High Cation Exchange Capacity Research Articles

Peanut cultivar response to residual soil test potassium in North Mississippi

AbstractThe average U.S. peanut (Arachis hypogaea L.) yield has increased by approximately 25% with the adoption of peanut cultivar ‘Georgia‐06G’. Since this adoption, many new high yielding runner cultivars with similar yield potential have been released. However, current nutrient recommendations are based on soil tests that were developed prior to the release of Georgia‐06G. Particularly for potassium, current soil test potassium (STK) critical values were established on soil textures with relatively low cation exchange capacity (CEC) but were not validated on soil textures with high CEC. This study aimed to evaluate the growth and yield response of five recently released peanut cultivars to four STK levels ranging from very low to medium based on Mississippi State University Extension soil testing recommendations. The STK classification levels were also based on two soil series categorized with high CEC—Leeper (∼38.4 meq 100 g−1) and Marietta (∼15.9 meq 100 g−1) soil series. Cultivars Georgia‐06G, ‘Georgia‐16HO’, ‘Georgia‐18RU’, FloRun ‘331’, and ‘AU‐NPL‐17’ were evaluated in this study. No STK × variety interaction occurred, indicating similar K requirements across all varieties evaluated. However, a positive pod yield response occurred in both soil types when the average STK increased from 128 to 167 lbs ac−1 for all cultivars and site years. Critical STK values on both soils were greater than many current Extension recommendations, and the critical STK value of Leeper is greater than the Marietta soil series, likely due to the higher CEC value. These results demonstrate the need to adjust peanut STK sufficiency levels based on soil CEC. Further evaluation of modern peanut cultivar productivity response to STK sufficiency levels is needed for soils with moderate CEC.

Enhancing Growth and Health in Weanling Pigs: The Impact of Monzogranite Supplementation.

Monzogranite is known for its high surface area and cation exchange capacity, which play a crucial role in ameliorating the challenges by enhancing nutrient adsorption and facilitating nutrient availability during the weaning period. Weaned crossbred piglets (Duroc × Yorkshire × Landrace), initially weighing 5.36 ± 0.26 kg, were allocated into four treatments with 6 replicates each (10 pigs per replicate). The treatments encompassed CON (basal diet), Z0.1 (0.1% monzogranite supplementation in basal diet), Z0.2 (0.2% monzogranite supplementation), and Z0.3 (0.3% monzogranite supplementation). In phase 1, a linear increase in total average daily gain (ADG) was observed across treatment groups, with a concomitant linear increase in ADG and gain-to-feed ratio (G/F). The overall results showed a linear increase in ADG and G/F. A linear decrease in aspartate aminotransferase and lactate dehydrogenase levels was observed across treatment groups. Conversely, no significant differences were noted in the levels of albumin, alkaline phosphatase, alanine aminotransferase, high-density lipoprotein, low-density lipoprotein, total cholesterol, blood urea nitrogen, triglycerides, and gamma-glutamyl transferase among the treatment groups. Faecal scoring indicated a linear reduction in scores at Day 7 among the treatment groups. However, no significant differences were observed at Days 14 and 28. The assessment of immunoglobulins demonstrated a significant increase in both immunoglobulin G and immunoglobulin A levels in the Z0.1 treatment group compared to the CON. In both phase 1 and phase 2, a linear decrease in cortisol levels was evident. In conclusion, a linear increase in total ADG and G/F during phase 1, sustained across both phases, suggests monzogranite potential to enhance growth performance. Moreover, stress mitigation was shown through a consistent linear decrease in cortisol levels across phases. These findings underscore monzogranite multifaceted impact, emphasizing its potential as a dietary supplement to enhance growth, liver health, and stress resilience in weanling pigs.

Dissolution process and mechanism of montmorillonite in oxalic acid and sulfuric acid media at various pH levels

The dissolution of silicate minerals plays a crucial role in many natural geological processes. In order to better comprehend the reaction mechanisms and dissolution characteristics of montmorillonite in different acidic systems, the effects of interfacial reactions of montmorillonite with oxalic and sulfuric acid solutions at various pH levels on the ionic dissolution, crystal structure, and micro-morphology were studied, and the morphology of aluminum and saturation index of secondary mineral were simulated. It was shown that the dissolution amounts of Mg2+, Al3+ and Si4+ in montmorillonite structure decreased with the increase of pH value, which reflected the dependence of montmorillonite dissolution on the pH value of solution. The dissolution percentages of Mg2+, Al3+ and Si4+ after the reaction of montmorillonite with oxalic acid solution were greater than those in sulfuric acid solution, and the highest dissolution rate of Al3+, indicated that both ligands and protons attacked the surface sites of montmorillonite and accelerated the dissolution of ions. Moreover, oxalate ligands exerted specific binding effects on Al3+ ions. While reacting with oxalate and sulfate, the tetrahedral, octahedral and interlayer cations of montmorillonite exhibited the non-stoichiometric and inconsistent dissolution. The oxalate ligands have a strong complexation effect on Al3+, so that Al3+ in oxalate solution exists in the form of aluminum oxalate complex, which reduces the effective concentration of Al3+ in solution and promotes the dissolution of Al3+ in montmorillonite structure. The Mg2+ ions settled at octahedral substitution sites possessed weak stability, while those from the interlayer featured strong interlayer interchangeability, demonstrating the dissolution percentage up to 10.85 % and 8.62 % even in oxalic and sulfuric acid solutions at pH of 6.5. All secondary mineral phases in the solution were undersaturated, making the montmorillonite dissolution difficult to balance. Montmorillonite has a high cation exchange capacity, which makes it have a strong buffer capacity to exogenous acids. This study helps to explain the dissolution process of montmorillonite in inorganic and organic acid solutions at different pH value.

