Alkaline Mineralization Research Articles

Metasilicate-based alkaline mineral water improves the growth performance of weaned piglets by maintaining gut-liver axis homeostasis through microbiota-mediated secondary bile acid pathway

Metasilicate-based alkaline mineral water improves the growth performance of weaned piglets by maintaining gut-liver axis homeostasis through microbiota-mediated secondary bile acid pathway

Alkaline Mineral Complex Water Attenuates Transportation-Induced Hepatic Lipid Metabolism Dysregulation by AMPKα-SREBP-1c/PPARα Pathways

Transportation, an unavoidable process in livestock farming, causes metabolic disorders in the body, which then lead to endocrine disruption, being immunocompromised, and growth suppression. Lipid metabolism dysregulation is a critical phenotype induced by transportation. The liver is a vital organ in lipid metabolism, with a role in both lipid synthesis and lipolysis. However, the specific mechanisms by which transportation affects hepatic lipid metabolism remain unclear. This study employed rats as a model to investigate the effects of transportation on hepatic lipid metabolism. Rats subjected to transportation showed altered serum lipid profiles, including decreased serum triglyceride (TG), low-density lipoprotein cholesterol (VLDL-C), and non-esterified fatty acid (NEFA) immediately after transportation (IAT) and serum total cholesterol (TC) on day 3, and increasing serum TG, TC, and low-density lipoprotein cholesterol (LDL-C) on day 10. Meanwhile, fatty droplets in the liver were also reduced at IAT and increased on days 3 and 10. Notably, transportation also affected hepatic-lipid-metabolism-related enzyme activities and signaling pathways, such as increased AMP-activated protein kinase alpha (AMPKα) phosphorylation and modulations in key proteins and genes related to lipid metabolism, decreased hepatic acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) activities at IAT, and increased carnitine palmitoyl transferase 1 alpha (CPT-1α) at IAT and ACC and CPT-1α activities on days 3 and 10. Supplementation with alkaline mineral complex water (AMC) before and after transportation mitigated the adverse effects on hepatic lipid metabolism by modulating the AMPKα-SREBP-1c/PPARα pathway, enhancing lipid synthesis, and reducing the oxidative catabolism of fatty acids. AMC inhibited the transportation-induced activation of AMPKα and restored the balance of lipid-metabolism-related enzymes and pathways. These findings highlight AMC’s potential as a therapeutic intervention to alleviate transportation-induced lipid metabolism disorders, offering significant implications for improving animal welfare and reducing economic losses in livestock farming.

Unraveling the Distribution of Black Carbon in Chinese Forest Soils Using Machine Learning Approaches

AbstractBlack carbon (BC) is a highly persistent yet poorly understood component of forest soil carbon reservoirs, while its inventory, distribution, and determining factors in forest soils on a large geographic scale remain unclear. Here, we characterized soil BC across 68 Chinese forest sites using benzene polycarboxylic acid method and developed machine learning (ML) models to predict and interpret potential impacts of soil organic matter (SOM) properties, soil physiochemical properties, meteorological conditions, wildfire history, and microbial diversity on BC. Results revealed that SOM properties were the most critical in predicting BC, complemented by the negative impact of mean annual temperature and alkaline mineral composition. The superior prediction accuracy for BC with higher condensed aromaticity (more benzene hexa‐ and penta‐carboxylic acid monomers) likely results from its simpler sources and greater resistance to transformation. This study introduces an effective ML model for predicting and interpreting soil BC inventory to better understand BC cycling.

