Cation Exchange Research Articles

Cation exchange resin coupled with bacterial pretreatment to promote waste activated sludge reduction: Performance and mechanism

Due to the rapid advancement of industrialization and urbanization, there has been a significant rise in the generation of industrial wastewater and domestic wastewater, which results in the rapid increase of waste activated sludge (WAS). However, the complex structure and slow hydrolysis of sludge limit aerobic digestion of WAS. This study evaluated the effect of lysozyme-secreting strain Proteus mirabilis sp. SJ25 and the new isolation of surfactant-secreting strain Enterobacter cloacae sp. WH11 on the promotion of sludge hydrolysis, and introduced cation exchange resin (CER) to enhance the promotion effect. The reduction efficiencies of suspended solids (SS) and volatile suspended solids (VSS) enhanced by 25.0 and 24.9 %, respectively, and the soluble chemical oxygen demand (SCOD) release was increased by 2370.27 mg/L when the inoculum of strain SJ25 and strain WH11 were 3 % and 6 %, and the dosage of CER was 2.0 g/g SS against the control. The fluorescence region integral (FRI) results showed a significant quantity of dissolved organic matter (DOM) was let out, and the biodegradability of the sludge was improved. The alterations in several physicochemical characteristics of the sludge also suggested that the extracellular polymeric substances (EPS) were disrupted and an enormous quantity of sludge cells were lysed. In addition, functional gene prediction from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database indicated that CER coupled with bacterial pretreatment enhanced microbial metabolic capacity. This work suggests a novel pathway for the development of novel pretreatment methods to promote sludge hydrolysis.

Alkali and alkaline earth ion exchange affinity in ETS-10 toward aqueous lithium separation

Continuous ion exchange is a more sustainable alternative to current methods for removing common impurities from lithium sources. In this work, we examine ion-adsorbent interactions for Mg2+ and Ca2+ with microporous titanosilicate ETS-10, an ion exchange solid with promising performance, using experimental and computational (density functional theory, DFT) methods. Ion exchange affinity for Mg2+ and Ca2+ using the Na+-form of ETS-10 are quantified from measured equilibrium isotherms, analyzed using a modified Langmuir isotherm accounting for overall stoichiometric desorption/adsorption in the cation exchange process. The equilibrium constant for ion exchange using Na-ETS-10 is greatest for Ca and decreases in order of Mg, K, and Li, respectively. These differences in ion exchange affinity are consistent with trends in DFT-derived ion exchange energies, which account for hydration and solvation of cations using a thermochemical cycle. These equilibrium constant values and ion exchange energies suggest that exchange of Ca2+, Mg2+, and K+ using Na-ETS-10 is more favorable than that of Li+. Indeed, competitive ion exchange of equimolar aqueous mixtures of Li+ and each of K+, Mg2+, or Ca2+ demonstrate selective uptake of the non-lithium cation into the solid, thereby concentrating Li+ in the aqueous solution while removing impurity cations.

Experimental and molecular insights into ionic liquid-based recovery of valuable metals from spent lithium-ion batteries

A new type of collaborative extractants consisting of the ionic liquid (IL) 1-aminoprooyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide, ([APMIM][Tf2N]) and Cyanex 923 (C923) is first applied for selective extraction of valuable metals from spent lithium-ion batteries (LIBs). The one-stage extraction efficiencies of Co2+, Ni2+ and Mn2+ are up to 99.87 %, 97.74 %, 99.98 %, respectively, at the optimal conditions, and the high-purity Li+ was enriched at the raffinate. It is found that the extraction process follows the so-called “cation exchange mechanism”, and the molecular-level mechanism is revealed via quantum chemical (QC) calculations. The findings show that C923 plays the role of coordinating with metal ions, the cation of IL exchanges metal ions from the aqueous to organic phases, and the anion [Tf2N]- of IL can stabilize the complex species of metal ion-[Tf2N]--C923 in organic phase. This work provides new insights for the design of novel IL-based extractants for the recycling of spent LIBs.