Effect of Three Different Types of Biochar on Bioelectricity Generated from Plant Microbial Fuel Cells under Unsaturated Soil Condition.

Plant microbial fuel cell (PMFC) is an emerging technology, showing promise for environmental biosensors and sustainable energy production. Despite its potential, PMFCs struggle with issues like low power output and limited drought resistance. Recent studies proposed that integrating biochar may enhance PMFC performance due to its physicochemical properties. The influence of different biochar types on PMFC efficiency has been minimally explored. This study aims to fill this gap by evaluating the performance of PMFCs integrated with various biochar types under unsaturated soil conditions. The study found that the addition of biochar types─specifically reed straw biochar (RSB), apple wood biochar (AWB), and corn straw biochar (CSB)─significantly influenced the performance of PMFCs. RSB, with its large surface area and porous structure, notably increased the current output by reducing soil resistance and enhancing electron transfer efficiency in microbial reduction reactions, achieving a peak power density of approximately 1608 mW/m2. AWB, despite its less porous structure, leveraged its high cation exchange capacity and hydrophilic functional groups to foster microbial community growth and diversity, thereby also increasing bioelectricity output. Conversely, CSB, with its large surface area, showed the least improvement in PMFC performance due to its layered structure and lower water retention capacity. Additionally, under drought conditions, PMFCs with added RSB and AWB exhibited better drought resistance due to their ability to improve soil moisture characteristics and enhance soil conductivity. The addition of biochar reduced soil resistance, increasing the bioelectric output of PMFCs and maintaining good performance even under low moisture conditions. This study highlights the critical role of biochar's surface area and functional groups in optimizing PMFC performance. It enhances our understanding of PMFC optimization and might offer a novel power generation method for the future, while also presenting a fresh strategy for soil monitoring.

Sorption interactions and behavior of bentonite-lignite based composite toward immobilization of dyes, pharmaceuticals and surfactants

The presence of dyes, pharmaceuticals, and surfactants in the environment results from extensive industrial and societal progress, prompting the need to explore efficient and safe techniques for their removal. Common concentrations in wastewater can range from micrograms to milligrams per liter, which is concerning due to their persistence and potential health impacts. The sustainable approach of using a nonconventional, eco-friendly mineral-organic composite might address this environmental issue. This study focuses on utilizing a composite of bentonite (BEN) and lignite (LIG) as a sorbent for dyes: Rhodamine b (RB), Remazol brilliant blue r (RBBR), pharmaceuticals: ibuprofen (IB), sulfamethoxazole (STX), and surfactant: sodium dodecylbenzenesulfonate (SDBS) from both synthetic solutions and real wastewater. BEN was chosen for its high cation exchange capacity, while LIG was selected for its ability to adsorb both anionic and cationic formsdiverse functional groups. The composite with BEN to LIG ratio of 20:80 (BL 20:80) demonstrated superior sorption capacity. The adsorption performance is quantified, showing removal efficiencies of up to 18.9 mg RBBR/g, 22.8 mg RB/g, 1.77 mg IB/g, 1.47 mg STX/g, and 4.7 mg SDBS/g. Sorption efficiency is influenced by factors such as the initial sorbate concentration, the pH of the solution, the form of sorbates, and the adsorbents textural, physicochemical (point of zero charge pHZPC), ion-exchange capacity, hydrophobicity/hydrophilicity) properties. Generally, STX and RB is favored by slightly acidic conditions (pH 4-7), while RBBR and IB are favored by alkaline conditions (pH >7). The complex physical sorption mechanism includes hydrogen bonding, electrostatic and dispersion forces, as well as π-π interactions. Nuclear magnetic resonance spectroscopy (NMR) suggests that a significant portion of the hydrogen bonding interactions contributes to RB adsorption. The sorption results indicate that the specially-designed mineral composite can effectively remove various chemically distinct organic compounds from real wastewater. Subsequent investigations will focus on the granulated BL 20:80 composite and its applicability in dynamic column systems. This aligns with the ongoing development of purification technologies.

