Remediation Of Contaminated Soils Research Articles

Sustainable remediation of Cr(VI)-contaminated soil by soil washing and subsequent recovery of washing agents using biochar supported nanoscale zero-valent iron

Soil contamination by Cr(VI) has attracted widespread attention globally in recent years, but it remains a significant challenge in developing an environmentally friendly and eco-sustainable technique for the disposal of Cr(VI)-contaminated soil. Herein, a sustainable cyclic soil washing system for Cr(VI)-polluted soil remediation and the recovery of washing agents using biochar supported nanoscale zero-valent iron (nZVI-BC) was established. Citric acid (CA) was initially screened to desorb Cr(VI) from contaminated soil, mobilizing Cr from the highly bioaccessible fractions. The nZVI-BC exhibited superior properties for Cr(VI) and Cr(total) removal from spent effluent, allowing effective recovery of the washing agents. The elimination mechanism of Cr(total) by nZVI-BC involved the coordinated actions of electrostatic adsorption, reduction, and co-precipitation. The contributions to Cr(VI) reduction by Fe0, surface-bound Fe(II), and soluble Fe(II) were 0.6 %, 39.8 %, and 59.6 %, respectively. Meanwhile, CA favored the activity of surface-bound Fe(II) and Fe0 in nZVI-BC, enhancing the production of soluble Fe(II) to strengthen Cr(VI) removal. Finally, the recovered washing agent was proven to be reused three times. This study showcases that the combined soil washing using biodegradable chelant CA and effluent treatment by nZVI-BC could be a sustainable and promising strategy for Cr(VI)-contaminated soil remediation.

Remediation Technologies of Contaminated Sites in China: Application and Spatial Clustering Characteristics

Screening remediation technologies through the lens of green, low-carbon, and sustainable development is crucial for contaminated land management. To better understand the applicability of remediation technologies, this paper explored their application in China based on a survey of 643 cases. By employing coupled analysis and local spatial autocorrelation methods, this study reveals the alignment between remediation technologies and pollutants, along with their spatial distribution and clustering patterns. Specifically, the four primary remediation technologies identified were cement kiln co-processing (CKCP), chemical oxidation/reduction (CO/CR), thermal desorption (TR), and solidification and stabilization (S/S), collectively accounting for over 90% of the cases. Additionally, our findings indicated significant variation in how different pollutants respond to remediation technologies, largely attributable to the characteristics of the pollutants. We observed High–High clustering patterns for CKCP, CO/CR, TR, and S/S. These were predominantly found in Jiangsu, Chongqing, Shandong, and Guizhou for CKCP and CO/CR and in Hebei, Jiangsu, Shanghai, and Chongqing for CO/CR. TR exhibited a High–High clustering in Shanghai, as did S/S. This research contributes to reducing the economic and resource costs associated with the trial-and-error of screening contaminated soil remediation technologies, offering valuable scientific and technological guidance for contaminated land regulation.

Comparative life-cycle sustainability assessment of centralized and decentralized remediation strategies at the city level

Remediation of contaminated soil at industrial sites has become a challenge and an opportunity for sustainable urban land use, considering the substantial secondary impacts resulting from remediation activities. The design of soil remediation strategies for multi-site remediation from a regional perspective is of great significance for cities with a large number of brownfields. Centralized and decentralized facilities have been studied in different environmental fields, yet limited research has focused on centralized soil remediation, specifically the treatment of contaminated soil from different sites through the construction of shared soil treatment facilities. This study proposes a framework for comparing centralized and decentralized strategies for contaminated soil remediation based on the integration of life-cycle sustainability assessment and multi-objective optimization. With Zhuzhou, an industrial city in China, serving as an example, results show that after optimization, the centralized scenario can reduce total environmental impacts by 25 %–41 %. In addition, the centralized scenario can reduce economic costs by 27 %–39 %, saving up to 176 million USD. The advantages of the centralized soil remediation strategy include: (1) increased use of soil washing, (2) reduced use of off-site disposal, and (3) reduced construction and efficient utilization of soil treatment facilities. In conclusion, the centralized strategy is relatively suitable for cities or areas with a large number of medium or small-sized contaminated sites. The built framework can quantitatively evaluate multiple sites soil remediation at both the city and individual site level, allowing for a straightforward and objective comparison with the optimal remediation design.

