Remediation Strategies Research Articles

A study on the monitoring of LNAPL migration using ERT.

This study employs electrical resistivity tomography (ERT) to experimentally investigate the migration characteristics of light non-aqueous phase liquids (LNAPL) under various groundwater conditions. Through cross-hole measurements and time-lapse inversion, the migration process of LNAPL under three scenarios-unsaturated conditions, constant groundwater levels, and declining water levels-was systematically analyzed. The results indicate that LNAPL migration behavior exhibits significant differences under different conditions. Under unsaturated conditions, the vertical migration rate of LNAPL gradually decreases over time, with an average rate of 1.06 cm/h, and is influenced by preferential migration pathways formed in coarse-grained regions. At constant water levels, the migration of LNAPL is significantly constrained by the groundwater level, spreading horizontally near the water table after reaching it, with an average rate of 0.51 cm/h. When the groundwater level declines, LNAPL migrates rapidly downward along preferential flow paths, with an average rate increasing to 1.45 cm/h. Miller Soil Box experiments further reveal the relationship between LNAPL content and electrical resistivity, showing that an increase in LNAPL can significantly alter soil resistivity, especially under low moisture conditions. Overall, this study confirms the monitoring advantages of ERT technology for LNAPL migration behavior under different conditions and provides important references for remediation strategies at contaminated sites.

A spatial interpolation method based on 3D-CNN for soil petroleum hydrocarbon pollution.

Petroleum hydrocarbon pollution causes significant damage to soil, so accurate prediction and early intervention are crucial for sustainable soil management. However, traditional soil analysis methods often rely on statistical methods, which means they always rely on specific assumptions and are sensitive to outliers. Existing machine learning based methods convert features containing spatial information into one-dimensional vectors, resulting in the loss of some spatial features of the data. This study explores the application of Three-Dimensional Convolutional Neural Networks (3DCNN) in spatial interpolation to evaluate soil pollution. By introducing Channel Attention Mechanism (CAM), the model assigns different weights to auxiliary variables, improving the prediction accuracy of soil hydrocarbon content. We collected soil pollution data and validated the spatial distribution map generated using this method based on the drilling dataset. The results indicate that compared with traditional Kriging3D methods (R2 = 0.318) and other machine learning methods such as support vector regression (R2 = 0.582), the proposed 3DCNN based method can achieve better accuracy (R2 = 0.954). This approach provides a sustainable tool for soil pollution management, supports decision-makers in developing effective remediation strategies, and promotes the sustainable development of spatial interpolation techniques in environmental science.

Adsorption Characteristics of Cadmium onto Calcite and Its Agricultural Environmental Relevance

Calcite (CaCO3), a common component of calcium-based fertilizers, has been recognized for its effectiveness as a cadmium (Cd) immobilization agent in the solidification/stabilization (S/S) method. This strategy is a widely used chemical remediation technique aimed at reducing the bioavailability and toxicity of Cd in contaminated soils. This study comprehensively evaluated the potential of calcite for Cd remediation through geochemical analyses, including adsorption isotherms, saturation index, ion concentration changes, and X-ray diffraction (XRD) analysis. Adsorption isotherm experiments indicated that Cd adsorption onto calcite aligns more closely with the Freundlich isotherm model, suggesting a heterogeneous surface with a maximum adsorption capacity of 1.56 mg g−1. Based on chemical states result, optimal conditions for CdCO3 precipitation with low Cd concentrations were identified at pH above 7.9. XRD analysis confirmed the formation of Ca0.67Cd0.33CO3 at higher Cd concentrations, indicating that chemisorption is the dominant immobilization mechanism. Additionally, variations in Ca2+ and CO32− concentrations supported the substitution of Cd for Ca on the calcite surface. These findings highlight calcite’s potential as an effective material for Cd immobilization, providing valuable insights for the developing more sustainable soil remediation strategies.

Biophysics-guided uncertainty-aware deep learning uncovers high-affinity plastic-binding peptides.

