Remediation Of Sites Research Articles

Unmaking the bomb: environmental cleanup and the politics of impossibility

Unmaking the bomb: environmental cleanup and the politics of impossibility

Lignin degradation by a novel thermophilic and alkaline yellow laccase from Chitinophaga sp.

The characterization of the novel yellow laccase, Lac_CB10, derived from Chitinophaga sp. CB10, represents a significant advancement with broad implications. This enzyme displays exceptional stability and functionality under extreme conditions, operating effectively under both alkaline (pH 10.5) and thermophilic (80-90°C) environments. Its capability to maintain considerable activity over extended periods, even at high temperatures, showcases its potential for various industrial applications. Moreover, its distinctive ability to efficiently degrade lignin-demonstrated by a significant 52.27% degradation within 32 h-signifies a promising avenue for biorefinery processes. This newfound laccase's characteristics position it as a crucial asset in the realm of bioremediation, particularly in scenarios involving contamination at extreme pH and temperature levels. The study's findings highlight the enzyme's capacity to address challenges in industrial processes and environmental cleanup, signifying its vital role in advancing biotechnological solutions.

Phosphate adsorption on dried alum sludge: Modeling and application to treatment of dairy effluents

This study evaluates Alum sludge from drinking water treatment plants for the efficient and cost-effective removal of phosphates from aqueous solutions. Extensive characterization and batch experiments have established that optimal phosphate removal was achieved with a sludge dosage of 20 g L−1 (at an initial phosphate concentration of 100 mg L−1), a pH of 5, a temperature of 23 °C, and a stirring speed of 200 rpm. These conditions significantly reduced phosphate levels, ensuring compliance with legal discharge limits. The Langmuir isotherm, pseudo-second-order kinetic and intraparticle diffusion models best described the adsorption process, highlighting the spontaneous and endothermic nature of the phenomenon. The sludge effectively reduced phosphate concentrations to acceptable levels when applied to dairy effluents. This study underscores the potential of Alum sludge as a viable solution for phosphate management in environmental cleanup efforts.

Synthesis and application of dual-functional sorbent SBA-15-Fe3O4-PDA-ODA for removing both water soluble and insoluble pollutants

In this study, inorganic-organic hybrid sorbent SBA-15-Fe3O4-PDA-ODA with functional groups having affinity for both water-soluble and insoluble pollutants was synthesized for treatment of wastewater where Malachite Green (MG) dye and motor oil coexist. In order to enhance the specific interactions between the sorbent and dye via functional groups of polydopamine (PDA), Fe3O4 nanoparticles were encapsulated with SBA-15 and surface functionalization with PDA was accomplished and then the surface of Fe3O4-SBA-15-PDA was modified with octadecylamine (ODA) to remove the oil present in the same environment with dye. While the SBA-15-Fe3O4-PDA-ODA directed to the aqueous phase by magnet provided MG removal thanks to the hydrophilic groups of PDA, it provided motor oil removal thanks to hydrophobicity of ODA when directed to the oil phase. 99.20 % dye removal and 9.24 g/g oil adsorption capacity were achieved from the environment where oil and dye were present together. Besides, the adsorption of MG on Fe3O4-SBA-15-PDA was searched at various pH, dye concentration, adsorbent dosage, and temperature in order to propose optimum experimental conditions for removal of dye and maximum adsorption capacity was determined as 95.83 mg g−1 at optimum conditions (10 mg adsorbent, 10 mg L−1 MG concentration, pH 9). Interaction mechanism between dye and Fe3O4-SBA-15-PDA was explained by studying the adsorption behavior of sorbent derived from the isotherm and kinetic results. The sorbents were characterized by FT-IR, XRD, SEM, N2-adsorption/desorption, water-contact-angle, and VSM measurements. SBA-15-Fe3O4-PDA-ODA sorbent was tested for three successive adsorption cycles for both dye and oil and eventuated insignificant loss in activity when they were recycled. Easy and low-cost fabrication protocol, controllable removal ability of dye and oil will facilitate its versatility in environmental cleanup process for water soluble and insoluble pollutants.