Recovery of Gold Ions from Thiosulfate Solution Using an Electrogenerative Process

Traditional zinc powder cementation method for recovering gold ions from thiosulfate solution has the disadvantages such as high consumption of active metal, surface passivation, and co-deposition of copper ions. The key to solving these issues is providing the necessary electrons for the reduction of Au(S2O3)23- while avoiding direct contact between zinc powder and the leaching solution. In this study, a novel electrogenerative device with ion exchange membranes separating the anode and cathode is developed for the recovery of gold ions from thiosulfate solution. The oxidation reaction of zinc electrode occurs in the anode chamber, while the reduction reaction of gold ions occurs on a platinum electrode in the cathode chamber. The optimal experimental conditions for the gold recovery are determined to be using a cation exchange membrane, with the anode solution of 0.08M ZnSO4, pH = 6, and the cathode solution of 0.10M Na2S2O3, 5mM CuSO4, 0.5M NH3·H2O, pH = 10, with an initial gold concentration of 10mg/L. It obtains the gold recovery of 99.59%. Compared the zinc powder cementation method with the similar gold recovery, the electrogenerative process reduces zinc consumption by 67% and prevents the passivation on the zinc surface caused by copper, oxygen, and sulfur.

Soil application potential of post-sorbents produced by co-sorption of humic substances and nutrients from sludge anaerobic digestion reject water

This study introduces a novel soil conditioning approach using humic substances (HSs) and nutrients co-recovered from reject water from sewage sludge anaerobic digestion. For the first time, HSs and nutrients were simultaneously recovered through sorption on low-cost, environmentally inert materials: natural rock opoka (OP) and waste autoclaved aerated concrete (WAAC). This innovative application of OP and WAAC as carriers and delivery agents for soil-relevant substances offers potential for resource recovery and soil conditioning. Results indicate that the post-sorption opoka (PS-OP) and post-sorption waste autoclaved aerated concrete (PS-WAAC) effectively release retained HSs at 350–480 μg g⁻1 d⁻1, respectively. These materials also show potential as NPK fertilizers, releasing 280–430 μg g⁻1 d⁻1 N-NH₄⁺, 80–150 μg g⁻1 d⁻1 P-PO₄³⁻, and 270–350 μg g⁻1 d⁻1 K⁺. Additionally, PS-OP demonstrated promising fungicide properties, reducing P. diachenii growth by 31% at a concentration of 1 g L⁻1. A two-way ANOVA indicated that the effects of PS-OP and PS-WAAC on soil physicochemical and biological parameters varied with plant species. Both post-sorbents improved the quality of soil collected from sand mining area, increasing cation exchange capacity by 7%–85% and organic matter content by 10%–58%. They also enhanced the functional potential of soil microbial communities, increasing their metabolic activities by 23%–36% in soils sown with clover and by 33%–39% in soils sown with rapeseed. An opposite effect was observed in soils sown with sorghum, suggesting these amendments may not universally act as plant biostimulants. The effectiveness of these post-sorbents in enhancing plant growth varied depending on plant species and the mineral base of the post-sorbent. PS-OP increased the total length of clover and sorghum by 41% and 36%, and their fresh biomass by 82% and 80%, respectively. In turn, PS-WAAC increased the total length of clover and sorghum by 76% and 17%, and their fresh biomass by 29% and 15%, respectively. It was notably more effective than PS-OP for rapeseed. This study proposes a strategy to decrease reliance on non-renewable resources and costly sorbents while minimizing environmental impact. It shows that PS-OP and PS-WAAC can enhance soil quality, microbial activity, and plant growth. Given their origins, these amendments are recommended for soil remediation, particularly in degraded areas. Future research should focus on optimizing their application across various plant species to maximize effectiveness.

Preparation and Application of Weak Cation Exchange Resin Based on Thiol Click Reaction.