Low-cost dealkalization of bauxite residue by gypsum coordinated with industrial iron salt: Mineralogical mechanisms and field practice

The sustained-release of alkalinity in bauxite residue hinders the soil formation and ecological restoration processes in disposal areas. Ferric salts (Fe3+), known for their rapid neutralization reaction process and straightforward operational simplicity, showed a synergistic advantage with gypsum (CaSO4) in the alkaline regulation of bauxite residue. Nevertheless, the mineralogical mechanisms of the reaction between Fe3+ and Ca2+ and alkaline minerals in bauxite residue remained unclear. The present study aimed to elucidate the geochemical stability mechanisms of sodalite and cancrinite, major alkaline minerals in bauxite residue, driven by Fe3+ and Ca2+ from a mineral structural perspective and the integrated restoration effect was demonstrated by the field experiment. Unreacted shrinking core model (USCM) calculations demonstrated that Fe3+ was able to enter the lattice structure of sodalite and cancrinite to replace Na+ and assisted Ca2+ in successfully replacing Na+ in cancrinite. Moreover, Fe3+ and Ca2+ facilitated the formation of insoluble coating layers on their surface. In the lattice structure of sodalite and cancrinite, the replacement reaction for Na+ was influenced by the competition between Fe3+ and Ca2+. The Ca2+ preferentially replaced Na+, while Fe3+ accumulated near the Si-O bonds, balancing the negative charges of the Si-O and Al-O tetrahedra structure and further inhibited alkaline mineral dissolution. The pH and EC of bauxite residue decreased from 10.52 to 7.60 and 712 μS/cm to 501 μS/cm, respectively, after a one-year field-scale amelioration by the integration of Fe3+ and Ca2+. These findings highlighted the synergistic roles of Fe3+ and Ca2+ in regulating the alkalinity of bauxite residue and provided a practical strategy for ecological restoration in disposal areas.

Study of GaN solubility in ammonothermal alkaline solution

The solubility of gallium nitride in supercritical ammonia containing an alkaline mineralizer, sodium amide, was investigated. Twenty dissolution processes were carried out at constant ammonia pressure and constant mineralizer concentration. In each process, the solubility of four ammonothermal GaN crystals was analyzed at four different temperatures and five different times. By analyzing the total mass loss of all crystals in a given process, the time interval at which the solubility of GaN stopped changing was determined, indicating the saturated state of the solution. Based on these data, the solubility curve was determined. Retrograde solubility was observed. The impact of surface preparation of GaN samples and its correlation with the quantity of dissolved material was investigated. It was shown that as-grown and optically smooth surfaces dissolved slower than mechanically treated (000-1) GaN surfaces. These are important data for ammonothermal crystallization processes using native GaN seeds with differently prepared (000-1) surfaces.

Effect of integration of mechanical ball milling and flue gas desulfurization gypsum on dealkalization of bauxite residue

The synergistic impact of mechanical ball milling and flue gas desulfurization (FGD) gypsum on the dealkalization of bauxite residue was investigated through integrated analyses of solution chemistry, mineralogy, and microtopography. The results showed a significant decrease in Na2O content (>30 wt.%) of FGD gypsum-treated bauxite residue after 30 min of mechanical ball milling. Mechanical ball milling resulted in differentiation of the elemental distribution, modification of the minerals in crystalline structure, and promotion in the dissolution of alkaline minerals, thus enhancing the acid neutralization capacity of bauxite residue. 5 wt.% FGD gypsum combined with 30 min mechanical ball milling was optimal for the dealkalization of bauxite residue.

Biochar Blended with Alkaline Mineral Can Better Inhibit Lead and Cadmium Uptake and Promote the Growth of Vegetables.