Assessment of the benefits and risks of sewage sludge application as soil amendment for agriculture in Eswatini

Sewage sludge is an important soil conditioner, and source of nutrients with a potential for use in agriculture. However, such benefit needs to be weighed against the risks due to the presence of heavy metals, and other substances that may endanger human health, plants, soil and the ecosystem. This research had the objective of evaluating the agricultural potential of sewage sludge together with the risks that may be present in use. Samples of sewage sludge from seven wastewater treatment plants in Eswatini were analyzed for selected physical and chemical parameters, and heavy metal concentrations using commonly established laboratory procedures. The analysis results indicated that, sludge samples exhibited high organic matter content, cation exchange capacity, macro nutrients such as nitrogen and phosphorus and micro nutrients (trace metal elements) needed for plant growth. Anaerobically digested sludge samples showed higher carbon to nitrogen ratio because of biomass loss in the form of methane and carbon dioxide. The heavy metal concentrations are all within safe limits except the sludge from Matsapha area that had levels of chromium, and nickel above regulatory limits. With respect to their heavy metal contents, most of the sludge samples would qualify as Class A sludge ready to be used as organic fertilizer for agriculture without regular monitoring of heavy metals in the soil to which they are applied. The study results indicated the importance of sewage sludge for their agricultural potential through supplementation of both micro and macro nutrients needed for plant growth, for improving the soil properties such as water holding capacity and permeability, through the increase of organic matter content, and retention of nutrients due to the high cation exchange capacity. All these benefits are realized with sewage sludge being a lower cost alternative to commercial fertilizers. Moreover, the low concentration of heavy metals present in the sludge presents lower risk that may arise in the course of utilizing the sludge as agricultural supplement. Key words: Agriculture, fertilizer, heavy metals, nutrient, sewage, sludge, nitrogen, phosphorous

Zn-doped bentonite catalysts for waste engine oil cracking: Thermal treatment offers a cleaner alternative to acid activation

This study investigates the cracking of waste engine oil (WEO) using bentonite clay (BC) activated through acid and thermal methods, as well as with Zn-doped BCs. Acid activation with 1 M HCl and Zn doping did not alter the BC catalyst’s structure. XRD and SAED analyses confirmed the crystallinity, while TEM showed partial destruction of the layered structure. XRF analysis indicated reduced Al and Si content upon Zn-doping due to high cation exchange capacity. Zn-doping decreased surface area and pore volume but increased acidic sites in acid-treated catalysts, although Zn suppressed these sites in calcined BC. Zn-doped catalysts displayed higher thermal stability. Cracking WEO at 450 °C for 45 min, with and without catalysts, yielded high liquid product recovery (72.6 %–82.8 %), primarily carboxylic acids and aromatics. This demonstrates the potential of Zn-doped BC as an effective catalyst for converting WEO into valuable products, aiding waste management and resource utilization.

(Invited) Zwitter Ion-Promoted Hybrid Sepiolite Membranes for Energy Applications

Functionalized natural clays exhibit significant potential as electrode materials, solid-state electrolytes and separators in energy storage and conversion devices. Features that evoke interest in clay minerals are their (1) porous structures and adsorption properties, (2) tunable surface areas, (3) remarkable thermal and mechanical stabilities, (4) abundant natural reserves, and (5) cost. By tweaking such features along with functionalization with desired molecules, they can be used as an ideal candidate for solid-state electrolyte and battery separators. Naturally occurring clays possess layered silicate structures with interchangeable, intercalated ions and tunable chemical properties. Among them, sepiolite, which is a hydrated magnesium silicate, is one of the most appealing clays having a high-aspect ratio. The blocks and channels in sepiolite with discontinuity in the external silica sheet expose a significant number of surface-silanol groups directly accessible to functionalize with organic and inorganic species. Moreover, its exceptionally high surface area and high cation exchange capacity (CEC) compared to other clays enables easy functionalization, thereby imparting exceptional mechanical durability and material properties that can be used for myriads of applications.In this work a sustainable, cost-effective, environmentally benign, carbon-neutral, and bio-friendly sepiolite clay composites have been developed using betaine and ionic liquid without the use of polymers, metals, or carbon-based precursors.Betaine-modified sepiolite clay composites have been synthesized to fabricate flexible and mechanically robust membranes. These membranes are characterized using powder X-ray diffraction, ATR-FTIR, XPS, surface area analyses, rheology, and imaging techniques (e.g., SEM). Morphological analyses reveal sepiolite possesses needle-shaped morphology in a highly aggregated state. The addition of betaine disaggregates such bundles, forming a 3D network with unique “clay anemone” structures. The XRD patterns are consistent with the literature reflecting no change in the d-spacing and corresponding 2θ value (d100 2θ = 7.4 ͦ) before and after betaine treatment. This provides strong evidence of modification limited to the external surface. ATR-FTIR spectra of the sepiolite-betaine composite membranes show the presence of 935, 1330,1391, and 1616 cm-1 frequencies that correspond to C-N-C, N-C-H, C-N and C=Ostretching respectively. This suggests the successful functionalization of sepiolite clay by betaine through an intercalation mechanism. Further, the electrochemical properties of betaine-modified sepiolite membranes are investigated by electrochemical impedance spectroscopy (EIS) measurements to study the ion dynamics of the hybrid membranes. The room temperature ionic conductivities of these membranes are measured using lithium perchlorate (LiClO4) in ethylene carbonate (EC) and dimethyl carbonate (DMC) mixed solvent (1:1). The concentration of LiClO4 is varied to monitor the change in ionic conductivity and ease of ion transfer through the membranes. The highest ionic conductivity is observed in 0.1M LiClO4 concentration which is superior to the ionic conductivity of sepiolite or hybrid materials with carbon-based precursors, metal ions, quantum dots, or polymers. Viscoelastic properties of the sepiolite slurries with varying concentrations of betaine are also studied to investigate the interaction mechanism between the sepiolite-betaine system and correlate the impact of these interactions on the structure and ionic conductivity of the hybrid sepiolite membranes. Contrary, the IL-sepiolite membranes exhibit superior ionic conductivity compared to betaine-sepiolite membranes, which gives a distinct advantage in the physicochemical and electrochemical properties. The composites are synthesized with varying concentrations of ionic liquid-to-clay ratios and pressed into pellets for conductivity measurements. The highest ionic conductivity of 1 x 10-2 S/cm is achieved by modifying the clay with 10 wt. % IL specimens. This helps to improve the ionic conductivity of the IL-clays. The XRD spectra of sepiolite-IL composites show almost no change in the 2 theta values and peak intensities compared to the pristine sepiolite, confirming the crystalline structure of the sepiolite clay is intact after functionalization with IL. The ATR-FTIR confirms the IL-sepiolite modification with the appearance of a new band at 1345 cm-1 that is attributed to -CH stretching frequencyfrom the alkyl chains of IL present in the clay structures.We have developed a new approach using earth-abundant silicate-based materials to synthesize hybrid zwitterion-modified sepiolite clay membranes. Such materials are not only flexible and mechanically durable, but they also exhibit enhanced ionic conductivity and show exceptional thermal and chemical durability at temperatures above 300 °C and with most aggressive organic solvents, making them a superior candidate for an ergonomic and eco-friendly membrane-based separator for energy devices and gas absorption. Current work is in progress to understand the fundamentals underlying the unique structure-property relationship of hybrid sepiolite, zwitterion-silicate interactions, and conductivity variance with sepiolite architectures, thereby exploiting newer and better properties for application in catalysis, flexible electronics, and biomedical fields. Figure 1