Using poly(styrene-divinylbenzene) microspheres as stationary phase matrix and mercaptosuccinic acid as a modifier, a new weak cation exchange resin was synthesized by thiol click reaction. The conditions for thiol-chlorine click reaction and thiol-alkene click reaction were optimized. The surface morphology and chemical composition of the modified microspheres were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and an elemental analyzer. The stationary phase can achieve the separation of six common cations within 25min. A homemade weak cation chromatographic column was used to determine the impurities of Na+ and K+ and the content of tetramethylammonium ions in tetramethylammonium hydroxide samples. The method showed a good linear correlation in the range of 0.1-500.0mg/L with correlation coefficients of 0.9998-0.9999, and the limits of detection (signal-to-noise ratio ≥ 3) were 0.01-0.20mg/L. The intra-day relative standard deviations (RSDs) were in the range of 1.1%-4.4%, and the inter-day RSDs were in the range of 0.8%-14.8%. The spiked recoveries were in the range of 91.92%-119.86%. The results showed that the prepared stationary phase exhibited effective separation ability and good reproducibility, which was suitable for the analysis of the impurities of Na+, K+, and the content of tetramethylammonium in the tetramethylammonium reagents.

Pelatihan Pembuatan Pupuk Hayati di Desa Gondel, Kecamatan Kedungtuban, Kabupaten Blora, Jawa Tengah

The rice productivity in Gondel Village, Kedungtuban District, Blora Regency, Central Java, has declined. Factors such as attacks by plant pests and diseases (OPT), climate change (DPI) impact, and decreasing soil quality are the leading causes of crop failure. This training aims to enhance the understanding and skills of Gondel Village farmers in making biofertilizers and introducing environmentally friendly pest and disease control methods. The activity involved 40 farmers from 8 farmer groups (Gemah Ripah, Margo Mulyo, Ngudi Makmur, Sido Dadi, Sido Makmur, Tambah Makmur, Tambah Rizki, and Sri Mulyo), with each group represented by five farmers. The training methods included analysis of soil chemicals, socialization, practical propagation of Trichoderma sp. on rice media, and biofertilizer production. Pre-test and post-tests were conducted to assess the improvement in farmers' knowledge. Trichoderma biofertilizer was formulated using carriers such as a) Manure and b) Compost, zeolite, and humic acid. The results of the soil chemical properties analysis showed that farmers' use of chemical fertilizers was very intensive, resulting in very high levels of phosphorus (P) and calcium (Ca) and high levels of potassium (K), magnesium (Mg), and cation exchange capacity (KTK). Evaluation results indicated that the training significantly improved the farmers' knowledge of biofertilizer production in theory and practice. However, some farmers still need further guidance on the propagation of the biological agent Trichoderma sp.

Physicochemical characteristics of andisols and their correlation to potato yield based on land mapping units

The high phosphate retention in andisol soil is often associated with a decrease in potato yield. Additionally, identification of the physical and chemical characteristics of andisols and their correlation to potato yield through soil mapping units (SMUs) is necessary to facilitate field surveys. Therefore, this study aimed to identify the physicochemical characteristics of andisols with a focus on available phosphorus (P) and the correlation to potato production based on SMUs. The experiment was conducted in Karo District, North Sumatra, Indonesia, from July 2022 to February 2023. A descriptive-analytical method was used by overlaying maps of slope, soil types, and altitude until 10 SMUs were selected that were planted with potatoes. Soil physicochemical properties were identified, while Pearson correlation analysis was performed on available-P and potato yield using IBM SPSS software. The results showed that the silt and clay fractions positively correlated with available-P in andisols. All soil physical characteristics were categorized as very weak to weak in supporting potato yield. A total of four SMUs including 1, 5, 8, and 10 were found to have lower available-P and very low to moderate correlations with soil pH, organic-C, C:N ratio, cation exchange capacity (CEC), as well as total-P. Based on the results, potato yield could increase by 1.765 and 0.380 tons ha-1 through the addition of organic-C and C:N ratio in Karo District. Therefore, soil amendment is required as an alternative to improve andisols soil.