Three successive vegetable pot experiments were conducted to assess the effects on the long-term immobilization of heavy metals in soil and crop yield improvement after the addition of peanut shell biochar and an alkaline mineral to an acidic soil contaminated with lead and cadmium. Compared with the CK treatment, the change rates of biomass in the edible parts of the three types of vegetables treated with B0.3, B1, B3, B9, R0.2 and B1R0.2 were -15.43%~123.30%, 35.10%~269.09%, 40.77%~929.31%, -26.08%~711.99%, 44.14%~1067.12% and 53.09%~1139.06%, respectively. The cadmium contents in the edible parts of the three vegetables treated with these six additives reduced by 2.08%~13.21%, 9.56%~24.78%, 9.96%~35.61%, 41.96%~78.42%, -4.19%~57.07% and 12.43%~65.92%, respectively, while the lead contents in the edible parts reduced by -15.70%~59.47%, 6.55%~70.75%, 3.40%~80.10%, 55.26%~89.79%, 11.05%~70.15% and 50.35%~79.25%, respectively. Due to the increases in soil pH, soil cation-exchange capacity and soil organic carbon content, the accumulation of Cd and Pb in the vegetables was most notably reduced with a high dosage of 9% peanut shell biochar alone, followed by the addition of a low dosage of 1% peanut shell biochar blended with 0.2% alkaline mineral. Therefore, the addition of a low dosage of 1% peanut shell biochar blended with 0.2% alkaline mineral was the best additive in increasing the vegetable biomass, whereas the addition of 9% peanut shell biochar alone was the worst. Evidently, the addition of 0.2% alkaline mineral can significantly reduce the amount of peanut shell needed for passivating heavy metals in soil, while it also achieves the effect of increasing the vegetable yield.

Mineral and Geochemical Features of Zeolite-Silica Deposits of the Pauzhetka Geothermal Field (Southern Kamchatka)

On the Pauzhetka geothermal field the mineral deposits which are formed, when dumping thermal water of separators of wells, are allocated. Compositions, structure and geochemical properties of this precipitation on pro-deleting and in vertical slits of “raincoats” are studied. It is established that they are put X-ray amorphous mordenite – opal mixes (in the beginning dumping of thermal waters), further precipitation becomes completely siliceous. The zeolitic component of mineral deposits defines their high sorption properties in the relation of Au, Ag, Hg, As, Rb, Sr, Ba, Cs, etc. elements; in a mordenitovy matrix sulfides of iron, silver, copper are formed. It is shown that the mineral deposits which are formed on the day surface of the Pauzhetka geothermal field are the indicator of alkaline mineral- and the ore-forming processes on the lower horizons of the Pauzhetka hydrothermal system.

Investigation of nanoscale interfacial bonding properties in foamed asphalt cold recycled mixtures under chloride salt erosion

Salt-induced erosion from de-icing salts in Northern China and sea salt in Eastern coastal areas significantly compromises asphalt pavement integrity. A selection was made of four different types of foamed asphalt with different levels of water content, two types of aged asphalt, and three typical minerals (α-quartz, calcite, and bauxite), in addition to three chloride salt solutions (NaCl, CaCl2, MgCl2). It was found that (1) in dry conditions, the moisture level of foamed asphalt noticeably influences the adhesive performance at the juncture between asphalt and aggregates. Unlike acidic minerals, the bond strength between alkaline and neutral minerals and foamed asphalt increases as the water content of the foamed asphalt rises; (2) chloride salt solutions presence and increased levels significantly reduced the bond strength between asphalt and aggregates, particularly impacting neutral and alkaline minerals (in the presence of 10 % NaCl solution, the work of adhesion was reduced by 83.82 % and 87.48 %, respectively); (3) the influence of diverse chloride salts on the interfacial adhesive performance of asphalt mixtures varied, with the three chloride salts reducing the asphalt-aggregate interfacial adhesion work by 44.52 %, 21.90 %, and 34.94 %, respectively. (4) the investigation determined that the mineral composition considerably influences the hygroscopic sensitivity of asphalt mixtures. Minerals of an acidic nature exhibit superior moisture resistance when juxtaposed with alkaline counterparts, recommending the adoption of acidic aggregates in scenarios demanding elevated mixture stability.

Eco-Friendly Fungal Chitosan-Silica Dual-Shell Microcapsules with Tailored Mechanical and Barrier Properties for Potential Consumer Product Applications.