Characterization of heavy metal-associated bacteria from petroleum-contaminated soil and their resistogram and antibiogram analysis.

The aim of the current study was to screen and identify heavy metal (chromium, cadmium, and lead) associated bacteria from petroleum-contaminated soil of district Muzaffarabad, Azad Jammu and Kashmir, Pakistan to develop ecofriendly technology for contaminated soil remediation. The petroleum-contaminated soil was collected from 99 different localities of district Muzaffarabad and the detection of heavy metals via an atomic absorption spectrometer. The isolation and identification of heavy metals-associated bacteria were done via traditional and molecular methods. Resistogram and antibiogram analysis were also performed using agar well diffusion and agar disc diffusion methods. The isolated bacteria were classified into species, i.e., B. paramycoides, B. albus, B. thuringiensis, B. velezensis, B. anthracis, B. pacificus Burkholderia arboris, Burkholderia reimsis, Burkholderia aenigmatica, and Streptococcus agalactiae. All heavy metals-associated bacteria showed resistance against both high and low concentrations of chromium while sensitive towards high and low concentrations of lead in the range of 3.0 ± 0.0mm to 13.0 ± 0.0mm and maximum inhibition was recorded when cadmium was used. Results revealed that some bacteria showed sensitivity towards Sulphonamides, Norfloxacin, Erythromycin, and Tobramycin. It was concluded that chromium-resistant bacteria could be used as a favorable source for chromium remediation from contaminated areas and could be used as a potential microbial filter.

Petroleum-contaminated soil bioremediation and microbial community succession induced by application of co-pyrolysis biochar amendment: An investigation of performances and mechanisms

This study aimed to remediate petroleum-contaminated soil using co-pyrolysis biochar derived from rice husk and cellulose. Rice husk and cellulose were mixed in various weight ratios (0:1, 1:0, 1:1, 1:3 and 3:1) and pyrolyzed under 500 °C. These biochar variants were labeled as R0C1, R1C0, R1C1, R1C3 and R3C1, respectively. Notably, the specific surface area and carbon content of the co- pyrolysis biochar increased, potentially promoting the growth and colonization of soil microorganisms. On the 60th day, the microbial control group achieved a 46.69% removal of pollutants, while the addition of R0C1, R1C0, R1C3, R1C1 and R3C1 resulted in removals of 70.56%, 67.01%, 67.62%, 68.74% and 67.30%, respectively. In contrast, the highest efficiency observed in the abiotic treatment group was only 24.12%. This suggested that the removal of petroleum pollutants was an outcome of the collaborative influence of co-pyrolysis biochar and soil microorganisms. Furthermore, the abundance of Proteobacteria, renowned for its petroleum degradation capability, obviously increased in the treatment group with the addition of co-pyrolysis biochar. This demonstrated that co-pyrolysis biochar could notably stimulate the growth of functionally associated microorganisms. This research confirmed the promising application of co-pyrolysis biochar in the remediation of petroleum-contaminated soil.

