite mining waste

The understanding of tungsten (W) mineral weathering and mobilization in nature remains limited due to W being a transition element with a wide range of oxidation states, which enables it to form a variety of complex chemical compounds. This study examined W mining waste at the abandoned Wolfram Camp mine in North Queensland, Australia, to address this gap. The mineralogical analysis showed the W tailings primarily consisted of silicates, including quartz, illite/mica, plagioclase, and K-Feldspar, with low WO3 content. Static acid mine drainage (AMD) tests indicated most tailings were non-acid forming, while groundwater samples exhibited acidification, with pH ranging from 3.8 to 5.2. The reprocessing trials using gravity separation and bioleaching demonstrated promising results, suggesting both techniques could effectively recover resource and decontaminate the mining waste. The gravity separation reprocessing test has successfully recovered 48.4% W from the tailings, with the resulting W concentrate achieving a 21.6% WO3 grade. On the other hand, the bioleaching reprocessing exhibited a remarkable 44-fold enrichment of W from the tailings, with 2.2% W in the AMD sediment. Synchrotron-based XFM/μ-XANES imaging analysis revealed significant wolframite weathering in reprocessed W concentrates. This study proposed a comprehensive approach, integrating environmental remediation and resource recovery technologies, to repurpose abandoned W mining waste. Passive treatment appears to be an economical option for remediating abandoned W mine sites. The findings provide valuable insights for sustainable W mining waste management and the rehabilitation of the abandoned Wolfram Camp W mine site.

Accurate construction of Cd/CdS/g-C3N4 heterojunction interface for efficient photocatalytic tetracycline degradation and Cr6+ reduction

With the increasing attention paid to environmental issues and the rapid development of photocatalytic environmental remediation technology, it is of great significance to develop catalysts with efficient photocatalytic environmental remediation capabilities. Graphite phase carbon nitride and its heterojunction are ideal choices for photocatalytic environmental remediation. Accurately constructing stable and well contacted heterogeneous interfaces is an effective means to improve catalytic efficiency. Herein, stable Cd/CdS/CN heterojunction interface was successful constructed by an in-situ synthesis method. Cd/CdS/CN photocatalysts exhibits excellent environmental remediation potential, capable of removing 88 % of high concentration TC (40 mg/L) within 60 min, and reducing over 96 % of Cr(VI) (50 mg/L) within 25 min under visible light, with good cycling stability. In addition, the reaction mechanism and TC degradation pathway of the composite photocatalyst with good photocatalytic activity were analyzed in depth. The experimental results confirmed that the synergistic effect of Z-Scheme heterojunction and Ohmic junction significantly improved the separation and migration of photogenerated carriers in the system, and maintained a high redox ability. This work provides a new reference for constructing CN based heterojunction photocatalysts with close contact.

Adsorption of Cobalt Ions by Activated Carbon Prepared from Agricultural Waste Residues and Treated with Magnetic Nanomaterials: A Review

General Background: The study of heavy metal adsorption is crucial for environmental protection and industrial wastewater management. Specific Background: The adsorption of cobalt ions (Co2+) by activated carbon derived from agricultural waste, enhanced with magnetic nanomaterials, has garnered significant interest due to its potential for cost-effective and efficient wastewater treatment. Knowledge Gap: Despite numerous studies, there remains a lack of comprehensive research on the specific combination of agricultural waste-derived activated carbon and magnetic nanomaterials for Co2+ adsorption. Aims: This study aims to meticulously review the existing literature on the preparation of activated carbon from agricultural residues, the enhancement of its properties with magnetic nanomaterials, and its effectiveness in Co2+ ion adsorption. Results: The review demonstrates that activated carbon with a large specific surface area and diverse functional groups significantly improves Co2+ adsorption. The incorporation of magnetic nanomaterials further enhances this efficiency due to increased surface area and magnetic properties. Novelty: This research uniquely combines agricultural waste valorization with advanced nanotechnology, presenting a sustainable and innovative approach to heavy metal adsorption. Implications: The findings underscore the dual environmental benefits of recycling agricultural waste and mitigating industrial pollution, offering a cost-effective and efficient solution for cobalt ion recovery from wastewater. This study serves as a valuable resource for researchers and engineers focusing on sustainable environmental remediation technologies. Highlights: Enhanced Adsorption: Magnetic nanomaterials boost activated carbon's efficiency. Sustainable Solution: Agricultural waste-derived activated carbon is eco-friendly and cost-effective. Comprehensive Insight: Review identifies research gaps and future directions. Keywords: cobalt ion adsorption, activated carbon, agricultural waste, magnetic nanomaterials, wastewater treatment