Effects of aging processes on spent mushroom Substrate-Derived Biochar: Adsorption characteristics of Cd(II) and Cr(VI)

To explore how chemical, physical and biological process impact the adsorption capacity of biochar for cations and anions, five kinds of spent mushroom substrate biochars including PB (carbonized Auricularia auricula substrate at 600 °C for 6 h), NB (Aged PB at 25 °C and 40 % moisture for 12 mon), AB (PB treated with 20 % mixed acid solution at 70 °C for 6 h), FB (PB subjected to 16 freeze–thaw cycles between − 20 °C and 25 °C) and MB (PB incubated with microbes from contaminated soil for 15 cycles) were prepared under simulated conditions, the internal mechanisms were revealed. Results showed that all aging processes caused a variation in crystal quantity and structure on different biochar. AB, NB and MB had higher hydrophilicity and polarity, and more positive charges than PB. Moreover, AB and MB had a higher cation exchange capacity (CEC) (70.7 and 75.3 cmol/kg) and more oxygen-containing functional groups than PB. MB has the maximum adsorption capacity for Cd(II) (24.2 mg/g), followed by PB (23.5 mg/g), FB (22.7 mg/g), NB (22.2 mg/g), and AB (22.0 mg/g). Langmuir model better described the Cd(II) adsorption onto NB, FB, and PB, while Freundlich better described AB and MB. As for Cr(VI), the maximum adsorption capacity followed the order: MB (24.1 mg/g) > AB (23.7 mg/g) > FB (23.5 mg/g) > PB (23.0 mg/g) > NB (22.7 mg/g). Langmuir model was better for Cr(VI) adsorption onto FB and PB, while Freundlich was better for AB, NB and MB. The pseudo-first-order kinetic model fits for Cd adsorption by FB，while the pseudo-second-order kinetic model fit for the adsorption of Cd and Cr by other biochars. The adsorption of Cr by all biochars was significantly related to the content of lactone group. Acidification and organic acids from microorganisms increased the pHPZC values of AB and MB, which was not conducive to the adsorption of Cd. The surface fragmentation of FB caused by the freezing and thawing process promoted its adsorption of Cd.

MINERALOGIA, GEOQUÍMICA, FERTILIDADE E ORIGEM DOS SEDIMENTOS DE PRAIA (BARRA EM PONTAL) DAS BACIAS DOS RIOS PURUS E JURUÁ NOS TERRENOS DO ESTADO DO ACRE