Microstructural Evaluation and Linkage to the Engineering Properties of Metal-Ion-Contaminated Clay

The rapid progress of urbanization and industrialization has led to the accumulation of large amounts of metal ions in the environment. These metal ions are adsorbed onto the negatively charged surfaces of clay particles, altering the total surface charge, double-layer thickness, and chemical bonds between the particles, which in turn affects the interactions between them. This causes changes in the microstructure, such as particle rearrangement and pore morphology adjustments, ultimately altering the mechanical behavior of the soil and reducing its stability. This study explores the effects of four common metal ions, including monovalent alkali metal ions (Na+, K+) and divalent heavy metal ions (Pb2+, Zn2+), with a focus on how ion valence and concentration impact the soil’s microstructure and mechanical properties. Microstructural tests show that metal ion incorporation reduces particle size, increases clay content, and transforms the structure from layered to honeycomb-like. Small pores decrease while large pores dominate, reducing the specific surface area and pore volume, while the average pore size increases. Although cation exchange capacity decreases, cation adsorption density per unit surface area increases. Monovalent ions primarily disperse the soil structure, while divalent ions induce coagulation. Macro-mechanical tests reveal that metal ion contamination reduces porosity under loading, with compressibility rises as the ion concentration increases. Soils contaminated with alkali metal ions shows higher compression coefficients at all loads, while heavy metal ions cause higher compression under lower loads. Shear strength, the internal friction angle, and cohesion in metal-ion-contaminated clay decrease compared to uncontaminated field-state clay, with greater declines at higher ion concentrations. The Micropore Morphology Index and hydro-pore structural parameter effectively characterize both micro- and macrostructural properties, establishing a quantitative relationship between HPSP and the engineering properties of metal-ion-contaminated clay.

Unravelling Coupled Hydrological and Geochemical Controls on Long-Term Nitrogen Enrichment in a Large River Basin.

Many groundwater and surface water bodies around the world show a puzzling and often steady increase in nitrogen (N) concentrations, despite a significant decline of agricultural N inputs. This study uses a combination of long-term hydrogeochemical and hydraulic monitoring, molecular characterization of dissolved organic matter (DOM), column experiment, and reactive transport modeling to unravel the processes controlling N-reactive transport and mass budgets under the impacts of dynamic hydrologic conditions at a field site in the central Yangtze River Basin. Our analysis shows that the desorption of ammonium (NH4+) from sediments via cation exchange reactions dominates N mobilization and aqueous N concentrations, while the mineralization of organic N compounds plays only a minor role. The reactive transport modeling results illustrate the important role of cation exchange reactions that are induced by temporary NH4+ input and cation concentration changes under the impact of both seasonal and long-term hydrologic variations. Historically, cation exchangers have acted as efficient storage devices and mitigated the impacts of high levels of NH4+ input. The NH4+ residing on cation exchanger sites later acts as a long-term N source to waters with the delayed desorption of sediment-bound NH4+ induced by the change of hydrologic conditions. Our results highlight the complex linkages between highly variable hydrologic conditions and NH4+ partitioning in near-surface, river-derived sediments.

Efficient Defect-Driven Cation Exchange beyond the Nanoscale Semiconductors toward Antibacterial Functionalization.

Defect engineering is an exciting tool for customizing semiconductors' structural and optoelectronic properties. Elaborating programmable methodologies to circumvent energy constraints in multievent inversions expands our understanding of the mechanisms governing the functionalization of nanomaterials. Herein, we introduce a novel strategy based on defect incorporation and solution rationalization, which triggers energetically unfavorable cation exchange reactions in extended solids. Using Sb2X3 + Ag (I) → Ag: Sb2X3 (X= S, Se) as a system to model, we demonstrate that incorporating chalcogen vacancies and AgSbVX complex defects into initial thin films (TFs) is crucial for activating long-range solid-state ion diffusion. Additional regulation of the Lewis acidity of auxiliary chemicals provides an exceptional conversion yield of the Ag precursor into a solid-state product up to 90%, simultaneously transforming upper matrix layers into AgSbX2. The proposed strategy enables tailoring radiative recombination processes, offers efficiency to invert TFs at moderate temperatures quickly, and yields structures of large areas with substantial antibacterial activity in visible light for a particular inversion system. Similar customization can be applied to most sulfides/selenides with controlled reaction yields.