Elucidating the degradation mechanisms of perfluorooctanoic acid and perfluorooctane sulfonate in various environmental matrices: a review of green degradation pathways.

Given environmental persistence, potential for bioaccumulation, and toxicity of Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), the scientific community has increasingly focused on researching their toxicology and degradation methods. This paper presents a survey of recent research advances in the toxicological effects and degradation methods of PFOA and PFOS. Their adverse effects on the liver, nervous system, male reproductive system, genetics, and development are detailed. Additionally, the degradation techniques of PFOA and PFOS, including photochemical, photocatalytic, and electrochemical methods, are analyzed and compared, highlighted the potential of these technologies for environmental remediation. The biotransformation pathways and mechanisms of PFOA and PFOS involving microorganisms, plants, and enzymes are also presented. As the primary green degradation pathway for PFOA and PFOS, Biodegradation uses specific microorganisms, plants or enzymes to remove PFOA and PFOS from the environment through redox reactions, enzyme catalysis and other pathways. Currently, there has been a paucity of research conducted on the biodegradation of PFOA and PFOS. However, this degradation technology is promising owing to its specificity, cost-effectiveness, and ease of implementation. Furthermore, novel materials/methods for PFOA and PFOS degradation are presented in this paper. These novel materials/methods effectively improve the degradation efficiency of PFOA and PFOS and provide new ideas and tools for the degradation of PFOA and PFOS. This information can assist researchers in identifying flaws and gaps in the field, which can facilitate the formulation of innovative research ideas.

Educational Approaches for Integrating Advanced Environmental Remediation Technologies into Environmental Engineering: The ‘Four Styles’ Model

Educational Approaches for Integrating Advanced Environmental Remediation Technologies into Environmental Engineering: The ‘Four Styles’ Model

Organic pollutant degradation over highly efficient Mn–Mo(O,S)2 oxysulfide photocatalyst under visible light illumination

Metal oxide semiconductor photocatalysts have received remarkable consideration as a promising technology for environmental remediation and energy conversion. Oxysulfide semiconductors have narrow band gaps which are appropriate for photocatalytic removal of toxic organic pollutants under visible light illumination. For the elimination purpose of these pollutants, Mo(O,S)2, Mn(O,S)2, and Mn–Mo(O,S)2 oxysulfide catalysts containing various Mn contents were synthesized at low temperatures via a simple method. The structural, morphological, electrochemical, compositional, and optical properties of the as-synthesized catalysts were exhaustively characterized. The photocatalytic degradation activity of the bares Mo(O,S)2, Mn(O,S)2, and other Mn–Mo(O,S)2 compositions were evaluated over different types of organic pollutants under visible light illumination. The addition of Mn in Mo(O,S)2 structure improved the photodegradation activity, and Mn–Mo(O,S)2-30 was found to be the best composition with superior photodegradation performance towards the four cationic, anionic, and neutral dyes. The degradation efficiency of 10 ppm of MB, and MO dyes reach 99.7 % and 98.6 %, within 30 and 120 min, respectively. Mn–Mo(O,S)2-30 catalyst also shows a good photodegradation performance on Rh B and NR organic pollutants. According to the recycling test, the catalyst exhibited excellent performance. The photodegradation follows pseudo-first order kinetics with a rate constant of 0.097 and 0.036 min−1 for MB and MO dyes, respectively. The trapping experiment showed that superoxide anion radicals (O2•-) and holes (h+) are the responsible active species for the degradation on MO and MB, respectively. The novelty of using Mn–Mo(O,S)2-30 for various dyes degradation lies in its remarkable catalytic properties.