The Acre state is in the southwestern part of the Brazilian Amazon region with an area of 164.123.738 km2 and a low population density (5.52 inhabitants/km2 for 2021). The geological context is mainly related to recent units that outcrop at the Acre basin and associated with the Solimões Formation, besides old alluvial terraces that follow main drainages. The Solimões Formation comprises fossil-bearing clayey siltstones intercalated to fine sandstones. The old alluvial terraces are composed by sand, silt, clay, and occasionally fossil fragments. The area of the Acre state is crossed by two main hydrographic basins: The Purus and Juruá rivers in the eastern and western part, respectively. Both rivers are the so-called “white-water rivers”. They exhibit a typical dendritic drainage pattern and are extremely meandering what give rise to lakes formed after abandoned meanders. During dry season, several beaches (point bars) are exposed on river‘s meanders, frequently used for swimming but also playing a very important role in the small-scale agriculture. These beaches are also used for planting corn (Zea-Mays) and beans (Vigna unguiculata (L) Walp). The main purpose of this work is to investigate the mineralogical and geochemical aspects of those beach sediments to understand their high fertility and to identify their primary source. Fourteen stations were selected for sampling purposes throughout the river valley close to BR-364 highway. Laboratory analyses were carried out as follow: grain sizes, x-ray diffraction, scanning electron microscopy and optical microscopy of heavy minerals concentrates; sediment whole chemistry (major and traces elements analyses including rare-earth elements) by means of ICP-MS; macronutrients (P, Mg, Ca, and K) besides available Na and Al and organic matter. The river sediments are mainly fine-grained, angular sub-angular and selected moderately. Mineralogical assemblage is represented by quartz, clay minerals (smectite, illite and kaolinite) and feldspars (K-feldspars and albite). The heavy minerals contents ranged from 0.5 to 4.6% and are mainly represented by zircon, epidote, kyanite, tourmaline, garnet, rutile, apatite, staurolite, ilmenite and hematite. Chemical results shown that the sediments are mainly composed by SiO2, besides minor amounts of Al2O3, Fe2O3, K2O, CaO and MgO, what is compatible with mineralogical composition. High SiO2 contents are mainly related to quartz and Al2O3 contents reflects the presence of clay minerals. Contents for alkaline and alkali-earths are relatively high for such beach environment related to feldspars and smectites. P2O5 is related to apatite and can also be adsorbed on smectite. Fe2O3 contents are mainly associated to smectite and a minor amount to ilmenite and hematite, the most common opaque minerals found in the beach sediments. Strong correlation coefficients were observed between Al2O3 and most major and trace elements, except for Zr, Hf, Ni and As. On the other hand, strong negative correlation was obtained between SiO2 and major and trace elements what points to the importance of smectites as scavenger of trace elements in such environment. The chemical results were compared with the mean of the Upper Crust and post-Archean Australian Shales (PAAS) and show that they are impoverished in MgO, CaO, Na2O and K2O in comparison with the former and MgO, in comparison with the latter. Such impoverishment is higher in samples enriched on sand fraction. The same comparison was carried out with the Chinese Changliang and Huanghe river sediments, showing impoverishment in CaO and MgO in comparison with the Changjiang River and MgO, CaO, Na2O and Sr, in comparison with the Huanghe River. The small value obtained for the Chemical Index of Alteration (CIA) shows that these sediments have experienced small degree of chemical weathering and consequently, physical weathering has prevailed in the source area. The beach sediments also exhibit high immature index as evidenced by the following very low rations: SiO2 / Al2O3 (11,64) and K2O/ Na2O (2,08). Rare-earth elements were normalized to the Upper Crust and to the PAAS patterns. They show similar patterns of LREE depletion and HREE enrichment. On the other hand, normalized to the chondrites present enrichment in LREE and horizontalization of the HREE, with similar standards of distribution between each other, presenting typical Eu negative anomalies of granitic and intermediary nature rocks. Analytical results for macronutrients exhibited high concentrations for P, Mg, Ca and K, and low contents of available Na and Al. Organic matter contents in below 1%. The sediments show high cation exchange capacity, base saturation over 70% and low Na and Al saturation. Accordingly, those sediments can be interpreted as representing a redistribution of the recent Miocene sediments (Solimões Formation) and the own sediments that were deposited in old alluviums. Chemical and mineralogical characteristics with a silty granulometry indicate that beach sediments are like the eutrophic cambisols.

Synthesis and Characterization of Nanocomposite Hydrogels Based on Poly(Sodium 4-Styrene Sulfonate) under Very-High Concentration Regimen of Clays (Bentonite and Kaolinite).

The aim of this work was to synthesize and study the functional properties of polymer-clay nanocomposite (PCNCs) based on poly(sodium 4-styrene sulfonate) (NaPSS) and two types of clay in the dispersed phase: bentonite and kaolinite, in order to advance in the development of new geomimetic materials for agricultural and environmental applications. In this study, the effect of adding high concentrations of clay (10-20 wt. %) on the structural and functional properties of a polymer-clay nanocomposite was evaluated. The characterization by infrared spectroscopy made it possible to show that the PCNCs had a hybrid nature structure through the identification of typical vibration bands of the clay matrix and NaPSS. In addition, scanning electron microscopy allowed us to verify its hybrid composition and an amorphous particle-like morphology. The thermal characterization showed degradation temperatures higher than ~300 °C with Tg values higher than 100 °C and variables depending on the clay contents. In addition, the PCNCs showed a high water-retention capacity (>2900%) and cation exchange capacity (>112 meq/100 g). Finally, the results demonstrated the ability of geomimetic conditioners to mimic the structure and functional properties of soils, suggesting their potential application in improving soil quality for plant growth.