Comparative efficacy of wheat-straw biochar and chicken-waste compost on cadmium contaminated soil remediation, reducing cadmium bioavailability and enhancing wheat performance under cadmium stress

Cadmium (Cd) pollution of soil and food crops is a widespread environmental issue caused by excessive industrialization, unsustainable urbanization, and intensive farming practices. Cd, a hazardous element, poses significant risks to agro-environmental sustainability, food safety, and human health. Using organic materials such as biochar and compost to stabilize Cd in contaminated soil is an environmentally benign and cost-effective strategy for remediating moderately to highly polluted soil. However, in response to the scarcity of comparative studies on biochar and compost efficacy, this research explores the impact of wheat-straw biochar and chicken waste compost on Cd-contaminated soil remediation. A greenhouse experiment using two application rates (1.5 % and 2.5 %) of biochar and compost in 10 mg kg−1 Cd-contaminated soil revealed significant (p≤0.05) effects. The 2.5 % compost application increased soil organic carbon (SOC) from 0.45 % to 0.85 %, while 2.5 % biochar enhanced soil pH from 7.1 to 7.7 and electrical conductivity (EC) from 0.33 to 0.44 dSm−1. Notably, 2.5 % biochar significantly reduced Cd bioavailability from 9.49 to 4.90 mg kg−1, root accumulation from 29.8 to 16.4 mg kg−1 and shoot translocation from 16.8 to 8.4 mg kg−1. This reduction was confirmed through translocation factor (51.5 %) and immobilization efficiency (48.4 %). Furthermore, 2.5 % biochar improved chlorophyll content (a, b, and total) and wheat morphological attributes under Cd stress in soil. Overall, higher rates of biochar (2.5 %) and compost (2.5 %) effectively mitigate Cd uptake, improve soil properties, and enhance physiological and morphological responses, suggesting their promise for sustainable soil management practices.

Change of soil bacterial communities in chemically stabilized chromium contaminated soils in an accelerated aging experiment

Chemical stabilization is a common strategy to clean Cr(VI) contaminated soils. Although many studies have reported both short-term and long-term performance of chemical stabilization, there is no work addressing the impacts of long-term Cr stability on soil bacterial communities after stabilization. In this study, an accelerated aging system that synchronized simulation acid rain leaching and freeze-thaw cycles was established for the first time. We investigated the change of Cr content, environmental variables and bacterial community structure after chemical stabilization by 50-year acid rain leaching and freeze-thaw cycle simulation. Chemical stabilization effectively decreased the content of soil Cr(VI), total Cr in leachate and Cr(VI) in leachate. Different aging conditions altered soil Cr(VI), total Cr in leachate and Cr(VI) in leachate to different extents, hinting at distinct mechanisms of long-term Cr instability between acid rain leaching and freeze-thaw cycle. Cr(VI) and chemical stabilization were identified as the most influential factors affecting soil bacterial community structure, and acid rain leaching and freeze-thaw cycle exhibited considerable but distinct impacts. Our findings provided deeper insights into the long-term restoration of bacterial community in chemically stabilized Cr(VI) contaminated soil and the long-term risk assessment of contaminated soil remediation.

Enhanced thermal desorption of chlorinated hydrocarbons by nanoscale zero-valent iron: the effect of in situ dechlorination.

Thermal desorption provides an efficient solution to remediate soil contaminated with chlorinated organic pollutants. However, enhanced desorption efficiency is desired to facilitate easier and less costly remediation. Hence, nanoscale zero-valent iron (nZVI) was combined with thermal desorption to remove trichloroethene (TCE) and trichlorobenzene (TCB) from soil in a laboratory-scale study. The addition of nZVI greatly improved the desorption efficiency, especially at low temperature with 99.6% of TCE and 98.8% of TCB removed at 300 °C for 2 h. Characterization results revealed that the addition of nZVI loosened the structure of soil, preventing the soil from agglomerating during the thermal treatment. Besides, the analyses of dechlorination intermediates and the variation of Fe species proved the in situ dechlorination effect of nZVI and the redox cycle of Fe was revealed. Moreover, the influences of nZVI dosage and treatment time on thermal treatment were assessed. This study not only offers new perspectives for contaminated soil remediation, but also provides mechanistic insights into the dechlorination effect of nZVI in the thermal desorption.