Photocatalytic Removal of Emerging Contaminants from Water using Metal Oxide-based Nanoparticles

Abstract: Water contamination resulting from industrial and anthropogenic activities is a major problem in many countries throughout the world. Effective water treatment technologies are necessary to address this issue. Emerging pollutants (EPs) are reaching the aquatic environments from point and diffuse sources constantly. These are the substances that are not regularly monitored, yet have the potential to infiltrate the environment and harm the ecosystem and human health. Because of their ecological and sustainable properties, interest in improved photocatalytic technologies based on metal oxide-based nanomaterials has grown tremendously over the years to address this water contamination. Pollutant degradation, water splitting, carbon dioxide reduction, nitrogen reduction, and microbial inactivation are just a few of the applications of photocatalysis. However, to maintain its environmentally favourable status, new solutions must be found to assure long-term viability. Here we review, emerging organic pollutants, conventional water treatment, advanced oxidation methods, photocatalytic mechanisms, photocatalyst support materials, synthesis, and characterization of metal oxides and metal oxide nanoparticles in the removal of emerging contaminants. The purpose of this review is to reach a broader readership by giving a simple comprehension of the fundamentals and advances of metal-oxide-driven photocatalysis for environmental clean-up.

Spatiotemporal dynamic temperature variation dominated by ion behaviors during groundwater remediation using direct current

Direct current (DC) electric field has shown promising performance in contaminated site remediation, in which the Joule heating effect plays an important role but has been previously underappreciated. This study focuses on the spatiotemporal characteristics and mechanism of temperature change in heterogeneous porous media with applied DC. The heating process can be divided into four phases: preferential heating of the low permeability zone (LPZ), rapid heating in the middle region, temperature drop and hot zone shift, and reheating. The dynamic ion behaviors with complex interplays among reactions, electrokinetic-driven migration, and mixed convection induced an uneven redistribution of ions and dominated the heating rate and temperature distribution. The concentration of major ions near the pH jump decreased to 1% of the initial value, even though ions were continuously pumped into the heating zone. This ion depletion caused a drop in current, heating rate, and temperature. Here ions cannot be delivered rapidly into the ion-depleted zone by electromigration due to the potential flattening in the surrounding region. The presence of LPZ intensified the nonuniformity of ion redistribution, where a regional focusing of water-soluble ions was observed, and weakened the temperature rebound compared with that using homogeneous sand. These results provide a new perspective on the regulation of DC heating in site remediation.

Hydrogen peroxide production via pH manipulation using Visible-Light photocatalyst (ZnIn2S4) conjugated with Oxygen-Modified black carbon

Hydrogen peroxide (H2O2), a powerful oxidizing agent, plays a critical role in various sectors including bleaching, wastewater treatment, sterilization, chemical manufacturing, healthcare, energy generation, and environmental cleanup. The conventional method for producing H2O2, known as the anthraquinone process, faces challenges due to its economic inefficiencies and significant safety concerns. This has spurred interest in developing safer and more environmental friendly photocatalysts for H2O2 production. These photocatalysts, when dispersed in water and exposed to sunlight, generate H2O2 by extracting oxygen from the air and hydrogen from water. Our research explores the use of zinc indium sulfide (ZnIn2S4), a material that is photoactive under visible light, which accounts for about 43 % of the solar spectrum. Initially, the pH of the solution was not modified, leading to the ionization of Zn and In. However, upon optimizing the experimental conditions, we observed a substantial reduction in particle ionization and an increase in H2O2 yield. Additionally, by integrating black carbon with oxygen functional groups into the ZnIn2S4 matrix, we achieved a 14 % increase in production efficiency compared to traditional methods.

(Bio)electrochemical system: A systematic approach from agricultural waste to sewage wastewater treatment with nutrients and hydrogen recovery

Sustainable biowaste utilization is currently an interesting research area to enhance its conversion to value-added products. Electrochemical and bioelectrochemical technologies are cracking up the fractionization of various types of waste for environmental cleanup processes. In the present study, agricultural waste-based extracted material was used to capture the nutrients and/or pollutants from the anaerobic bioelectrochemically treated sewage wastewater (SWW). Hydrogen production potential of 15.52–11.77 times higher than the single carbon source indicated efficient utilization of organic and inorganic matters by extant microorganisms in the SWW. The electrochemical hemicellulose (HC) extraction, nutrient recovery and other components like applied potential (mV), NaOH (M) and rice straw load (%) analysis were evaluated at three factors and three levels. The N/C ratio of 0.06 and the highest functionalities in the 150-mV extracted HC, confirm its suitability to trap nutrients/pollutants from wastewater. With the potential to substitute expensive adsorbents in the future, the additional advantage of HCs being useful in the recovery of ammonium ions for use in agriculture could positively impact the global food security program. The aim of the study is not only the recovery of nutrients from waste but also to unravel the clean path of waste management with possible green energy production.

