Remediation Of Sites Research Articles

Design and regulation of engineered bacteria for environmental release.

Emerging products of biotechnology involve the release of living genetically modified microbes (GMMs) into the environment. However, regulatory challenges limit their use. So far, GMMs have mainly been tested in agriculture and environmental cleanup, with few approved for commercial purposes. Current government regulations do not sufficiently address modern genetic engineering and limit the potential of new applications, including living therapeutics, engineered living materials, self-healing infrastructure, anticorrosion coatings and consumer products. Here, based on 47 global studies on soil-released GMMs and laboratory microcosm experiments, we discuss the environmental behaviour of released bacteria and offer engineering strategies to help improve performance, control persistence and reduce risk. Furthermore, advanced technologies that improve GMM function and control, but lead to increases in regulatory scrutiny, are reviewed. Finally, we propose a new regulatory framework informed by recent data to maximize the benefits of GMMs and address risks.

Advances in Autonomous Robotics for Environmental Cleanup and Hazardous Waste Management

This research investigates the progress made in autonomous robots for environmental cleaning and hazardous waste management. The objective is to evaluate their efficacy, adaptability, and prospective influence on existing methods. The study used a secondary data review process to combine information from several case studies, technical breakthroughs, and upcoming robot trends. Autonomous robots improve cleaning efficiency and safety in soil cleanup, oil spill response, garbage sorting, and disaster recovery. AI, sensors, and multi-modal robots boost performance. However, sensor accuracy, navigation, and energy management issues persist. The paper emphasizes the policy implications, such as the need for uniform rules, more investment in research and development, and the significance of addressing ethical and social concerns. By focusing on these specific areas, the incorporation of autonomous robots may be enhanced, resulting in more efficient and environmentally friendly solutions for handling environmental risks and waste.

Evolution of pollutant biodegradation.

Pollutant-derived risks to human and environmental health are exacerbated by slow natural attenuation rates, often driven by pollutant toxicity to microorganisms that can degrade them or limitations to the ability of microorganisms to metabolise them. This review explores mechanisms employed by bacteria to protect themselves from pollutant toxicity in the context of the evolution of pollutant-degrading abilities. The role of promiscuous enzymes in pollutant transformation is subsequently reviewed, highlighting the emergence of novel metabolic pathways and their transcriptional regulation in response to pollutant exposure, followed by the gene transcription regulation to optimise the cellular component synthesis for adaptation on the novel substrate. Additionally, we discuss epistatic interactions among mutations vital for this process both at macromolecular and at cellular levels. Finally, evolutionary constraints towards enhanced fitness in the context of pollutant degradation are considered, the constraints imposed by the epistasis from mutations on both enzyme level and cellular level, concluding with challenges and emerging opportunities to develop sustainable contaminated site remediation technologies. KEY POINTS: •Pollutants can exert toxicity on cellular membrane, enzyme and gene transcription. •Bacteria can patch promiscuous enzymes into novel pathway to degrade pollutants. •The evolution trajectory is constrained by epistasis from mutations on enzyme and cellular level.

Insights into the expeditious photocatalytic performance of greenly fabricated CeVO4 nanoparticles using Polyalthia longifolia leaf extract

The application of nanomaterials to address environmental challenges has evolved substantially to eliminate pollutants from wastewater as part of environmental cleanup, a growing important research arena. Using green photocatalysts is a noteworthy and economical method that significantly advances environmentally sustainable remediation. This work disclosed the bio-inspired production of cerium vanadate nanoparticles (CeVO4 NPs) were prepared through a green chemistry protocol employing Polyalthia longifolia leaf extract. Key traits of CeVO4 nanoparticles were determined by applying a variety of characterization tools, including X-ray diffraction (XRD), Raman, Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UVDRS), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), and high-resolution transmission electron microscopy (HRTEM). CeVO4 nanoparticles displayed a pseudo-spherical topology with a particle size of 17.77 nm, and the band gap was determined as 2.76 eV. The photocatalytic ability of the as-produced CeVO4 NPs was scrutinized for the decomposition of Congo red (CR) dye. Under optimal conditions, the fabricated CeVO4 nanoparticles demonstrated excellent Congo red dye degradation performance. The effect of hydrogen peroxide (H2O2) dosage, nanoparticle dosage, dye concentration, contact time, scavenging test, and reusability of prepared photocatalyst had an excellent impact on dye decomposition ability. The findings revealed that in just 8 min, 97.79 % of the CR dye had been degraded completely. The pseudo-first-order (PFO) kinetics model aligns with the CR dye decomposition kinetics. In conclusion, this study describes the fabrication of a CeVO4 photocatalyst that exhibits impressive performance, particularly in natural sunlight, suggesting that it could be used in wastewater treatment.