Iron Contaminated Soils Remediation Using Secondary Metabolites of Trichoderma harzianum T10 and Its Effect on Spinach Growth

Iron Contaminated Soils Remediation Using Secondary Metabolites of Trichoderma harzianum T10 and Its Effect on Spinach Growth

Clarification of generation mechanism of volatilization flux based on detailed analysis of transport phenomena near the ground surface and quantitative evaluation of influencing factors

Assessing human health risks associated with inhalation exposure of volatile chemical substances (VCSs) volatilized from contaminated soil requires quantitative evaluation of volatilization fluxes (VFs) and an understanding of how environmental factors impact VF generation. We developed a numerical model that considers advection-dispersion and VCSs volatilization in unsaturated soil, enabling VF prediction through parameter optimization using soil column tests. We conducted parametric analyses to assess how key parameters, such as soil particle size, contamination depth, temperature, and surface soil thickness affect VF generation. By analyzing VCS transport near the ground surface, we uncovered the mechanisms underlying VF generation. We also identified characteristic differences in VF generation behavior linked to soil particle size and gas saturation at the ground surface. Under specific soil particle size conditions, significant VF generation occurred even when contamination was deep underground. This was primarily observed when capillary effect was pronounced, and VCSs continued to be supplied to the ground surface through upward advection. Considering the significant impact of VF generation on human health, our parametric study provides valuable insights into relationships between different parameters and VF behavior, especially under varying ground surface temperatures and surface soil thicknesses. This study contributes to developing effective remediation and risk-reduction strategies. Environmental ImplicationThis research examines the environmental implications of volatile chemical substances (VCSs), including hazardous materials like benzene and trichloroethylene, in contaminated soil. VCSs pose health risks when they volatilize from soil. The study quantifies volatilization fluxes (VF) and elucidates the environmental factors affecting VF generation. These findings are vital for effective environmental management. By comprehending the mechanisms governing VF generation, particularly regarding soil properties like particle size, this research enhances the effectiveness of soil contamination remediation and risk reduction. It emphasizes the essential need for a comprehensive VCS assessment in contaminated soils to protect both human health and the environment.

Effect of EDDS on the rhizosphere ecology and microbial regulation of the Cd-Cr contaminated soil remediation using king grass combined with Piriformospora indica

The negative impacts of soil heavy metals composite pollution on agricultural production and human health are becoming increasingly prevalent. The applications of green chelating agents and microorganisms have emerged as promising alternate methods for enhancing phytoremediation. The regulatory effects of root secretion composition, microbial carbon source utilization, key gene expression, and soil microbial community structure were comprehensively analyzed through a combination of HPLC, Biolog EcoPlates, qPCR, and high-throughput screening techniques. The application of EDDS resulted in a favorable rhizosphere ecological environment for the king grass Piriformospora indica, characterized by a decrease in soil pH by 0.41 units, stimulation of succinic acid and fumaric acid secretion, and an increase in carbon source metabolic activity of amino acids and carbohydrates. Consequently, this improvement enhanced the bioavailability of Cd/Cr and increased the biomass of king grass by 25.7%. The expression of dissimilatory iron-reducing bacteria was significantly upregulated by 99.2%, while there was no significant difference in Clostridium abundance. Furthermore, the richness of the soil rhizosphere fungal community (Ascomycota: 45.8%, Rozellomycota: 16.7%) significantly increased to regulate the proportion of tolerant microbial dominant groups, promoting the improvement of Cd/Cr removal efficiency (Cd: 23.4%, Cr: 18.7%). These findings provide a theoretical basis for the sustainable development of chelating agent-assisted plants-microorganisms combined remediation of heavy metals in soil.