Congener-specific fate and impact of microcystins in the soil-earthworm system

Microcystins (MCs) have a significant influence on aquatic ecosystems, but little is known about their terrestrial fate and impact. Here, we investigated the fate of two MCs (MC-LR and MC-RR) in the soil-earthworm system, with consideration of their congener-specific impact on earthworm health, soil bacteria, and soil metabolome. Although MCs had little acute lethal effect on earthworms, they caused obvious growth inhibition and setae rupture. Relative to MC-RR, MC-LR exhibited higher bioaccumulation and the resulting dermal lesions and deformation of longitudinal muscles. While the incorporation of both MCs into soils stimulated pathogenic bacteria and depressed oxidative stress tolerant bacteria, the response among soil nitrification and glutathione metabolism differed between the two congeners. The dissipation kinetics of MCs obeyed the first-order model. Earthworms stimulated soil N-cycling enzyme activities, increased the abundance of MC-degrading bacteria, and promoted bacterial metabolic functions related to glutathione metabolism, xenobiotics biodegradation, and metabolism of amino acids that comprise MCs, which accelerated the dissipation of MC-LR and MC-RR by 227% and 82%, respectively. These results provide evidence of significant congener differences in the terrestrial fate and impact of MCs, which will enable a better understanding of their role in mediating soil functions and ecosystem services.

Automated SEM analysis of particles in Hanford tank waste

Multiple bench-scale filtration campaigns of Hanford tank waste supernatant on a backpulseable dead-end filtration skid have provided greater insight into the solids that cause fouling and reduce filter performance. The solids collected during each campaign were concentrated from the backpulse solutions and examined using automated particle analysis (APA) methods with scanning electron microscopy and X-ray energy dispersive spectroscopy to categorize particle types and their morphological characteristics. We show that with APA, thousands of particles can be analyzed to provide accurate insight into the phases that may be impacting filter performance.

A novel photocatalytic activity of Bi2S3 nanoparticles for pharmaceutical and organic pollution removal in water remediation

In recent times, there has been a surge of interest in the unique characteristics and possible applications of nanoparticles in various fields, including environmental clean-up. The contamination of water sources with pharmaceutical and organic substances has emerged as a significant environmental concern. Semiconductor nanoparticles, particularly Bi2S3 nanoparticles, have garnered considerable attention due to their efficacy and environmentally friendly nature in advanced oxidation processes (AOPs). These nanoparticles have shown remarkable photocatalytic abilities in the destruction of pollutants when exposed to UV–visible light. This study covers the production, characterization, and degradation of Bi2S3 nanoparticles in relation to organic and pharmaceutical contaminants. By utilizing co-precipitate methods, it becomes possible to precisely manipulate the size, shape, and composition of the nanoparticles, which are crucial factors in determining their catalytic effectiveness. The created nanoparticles are then examined using various analytical techniques, such as Powder X-ray Diffraction (P-XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), UV-visible spectroscopy, Photoluminescence study (PL), colour chromaticity coordinates (CIE), and Dynamic light scattering study (DLS). The catalytic capability of the synthesised compounds was compared to the degradation of Picric acid and paracetamol as model pollutants. The observed photocatalytic activity of these nanoparticles indicates their potential in water purification and environmental clean-up. The findings suggest that incorporating these nanoparticles into practical systems for pollutant degradation is feasible and can be applied in diverse scenarios. The results shed light on the efficient utilization of Bi2S3 nanoparticles as photocatalysts for the oxidation of drugs and organic contaminants. By utilizing Bi2S3 nanoparticles, the elimination of pharmaceutical and organic pollutants from water sources becomes achievable, thereby contributing to the preservation and safeguarding of the environment and public health.