Commercial perfume microcapsules are becoming popular across the globe to fulfill consumers' demands. However, most of microcapsules rely on synthetic polymers and/or animal-sourced ingredients to form the shells. Therefore, replacement of the shell materials is imperative to minimize environmental microplastic pollution, as well as to meeting peoples' needs, religious beliefs, and lifestyles. Herein, we report a methodology to fabricate environmentally benign dual-shell (fungal chitosan-SiO2) microcapsules laden with fragrance oil (hexyl salicylate). Anionically stabilized oil droplets were coated with fungal chitosan via interfacial electrostatic interactions at pH 2, which were then covered by an inorganic coating of SiO2 produced via external alkaline mineralization of sodium silicate. Core-shell microcapsules with a spherical morphology were achieved. Under compression, dual-shell chitosan-SiO2 microcapsules yielded a mean nominal rupture stress of 3.0 ± 0.2 MPa, which was significantly higher than that of single-shell microcapsules (1.7 ± 0.2 MPa). After 20 days in neutral pH water, only ∼2.5% of the oil was released from dual-shell microcapsules, while single-shell microcapsules cumulatively released more than 10%. These findings showed that the additional SiO2 coating significantly enhanced both mechanical and barrier properties of microcapsules, which may be appealing for multiple commercial applications, including cosmetics and detergents.

Interactions between organic matter and alkaline minerals in bauxite residue: implication for soil restoration.

Ecological restoration of bauxite residue has received extensive attention, and organic matter plays a crucial role in the soil formation process of bauxite residue. However, the interaction between organic matter and alkaline minerals in bauxite residue is not well understood. In this work, molecular spectroscopic techniques combined with isothermal titration calorimetry (ITC) were employed to investigate the interactions between humic acid (HA) and four representative alkaline minerals in bauxite residue (calcite, garnet, sodalite, and cancrinite). The results show that the adsorption processes of HA onto calcite and garnet were primarily governed by monolayer surface adsorption and controlled by surface reactions, which were different for sodalite and cancrinite. Both garnet and cancrinite had strong binding affinities with fluorescent HA, while cancrinite only bound with a small fraction of HA. In contrast, the bindings of calcite and sodalite with fluorescent HA were weak. The ITC results indicate distinct thermodynamic properties of different alkaline minerals in the interaction with HA. The molar enthalpy of calcite was - 45.88kJ/mol, which was much higher than those of garnet, sodalite, and cancrinite, suggesting that calcite exhibited a relatively uniform interaction mechanism with HA dominated by enthalpy change, while the others showed heterogeneous entropy-driven mechanisms. The findings contribute to a better understanding on the microscale connections between organic matter and alkaline minerals in bauxite residue.

Carbon dioxide removal efficiency of iron and steel slag in seawater via ocean alkalinity enhancement

Ocean alkalinity enhancement (OAE) via the enhanced weathering of alkaline minerals is a promising carbon dioxide removal (CDR) technology. Theoretically, these includes iron and steel slags, although their dissolution kinetics in seawater are unknown. Here, we conducted lab-scale experiments to assess the alkalinity generation potential and dissolution kinetics of various slags in seawater. We show that the alkalinity generated per mass of iron slag was logarithmic, i.e., higher amounts of iron slag added had diminishing alkalinity returns. In contrast, the relatively quick dissolution of steel slags and their linear generation of alkalinity per mass of feedstock dissolved in seawater makes them better OAE candidates. Furthermore, despite the presence of potentially toxic metals in these feedstocks, their low to non-existent presence as dissolution products suggests that harmful concentrations should not be reached, at least for the slag tested here. Finally, if all steel slag produced annually was used for OAE, between 10 and 22 gigatonnes of CO2 could be captured cumulatively by 2,100, highlighting significant CDR potential by slags.