Density functional theory study of Chlorine, Fluorine, Nitrogen, and Sulfur doped rutile TiO2 for photocatalytic application

This study uses the Quantum ESPRESSO code to introduce Hubbard correction (U) to the density functional theory (DFT) in order to examine the effects of non-metals (C, F, N, and S) doping on the structural, electronic, and optical characteristics of rutile TiO2. Rutile TiO2 is a substance that shows promise for use in renewable energy production, including fuels and solar energy, as well as environmental cleanup. Its wide bandgap, however, restricts their uses to areas with UV light. In order to move the rutile TiO2 absorption edge toward visible light, one atom of each dopant was substituted at oxygen atom locations in this work. The calculated band structures yielded a bandgap of 3.03 eV for pure rutile TiO2, which is in good agreement with the experimental measurement. The bandgap of all doped materials, with the exception of F-doped TiO2, displayed a redshift. The absorption edges in C, N, and S-doped TiO2 are displaced toward the visible area, as indicated by the imaginary component of the dielectric function peaks. The appropriateness of C, N, and S-doped TiO2 for photocatalysis applications is demonstrated by the shift in the absorption coefficient to the highest wavelength. The presence of extra charges that attenuate the transmission of light in materials is shown by the increase in refractive index following doping. Furthermore, this discovery is crucial for experimentalists since it helps them understand how non-metal doping affects the characteristics of rutile TiO2 for photocatalysis applications.

Computational analysis of linear chain of holey nanographene and their molecular characterizations.

Holey nanographene, an allotrope of carbon arranged in two dimensions, has gained remarkable attention as a nanomaterial with several potential uses in numerous industries, such as electronics, energy storage, healthcare, and environmental cleanup, because of its high carrier mobility, flexibility, transparency, high surface area, conductivity, and chemical stability. The fundamental holey nanographene is assembled in a linear form to create the holey nanographene chain (HNC) that is being discussed. To fully utilize it in various applications, it is essential to comprehend the basic ideas guiding its behavior at the nanoscale; for that, we find various topological indices for this holey nanographene chain using the cut method. Because topological indices are a robust mathematical tool that links molecular structure with chemical, physical, and biological properties, they are essential in diverse areas, namely chemistry, pharmaceutical research, environmental science, and materials science METHODS: The cut method is essential for calculating topological indices in large structures as standard definitions become increasingly complex for such computations. In this study, we apply the cut method to compute each topological index for holey nanographene structures, which involves extensive summations. MATLAB software is employed to simplify these calculations. To generate the DDSV (Distance Degree Sequence Vector) for each vertex within any dimension of holey nanographene, we utilize the NEWGRAPH interface. Python code is then used to analyze the DDSVs assigned to each vertex. Additionally, MATLAB code is applied to validate the numerical results derived from analytical formulae for the topological indices of the HNCs under consideration.

Research on bioaugmented slurry remediation of PAHs in actual contaminated soil: Screening microbial agents and optimizing key parameters.

Bioaugmented slurry technology is a sustainable remediation technology for PAHs-contaminated soil. However, the lack of experimental data on the remediation of complex, actual contaminated soils has hindered the practical application of this technology. This study explored the bioaugmented degradation of PAHs using actual soil slurry with and without the addition of microbial agents in the microscopic world. NS4 has the highest degradation efficiency. The response surface method was used to determine the effects of water-soil ratio, temperature, aeration rate and their interaction on the degradation of PAHs. Temperature significantly affects the degradation of phenanthrene, and the aeration rate significantly affects the degradation of pyrene. The influence of each factor follows the order: aeration rate>temperature>water-soil ratio. The highest degradation rates of phenanthrene and pyrene are observed at a water-soil ratio of 3:1, a temperature of 30°C, and an aeration rate of 2L/min. Under the optimal conditions, the addition of either peptone or Tween-80 increased the degradation rate. Peptone and Tween-80 can effectively enhance the growth rate of microorganisms and the release of PAHs in actual contaminated soil. In conclusion, by screening microbial agents suitable for real contaminated soils and maintaining the dynamic stability of the bioaugmented slurry system by optimizing key influencing factors, efficient, green, and low-energy remediation of PAHs-contaminated sites can be achieved.