Spatial variability of clay minerals in a semi-arid region of Turkiye

Clay minerals are the source of many chemical and physical properties that influence the provision of soil-based ecosystem services. This study aimed to identify the most significant soil characteristics contributing to the spatial variability of clay minerals in a semi-arid region of Turkiye. Additionally, the study assessed the predictive capabilities of Classification and Regression Tree (CART), Random Forest Regression (RF) and eXtreme Gradient Boosting Regression (XGBoost) in estimating soil clay mineral content. Smectite+vermiculite (SMVR) was the most abundant clay mineral in the study area, followed by illite and kaolinite. Hyperparameter tuning significantly improved model accuracy, with root mean square error (RMSE) reductions ranging from 2.53% to 97.3%. The machine learning algorithms demonstrated varying performances in spatial prediction accuracy. The RF model achieved the lowest RMSE (8.587%) and the highest R2 values (0.796) for predicting SMVR. The XGBoost outperformed other models for kaolinite (RMSE: 4.814%, R2:0.713) and illite (RMSE:7.368%, R2:0.613). Exchangeable cations, particularly magnesium (Mg) and calcium (Ca), were identified as crucial factors influencing the spatial distribution of clay minerals. Among these, M concentration had the strongest influence on predicting both SMVR (38.1%) and illite (26.3%). Conversely, for kaolinite prediction, Ca concentration played the most significant role (38.7%), followed by Mg (19.93%). In conclusion, this study demonstrates the effectiveness of machine learning models, particularly XGBoost which achieved the lowest RMSE for all clay minerals investigated. These models offer a valuable tool for predicting clay mineral content in the Kazova Plain. The findings highlight the importance of parent material, weathering processes, and specific soil properties, such as exchangeable cations, in shaping clay mineral distribution. This knowledge not only contributes to a deeper understanding of soil formation in semi-arid environments but also practical applications. For instance, by predicting the abundance of SVMR, known for its high cation exchange capacity land managers can develop targeted strategies for optimizing fertilizer application in the Kazova Plain.

Taking Advantage of Disposal Bamboo Chopsticks to Produce Biochar for Greenhouse Crop Cultivation

Biochar is a value-added product that can be used for many purposes, particularly for environmental and agricultural purposes. In this study, pyrolysis at 450–500 °C was used to upgrade urban waste such as disposable bamboo chopsticks (DBCs) into biochar. The properties of DBC biochar were analyzed, and the biochar was subsequently used to cultivate Romaine lettuce to assess its potential as a soil amendment. Its properties, including specific surface area (SSA), pore size, pore volume, pH, cation exchange capacity (CEC), contents of carbon (C), hydrogen (H), nitrogen (N), oxygen (O), macronutrient content, and the atomic ratio of H/C, O/C, (O+N)/C, and C/N, were analyzed. The experimental pots consisted of four treatments, each with ten replicates: unamended soil (TC), soil amended with 10% (w/w) vermicompost (TV), soil amended with 10% vermicompost mixed with 1.5% biochar (TVB1.5), and soil amended with 10% vermicompost mixed with 2.5% biochar (TVB2.5). Fundamental physicochemical soil properties and plant yield (plant height, leaf width, number of leaves, and fresh weight) were investigated. The results indicated that the DBC biochar was neutral (pH 6.80) and had a high CEC (10.86 cmol/kg), 66.80% C, 3.76% H, 25.93% O, and 0.61% N. It had mesopores (39.077 Å), a large SSA (0.542 m2/g), and a pore volume of 0.005 cc/g. The biochar exhibited high aromaticity and hydrophobicity. Based on these results, the DBC biochar has the potential to be used as a soil amendment: it significantly enhances soil quality and increases plant yields. The application of 2.5% biochar resulted in the highest yield. Doi: 10.28991/ESJ-2024-08-03-07 Full Text: PDF

Biochar – a sustainable soil conditioner for improving soil health, crop production and environment under changing climate: a review

Land degradation and climate change, two intricately intertwined phenomena, demand appropriate management solutions to effectively tackle the escalating issues of food and nutritional security. In this context, the realm of agriculture confronts formidable challenges in its pursuit of soil resource reclamation, improving water quality, mitigating climate change, and maintaining soil and natural resources for posterity. Central to these aspirations is the preservation of an optimum organic matter, serving as a linchpin threshold is crucial for protecting the physical, chemical, and biological integrity of the soil, while simultaneously sustaining agricultural productivity. To address these multifaceted challenges, the introduction of diverse organic amendments has emerged as a crucial strategy. Noteworthy among these is the application of biochar, which functions as a soil conditioner capable of bolstering soil health, mitigating the impact of climate change, and securing global food security. Biochar is a carbon-enriched substance produced through pyrolysis of assorted biomass waste. It has a larger surface area, higher cation exchange capacity, and an extended carbon storage capability. The strategic integration of biochar production and subsequent soil application engenders an array of benefits, encompassing the amelioration of soil physical properties, augmented retention and the availability of nutrients, and the enhancement of biological activity, resulting in higher agricultural yields and societal benefits through the curtailment of soil to atmosphere greenhouse gas emissions. Additionally, biochar demonstrates its efficacy in the realm of environmental restoration by serving as a medium for extraction and elimination of heavy metals, which often pervade aquatic ecosystems and soil matrices. This review addressed the need for biochar production, characterization, soil health, the possibility for environmental restoration, and crop yield fluctuations owing to climate change.