Geochemical study of heavy metals in samples from dumpsites at Onitsha, Anambra Basin, Southeastern Nigeria

Core (0-60cm) samples were collected from selected dumpsites at Onitsha and control site at Awka, Nigeria. Physiochemical parameters (particle size distribution, cation exchange capacity (CEC), pH, Organic Matter (OM in %)) and heavy metals (Lead (Pb), Copper (Cu), Zinc (Zn), Chromium (Cr), Nickel (Ni), Aluminium (Al), Cobalt (Co), Molybdenium (Mo), Cadmium (Cd), Manganese (Mn) and Silicon (Si)) were analyzed using standard methods. The result of the physiochemical analysis shows that the samples were generally sandy with acidic pH values (4.89-6.24); OM ranged from 5.693-27.71%; CEC ranged from 0.072-0.62(Cmol/kg). Comparatively, DS 5 (Obosi) has the highest levels of these heavy metals followed by DS 2 (Woliwo). The order is Bida < Okpoko <Obosi 1 < Woliwo < Obosi 2. The levels of these heavy metals were above the control values. They were equally above national and international guidelines. Enrichment Factor (EF) values varied between no enrichment to extremely severe enrichment. Pollution load index (PLI) indicated that all the sampled sites were polluted while the ecological risk of heavy metals varied between low contamination to high contamination. The prevailing indiscriminate disposal of wastes occasioned by nonexistence of appropriate disposal facilities is the direct cause of the situation. Proactive measures and regular environmental monitoring must be taken to minimize further deterioration as the contaminants pose serious deleterious effects on human and soil organisms.

Groundwater Geochemistry in the Karst-Fissure Aquifer System of the Qinglian River Basin, China

The Qinglian River plays a significant role in China’s national water conservation security patterns. To clarify the relationship between hydrogeochemical properties and groundwater quality in this karst-fissure aquifer system, drilling data, hydrochemical parameters, and δ2H and δ18O values of groundwater were analyzed. Multiple indications (Piper diagram, Gibbs diagram, Na+-normalized molar ratio diagram, chloro-alkaline index 1, mineral saturation index, and principal component analysis) were used to identify the primary sources of chemicals in the groundwater. Silicate weathering, oxidation of pyrite and chlorite, cation exchange reactions, and precipitation are the primary sources of dissolved chemicals in the igneous-fissure water. The most relevant parameters in the karst water are possibly from anthropogenic activities, and other chemicals are mostly derived from the dissolution of calcite and dolomite and cation exchange reactions. Notably, the chemical composition of the deep karst water from the karst basin is mainly influenced by the weathering of carbonate and cation exchange reactions and is less affected by human activities. The hydrogeochemical properties of groundwater in the karst hyporheic zone are influenced by the dissolution of carbonates and silicates, evaporation, and the promotion effect of dissolution of anorthite or Ca-containing minerals. Moreover, the smallest slope of the groundwater line from the karst hyporheic zone among all groundwater groups revealed that the mixing effects of evaporation, isotope exchange in water–rock interaction or deep groundwater recharge in the karst hyporheic zone are the strongest. The methods used in this study contribute to an improved understanding of the hydrogeochemical processes that occur in karst-fissure water systems and can be useful in zoning management and decision-making for groundwater resources.

Screening of Cation Exchange Membranes for an Anthraquinone‐Ferrocyanide Flow Battery

AbstractThe disodium salt of 9,10‐anthraquinone‐2,7‐disulphonic acid (2,7‐AQDS) is an interesting platform for developing anthraquinone derivative negolytes for aqueous organic flow batteries. Recently, ammonium sulphate supporting electrolytes have been considered for improved stability and solubility. This work advances the 2,7‐AQDS/ferrocyanide flow battery with an ammonium sulphate supporting electrolyte (pH 5) by studying the suitability of six commercially available cation exchange membranes: E‐620, NR‐212, FS‐930, F‐1075‐PK, F‐1850 and N‐115. Cell cycling under galvanostatic regime plus potential hold was performed to determine coulombic efficiency, energy efficiency and accessible capacity for each membrane as well as capacity fade rate for three selected membranes under extended operation. Cell cycling under galvanostatic control only was carried out to observe transient membrane behavior alongside accessible capacity and apparent capacity fade rate. It was found that the capacity set by the limiting negolyte is consistent with 1.5 electrons per 2,7‐AQDS molecule and that energy efficiency shows a simple direct relationship to membrane thickness, with one exception. Meanwhile, four membranes displayed similar apparent capacity fade rates at this laboratory scale irrespective of their thickness, with capacity loss explained in terms of crossover. The best overall performance was attained by the thinnest membranes, E‐620 and NR‐212.