Plastic pollution, particularly microplastics (MPs), poses a significant global threat to ecosystems and human health, necessitating innovative remediation strategies. Biocompatible and biodegradable plastic-binding peptides (PBPs) offer a potential solution through targeted adsorption and subsequent MP detection or removal from the environment. A challenge in discovering plastic-binding peptides is the vast combinatorial space of possible peptides (i.e., over 1015 for 12-mer peptides), which far exceeds the sample sizes typically reachable by experiments or biophysics-based computational methods. One step towards addressing this issue is to train deep learning models on experimental or biophysical datasets, permitting faster and cheaper evaluations of peptides. However, deep learning predictions are not always accurate, which could waste time and money due to synthesizing and evaluating false positives. Here, we resolve this issue by combining biophysical modeling data from Peptide Binder Design (PepBD) algorithm, the predictive power and uncertainty quantification of evidential deep learning, and metaheuristic search methods to identify high-affinity PBPs for several common plastics. Molecular dynamics simulations show that the discovered PBPs have greater median adsorption free energies for polyethylene (5%), polypropylene (18%), and polystyrene (34%) relative to PBPs previously designed by PepBD. The impact of including uncertainty quantification in peptide design is demonstrated by the increasing improvement in the median adsorption free energy with decreasing uncertainty. This robust framework accelerates peptide discovery, paving the way for effective, bio-inspired solutions to MP remediation.

Fungal bioaugmentation enhanced herbicide removal via soil microbial fuel cell: Taking Myrothecium verrucaria and haloxyfop-P as an example.

Microbial fuel cell (MFC), which produces electricity while removing pollutants, is a green approach of ecological restoration. Whether fungal bioaugmentation could enhance the herbicide removal in MFC has not been fully investigated. This study aims to construct the fungal-augmented MFC device, compare the effects of different types of remediation against soil haloxyfop-P, and explore the mechanisms of xeno-fungusphere MFC in alleviating organic pollution. The Myrothecium verrucaria addition achieved the current density of 15.27μA/cm2 and power density (PD) of 1.174μW/cm2, which were much higher than those with indigenous microbes and MFC alone. On day 60, the haloxyfop removal efficiency of 93.7% was achieved with the M. verrucaria bioaugmentation, and double herbicide further increased the removal efficiency to 97.9%, along with PD of 9.3μW/cm2. The M. verrucaria addition significantly changed the correlation pattern between bacterial genera, as well as between dominant genera and herbicide degradation, electrogenesis, edaphic factors and functional abundance. Facing herbicide challenge, the biogeochemical processes of C/N/Fe/Mn/S were reorganized in MFC microbiota, which were also profoundly impacted by bioelectric field and xeno-fungusphere. The MFC degradation of haloxyfop-P followed the second-order kinetics; the fungal addition reduced the gap between the highest occupied molecular orbitals and lowest unoccupied molecular orbitals of herbicide molecules, and reduced the energy barrier for the herbicide transformation. Compared with MFC alone, xeno-fungusphere MFC had a better effect, which can remediate the soil without additional power supply, making it a cost-effective self-sustaining remediation strategy.

An In-depth Analysis of Science Teachers' Knowledge, Attitudes, and Skills Towards Cognitive Conflict Strategies, Multiple Representations Model, and Misconception Remediation Strategies in Terms of Demographic Aspects

An In-depth Analysis of Science Teachers' Knowledge, Attitudes, and Skills Towards Cognitive Conflict Strategies, Multiple Representations Model, and Misconception Remediation Strategies in Terms of Demographic Aspects

Distinct Behavioural and Brain Response Profiles Between Arithmetic Word Problem Solving and Sentence Comprehension in Third and Fourth Graders.