Ex-situ phytoextraction using Pteris vittata as a sustainable way to protect soil resource

Chemical industrial sites are potential land resources for urban construction, but the high concentration of heavy metals in soil restricts their timely redevelopment. Remediation treatment must be performed before the reutilization of these sites. Aiming to investigate the potential of Pteris vittata to remove arsenic (As) from an As-contaminated chemical industrial site, a 16-month ex-situ field experiment was conducted to monitor the dynamics of growth and As uptake of P. vittata. The shoot (pinnae and petiole) biomass increased linearly with the extension of time, and reached 1342 g m−2 at the time of ∼16 months after transplantation. The shoot As concentration in pinnae showed a “large increase followed by small decrease” tendency and reached its highest value of 2550 mg kg−1 at the time of ∼10 months after transplantation. Compared with the control that removed 5.1 kg As ha −1, the addition of potassium dihydrogen phosphate at the dose of 600 mg (P2O5) kg−1 or ammonium dihydrogen phosphate at the dose of 300 mg (P2O5) kg−1 increased the As removal by P. vittata to ∼13.0 kg ha−1. The total cost of ex-situ phytoremediation was 41.6 US$ t−1, being ∼67% lower than that of common site remediation technologies such as soil washing. Ex-situ phytoremediation is suggested to enable a timely re-development of land resource and a sustainable protection of soil resource.

Stable and highly efficient extraction of U(VI) from seawater by covalent organic frameworks and amidoxime co-functionalized MXene

Seawater is rich in uranium resources, but the marine environment is complicated and changeable, as well as the presence of a lot of competing ions. These are disturbing factors that cannot be ignored in seawater uranium extraction. The synthesis of adsorbents with good stability, high selectivity and large adsorption capacity has been the focus of attention. The composite adsorbent MXene-AO@LZU1 was prepared using electrostatic self-assembly of transition metal carbides and nitrides (MXenes) with structurally stable covalent organic frameworks (COF-LZU1). The results of characterizations showed that MXene-AO@LZU1 was rich in functional groups and had an effective improvement in specific surface area. MXene-AO@LZU1 exhibited an efficient performance for [UO2(CO3)3]4- with an adsorption saturation capacity of 88.8 mg·g−1. The adsorption amount in the simulated seawater also reached 6.8 mg·g−1. MXene-AO@LZU1 had a good selectivity for uranium and outstanding stability under various extreme conditions. In addition, XPS showed that the adsorption of uranium by MXene-AO@LZU1 relied mainly on the complexation of oxygen/nitrogen-containing functional groups with [UO2(CO3)3]4-. This study explored the great potential of MXenes and COFs in seawater uranium extraction, indicating that MXene-AO@LZU1 was an efficient and stable adsorbent with good development prospects. This finding was of great importance for the application of composite materials in actual environmental cleanup, and could be extended to efficiently remove other pollutants by rational ligands design.

Nano-engineered Solutions for Sustainable Environmental Cleanup

Nano-engineered Solutions for Sustainable Environmental Cleanup

Optimizing levofloxacin decontamination in aquatic environment: Iron-modified biochar in heterogeneous Fenton processes with peroxide and persulfate

This study evaluates the effectiveness of iron-modified biochar (Fe-BC) in fixed-bed heterogeneous Fenton processes for levofloxacin (LFX) removal, a widely-used fluoroquinolone antibiotic. The objective is to optimize parameters such as pH, oxidants (H2O2 and S2O82−), and biochar forms (functionalized and raw) using factorial analysis of mixed data (FAMD) and response surface methodology (RSM). These optimizations identified the ideal conditions for maximal LFX removal. The most effective removal with Fe-BC occurred at 2.5 mM H2O2 and pH 7.5, while the optimal S2O82− conditions were 1.6 mM at pH 2.8. Both Fe-BC and raw biochar (RBC) showed the highest adsorption at pH 5.8. In adsorption-only, RBC and Fe-BC reduced LFX to 530 μg/L and 335 μg/L, respectively, in 60 min. The oxidation process further decreased LFX levels to between 8.9 μg/L and 0.1 μg/L using S2O82− and H2O2, respectively. The research expanded upon a kinetic model, incorporating the calculation of kinetic constants for both adsorption and oxidation processes, to deepen our understanding of the intricate degradation dynamics at play. Identifying by-products was crucial in elucidating degradation pathways. These findings are vital for environmental remediation, demonstrating the efficiency of Fe-BC in removing harmful antibiotics from water. This research highlights the potential of modified biochar in environmental clean-up, especially for water contaminated with antibiotics. The results emphasize the importance of optimizing treatment conditions for effective antibiotic removal, contributing valuable insights to the field of environmental remediation.