Quantifying the Pore Heterogeneity of Alkaline Lake Shale during Hydrous Pyrolysis by Using the Multifractal Method

Distinguishing itself from marine shale formations, alkaline lake shale, as a significant hydrocarbon source rock and petroleum reservoir, exhibits distinct multifractal characteristics and evolutionary patterns. This study employs a combination of hydrous pyrolysis experimentation, nitrogen adsorption analysis, and multifractal theory to investigate the factors influencing pore heterogeneity and multifractal dimension during the maturation process of shale with abundant rich alkaline minerals. Utilizing partial least squares (PLS) analysis, a comparative examination is conducted, elucidating the disparate influence of mineralogical composition on their respective multifractal dimensions. The findings reveal a dynamic evolution of pore characteristics throughout the maturation process of alkaline lake shale, delineated into three distinct stages. Initially, in Stage 1 (200 °C to 300 °C), both ΔD and H demonstrate an incremental trend, rising from 1.2699 to 1.3 and from 0.8615 to 0.8636, respectively. Subsequently, in Stages 2 and 3, fluctuations are observed in the values of ΔD and D, while the H value undergoes a pronounced decline to 0.85. Additionally, the parameter D1 exhibits a diminishing trajectory across all stages, decreasing from 0.859 to 0.829, indicative of evolving pore structure characteristics throughout the maturation process. The distinct alkaline environment and mineral composition of alkaline lake shale engender disparate diagenetic effects during its maturation process compared with other shale varieties. Consequently, this disparity results in contrasting evolutionary trajectories in pore heterogeneity and multifractal characteristics. Specifically, multifractal characteristics of alkaline lake shale are primarily influenced by quartz, potassium feldspar, clay minerals, and alkaline minerals.

Effects of dietary supplementation with alkaline mineral complex on in vitro ruminal fermentation and bacterial composition

IntroductionDairy industry growth faces challenges in China due to inadequate forage, leading to high-concentrate diets and potential rumen issues. Buffering agents, like sodium bicarbonate, play a crucial role in stabilizing rumen pH. Alkaline Mineral Complex (AMC), a liquid additive with a pH of 14, shows promise in supporting dairy cow health and mitigating heat stress through ionization.MethodsThis experiment was aimed to study the effect of adding AMC to total mixed ration (TMR) on in vitro ruminal fermentation and bacterial composition. AMCat 1, 2, 4, and 8 mL/kg was added to the substrate (0.5 g TMR). Nutrient digestibility was measured after 48 h fermentation, and fermentation parameters and microbial composition were measured after 48 h fermentation.Results and discussionThe results of the experiment indicated that: The different concentrations of AMC showed a significant impact on time taken for gas production to reach 1/2 of the total gas production (HT) parameters (p < 0.05). Linear pH increase occurs at 6 and 24 h with rising AMC concentration (p < 0.05), showing a quadratic trend at 12 h (p < 0.05). The optimal buffering effect on rumen acid-base balance was observed at a 2 mL/kg concentration of AMC. Microbial diversity analysis indicated that there was no significant change in α-diversity with different AMC concentrations (p > 0.05). The microbial level demonstrated no significant difference in species diversity of rumen fluid bacteria among the various AMC concentration treatment groups compared to the control group, further supporting that the advantage of adding AMC in stabilizing the rumen environment without altering the structure of the rumen microbiota. Besides, the addition of AMC significantly increased the concentrations of acetate, propionate, total fatty acids (TVFA), and NH3-N, suggesting that AMC contributed to enhancing the energy and nitrogen utilization efficiency in ruminants. Based on the above detection indicators, we recommend that the most favorable concentration is 2 mL/kg.

The study on mechanism of water–rock reaction in shale oil formation rich in alkaline minerals in Mahu Sag by using supercritical CO2