Word problems are essential for math learning and education, bridging numerical knowledge with real-world applications. Despite their importance, the neural mechanisms underlying word problem solving, especially in children, remain poorly understood. Here, we examine children's cognitive and brain response profiles for arithmetic word problems (AWPs), which involve one-step mathematical operations, and compare them with nonarithmetic word problems (NWPs), structured as parallel narratives without numerical operations. Behavioural results suggested that AWP performance was associated with both reading comprehension and arithmetic fluency, whereas NWP performance correlated only with reading comprehension. Neuroimaging results revealed distinct neural substrates: AWP solving primarily activated the anterior insula, middle frontal gyrus and intraparietal sulcus, whereas NWP solving engaged in the inferior frontal gyrus, middle temporal gyrus and angular gyrus. Critically, we observed a developmental shift: Children showed heightened prefrontal activation during AWP solving, contrasting with increased posterior parietal engagement in adults. Moreover, although adults demonstrated brain-behaviour associations, with slower AWP solving linked to stronger parietal activation, this relationship was absent in children. Taken together, these findings suggest that AWP solving recruits specialized arithmetic brain circuits that undergo a frontal-to-parietal trajectory. Our study thus provides a neurological basis for AWP solving in children, emphasizing the crucial role of the fronto-insular-parietal network. These insights into brain-based contributions to developmental differences may guide the development of targeted remediation strategies and educational interventions tailored to individual learning needs.

Enhancing Miscanthus floridulus remediation of soil cadmium using Beauveria bassiana FE14: Plant growth promotion and microbial interactions.

Soil heavy metal pollution presents substantial risks to food security and human health. This study focused on the efficiency of plant growth-promoting fungus-Beauveria bassiana FE14 and Miscanthus floridulus on the synergistic remediation of soil Cd contamination. Results revealed that B. bassiana FE14 significantly enhanced the growth of M. floridulus, substantially decreased Cd content in soil by 79.39 %, and modified enzyme activities (superoxide dismutase, peroxidase, and catalase) to alleviate Cd-induced oxidative stress in plants, determined by the physical and chemical indicators and enzyme activities of soil and plant. Based on microbiome analysis, this study also found significant changes in the composition, structure, and molecular ecological network of endophytic bacterial communities in roots, but this study had little effect on the bacterial and fungal communities in rhizosphere soil. In addition, the key genera (including Sphingomonas, unclassified_Comamonadaceae, Massilia, Bradyrhizobium, and Paraglomus) and key genes/enzymes (including cadC, zinc transporter, zinc and cadmium transporter, exoZ/Y/Z, catalase-peroxidase, superoxide dismutase, nitrite reductase, acid phosphatase, etc.) were involved in promoting plant growth and alleviating Cd stress. These findings revealed the potential of B. bassiana FE14 and M. floridulus working in synergy to enhance the phytoremediation efficiency of Cd-contaminated soils, thus presenting a promising approach for integrated plant-microbe remediation strategies.

Enhanced Pb immobilization by CaO/MgO-modified soybean residue (okara) in phosphate mining wasteland soil: Mechanism and microbial community structure.

Lead (Pb) contamination is an inevitable consequence of phosphate mining, necessitating the development of effective remediation strategies. This study investigated the use of CaO/MgO-modified okara (CMS) as an eco-friendly approach to remediate Pb-contaminated soils from phosphate mining wastelands. In the present study, following 30d of CMS application, the exchangeable Pb content was significantly decreased to 10.46%, with the majority of Pb transforming into more stable forms: carbonate-bound Pb (56.44%), Fe/Mn oxide-bound Pb (11.03%), and organic-bound Pb (19.58%). Additionally, the treatment led to a substantial enhancement in total phosphorus, available phosphorus, ammonium, and soil organic matter, thereby improving soil fertility. The microbial community structure was also significantly influenced by CMS, with a notable increase in Firmicutes to 45%. Key genera within the microbial community included Azospirillum, Pseudoxanthomonas, Sphingomonas, and Microvirga, with Pseudoxanthomonas and Massilia being the main differential species. These genera were significantly positively correlated, contributing to the maintenance of microbial community homeostasis and promoting the production of CO32- and PO43-, which further accelerated Pb immobilization. The results indicate that CMS is an effective amendment for Pb immobilization in contaminated soils, enhancing soil fertility and modulating the microbial community to promote Pb stabilization. This provides valuable insights into the ecological remediation of Pb-contaminated soils and water bodies, highlighting the potential of waste reuse in environmental management.