Polymer/phytochemical mediated eco-friendly synthesis of Cu/Zn doped hematite nanoparticles revealing biological properties and photocatalytic activity

Abstract Unique magnetically recoverable copper/zinc-doped hematite nanoparticles, were synthesized by using a co-precipitation process with polymer polyvenylpyrodine and an aqueous extract of the Azadirachta indica plant serving as the capping and stabilizing agent. Hematite nanoparticles are the most stable form of iron oxide at room temperature, the presented work concentrated on the effects and comparisons of chemically and green synthesized doped materials that serve a dual role as reducing agents: supporting biomedical application and catalyzing environmental cleanup through photocatalysis. The prepared nanoparticles were characterized using X-ray diffraction, UV–vis spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, vibrating-sample magnetometry, scanning electron microscopy, and transmission electron microscopy techniques to examine the produced material. The average grain size for doped hematite nanoparticles was found to be 13.33–19.90 nm based on X-ray diffraction measurements. The Fourier-transform infrared spectroscopy spectrum demonstrates the function of the biomolecules in the extract in capping the nanoparticles. The ferrimagnetic character of the produced nanoparticles demonstrated by the Vibrating-sample magnetometer investigation showed dependence at 300 K. According to the phytochemical study, A. indica has components that enhance its photocatalytic and antioxidant activity. In comparison, chemical/green synthesized doped hematite nanoparticles demonstrated noticeably higher photocatalytic activity for the oxidative breakdown of hazardous organic dyes Rhodamine blue and Congo red. Additionally, the photocatalyst displayed outstanding stability for the reaction. Radical scavenger assays 2,2-diphenyl-1-picrylhydrazyl and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) were used to measure antioxidant capability. Based on the assay, the bran and husk fractions displayed higher levels of antioxidant activity. This research is regarded as a novel step in the production of doped hematite nanoparticles with particular photocatalytic and biological characteristics for wide use in environmental, and agricultural areas.

Recent advances on dioxin and furan (dibenzofuran) based pollutants from analytical, environmental, and health perspectives.

Dioxins and analogous derivatives pose significant concerns due to their impact on human health through both acute and prolonged exposures. They have the potential to resist natural degradation processes; therefore, they tend to accumulate in water, sediments, fish, meat, and human adipose tissue. As a result, concerns to both environmental and human health arise among the scientific community and environmental health organizers. Herein, we provide a comprehensive review highlighting recent findings of dioxin and furan pollution with a focus on major environmental and health aspects associated with the exposure to dioxin and its derivatives by assessing the routes of exposure, toxicity, and modes of action. Moreover, VOSviewer was used to understand the research interest within the scientific community in the study of dioxins and furans. Various strategies like remediation, methods of extraction and analysis, as well as protocols required to improve compound filtration and mineralization to enhance the efficiency of environmental cleanup processes.

Advances in waste-derived functional materials for PFAS remediation.

Per- and polyfluoroalkyl substances (PFAS) are synthetic organofluoride compounds, widely used in industries since the 1950s for their hydrophobic properties. PFAS contamination of soil and water poses significant environmental and public health risks due to their persistence, chemical stability, and resistance to degradation. The Chemical Abstracts Service catalogs approximately 4300 PFAS globally. Research in various regions such as North America, Asia, Europe, and remote polar zones has revealed the accumulation of perfluorooctane sulfonate (PFOS) in the tissues of various animal species, with concentrations reaching up to 1900ng/g in aquatic species like dolphins and whales. Researchers have employed various remediation techniques such as solvent extraction, ion exchange, precipitation, adsorption, and membrane filtration, each of which has its drawbacks. Adsorption, particularly using waste-derived functional materials like biochar, is emerging as a promising method for PFAS remediation due to its cost-effectiveness and sustainability. For example, waste timber-derived biochar exhibits adsorption efficiency comparable to commercial activated carbon. This review highlights advancements in using agricultural, industrial, and biological waste-derived materials for sustainable PFAS remediation. We discuss innovative modification techniques like hydrothermal synthesis, pyrolysis, calcination, co-precipitation, the sol-gel method, and ball milling. The study also examines adsorption mechanisms, factors affecting adsorption efficiency, and the technological challenges in scaling up waste-derived material use. It aims to explore developments, challenges, and future directions for using these materials for efficient PFAS remediation and contributing to sustainable environmental cleanup solutions.