Mineralogy and geotechnical properties of alkaline-activated kaolin with zeolitic tuff and cement kiln dust as landfill liners

Mixtures of variable proportions of kaolin, quartz sand, zeolitic tuff, and cement kiln dust were blended while adding an 8 M sodium hydroxide (NaOH) solution to allow alkali-activation of kaolin and achieve the optimum strength. This study investigated the mineralogy, microstructure, and geotechnical properties of the prepared mixtures. The aim was to produce a sustainable, environmentally friendly landfill liner. The samples were compacted in stainless steel molds to a maximum dry density and optimum moisture content, extruded from the molds, and left to cure in an oven at varying temperatures from 40°C to 80°C for 24 h. The investigations included XRD, SEM, unconfined compressive strength, and hydraulic conductivity tests. Test results showed the development of a hydroxysodalite binder due to the alkali reaction of kaolin, which caused an increase in strength ranging from 20 to 25 MPa depending on the curing temperature. Alkaline activation was effective even at temperatures as low as 40°C. A mixture of 100 units of kaolin, 45 units of sand, 45 units of zeolitic tuff, and 10% by weight cement kiln dust (CKD) with an 8 M sodium hydroxide activator was found to best achieve the required strength and hydraulic conductivity of 10−9 m/s for the landfill liner. The zeolitic tuff with high cation exchange capacity, available in the mixture, absorbs contaminants in the leachate and prevents pollution of the groundwater. The use of cement kiln dust contributes to enhancing strength and solving an acute environmental problem.

Synthesis of geopolymer powder and beads based on red clay waste for the adsorption of methyl orange dye from aqueous solutions: Characterization, application of response surface methodology, and cost analysis

The current research focuses on the valorization of red clay waste (RCW) to develop alumino-silicate geopolymer binders (GPP) and geopolymer spheres obtained from GPP powder modified with sodium alginate (Alg/GPP). GPP and Alg/GPP were applied in the environmental field for the retention of methyl orange (MO) from an aqueous solution. The raw material and the synthesized geopolymers were characterized by various physico-chemical methods. The results of XRF, XRD, and FTIR confirmed the successful synthesis of GPP and Alg/GPP, while the SEM/EDX findings revealed the homogeneous surface of the adsorbents. A significant specific surface area was detected for GPP (73.56 m2/g) and Alg/GPP (91.24 m2/g) with a high cation exchange capacity around 122 meq/100g for GPP and 185 meq/100g for Alg/GPP. The removal process was performed using the response surface methodology according to the Box-Behnken design, optimizing the retention efficiency of MO by different factors, including temperature, initial concentration, solution pH, and contact time. The obtained data was treated through the analysis of variance (ANOVA) and fitted by a quadratic polynomial model based on multiple regression analysis. In an acidic medium at 45 °C, the optimal conditions for MO retention were estimated to be 120 mg/L of MO concentration in 55 min using GPP and 180 mg/L of MO concentration in 20 min using Alg/GPP. The pseudo-second-order kinetics were more appropriate for describing the MO removal onto GPP and Alg/GPP adsorbents. The Langmuir model identified a high retention capacity of MO around 94.78 mg/g via GPP and 224.85 mg/g via Alg/GPP. The thermodynamic data confirmed that the elimination of MO dye onto GPP and Alg/GPP adsorbents was endothermic, favorable, and spontaneous. This study provided insights into the valorization of composite materials based on solid waste in dye retention, which can potentially be employed in wastewater treatment.

Applying coal char to cattle pens for sustainable agriculture in the semiarid US High Plains

AbstractApplying high carbon (C) additive to cattle pens and land application of the resultant manure mix offers a potential strategy for optimizing manure and soil management while mitigating environmental concerns. An experiment was conducted in western Nebraska from 2019 to 2022 to evaluate the effect of adding coal char (∼290 g C kg−1 by wt.) on feedlot manure's properties and stability and the interacting effect of manure‐char on crop yields in a corn (Zea mays L.)–dry bean (Phaseolus vulgaris L.)–corn rotation. Treatments in the crop field included manure from pens with or without char (each at 34 and 68 Mg ha−1; low and high rate), urea at 100% recommended nitrogen (N) rate with or without 45 Mg char ha−1, and a control. Applying char to pens kept them drier following snowfall events. The high surface area and cation exchange capacity of char improved soil and manure nutrient retention. The 100% urea‐N plus char treatment had a greater corn yield than the low‐rate char–manure mix or high‐rate manure in 2020. In 2021, there was a trend for higher bean yields with the high char–manure rate treatment than the control. In 2022, all the fertilized treatments had greater grain yields than the control. A one‐time high‐rate char–manure mix or manure application could replace 314 kg N ha−1 and 90 kg P2O5 ha−1 over 2 years without any yield penalty. This study underscores the synergy between char and manure or chemical fertilizers to improve nutrient balance and supply, ultimately enhancing crop production.