Organic acid release and microbial community assembly driven by phosphate-solubilizing bacteria enhance Pb, Cd, and As immobilization in soils remediated with iron-doped hydroxyapatite.

Although iron-doped hydroxyapatite (Fe-HAP) and its composites have been reported to immobilize arsenic (As), lead (Pb), and cadmium (Cd), its practical application is limited by the inefficient release of iron and phosphate. In this study, Ochrobactrum anthropic, a phosphate-solubilizing bacterium isolated from a lead-zinc smelting site, was employed to enhance multi-heavy metal immobilization in Fe-HAP-amended soils. O. anthropic secreted low-molecular-weight organic acids, promoted phosphate (25.6 mg/L) and iron (14.2 mg/L) release from Fe-HAP, and minimally disrupted native bacteria. Compared to CK, the combination of 2 % O. anthropic (v/w) and Fe-HAP (Fe-to-HAP ratio of 1:1) significantly increased the residual fractions of Cd, Pb, and As by 109.09 %, 49.21 %, and 25.00 %, respectively. The combined treatment also improved available phosphorus, available nitrogen, and acid phosphatase activity by 233.24 %, 196.55 %, and 246.45 %, respectively. Furthermore, O. anthropic facilitated the recruitment of phylum Firmicutes and genera Acidovorax, Sedimentibacter, and Brevundimonas, shifting the bacterial community from specialists to generalists. Positive correlations were observed between residual fractions of Pb, Cd, As, well-crystallized As, and the abundance of Firmicutes, Acidovorax, and Sedimentibacte. These findings demonstrate the potential of an O. anthropic-driven Fe-HAP remediation strategy for the eco-friendly restoration of barren and polymetallic-contaminated soils.

Exploring effective video-review strategies of patient encounters for medical students: precepted review versus peer discussion

ABSTRACT Background Video-recordings review of patient encounters is reported to improve the clinical performance of medical students. However, evidence on specific remediation strategies or outcomes are lacking. We aimed to implement videorecording-based remediation of standardized patient encounters among medical students, combined with preceptor one-on-one feedback or peer group discussion, and evaluate the effectiveness of the two remediation methods using objective structured clinical examination (OSCE). Methods Following standardized patient encounters, 107 final-year medical students were divided into two groups based on different remediation methods of video review: (1) precepted video review with preceptor feedback (N = 55) and (2) private video review and subsequent peer group discussion under supervision (N = 52). All students underwent twelve-stations of OSCE both before and after the video review. Students’ pre- and post-remediation OSCE scores, self-efficacy level in patient encounters, and level of educational satisfaction with each method were assessed and compared between different video-based remediation methods to evaluate their respective effects. Results After remediation, the total and subcomponent OSCE scores, such as history taking, physical examination, and patient – physician interaction (PPI), among all students increased significantly. Post-remediation OSCE scores showed no significant difference between two remediation methods (preceptor module, 79.6 ± 4.3 vs. peer module, 79.4 ± 3.8 in the total OSCE score). Students’ self-efficacy levels increased after remediation in both modules (both p-value <0.001), with no difference between the two modules. However, students’ satisfaction level was higher in the preceptor module than in the peer module (80.1 ± 17.7 vs. 59.2 ± 25.1, p-value <0.001). Among students with poor baseline OSCE performance, a prominent increase in PPI scores was observed in the preceptor-based module. Conclusion Video-based remediation of patient encounters, either through preceptor review with one-on-one feedback or through private review with peer discussion, was equally effective in improving the OSCE scores and self-efficacy levels of medical students. Underperforming students can benefit from precepted video reviews for building PPI.