Wireless Communication based Water Surface Cleaning Boat

—It is very dreadful that huge liters of excrement are being deposited into the rivers across our country. The pollutants and toxins are assisting the amassing of the toxicant in water thus affecting aquatic life. Only when the detritus floating above the water bodies become persistent, the governments’ plan of action is set about and unfortunately by that time, the life cycle in that water body breaks. This research work focuses on deploying a solution for the unfavorable effects on the floating refuse, and henceforth reduces the pollution caused due to the unsettled wastes including plastics and plant weeds. The project aims to develop a waste collecting boat to scavenge the water body and abolish the floating waste. This is done by employing a conveyor belt connected to the front line of the boat. Boat movement is established using a remotecontrol application by incorporating an RF module along with an encoder-decoder pair. This method will reduce the cost of operation because of less human involvement and labor. Major challenges in implementing the boat are compact mechanical design and reliable power supply. The principle feature of this boat is the collection of refuse and floating weeds from the surface of the water into a basket which is removable [2]. Key Words: IoT (Internet of Things), Water Surface Cleaning, Gear Motors, Conveyor System, Arduino Uno, IR Sensors, Boat Controller, Arduino IoT Cloud, Garbage Collection, Autonomous Navigation, Remote Monitoring, Environmental Cleanup, Sustainability, Pollution Control, Scalable Solution, Real-time Feedback, Smart Technologies, Automation, Water Pollution, Adaptive Systems

Hybrid Bilayer Interfaces within Reversed-Phase Chromatographic Silica Formed by Self-Assembly of Long-Chain Primary Alcohols.

Modification of silica interfaces by covalent attachment of functional ligands is a primary means of controlling the interfacial chemistry of porous silicas used in separations, environmental cleanup, and biosensing. Recently, modification of hydrophobic, n-alkyl-silane-functionalized interfaces has been achieved through self-assembly of zwitterionic phospholipids or mixed-charged surfactants to form "hybrid bilayers", producing interfaces that mimic lipid-bilayer partitioning and provide shape-selective partitioning of aromatic hydrocarbons. Charged headgroups, however, introduce electrostatic interactions that strongly influence the retention of ionizable solutes and require careful control over pH and ionic strength in the solution phase. In this work, we propose modification of C18-functionalized chromatographic silica surfaces through self-assembly of long-chain primary alcohols to form uncharged hybrid-bilayer surfaces. Hybrid bilayers formed from alcohols ranging from C12OH to C22OH are investigated with in situ confocal-Raman microscopy, and the spectra indicate that they form highly ordered n-alkane structures, with order increasing as a function of alcohol chain length. Temperature-dependent Raman spectra of C12OH-C22OH hybrid bilayers were collected to investigate their melting transitions. Multivariate curve resolution of these spectra show broad, two-component melting transitions, indicating alcohol and C18 alkyl chains melt simultaneously. These results suggest an interdigitated interfacial structure, where the hydrocarbon chains of the adsorbed alcohol extend into the underlying C18 chains, ordering both layers. Interdigitation is confirmed by a temperature-dependent study of a deuterated C16-OH bilayer, where spectrally resolved Raman bands from deuterated and protiated hydrocarbons melt together. Finally, n-alkyl alcohol bilayers were tested for protein repellency, where no protein adsorption was observed when equilibrated with ∼1 mg/mL bovine serum albumin. Bilayers C16OH in chain length are shelf stable at refrigerated temperatures for months. These results demonstrate long-chain alcohol bilayers can be utilized to control the interfacial hydrocarbon structure of C18-modified silica and have potential for use in separations, biosensing, and anti-biofouling applications.

ZIF-8 metal-organic frameworks and their hybrid materials: emerging photocatalysts for energy and environmental applications.