Spatial pattern, source apportionment, and source-oriented health risk quantifying of heavy metals in farmland soils of southern China.

The contamination of heavy metal has permeated many parts of China, especially in densely populated and industrialized southern China. This study focused on the degree of pollution in farmland soil heavy metals (HMs), and its spatial distribution characteristics and source apportionment. Meanwhile, we conducted an evaluation of the health risks attributed to soil HMs and analyzed the factors that impact them. We found that the distribution of five heavy metals is mainly concentrated in the east-central and southern parts of the study area. Specifically, Cd and Hg have high levels of pollution and present potential ecological risks. The pollution sources of five HMs were analyzed utilizing positive matrix factorization. The results revealed that the contribution of different sources keeps the following order: natural source (42.42%), agricultural activities (29.93%), industrial pollution source (20.49%), and atmospheric deposition pollution (7.16%). The non-carcinogenic risks to residents were acceptable, whereas the carcinogenic risks were relatively high. Children and the elderly are more vulnerable to the negative effects of Cr, As. Using structural equation modeling, we found soil property is a vital factor affecting soil contamination, with the soil organic matter and cation exchange capacity having a relatively greater impact on heavy metals pollution. Our study provides some data reference and guidance for soil ecological protection and restoration.

Toward circular greenhouse wastewater reuse: advancements in cation exchange membranes for selective Na+/K+ separation using electrodialysis systems

ABSTRACT Driven by the growing need for alternative water sources and forthcoming stringent nutrient discharge regulations, there is growing interest in developing selective membrane solutions to facilitate circular greenhouse wastewater reuse (as emphasized in the European Union's Horizon 2020 ULTIMATE project). For electrodialysis systems, sodium (Na+) over potassium (K+) selective membranes are essential to achieve minimal liquid discharge. This study addresses the challenge of developing selective, efficient, and scalable Na+/K+ cation exchange membranes. State-of-the-art cation exchange membrane developments were reviewed and the functionalization of commercial membranes with crown ethers was identified as a promising approach. Two crown ether–modified membranes (15-crown-5 (15C5) and 18-crown-6 (18C6)) were developed, characterized, and tested in equimolar and greenhouse wastewater binary feed ratios. While the results demonstrated low overall selectivity, the 15C5-modified membrane showed a marginal enhancement in K+ selectivity, suggesting the need for further optimization. The study concludes with recommendations for the future development of Na+/K+ selective membranes, highlighting the potential of machine learning approaches to expedite progress. This research provides a foundational step toward practical and scalable Na+/K+ ion separation solutions, for achieving minimal liquid discharge in greenhouse horticulture.

High-entropy alloy-enhanced ZnCdS nanostructure photocatalysts for hydrogen production

High-entropy alloys (HEA) have been shown to be potential cocatalysts for photocatalysis, but the design of ideal semiconductor/HEA composite photocatalysts is challenging due to the complexity of their composition and the interactions within multi-element systems. To address this issue, PtCuFeNiCo HEA was selected as a cocatalyst, and a ZnCdS/PtCuFeNiCo (abbreviated as ZnCdS/HEA) nanostructured photocatalyst was designed for hydrogen production from water splitting. ZnCdS/HEA was prepared using a simple liquid-phase precipitation method, a template-assisted cation exchange method, and an ultrasound-assisted recombination method. Photocatalytic experiments showed that the hydrogen production activity of ZnCdS/HEA under visible light was 5.99 mmol·g−1·h−1, which is 11.7 times that of ZnCdS and significantly higher than that of ZnCdS/Pt. Experiments and density functional theory calculations indicated that ZnCdS/HEA formed a Schottky heterojunction. The performance enhancement was attributed to the synergistic effect between PtCuFeNiCo HEA and ZnCdS, which enhanced light absorption, improved the separation and transfer of photogenerated electrons and holes, as well as provided abundant catalytic active sites and increased surface reaction activity. This study highlights the potential of HEAs and provides theoretical and experimental references for the rational design of efficient semiconductor/HEA composite materials.