Fabrication of a hyphenated S-scheme and Schottky-junction photocatalyst based on a ternary TiNbCTx@α-Bi2O3/ZnSe heterostructure with enhanced optical and photoelectrochemical properties

Environmental pollution by pharmaceuticals poses a serious threat to humans and animals. Hence there is a need for a low-cost, environmentally friendly, and sustainable treatment technology for environmental remediation. Herein, we report the synthesis of a novel TiNbCTx@α-Bi2O3/ZnSe ternary photocatalytic nanocomposite, characterised using spectroscopic and microscopic techniques. Moreover, the optical and photoelectrochemical properties of the photocatalysts were assessed using spectroscopic tools such as UV–Vis DRS, EIS and PL. The synthesised pristine, cubic ZnSe, monoclinic Bi2O3, α-Bi2O3/ZnSe and the ternary composites’ crystallinity were all confirmed by the co-existence of their crystal planes and bands in XRD, SAED, and Raman spectroscopy, correspondingly. SEM and TEM analysis confirmed the anticipated characteristic morphologies and the interfaces. Improved optical properties deduced from UV–Vis DRS measurements revealed α-Bi2O3 and ZnSe to have band gaps of 2.7 eV and 2.41 eV, respectively. Upon creating an α-Bi2O3/ZnSe heterostructure and TiNbCTx@α-Bi2O3/ZnSe ternary system, a red shift was observed in their band gaps, indicating improved optical properties. The electrochemical properties of the materials were determined using EIS. These were used to deduce the charge transfer kinetics of the heterostructure and ternary system, which showed TiNbCTx@α-Bi2O3/ZnSe to be an outstanding photocatalyst over the synthesised pristine materials and α-Bi2O3/ZnSe heterostructure. The photocurrent response of the TBZ-7 % exhibited enhanced generation and separation of photoexcited charge carriers 4 folds higher than those of pristine materials. The PL spectra of the TBZ-7 % showed low intensity due to the suppression of charge recombination rates. Moreover, the Nyquist and LSV plots of TBZ-7 % presented improved charge transfer ability and a prolonged lifetime of photoinduced charge carriers (280 ms), respectively. With these enhanced properties, TiNbCTx@α-Bi2O3/ZnSe ternary photocatalytic nanocomposite demonstrates the extraordinary potential for environmental remediation in degrading ARVs from water.

Suction influence on magneto-convective fluid flow embedded in a permeable media under internal friction

This work examines the natural convection flow of an incompressible, viscous, and electrically conducting fluid down a vertical flat plate in the presence of conduction, as well as the effects of suction, magnetic field, viscous dissipation, porous medium, and heat generation. The governing momentum and energy equations have numerical solutions. The impacts of suction, heat production, magnetic, porosity, and viscous dissipation parameters on two-dimensional flow are discussed. Graphical representations of the velocity profile, temperature distribution, skin friction, rate of heat transfer, and surface temperature distribution are shown. The presence of porous media and improving suction values improves the friction drag but diminishes the energy transfer. The thermal production parameter raises the energy inside the flow but diminishes the heat transfer coefficient. This work attempts to offer important insights into these intricate processes by examining the effects of controlling factors including magnetic fields, porous medium, and suction parameters. This research conclusion may find applications in coolers, heat exchangers, and environmental remediation technologies that are more effective, advancing engineering and sustainable practices.