The Mahu Sag of Junggar Basin, China is rich in alkaline minerals. Generally, the water–rock reactions between hydraulic fluid and alkaline minerals during the hydraulic fracturing process will lead to the precipitation of minerals and block the pore or wellbore, thereby affecting the recovery efficiency. Supercritical carbon dioxide (ScCO2) regarded as a fracturing fluid can significantly improve the recovery of shale oil resources, but there is limited research on the reaction of ScCO2 to water and rock in shale samples rich in alkaline minerals. Therefore, ScCO2 treatment experiments were conducted on shale samples rich in alkaline minerals under 80°C and 10 MPa. Before the experiments, X-ray powder diffraction (XRD) was applied to characterise the mineral properties of the three shale samples. In addition, the duration time of ScCO2 treatment was set at 7 and 20 days to observe the treatment time impacts on the pore structure. Scanning electron microscopy (SEM) analysis and the Mann–Whitney U test were conducted before and after ScCO2 treatment. SEM images show the changes in pore structure. Opening pores are observed due to the interaction between the alkaline mineral and ScCO2. The Mann–Whitney U test shows the changes in fracture toughness. The changes in pore structure also play an important role in fracture toughness. This study investigated the ScCO2 impacts on shale samples rich in alkaline minerals and the analysis of changes in pore structure and fracture toughness can provide theoretical and data evidence to enable on-site optimisation of the ScCO2 fracturing scheme.

Influence of ocean alkalinity enhancement with olivine or steel slag on a coastal plankton community in Tasmania

Abstract. Ocean alkalinity enhancement (OAE) aims to increase atmospheric CO2 sequestration in the oceans through the acceleration of chemical rock weathering. This could be achieved by grinding rocks containing alkaline minerals and adding the rock powder to the surface ocean where it dissolves and chemically locks CO2 in seawater as bicarbonate. However, CO2 sequestration during dissolution coincides with the release of potentially bioactive chemicals and may induce side effects. Here, we used 53 L microcosms to test how coastal plankton communities from Tasmania respond to OAE with olivine (mainly Mg2SiO4) or steel slag (mainly CaO and Ca(OH)2) as alkalinity sources. Three microcosms were left unperturbed and served as a control, three were enriched with olivine powder (1.9 g L−1), and three were enriched with steel slag powder (0.038 g L−1). Olivine and steel slag powders were of similar grain size. Olivine was added in a higher amount than the steel slag with the aim of compensating for the lower efficiency of olivine to deliver alkalinity over the 3-week experiment. Phytoplankton and zooplankton community responses as well as some biogeochemical parameters were monitored. Olivine and steel slag additions increased total alkalinity by 29 and 361 µmol kg−1, respectively, corresponding to a respective theoretical increase of 0.9 % and 14.8 % of the seawater storage capacity for atmospheric CO2. Olivine and steel slag released silicate nutrients into the seawater, but steel slag released considerably more and also significant amounts of phosphate. After 21 d, no significant difference was found in dissolved iron concentrations (>100 nmol L−1) in the treatments and the control. The slag addition increased dissolved manganese concentrations (771 nmol L−1), while olivine increased dissolved nickel concentrations (37 nmol L−1). There was no significant difference in total chlorophyll-a concentrations between the treatments and the control, likely due to nitrogen limitation of the phytoplankton community. However, flow cytometry results indicated an increase in the cellular abundance of several smaller (∼<20 µm) phytoplankton groups in the olivine treatment. The abundance of larger phytoplankton (∼>20 µm) decreased much more in the control than in the treatments after day 10. Furthermore, the maximum quantum yields of photosystem II (Fv/Fm) were higher in slag and olivine treatments, suggesting that mineral additions increased photosynthetic performance. The zooplankton community composition was also affected, with the most notable changes being observed in the dinoflagellate Noctiluca scintillans and the appendicularian Oikopleura sp. in the olivine treatment. Overall, the steel slag used here was more efficient for CO2 removal with OAE than the olivine over the 3-week timescale of the experiment. Furthermore, the steel slag appeared to induce less change in the plankton community than the olivine when comparing the CO2 removal potential of both minerals with the level of environmental impact that they caused.