In the face of escalating environmental challenges such as fossil fuel dependence and water pollution, innovative solutions are essential for sustainable development. In this regard, zeolitic imidazolate frameworks (ZIFs), specifically ZIF-8, act as promising photocatalysts for environmental remediation and renewable energy applications. ZIF-8, a subclass of metal-organic frameworks (MOFs), is renowned for its large specific surface area, high porosity, rapid electron transfer ability, abundant functionalities, ease of designing, controllable properties, and remarkable chemical and thermal stability. However, its application as a standalone photocatalyst is limited by issues such as particle aggregation, poor water stability, and insufficient visible light absorption. By integrating ZIF-8 with various photoactive materials to form composite catalysts, these drawbacks can be mitigated, leading to enhanced photocatalytic efficiency. The review discusses the synthesis, properties, and applications of ZIF-8-based photocatalysts in light-driven H2 evolution, H2O2 evolution, CO2 reduction, and dye and drug degradation. It also highlights the challenges and future research directions in developing cost-effective, scalable, and environmentally friendly ZIF-8 composites for industrial applications. The potential of ZIF-8 composites to contribute to sustainable global energy solutions and environmental cleanup is significant, yet further exploration is required to harness their capabilities thoroughly.

Benefits of Immobilized Bacteria in Bioremediation of Sites Contaminated with Toxic Organic Compounds.

Although bioremediation is considered the most environmentally friendly and sustainable technique for remediating contaminated soil and water, it is most effective when combined with physicochemical methods, which allow for the preliminary removal of large quantities of pollutants. This allows microorganisms to efficiently eliminate the remaining contaminants. In addition to requiring the necessary genes and degradation pathways for specific substrates, as well as tolerance to adverse environmental conditions, microorganisms may perform below expectations. One typical reason for this is the high toxicity of xenobiotics present in large concentrations, stemming from the vulnerability of bacteria introduced to a contaminated site. This is especially true for planktonic bacteria, whereas bacteria within biofilms or microcolonies have significant advantages over their planktonic counterparts. A physical matrix is essential for the formation, maintenance, and survival of bacterial biofilms. By providing such a matrix for bacterial immobilization, the formation of biofilms can be facilitated and accelerated. Therefore, bioremediation combined with bacterial immobilization offers a comprehensive solution for environmental cleanup by harnessing the specialized metabolic activities of microorganisms while ensuring their retention and efficacy at target sites. In many cases, such bioremediation can also eliminate the need for physicochemical methods that are otherwise required to initially reduce contaminant concentrations. Then, it will be possible to use microorganisms for the remediation of higher concentrations of xenobiotics, significantly reducing costs while maintaining a rapid rate of remediation processes. This review explores the benefits of bacterial immobilization, highlighting materials and processes for developing an optimal immobilization matrix. It focuses on the following four key areas: (i) the types of organic pollutants impacting environmental and human health, (ii) the bacterial strains used in bioremediation processes, (iii) the types and benefits of immobilization, and (iv) the immobilization of bacterial cells on various carriers for targeted pollutant degradation.

Photocatalytic removal of textile wastewater-originated methylene blue and malachite green dyes using spent black tea extract-coated silver nanoparticles

The spent black tea extract was utilized in order to synthesize the spent black tea silver nanoparticles (SBT-AgNPs). Various parameters were tested to yield the best production of SBT-AgNPs. The characterization was conducted by X-Ray diffraction, Scanning electron microscopy, Zeta potential and energy dispersive X-ray (EDX). The XRD analysis showed hkl planes corresponding to (111), (200), (220), (311) planes at 2θ theta deg 38.3°, 40.8°, 64.5°, and 74.2°. The scanning electron microscopy reported the plate like round shaped morphology of the AgNPs. The zeta potential was examined to be -17.5 mV and a size distribution by intensity of 157.6 d. nm was observed. The EDX was employed to determine the purity of samples by reporting a strong peak of silver (Ag). The degradation activity was examined by photocatalytic removal of methylene blue and malachite green dyes from textile wastewater. The textile wastewater showed a decrease of methylene blue by 25% and 58.3%. The malachite green was also reduced by 33.3% and 60%, which was remarkably significant owing to the presence of the complex factor in the natural environment. The study sets a promising record to harbor the full potential of available food waste resource, such as spent black tea to form SBT-AgNPs and its application in the dye removal from textile waste. The multifaceted outcomes of this study resulted in an eco-friendly procedure, thereby reusing the waste material for environmental cleanup.