Effects of biochar on the compressibility of soil with high water content

This study investigates the potential utilization of biochar in reclamation fills to improve the compressibility of soil with high water content. Biochar, a recycled carbon-rich biomass commonly used for contaminated soil remediation and carbon sequestration, is examined for its impact on the compression behavior of treated soils. The influence of biochar content, initial water content (w0), and biochar saturation on the compression behavior of biochar-treated soils with high water content is analyzed. The results revealed that the addition of both raw biochar and biochar saturated with water significantly enhances the remolded yield stress (σ′yr) and reduced the void ratio (eyr) at σ′yr. Raw biochar exhibits higher σ′yr and lower eyr values compared to water-saturated biochar, mainly due to its greater water absorbing potential of raw biochar. The variations of σ′yr and eyr induced by biochar can be attributed to the decrease in initial void ratio (e0) and the increase in void ratio at liquid limit (eL), which can be effectively normalized using empirical equation developed for reconstituted soil without biochar. Furthermore, the compression parameters (e*100 and C*c) show a decreasing trend with increasing biochar content and decreasing initial water content. Soil with saturated biochar displays higher e*100 and C*c values in comparison with soil with raw biochar. The changes in e*100 and C*c corresponded well to empirical equations developed for reconstituted soil without biochar, indicating that the compressibility changes induced by biochar depended on variations in physical properties (e0 and eL), following similar patterns observed in reconstituted soils without biochar. Therefore, the compression curve of biochar-treated soil in the postyield regime can be effectively normalized by using void index into the ICL or EICL, suggesting its practical applicability for predicting the compressibility of reclamation soil with biochar. These findings demonstrate that biochar-treated soil with high water content exhibits favorable geotechnical properties, making it suitable for use as soil reclamation fills or in landfill applications.

Design of a central tool for sustainability evaluation and weighting to decision-making support of contaminated soils remediation

Sustainable remediation remains unstandardized and ambiguously regulated, thereby limiting its adoption in the management of contaminated areas. Although a considerable number of tools are available for this purpose, numerous shortcomings continue to be detected, especially with regard to the integration of a complete assessment of impact and sustainability into a single framework. In view of these problems, the objective in this study was to develop and validate an integrated tool for assessing the sustainability of remediation techniques for contaminated soils. To support the sustainability analysis, were prepared impact assessment matrices, which list components and criteria for obtaining integrated impact scores for each sustainability dimension/pillar (i.e., social, economic, and environmental), factor, and component. These impact scores were incorporated and fitted into a mathematical model used to ascertain the sustainability of the techniques. The tool was subsequently validated by comparing and analyzing the sustainability with which five techniques: phytoremediation, electrokinetics and excavation/disposal (Case Study I), nanoremediation and soil washing (Case Study II). The techniques’ probabilities of sustainability followed the order presented in the preceding statement. The determination of sustainability was supported by the direct interaction between the effects derived under each dimension and technique. These findings led to the conclusion that the proposed tool prioritizes the basic principles of sustainability, which call for harmony among the three pillars, and that it is a favorable instrument for the evaluation and selection of a sustainable remediation technique.

Tetracycline removal from soil by phosphate-modified biochar: Performance and bacterial community evolution

Since the remediation performance of soil tetracycline pollution by original biochar is not ideal, many modified methods have been proposed to improve its performance. Considering the cost, complex modification process and environmental friendliness, many modified biochar are difficult to be used in soil environments. In this work, biochar derived from corn stover was modified using phosphate to increase the adsorption ability of soil tetracycline and alleviate the negative effects caused by tetracycline. The results showed that pyrolysis temperatures and anion types of phosphate (PO43−, HPO42−, H2PO4−) played important roles in the performance of modified biochar. Compared with original biochar, phosphate modified biochar not only improved the adsorption capacity, but also changed the adsorption behavior of tetracycline. Via SEM, BET and FTIR techniques, the intrinsic reasons for the increase of adsorption capacity were explained by the change of morphological structures as well as functional groups of the modified biochar. K3PO4 and high temperature (800 °C) maximally improved the surface morphology, increased the pore structure, changed the surface functional groups of biochar, and then increased the adsorption capacity of tetracycline (124.51 mg/g). Subsequently, the optimal material (K3PO4-800) was selected and applied for tetracycline contaminated soil remediation. Compared to the soil without remediation, K3PO4-800 modified biochar effectively reduced the effective concentration of tetracycline in soil, and improved soil K and P nutrition, and reshaped microbial communities. Our study showed that K3PO4-800 modified biochar was not only a good tetracycline resistant material, but also a good soil amendment.