Decrypting Molecular Mechanisms Involved in Counteracting Copper and Nickel Toxicity in Jack Pine (Pinus banksiana) Based on Transcriptomic Analysis.

The remediation of copper and nickel-afflicted sites is challenged by the different physiological effects imposed by each metal on a given plant system. Pinus banksiana is resilient against copper and nickel, providing an opportunity to build a valuable resource to investigate the responding gene expression toward each metal. The objectives of this study were to (1) extend the analysis of the Pinus banksiana transcriptome exposed to nickel and copper, (2) assess the differential gene expression in nickel-resistant compared to copper-resistant genotypes, and (3) identify mechanisms specific to each metal. The Illumina platform was used to sequence RNA that was extracted from seedlings treated with each of the metals. There were 449 differentially expressed genes (DEGs) between copper-resistant genotypes (RGs) and nickel-resistant genotypes (RGs) at a high stringency cut-off, indicating a distinct pattern of gene expression toward each metal. For biological processes, 19.8% of DEGs were associated with the DNA metabolic process, followed by the response to stress (13.15%) and the response to chemicals (8.59%). For metabolic function, 27.9% of DEGs were associated with nuclease activity, followed by nucleotide binding (27.64%) and kinase activity (10.16%). Overall, 21.49% of DEGs were localized to the plasma membrane, followed by the cytosol (16.26%) and chloroplast (12.43%). Annotation of the top upregulated genes in copper RG compared to nickel RG identified genes and mechanisms that were specific to copper and not to nickel. NtPDR, AtHIPP10, and YSL1 were identified as genes associated with copper resistance. Various genes related to cell wall metabolism were identified, and they included genes encoding for HCT, CslE6, MPG, and polygalacturonase. Annotation of the top downregulated genes in copper RG compared to nickel RG revealed genes and mechanisms that were specific to nickel and not copper. Various regulatory and signaling-related genes associated with the stress response were identified. They included UGT, TIFY, ACC, dirigent protein, peroxidase, and glyoxyalase I. Additional research is needed to determine the specific functions of signaling and stress response mechanisms in nickel-resistant plants.

Machine learning models for predicting thermal desorption remediation of soils contaminated with polycyclic aromatic hydrocarbons

Among various remediation methods for organic-contaminated soil, thermal desorption stands out due to its broad treatment range and high efficiency. Nonetheless, analyzing the contribution of factors in complex soil remediation systems and deducing the results under multiple conditions are challenging, given the complexities arising from diverse soil properties, heating conditions, and contaminant types. Machine learning (ML) methods serve as a powerful analytical tool that can extract meaningful insights from datasets and reveal hidden relationships. Due to insufficient research on soil thermal desorption for remediation of organic sites using ML methods, this study took organic pollutants represented by polycyclic aromatic hydrocarbons (PAHs) as the research object and sorted out a comprehensive data set containing >700 data points on the thermal desorption of soil contaminated with PAHs from published literature. Several ML models, including artificial neural network (ANN), random forest (RF), and support vector regression (SVR), were applied. Model optimization and regression fitting centered on soil remediation efficiency, with feature importance analysis conducted on soil and contaminant properties and heating conditions. This approach enabled the quantitative evaluation and prediction of thermal desorption remediation effects on soil contaminated with PAHs. Results indicated that ML models, particularly the RF model (R2 = 0.90), exhibited high accuracy in predicting remediation efficiency. The hierarchical significance of the features within the RF model is elucidated as follows: heating conditions account for 52 %, contaminant properties for 28 %, and soil properties for 20 % of the model's predictive power. A comprehensive analysis suggests that practical applications should emphasize heating conditions for efficient soil remediation. This research provides a crucial reference for optimizing and implementing thermal desorption in the quest for more efficient and reliable soil remediation strategies.