Personal exposure monitoring of fine and coarse particulate matter using exposure assessment models for elderly residents in Hong Kong

This study investigated the determinants of personal exposures (PE) to coarse (PM2.5-10) and fine particulate matter (PM2.5) for elderly communities in Hong Kong. The mean PE PM2.5 and PM2.5-10 were 23.6 ± 10.8 and 13.5 ± 22.1 μg/m3, respectively during the sampling period. Approximately 76% of study subjects presented statistically significant differences between PE and ambient origin for PM2.5 compared to approximately 56% for PM2.5-10, possibly due to the coarse-size particles being more influenced by similar sources (road dust and construction dust emissions) compared to the PM2.5 particles. Individual PE to ambient (P/A) ratios for PM2.5 all exceeded unity (≥1), suggesting the dominant influences of non-ambient particles contributed towards total PE values. There were about 80% individual P/A ratios (≤1) for PM2.5-10, implying possible effective infiltration prevention of larger size particulate matter particles leading to dominant influences from the outdoor sources. The higher concentration of NO3− and SO42− in PM2.5-10 compared to PM2.5 suggests possible heterogeneous reactions of alkaline minerals leading to the formation of NO3− and SO42− in PM2.5-10 particles. The PE and ambient OC/EC ratios in PM2.5 (8.8 ± 3.3 and 10.4 ± 22.4, respectively) and in PM2.5-10 (6.0 ± 1.9 and 3.0 ± 1.1, respectively) suggest possible secondary formed OC from surrounding rural areas. Heterogeneous distributions (COD >0.2) between the PE and ambient concentrations were found for both the PM2.5 and PM2.5-10 samples. The calibration coefficient as the association between personal and surrogate exposure measure of PE to PM2.5 (0.84) was higher than PM2.5-10 (0.52). The findings further confirm that local sources were the dominant contributor to the coarse particles and these coefficients can potentially be used to estimate different PE to PM2.5 and PM2.5-10 conditions. A comprehensive understanding of the PE to determinants in coarse particles is essential to further reduce potential exposure misclassification.

Semi-dry and aqueous carbonation of steel slag: Characteristics and properties of steel slag as supplementary cementitious materials

Accelerated carbonation of steel slag presents a viable method for CO2 sequestration and the valorized utilization of steel slag. This study aimed to investigate the impact of semi-dry and aqueous carbonation, as well as the carbonation degree, on the microstructure and properties of steel slag. Additionally, it evaluated the feasibility of utilizing carbonated steel slag as supplementary cementitious materials (SCMs). Steel slag was subjected to CO2 (20% volume percentage) at 2 bar pressure for both semi-dry and aqueous carbonation process at room temperature with water/solid ratio of 0.08 and 5, respectively. The carbonation duration was varied (10 min, 30 min, 60 min, and 120 min) to adjust the degree of carbonation. Mortars and pastes with 30 wt% carbonated steel slag were formulated and their compressive strength and volume expansion values were quantified. The findings revealed that the CO2 uptake values for steel slag after 2 hours of semi-dry and aqueous carbonation were only 3.75% and 1.50%, respectively. Compounds such as Ca(OH)2, Mg(OH)2, and Ca2SiO5 demonstrated high carbonation reactivity during the semi-dry carbonation process, whereas Ca(OH)2 and Mg(OH)2 exhibited only a marginal increase in aqueous carbonated steel slag. The specific surface area of steel slag increased with an increase in the carbonation degree, attributed to the formation of silica gel or amorphous C-S-H during carbonation. However, the hydration activity of carbonated steel slag diminished with an increased degree of carbonation due to the consumption of alkaline minerals. Conversely, pozzolanic activity was enhanced with a higher degree of carbonation, owing to the formation of silica gel. The cumulative heat release of cement containing SDC30 (semi-dry carbonation for 30 min) within 24 h and 72 hours showed increases of 16.0% and 3.5%, respectively, aligning with the compressive strength results. Semi-dry carbonation treatment significantly enhanced the early-stage cementitious properties of steel slag/cement composites. Specifically, the 3-day compressive strength of mortar containing 30 wt% SDC30 increased by 22.7% relative to the reference mortar, composed of 30 wt% uncarbonated steel slag and 70 wt% Portland cement. Carbonation markedly improved the volumetric stability of steel slag with the extent of improvement was positively correlated with the carbonation degree for both semi-dry and aqueous carbonated steel slag. Aqueous carbonation was more effective in promoting the hydration process of free CaO and MgO more effectively than semi-dry carbonation.