The Influence of Chemical Fertilizers on the Effectiveness of Biochar in Mitigating Cadmium Mobility in Soil

The focus of this study was to explore how various fertilizers influence the movement of cadmium in soil treated with biochar. The research utilized a strong acid sandy loam soil from Chanthaburi Province, naturally rich in organic matter with moderate cation exchange capacity and low nitrogen, potassium, phosphorus, sulfate, salinity and chloride levels. The soil was purposely contaminated with 50 mg kg-1 of cadmium and treated with biochar derived from water hyacinth through pyrolysis at 450°C for an hour. This biochar displayed moderate alkalinity, high organic matter, phosphorus, potassium, and cation exchange capacity, but low nitrogen content. Analytical techniques like Scanning Electron Microscopy and Fourier-Transform Infrared Spectroscopy were employed to study the surface characteristics of the biochar. The cadmium adding soil was blended with 10% biochar and various chemical fertilizers at a 0.04% ratio. Diethylenetriamine pentaacetate (DTPA) extraction was used to assess the bioavailability of cadmium to plants in the soil, while sequential extraction was conducted to identify the different forms of cadmium present in the soil. The study revealed distinct effects of different fertilizers on cadmium mobility. Fertilizers like 46-0-0 and 0-3-0 caused a transformation of cadmium from stable to less stable forms, increasing the bioavailability of cadmium to plants. Conversely, fertilizers such as 15-15-15, 0-0-50, 0-0-60, and 0-52-34 shifted cadmium from less stable to more stable forms, resulting in decreased cadmium extracted by DTPA. Other fertilizers showed no significant impact on cadmium mobility in the soil. A stepwise linear regression analysis highlighted that nitrogen content, potassium content, and electrical conductivity were influential factors affecting cadmium mobility.

Spatial variation in iodine content with relation to soil physicochemical properties in lower Himalayan region

Topography of a place has a significant impact on soil characteristics that ultimately influence soil iodine levels. Lower Himalayan region (LHR) in Pakistan has a wide range of climatic and geological variations. Hence, an investigation was conducted to analyze the iodine concentration and other physicochemical properties of soils in two LHR districts, Haripur and Mansehra. Spatial analysis indicated a decrease in iodine levels in the mountainous regions in comparison to the flat portions of LHR. Soil samples obtained from different locations across Haripur had a stronger affinity for iodine due to variations in solubility and adsorption of iodine to soil clay components, which can be attributed to lower pH, higher organic matter, and a higher cation exchange capacity (CEC). In contrast to the plains of Haripur, elevated locations in the Mansehra district had decreased levels of iodine, along with a higher soil pH and reduced soil organic matter. The soil erosion and depletion of soil micronutrients in the hilly region of Mansehra may be attributed to the unfavorable soil conditions and excessive precipitation. Presence of clay, iron (Fe), and aluminum (Al) in the soil led to a rise in iodine levels. Iodine concentrations exhibited an inverse relationship with soil acidity. Study revealed a direct correlation between soil iodine levels and their cation exchange capacity (CEC) and clay content. This study aims to gather fundamental data for the chosen regions of LHR to address illnesses caused by iodine deficiency.

Mapping of volcanic soil chemical properties with digital soil mapping after the prolonged eruption of Mt. Sinabung (2013-2020)

Volcanic soils in Indonesia cover an area of about 5.4 million ha and around 2.7 million ha in Sumatra. The prolonged eruptions of Mt. Sinabung in North Sumatra from 2013 to today eject pyroclastic materials, which blanketed and altered the soil surface. As a result, volcanic soil formed from these pyroclastic deposits. This study aims to map the chemical properties of volcanic soils after the prolonged eruption of Mt. Sinabung from 2013-2020. Thirty-four soil samples were collected at a depth of 0-20 cm according to the grid sampling system with an interval of 1x1 km covering an area of about 4,500 ha. Regression kriging (RK) was applied to predict the soil’s chemical properties and distribution spatially. The soil samples were air dried, sieved, and analyzed to determine soil pH (H2O and KCl), available, potential and retention P, organic carbon, total nitrogen, cation exchange capacity (CEC), and exchangeable basic cations. Soil pH (H2O) ranges from very acidic to neutral (4.14-6.52) and very acidic to acidic pH (KCl) (3.89-5.26), low to very high available-P (3.46-382.01 ppm), potential-P very low to very high (3.76-230.26 mg 100g-1), P-retention is categorized as very high (90-99%). The organic Carbon range from low to very high (1.73-13.05%), low to high total nitrogen (0.13-0.60%), low to high cation exchange capacity (11.78-97.71 cmolc kg-1), and exchangeable base cations are categorized as high with K values (1.60-2.98 cmolc kg-1). Na (3.72-7.45 cmolc kg-1) and Mg (5.79-12.15 cmolc kg-1) were categorized as high and Ca very low (0.039-0.157 cmolc kg-1). The estimated area of soils with pH between 4 and 5 is about 424.85 ha, and soils with pH between 5 and 6 covered an area of approximately 3,964.81 ha. Our findings suggest that persistent eruptions of Mt. Sinabung supply new plant nutrition, which can enrich and increase soil fertility in the future.