Hierarchically design MoS2/CdNi@RGO ultra-thin hybrid sheet for Photocatalytic degradation of organic contaminants fingerprinting in environmental matrices

The aim of this study was to synthesize effective and economical MoS2/CdNi@rGO photocatalysts and investigate their performance in the degradation of organic pollutants in synthetic effluent. The objective was to assess the characterization results of the synthesized photocatalysts using XRD, SEM/EDS, TEM/HR-TEM, Raman spectrum, and BET isotherm analysis tools. These analyses revealed the good adhesion of MoS2 with rGO and provided insights into the structure and properties of the materials. The results showed that the MoS2/CdNi@rGO photocatalysts exhibited remarkable degradation efficiency for organic pollutants such as Rhodamine-B, erichrome black, and malachite green. The outcomes of the study demonstrated that the MoS2/CdNi@rGO catalyst had the greatest rate constant for Rhodamine-B (RhB) decomposition. which would have been approximately 33 times higher than that of pure RGO (0.0121 min−1). The MoS2/CdNi@rGO photocatalysts also showed excellent recyclability and persistence across five recycle assays, indicating their potential for practical applications in wastewater treatment. The photocatalyst was moderately active, stable up to its fifth usage and stability of the photocatalyst before and after the photocatalytic reaction was also been studied using XRD and SEM. Further research in this area could lead to the development of advanced photocatalytic technologies for environmental remediation.

Nanoconfined Fe(II) releaser for long-term arsenic immobilization and its sustainability assessment

Ferrous (Fe(II))-based oxygen activation for pollutant abatements in soil and groundwater has attracted great attention, while the low utilization and insufficient longevity of electron donors are the primary challenges to hinder its practical applications. Herein, we propose a nanoconfined Fe(II) releasing strategy that enables stable long-term electron donation for oxygen activation and efficient arsenic (As) immobilization under oxic conditions, by encapsulating zero-valent iron in biomass-derived carbon shell (ZVI@porous carbon composites; ZVI@PC). This strategy effectively enhances the generation of reactive oxygen species, enabling efficient oxidation and subsequent immobilization of As(III) in soils. Importantly, this Fe(II) releaser exhibits strong anti-interference capability against complex soil matrices, and the accompanying generation of Fe(III) enables As immobilization in soils, effectively lowering soil As bioavailability. Soil fixed-bed column experiments demonstrate a 79.5 % reduction of the total As in effluent with a simulated rainfall input for 10 years, indicating the excellent long-term stability for As immobilization in soil. Life cycle assessment results show that this Fe(II) releaser can substantially mitigate the negative environmental impacts. This work offers new insights into developing green and sustainable technologies for environmental remediation.

A one-pot hydrothermal synthesis of Bi/Bi2O2CO3/Bi2WO6 catalyst with enhanced photocatalytic activity to tetracycline

BackgroundThe abuse and irrational discharge of tetracycline (TC) have threatened the surroundings of human beings. Semiconductor photocatalytic oxidation technology is an emerging green environmental remediation technology, which can be widely applied in wastewater treatment. MethodsThis work is the first attempt to prepare Z-scheme heterojunction Bi/Bi2O2CO3/Bi2WO6 ternary material through one-step hydrothermal synthesis method. Significant findingsAbout 95.5 % tetracycline (10 mg·L−1) have been degraded by Bi/Bi2O2CO3/Bi2WO6 ternary material after 120 min of simulated sunlight exposure. The degradation efficiency of TC was 2.04 and 3.01 times than those of Bi2WO6 and Bi2O2CO3, respectively. Radical trapping experiments and ESR analysis showed that h+, ·O2−, and ·OH played a joint role in the degradation of tetracycline. Based on liquid chromatography-mass spectrometry analysis, energy band analysis and theoretical calculations, the degradation mechanisms were identified. The excellence photocatalytic activity is mainly attributed to two aspects: (1) The generation of Z-scheme heterojunctions provided channels for carrier transfer, accelerated interface charge separation and suppressed the rapid recombination of photo generated carriers and holes; (2) The surface plasmon resonance effect of metallic Bi intensifies photon absorption and boost photocatalytic activity. This work offers a viable method for improving the photocatalytic activity of semiconductors made of bismuth on antibiotics.