Feasibility of using three solid wastes/byproducts to produce pumpable materials for land reclamation

Land reclamation is important for countries with limited land resources, and it requires a huge volume of filling materials. Traditional filling materials such as sand are depleting, which urges the discovery of new filling materials. The rapid growth of population and urbanization has also witnessed increasing solid waste generation. In this context, it is beneficial to turn the solid wastes into filling materials for land reclamation. This study, therefore, intended to reuse three solid wastes/byproducts, namely excavated marine clay (MC), incineration bottom ash (IBA), and ground granular blast-furnace slag (GGBS) to produce pumpable filling materials for land reclamation. Ordinary Portland cement (OPC) was utilized as a reference binder for comparison with GGBS. To this end, the workability (flowability and bleeding), appearance, unconfined compressive strength (UCS), mineralogy and microstructure, and leaching of heavy metals of the proposed materials were investigated. Considering the seawater exposure at land reclamation sites, the integrity of materials in water environments was examined. The results highlighted that for air-cured specimens, to achieve a target UCS of 100–200 kPa, the binder usage of IBA–MC–GGBS could be only half that of IBA–MC–OPC. In water environments, IBA–MC and IBA–MC–OPC generated cracks or were even dismantled, especially when soaked in seawater, posing a significant concern for land reclamation. However, IBA–MC–GGBS showed much higher resistance against seawater than IBA–MC and IBA–MC–OPC. The formation and growth of ettringite was the primary cause of the instability of IBA–MC and IBA–MC–OPC. The hydration of GGBS in IBA–MC–GGBS consumed alkaline minerals, which in turn suppressed the formation of ettringite. The results indicated the feasibility of using IBA–MC–GGBS as pumpable filling materials for land reclamation.

Role of the GLP2–Wnt1 axis in silicon-rich alkaline mineral water maintaining intestinal epithelium regeneration in piglets under early-life stress

Stress-induced intestinal epithelial injury (IEI) and a delay in repair in infancy are predisposing factors for refractory gut diseases in adulthood, such as irritable bowel syndrome (IBS). Hence, it is necessary to develop appropriate mitigation methods for mammals when experiencing early-life stress (ELS). Weaning, as we all know, is a vital procedure that all mammalian newborns, including humans, must go through. Maternal separation (MS) stress in infancy (regarded as weaning stress in animal science) is a commonly used ELS paradigm. Drinking silicon-rich alkaline mineral water (AMW) has a therapeutic effect on enteric disease, but the specific mechanisms involved have not been reported. Herein, we discover the molecular mechanism by which silicon-rich AMW repairs ELS-induced IEI by maintaining intestinal stem cell (ISC) proliferation and differentiation through the glucagon-like peptide (GLP)2–Wnt1 axis. Mechanistic study showed that silicon-rich AMW activates GLP2-dependent Wnt1/β-catenin pathway, and drives ISC proliferation and differentiation by stimulating Lgr5+ ISC cell cycle passage through the G1–S-phase checkpoint, thereby maintaining intestinal epithelial regeneration and IEI repair. Using GLP2 antagonists (GLP23−33) and small interfering RNA (SiWnt1) in vitro, we found that the GLP2–Wnt1 axis is the target of silicon-rich AMW to promote intestinal epithelium regeneration. Therefore, silicon-rich AMW maintains intestinal epithelium regeneration through the GLP2–Wnt1 axis in piglets under ELS. Our research contributes to understanding the mechanism of silicon-rich AMW promoting gut epithelial regeneration and provides a new strategy for the alleviation of ELS-induced IEI.