Sustainable per‐ and polyfluoroalkyl substances contaminated soil remediation: Evaluating the potential of thermal desorption

AbstractPer‐ and polyfluoroalkyl substances (PFASs) have been extensively utilized in various industries. These artificial compounds pose significant environmental and health concerns as they exhibit persistence in soil over long periods and can migrate through soil and groundwater. One potential method for addressing PFASs toxicity is thermal desorption, although its efficacy in calcareous soil remains understudied. In this experimental investigation, we aimed to evaluate the effectiveness of thermal desorption in removing PFASs from two types of calcareous soil: spiked clay and sandy clay loam soil. PFASs were spiked into soil samples, which were subsequently freeze‐dried and homogenized. The samples underwent thermal desorption, followed by extraction and analysis of remaining PFASs concentrations using UPLC MS/MS. The study examined the impact of different temperatures, times, and soil types on PFASs removal. Results revealed that the removal fraction of PFASs increased with higher temperatures, although the specific effect varied depending on the soil type and the characteristics of the PFASs. Optimal PFASs removal occurred within the temperature range of 350 to 450°C, with a treatment time of 40 to 60 min. ANOVA analysis indicated a significant interaction between temperature and time, highlighting the influence of temperature on PFASs desorption. The correlation coefficient demonstrated a negative relationship between temperature and PFASs removal from the soil sample. This study successfully demonstrated the effectiveness of thermal desorption in removing PFASs from calcareous soils. The findings contribute to the development of effective strategies for mitigating the environmental and health risks associated with PFASs contamination in soil.

EFFECTS OF MIXING ADDITION OF THE GREENERY WASTES ON THEIR REMEDIATING EFFECTS ON PETROLEUM POLLUTED SOIL

In this study, greenery wastes of Platycladus orientalis (Po) and the other 5 species which are commonly used in urban landscaping were collected. Monospecific greenery wastes and their 1:1 mixtures containing Po waste were used to treat contaminated soil with a petroleum content of 15.00 g/kg, to conduct a 150-day laboratory remediating experiment at 20-25℃, under a soil moisture of 50% of the saturated water holding capacity. The effects of mixed addition of greenery wastes on their re-mediating effects on contaminated soil were detected, to provide scientific basis for the reasonable utilization of greenery waste in contaminated soil remediation. The results indicated that: (1) Mixed addition of Po waste with Picea asperata (Pa), Acer truncatum (At), Ginkgo biloba (Gb) or Juniperus formosana (Jf) waste significantly enhanced their effect of removing petroleum contaminants, espe-cially for removing aromatic and non-hydrocarbon substances; while the mixed addition of Po waste with Pinus tabuliformis (Pt) waste significantly weakened their remediating effects. The mixed addition of Po waste with Gb or Jf waste significantly enhanced their effects of replenishing soil available N and P; the mixed addition of it with Pa, Pt, Gb or Jf waste tended to enhance their effects of stimulating the activities of soil invertase, urease, phosphatase and dehydrogenase, while the mixed of it with At waste tended to weaken their simulating effects. (2) Mixed litters with high contents of C, N, terpenoids and amino acids, and chemical dispersion facilitated the degradation of petroleum contaminants, while those with high contents of soluble saccharides and total organic acids/terpenoids led to contrast effects; mixed litters with high N content facilitated the increment of soil enzymatic activities, while those with high contents of total organic acids and terpenoids led to contrast effects. In conclusion, mixed addition of Po and Jf, Po and Gb, and Po and Pa wastes might enhance their overall remediating effects on petroleum contaminated soil, while mixed addition of Po and Pt wastes might weaken their ability of removing the contaminants, and this mixing form of greenery wastes should be avoided.