Atmospheric chemistry of microplastics: Transport, environmental impacts, and governance

The presence of microplastic particles, defined as plastics less than 5mm in dimension, presents a significant environmental challenge. Their ubiquity and the potential risks they pose for ecosystems and human health are widely recognized. This article delves into the atmospheric chemistry surrounding microplastics, examining their sources, impacts, and management. It reviews existing literature on their environmental occurrence, evaluates the processes they undergo in the atmosphere, their interaction with atmospheric elements, and the efficiency of current remediation strategies and policy measures. The analysis uncovers that microplastics (MPs) can carry harmful substances like heavy metals and persistent organic pollutants, facilitating their transport to diverse environmental contexts, thereby compromising air and water quality. The potential health repercussions, such as respiratory and cardiovascular problems, are also discussed. Effective removal techniques are identified, including Dissolved Air Flotation and coagulation methods that utilize metals, and emphasize the urgency for regulatory measures to combat microplastic contamination. This research contributes to a more profound comprehension of microplastics’ intricate environmental behavior and their possible effects. It offers valuable perspectives for devising strategies to curb their pollution, highlighting the significance of sustainable material use and responsible waste management. These insights are pivotal for shaping policies and directing future research to mitigate the environmental and health hazards of microplastics.

Modeling of asphaltene precipitation - part I: comparative study for asphaltene precipitation envelope prediction methods

The solubility of asphaltenes in crude oils is predominantly influenced by variations in temperature, pressure, and oil composition. These alterations can precipitate asphaltene deposition, resulting in diminished permeability, obstruction of wells and auxiliary surface facilities, and ultimately, a reduction or cessation of production. Therefore, it is imperative for upstream and downstream processing engineers to comprehend and predict asphaltene phase behavior to implement effective preventative and remedial strategies and minimize costs. Asphaltene precipitation can be predicted through the application of solubility and colloidal theories. In this study, cubic equations of state and cubic-plus-association equations of state are utilized as solubility theory-based methodologies. The advanced versions of the Peng-Robinson (APR78) and Soave-Redlich-Kwong (ASRK) cubic equations of state are compared with cubic-plus-association (CPA) equations of state using Multiflash software to predict fluid and asphaltene phase behavior. The simulation results demonstrate a strong correlation between the ASRK model and the CPA model, with a minor deviation from the results of the APR78 model. This observation suggests that these models can effectively predict asphaltene behavior and yield acceptable results when compared to experimental data for fluid and asphaltene. Considering the likelihood of asphaltene deposition within wells, hence, it is recommended to develop a model to determine the locations and quantities of deposition.

Nano-technology as an eco-friendly approach in agriculture

Global food security is now the most challenging issue due to the limited natural resources, low productivity of food crops in the agricultural sector, rapid climate changes and huge population growth. Researchers are trying to adopt newer innovations and technologies to increase the production of food crops to meet the demand. Nanotechnology is one of the most challenging technologies that could enhance the productivity of crops in sustainable agriculture, giving importance to nano-fertilizers, nano-pesticides, nano-biosensors and nano-material-based remediation strategies. The physical and chemical processes to produce nanoparticles (NP) have a detrimental effect on the ecosystem. Thus, green synthesis of NPs using various microorganisms offers a more promising and sustainable alternative. Nanotechnology is very promising as it has many potential benefits like improvement of food quality, minimization of agricultural inputs and enrichment of plants by absorbing nutrients from the soil. Nanoparticles can be used as nanofertilizers, distinct agrochemical carriers and site-targeted or regulated nutrition delivery with improved crop protection. The potential of nanomaterials offers a new green revolution in sustainable agriculture.

Pyrolysis as a Remediation Strategy for Weathered Oil-Contaminated Soil: The Role of Minerals and Native Organic Matter

Pyrolysis as a Remediation Strategy for Weathered Oil-Contaminated Soil: The Role of Minerals and Native Organic Matter

Arsenic modifies the microbial community assembly of soil-root habitats in Pteris vittata.