Synthesis of zinc oxide/bismuth oxide nanocomposite photocatalyst for visible light-assisted degradation of synthetic dyes and antibacterial application.

Contamination of water resources by artificial coloring agents and the increasing incidence of bacterial illnesses are two significant environmental and public health issues that are getting worse day by day. Traditional treatment techniques frequently fail to address these problems adequately in a sustainable and environmental friendly way. In response, our study presents a novel photocatalyst that demonstrates superior photodegradation capability and antibacterial qualities in catering the above issues. Sonochemical synthesis route was adopted to synthesize the nanocomposite of zinc oxide/bismuth oxide (ZnO-Bi2O3) along with pure ZnO and Bi2O3. X-ray diffraction investigation was performed to analyze the crystallographic structure and confirmed the formation of the composite. High-resolution transmission electron microscopic analysis showed that the particle size of the composite to be in 20 to 55nm range with the formation of heterojunction at ZnO/Bi2O3 interface. Fourier transformed infrared spectroscopic and micro Raman studies of the nanocomposite sample helped to detect the presence of stretching vibrations linked with Zn and Bi ions. X-ray photoelectron spectroscopy study revealed the chemical constitution and electronic states of the nanocomposite sample displaying the Zn 2p, Bi 4f, and O 1s spectral lines. Investigation on the photocatalytic efficiency of the samples was done and the results showed an appreciable increase in photodegradation efficiency for the composite sample in degrading methylene blue (93.24%) and Congo red (92.47%) dyes in 180min. The effect of pH, photocatalyst amount, and dye concentration on the efficiency of degradation was also been examined. Two primary causes of the enhanced performance of the composite are the generation of hydroxyl radicals (OH•) and the suppression of carrier recombination which is initiated by the synergistic combination of the two metal oxides in the nanocomposite. The nanocomposite sample was found to be stable and reusable for its effective use in environmental cleanup. By using the disk diffusion process, the antibacterial potential of the samples was analyzed and it was discovered that the nanocomposite showed an exceedingly superior antibacterial performance than the pristine samples in preventing the growth of two strains of bacteria, i.e., Escherichia coli and Staphylococcus aureus.

Self-sensitized Cu(ii)-complex catalyzed solar driven CO2 reduction.

Developing a self-sensitized catalyst from earth-abundant elements, capable of efficient light harvesting and electron transfer, is crucial for enhancing the efficacy of CO2 transformation, a critical step in environmental cleanup and advancing clean energy prospects. Traditional approaches relying on external photosensitizers, comprising 4d/5d metal complexes, involve intermolecular electron transfer, and attachment of photosensitizing arms to the catalyst necessitates intramolecular electron transfer, underscoring the need for a more integrated solution. We report a new Cu(ii) complex, K[CuNDPA] (1[K(18-crown-6)]), bearing a dipyrrin amide-based trianionic tetradentate ligand, NDPA (H3L), which is capable of harnessing light energy, despite having a paramagnetic Cu(ii) centre, without any external photosensitizer and photocatalytically reducing CO2 to CO in acetonitrile : water (19 : 1 v/v) with a TON as high as 1132, a TOF of 566 h-1 and a selectivity of 99%. This complex also shows hemilability in the presence of water, which not only plays a role in the proton relay mechanism but also helps stabilize a crucial Cu(i)-NDPA intermediate. The hemilability was justified by the formation of N3O (2) and N2O2 (3) coordinated congeners of the N4 bound complex 1. The overall mechanism was further investigated via spectroscopic techniques such as EPR, UV-vis, and spectroelectrochemistry, culminating in the justification of a single electron-reduced Cu(i)NDPA species as a proposed intermediate. In the next step, the binding of CO2 to the Cu(i) complex and subsequent electron transfer to form Cu(ii)-COO·- was indirectly probed by a radical trapping experiment via the addition of p-methoxy-2,6-di-tert-butylphenol that led to the formation of a phenoxyl radical. This work provides new strategies for designing earth-abundant robust molecular catalysts that can function as photocatalysts without the aid of any external photosensitizers.