Modeling and optimization of PAHs contaminated soil remediation using green solvent in a continuous flow by response surface methodology

Modeling and optimization of PAHs contaminated soil remediation using green solvent in a continuous flow by response surface methodology

Effects of biochar on earthworms during remediation of potentially toxic elements contaminated soils

With the widespread use of biochar for soil remediation and improvement, its effects on soil organisms are receiving increased attention. The impacts of biochar on earthworms are still poorly understood. This study aimed to assess the potential ecotoxicity of rice husk biochar (RB) and sludge biochar (SB) on earthworms during potentially toxic elements (PTEs) contaminated soil remediation. The results showed that high rates of RB addition (5% and 10%) caused earthworm mortality, but SB addition did not affect earthworm survival. When added at non-lethal rates (3%), RB and SB addition did not affect survival, weight loss, and PTEs accumulation of earthworms, while resulting in apparent avoidance behavior and oxidative stress response. Among them, RB addition was more likely to cause avoidance behavior, while SB addition had a more pronounced stress effect on earthworms. Additionally, the bacterial communities in the earthworm gut were more sensitive to biochar addition than those in soil. SB addition had a greater impact on earthworm gut bacterial communities than RB addition. The addition of RB and SB increased the abundance of Bacillaceae while decreasing the abundance of Rhizobiaceae in the earthworm gut. This change in the composition of bacterial community may impact the nitrogen cycle and organic matter degradation functions of earthworms. The study suggests that RB and SB may have different effects on earthworms during PTEs-contaminated soil remediation, depending on their properties. It will assist us to understand the potential ecotoxicity of biochar and provide several guidance for its safe application.

Application of Biochar for Ion-Adsorption of Rare Earth Contaminated Soil Remediation: A Review

Rare earth elements, particularly middle and heavy rare earth, are among the most valuable resources in the pursuit of a greener economy. The production of middle and heavy rare earth elements heavily relies on ion adsorption, which constitutes over 80% of global output and is centered in southern China. Unfortunately, the extensive mining activities have led to severe environmental pollution, resource depletion, and risks to human health. In contrast, biochar application offers a cost-effective and efficient phytoremediation solution. However, existing literature on the biochar application in IAT-Res mine tailings is limited. In this paper, we conducted a literature review and summarized the contaminations in the ion adsorption mine tailings, as well as explored the potential of using biochar to remediate contaminations. We aim to raise interest and encourage further research on utilizing biochar for pollution remediation in ion adsorption rare earth mine tailings. By effectively managing contamination, this approach can contribute to the sustainable supply of ion adsorption rare earth elements while ensuring their long-term viability.

Thermal plasma potential to remediate soil contaminated with diesel

Petroleum hydrocarbons (PHCs) are recognized as one of the major soil contaminants causing negative environmental impact. Thereby, PHCs remediation from the soil is essential. Hence, this experimental study aimed to assess the potential of thermal water vapor and air plasmas to remediate soil contaminated with habitually used PHCs – diesel. The impact of contaminant content in the soil on the remediation process also was estimated. The results of this research demonstrated that 99.9% contaminant removal efficiency was received proceeding diesel contaminated soil remediation in the environment of the thermal plasma in defiance of whether water vapor or air was employed as a plasma-forming gas. Moreover, the soil's contaminant content (80–160 g/kg) did not influence its' removal efficiency. The soil de-pollution process also caused the decomposition of the soils' natural carbon reserves since carbon content decreased from an initial 9.8 wt% in the clean soil to 3–6 wt% in the remediated soil. Furthermore, PHCs – diesel was decomposed into producer gas mainly consisting of H2, CO (also known as synthesis gas) and CO2. Thus, the thermal plasma offers a way not only to de-pollute the soil but also to reuse the PHCs present in the soil by breaking it down into gaseous products that can further be used to meet human needs.