Pteris vittata, renowned for its ability to hyperaccumulate arsenic, presents a promising solution to the escalating issue of global soil arsenic contamination. This fern cultivates a unique underground microbial community to enhance its environmental adaptability. However, our understanding of the assembly process and the long-term ecological impacts of this community remains limited, hindering the development of effective soil remediation strategies. This study addresses this gap by investigating soil-root habitats from three geographically diverse fields comprising a gradient of arsenic contamination, complemented by a time-scale greenhouse experiment. Field investigations reveal that arsenic stress influences community assembly dynamics in the rhizosphere by enhancing processes of homogeneous selection. Greenhouse experiments further reveal that arsenic exposure alters the assembly trajectory of rhizosphere communities by promoting key microbial modules. Specifically, arsenic exposure increases the enrichment of a core taxon (i.e. Rhizobiaceae) in the rhizosphere, both in field and greenhouse settings, boosting their abundance from undetectable levels to 0.02% in the soil after phytoremediation. Notably, arsenic exposure also promotes a pathogenic group (i.e. Spirochaetaceae) in the rhizosphere, increasing their abundance from undetectable levels to 0.1% in the greenhouse. This raise concerns that warrant further investigation in future phytoremediation studies. Overall, this study elucidates the assembly dynamics of the soil microbiome following the introduction of a remediation plant and emphasizes the often-overlooked impacts on soil microbial community following phytoremediation. By probing the ecological impacts of remediation plants, this work advances a more nuanced understanding of the complex ecological implications inherent in phytoremediation processes.

Effects of dimethylarsenate coprecipitation with ferrihydrite on Fe(II)-induced mineral transformation and the release of dimethylarsenate.

Organoarsenicals are toxic pollutants of global concern, and their environmental geochemical behavior might be greatly controlled by iron (Fe) (hydr)oxides through coprecipitation, which is rarely investigated. Here, the effects of the incorporation of dimethylarsenate (DMAs(V)), a typical organoarsenical, into the ferrihydrite (Fh) structure on the mineral physicochemical properties and Fe(II)-induced phase transformation of DMAs(V)-Fh coprecipitates with As/Fe molar ratios up to 0.0876±0.0036 under anoxic conditions and the accompanying DMAs(V) release were investigated. The presence of DMAs(V) during Fh formation gradually decreases the mineral crystallinity. With increasing DMAs(V) content, the specific surface areas of the coprecipitates are decreased owing to particle aggregation, while the micropore sizes are negligible changed. Fourier transformed infrared (FTIR) and As K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy show that, part of DMAs(V) binds to Fh surfaces in the coprecipitates by forming bidentate binuclear inner-sphere complexes through As-O-Fe bonds. During the reaction of the coprecipitate with 1 mM Fe(II) for 336 h, DMAs(V) inhibits the Fh transformation to goethite. No goethite forms at pH 4; at pH 7 low content of DMAs(V) hinders the further conversion of lepidocrocite to goethite, while high content of DMAs(V) completely inhibits goethite formation. DMAs(V) in the coprecipitate is continuously released into the solution, with the released proportion being generally increased with the increase of DMAs(V) content, pH and Fe(II) addition, probably owing to the desorption of weak inner- and outer-sphere DMAs(V) complexes bound on the Fh surfaces upon the Fh aging and transformation to lepidocrocite and goethite. These results provide deep insights into the fate and mobility of organoarsenical pollutants mediated by Fe (hydr)oxides in natural environments, and help design effective and ecofriendly remediation strategies for As polluted soils and sediments.