Link between Oil Pollution and Adverse Pregnancy Outcomes in the Niger Delta Region of Nigeria

Oil exploration in the Niger Delta has led to severe environmental pollution. This study investigates the association between exposure to crude oil and adverse pregnancy outcomes. 
 Study Design: This was a comparative cross-sectional study of the differences in adverse pregnancy outcomes of people living in heavily oil polluted and non-polluted communities
 Place and Duration of Study: Kegbara Dere (K-Dere), a rural Community in Ogoniland, Gokana Local Government Area, Rivers State and Obohia community in Ndoki kingdom, Ukwa East LGA of Abia state between June 2022 and Jan 2023.
 Methodology: We recruited 900 study participants (450 each from the crude oil impacted and the non-oil polluted communities) using multi-stage random sampling. Questionnaires were used to collect data on socio-demographics and adverse pregnancy history by case definitions using the adapted WHO indirect sisterhood method of maternal mortality estimate. Data was analyzed using IBM Statistical Package for Social Sciences (SPSS) version 25. Differences in proportions were compared using Chi Square test. The association between living in an oil polluted community or exposure to crude oil pollutants and adverse pregnancy outcomes was determined using crude odds ratio. Confidence intervals were determined at 95% level and a p-value of less than 0.05 was considered significant.
 Results: Pregnant women in the polluted community experienced a significantly higher prevalence of adverse outcomes, including stillbirth, abortion, and birth defects. The risk of experiencing an adverse pregnancy outcome was 30 times higher in the polluted area.
 Conclusion: This study suggests a strong link between oil pollution and pregnancy complications. Further research with robust designs is needed to confirm causality. Environmental cleanup and protective measures for pregnant women are crucial in these areas.

Enhanced inactivation of Staphylococcus aureus and Escherichia coli using conjugated polyindole polymer nanoparticles under visible light irradiation

AbstractThe areas of environmental cleanup and bacteria inactivation are particularly interesting in polymer‐based nanomaterials because of their unique physicochemical properties. Conjugated polymer nanoparticles (CP NPs) have potential uses in the biological and environmental, but little is known about them. This study aimed to examine the efficacy of CP nanoparticles in the photocatalytic inactivation of S. aureus and E. coli under visible irradiation (λ ≤ 420 nm), with minor enhancements observed. The simple and one‐step chemical oxidation technique was used to prepare CP nanoparticles. X‐ray powder diffraction (XRD), Fourier‐transform infrared spectroscopy (FT‐IR), Scanning electron microscope (SEM), Energy‐dispersive X‐ray (EDS), and Transmission electron microscopy (TEM) analyses were utilized to characterize the physicochemical properties of CP nanoparticles for comprehensive structural analysis. The synthesized CP nanoparticles exhibited outstanding photocatalytic disinfection capabilities, achieving a degradation of 98.6%. This research not only provides insights into the physical characteristics of CP nanoparticles but also illustrates their antibacterial efficacy against two different bacterial pathogens, namely S. aureus and E. coli. Therefore, this research highlights an eco‐friendly and inexpensive preparation of conjugated polymer nanoparticles for a wide range of applications.

A novel La2MnTiO6 perovskite for photocatalytic degradation of tetracycline hydrochloride

One of the majority of environmental pollution is caused by organic substances resulting from anthropogenic and industrial activities, such as dyes, antibiotics, and similar substances. Due to these pollutants’ strong stability, they are difficult to decompose, and their breakdown can only occur slowly through chemical or biological processes. Photocatalysis is a potential method for environmental clean-up with a significant oxidation capacity and a rapid response rate. Among them, double perovskite is an emerging alternative to single perovskite, which has recently shown comparable or even better performance for degrading organic pollutants. The first report on the synthesis of La2MnTiO6 (LMTO) double perovskite for tetracycline hydrochloride (TC) degradation was made in this work. By using XRD, FE-SEM, BET, and EDX analysis, the crystalline structure morphology, and elemental composition of the samples were identified. According to the calcination temperature, only at temperatures greater than 700 °C could the LMTO material be successfully formed. The photocatalytic performances of the prepared samples were evaluated by degrading TC under a UV LED lamp at 365 nm. The 800 °C calcined sample exhibited the highest TC degradation performance, reaching around 62% in 120 min. Besides, the LMTO might eliminate another medicine such as Ciprofloxacin (CIP). Overall, these results offer a potential strategy for employing LMTO photocatalysts to remove various antibiotics.