Technosols Made from Iron Mine Tailings and Construction and Demolition Waste as an Alternative for Sustainable Solid Waste Management

ABSTRACTBrazil faces urgent environmental challenges due to large waste production from mining and construction activities particularly regarding the disposal and management of the solid waste generated by these activities. The extraction of iron ore and the storage of tailings in dams, most of which are at imminent risk of rupture, represent foretold environmental disasters. Additionally, the disposal of construction waste raises environmental concerns due to the decreasing vailability of inert landfill space. To address these challenges, we evaluated the potential of Technosols made from construction and demolition waste (CDW) and iron mining tailing (IMT) in different proportions (60:40, 70:30, 80:20, and 100% of IMT and CDW, respectively) to support grass development. The Technosols were compared to a natural soil (Haplic Ferralsol). The soils were cultivated with Urochloa brizantha cv. Marandu in a field experiment conducted for 120 days. At the end of experiment, soil samples were collected and analyzed their chemical, physical, and mineralogical attributes, while plants were analyzed for dry biomass. Plants cultivated in Technosols exhibited dry biomass production 3.3‐fold (825 ± 270 g) greater than those cultivated in the natural soil (251 ± 77 g). Higher biomass production in the Technosols, especially in the TEC70:30, was associated with the favorable chemical conditions of these soils, such as slightly neutral pH (~7.5), higher cation exchange capacity (68.1 ± 12.4 mmol dm−3) and nutrient availability, especially Ca and P (57.8 ± 0.8 and 28.2 ± 0.4 mmol dm−3, respectively). These results aim to provide insights for the effective use of different Technosols in mitigating environmental impacts and promoting sustainable land and waste management practices, primarily to prevent future environmental disasters.

Interlayer Hydrogen Recombination from Hydrogen Boride Nanosheets Elucidated by Isotope Labeling.

In this study, deuterium boride (DB) nanosheets were synthesized as deuterated borophane through the ion exchange of magnesium cations in magnesium diboride with deuterons from a deuterium-type ion-exchange resin in acetonitrile. The Fourier-transform infrared absorption spectrum of DB exhibited clear isotope effects, namely the shift in the absorption peak of the B-H stretching vibrational mode to a lower wavenumber. Temperature-programmed desorption (TPD) from a mixture of DB and hydrogen boride (HB) nanosheets yielded a more intense hydrogen-deuterium (HD) signal compared to the H2 and D2 signals. This indicates that the release of hydrogen molecules from the HB nanosheets upon heating originated from interlayer hydrogen recombination rather than intralayer hydrogen recombination. TPD analysis of HB with graphene in different mixing ratios confirmed that the interlayer reaction is predominant in the lower-temperature (<623 K) regime. Meanwhile, the intralayer reaction could proceed in the higher-temperature (>623 K) regime, where hydrogen recombination occurs following H migration on the HB nanosheets.

Appraisal of groundwater suitability for drinking and irrigation utilities in the Cooum River basin, South India: Implications from uranium, nitrate, and fluoride health risks

The study reveals that 6% of groundwater samples exceed the WHO's recommended fluoride limit of 1.5 mg/L, and 15% surpass the nitrate standard of 45 mg/L, rendering the water unsuitable for drinking. Gibbs plot analysis identifies evaporation as the dominant factor affecting groundwater chemistry, while the Piper diagram classifies the water into mixed Ca–Mg–Cl and NaCl types, indicating natural processes and potential seawater intrusion. Cation exchange processes are observed in 75.5% of samples, as shown by Schoeller's indices. The hydrochemical facies evolution suggests freshening from recharge in most samples, with signs of salinity intrusion in others. Between 2010 and 2023, land use and land cover (LULC) changes show a significant increase in built-up areas, resulting in reduced groundwater recharge and heightened pollution risks. The classification accuracy is high, with an overall accuracy of 82.20% and a Kappa coefficient of 83.06%. Water Quality Index (WQI) assessment reveals that 47% of the groundwater samples are excellent for drinking, while 20.6% are suitable. Although 80% of the groundwater remains appropriate for agriculture, the study highlights the need for targeted groundwater management to address urbanization impacts and mitigate health risks from elevated nitrate ingestion, particularly for vulnerable populations such as children.