Effect of Phosphate Amendment on Cadmium Accumulation in Pepper (Capsicum annuum L.) Grown in Geogenic Cd-Rich Soil from the Karst Region

Soil in the karst region usually features high geogenic cadmium (Cd) and limited available phosphorus (P). Appropriate phosphate amendment is crucial for alleviating Cd accumulation in food crops and reducing health risks. However, the interaction of Cd and P in geogenic Cd-rich soil-plant systems is poorly understood. In this study, a pot experiment was conducted to investigate the translocation of Cd in the soil-pepper system under different amendment rates of Ca(H2PO4)2. The results showed that the biomass of pepper was not affected by the application rates of Ca(H2PO4)2, even up to 0.45 g/kg, but was affected by the application of nitrogen and potassium fertilizers. High contents of total Cd (6.19 mg/kg) and bioavailable Cd (2.72 mg/kg, 44%) in the studied soils resulted in elevated Cd content in pepper, and it decreased in the order of root (8.18 mg/kg) &gt; stem (4.89 mg/kg) &gt; fruit (3.88 mg/kg). This indicates that pepper planted in the studied soils may present potential health risks. Furthermore, phosphate amendment neither influences the bioavailable Cd in rhizosphere soil nor Cd uptake and transport in pepper plants. The findings of this study highlight that monocalcium phosphate is not a suitable choice for reducing the accumulation of Cd in pepper fruits in the studied soil and that other remediation strategies are needed.

CuAl-LDH Modified with Filamentous Macroalgae for Anionic Dyes Removal: A Study on Selectivity, Adsorption Efficiency, and Regeneration

Continuous modifications of Layered Double Hydroxides (LDH) materials are essential to enhance their structural stability and improve their capacity for pollutant adsorption, addressing the need for more effective remediation strategies in environmental applications. This research study has proposed the preparation of CuAl-LDH supported filamentous macroalgae of Spirogyra sp. (CuAl-LDH/SA) via coprecipitation and hydrothermal methods. The prepared CuAl-LDH/SA composites were investigated for the adsorption of direct yellow 12 (DY) and remazol red (RR) dyes in batch mode experiments. The structure and morphology of the prepared CuAl-LDH/SA were identified by X-ray Diffraction (XRD), Fourier Transform Infra Red (FT-IR), (Brunauer-Emmett-Teller) BET surface area, Thermogravimetry / Differential Thermal Analyzer (TG/DTA), and Scanning Electron Microscope (SEM). For the adsorption process, the effects of initial pH, contact time, initial concentration, temperature, adsorption selectivity, and adsorbent regeneration, as well as kinetics, isotherms, and thermodynamics were studied. The adsorption selectivity test resulted in the RR dye being more selective compared to DY. The maximum capacities for RR adsorption were 72.464 mg/g (pH = 2, 150 min, 303 K). CuAl-LDH/SA can be regenerated for 4 cycles with a percent removal of 29.32%. The adsorption process followed the intraparticle diffusion kinetics model and Langmuir isotherm. Thermodynamic studies showed that the adsorption of RR using CuAl-LDH/SA was endothermic and spontaneous. The results of this study indicate that CuAl-LDH/SA composite material shows potential material in the removal of anionic dyes from aqueous solutions. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Transformative Effects of Salinity on Sebkha Soil Properties: Unveiling Strength, Structure, and Stability through Advanced Remediation Strategies

This study investigates the effects of varying salinity levels on sebkha soils, focusing on their physical, mechanical, and chemical properties. Soil samples were collected from Tin silt sebkha in Ain M'lila across three different seasons, resulting in high salinity soil (HSS), medium salinity soil (MSS), and low salinity soil (LSS). The grain size distribution curves reveal that 70% of grains in both HSS and LSS have diameters less than 60 µm, with LSS containing 19% more particles smaller than 20 µm compared to HSS. Unconfined compressive strength (UCS) measurements show a significant decrease from 1100 kPa in LSS to 200 kPa in HSS, with corresponding peak strains increasing from 2.3% to 4.7%. Chemical analysis indicates that pH decreases from 8.17 in LSS to 6.79 in HSS, reflecting increased soil acidity with higher salinity. SEM images demonstrate that higher salinity results in a denser soil structure due to salt cementation, whereas lower salinity soils exhibit more micropores. The study highlights the need for comprehensive models integrating these properties to enhance predictive capabilities and inform effective soil management. Future research should explore remediation strategies using additives to improve soil strength and stability, addressing the challenges posed by salt dissolution and soil degradation.