Recent advances in valorization of lignocellulosic waste into biochar and its functionalization for the removal of chromium ions.

Lignocellulosic waste is a prevalent byproduct of agricultural and forestry activities which is an excellent feedstock for the preparation of biochar. This research area is of interest to the scientific community due to its potential in environmental remediation. In this regard, this review examines the latest advancements in transforming lignocellulosic waste into biochar and explores recent innovations in enhancing its functionality for chromium ion removal. It gives analysis on current methods for biochar production from lignocellulosic materials such as pyrolysis. Additionally focusing on improvements in production efficiency, structural properties, and surface modifications. The review also highlights various functionalization techniques, such as chemical activation and impregnation with metal oxides, that were innovated to improve adsorptive nature of biochar for chromium ions. While progress has been made, achieving scalability in lignocellulosic biochar production presents challenges, such as the high energy demands of pyrolysis, inconsistencies in feedstock quality, and the need for cost-effective functionalization methods. By summarizing recent research and technological progress, this paper aims to offer a clear perspective on the effectiveness of biochar derived from lignocellulosic waste in addressing contamination. Additionally, it discusses the ongoing challenges and future research directions needed to optimize biochar applications in environmental cleanup.

Effect of soil-groundwater system on migration and transformation of organochlorine pesticides: A review.

Soil is the place where human beings, plants, and animals depend on for their survival and the link between the various ecological layers. Groundwater is an important component of water resources and is one of the most important sources of water for irrigated agriculture, industry, mining and cities because of its stable quantity and quality. Soil and groundwater are important strategic resources highly valued by countries around the world. However, in recent years, the deterioration of the ecological environment of soil-groundwater caused by industrial, domestic, and agricultural pollution sources has continued to threaten human health and ecological security. Among them, organochlorine pesticides (OCPs), as typical organic pollutants, cause very serious pollution of soil and groundwater environment. However, most studies on the pollution of OCPs have focused on the aboveground or surface water environment, and little consideration has been given to the pollution and hazards of OCPs to the deep soil and groundwater environment, especially the effects of different environmental factors on the transport and transformation of OCPs in soil-groundwater. Moreover, in addition to the influence of a single factor on it, the interactions that arise between different factors cannot be ignored. This paper focuses on two major sources of OCPs in soil and groundwater environments, compiles and summarizes the effects of environmental factors such as pH, microbial communities and enzyme activities on the transport and transformation of OCPs in soil and groundwater systems, discusses the synergistic effects of individual environmental factors and others, and comprehensively analyses the effects of synergistic effects of various environmental factors on the transport and transformation of OCPs. In the context of ecological civilization construction, it provides the scientific basis and theoretical foundation for the prevention and treatment of OCPs-contaminated soil and groundwater, and puts forward new ideas and suggestions for the research and development of green, eco-friendly remediation and treatment technologies for OCPs-contaminated sites.

A novel immobilized bacteria consortium enhanced remediation efficiency of PAHs in soil: Insights into key removal mechanism and main driving factor.

The remediation of sites co-contaminated with polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) poses challenges for efficient and ecofriendly restoration methods. In this study, three strains (Pseudomonas sp. PDC-1, Rhodococcus sp. RDC-1, and Enterobacter sp. EDC-1) were isolated from sites contaminated with PAHs and HMs. The constructed bacteria consortium was then immobilized using biochar, bentonite, and peat. The immobilized bacteria consortium (IBC) demonstrated efficient removal ability of phenanthrene (58.1 %-73.4 %) and benzo[a]pyrene (69.6 %-83.5 %) during 60 days. Additionally, the IBC decreased soil bacterial richness and diversity, but increased the relative abundance of Proteobacteria phylum and Ochrobactrum genus, which were capable of degrading PAHs. Soil microbial co-occurrence network with IBC was classified into three main modules, and 14 genera were identified as keystone taxa linked to PAHs degradation and HMs resistance. The IBC enhanced the dioxygenase metabolic pathways for PAHs degradation, including phthalic acid and salicylic acid pathways, which became the main driving factor affecting PAHs removal efficiency based on the structural equation modeling analysis. This study confirmed the potential application of the constructed IBC in the bioremediation of soil co-contaminated with PAHs-HMs, and provides insights into key removal mechanism and main driving factor of the enhanced elimination of PAHs.