Search Results (277)

Functional gastrointestinal disorders (FGIDs) affect over 40% of the global population and represent a substantial health and economic burden. Gandhaga Dravagam (GD) is a classical Siddha mineral-based distillate prepared from sulfur, potassium nitrate, and alum, traditionally indicated for gastrointestinal complaints such as diarrhea, indigestion, and colonic spasm. This study aimed to standardize GD using organoleptic and physicochemical evaluation, qualitative acid-radical and basic-radical tests, elemental analysis by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), and X-ray Diffraction (XRD), as well as to assess its antispasmodic potential against acetylcholine (ACh)-induced contractions in an isolated rat ileum model. GD was a clear acidic liquid (pH 2.05 at 10% aqueous dilution) with a specific gravity of 1.0142 at 25 °C. Qualitative analysis confirmed carbonate, sulfate, phosphate, and nitrate radicals. ICP-OES identified sulfur (501.254 mg/L) as the predominant element, followed by aluminum (155.341 mg/L), potassium (100.121 mg/L), phosphorus (56.341 mg/L), and sodium (1.320 mg/L); arsenic, mercury, lead, manganese, and magnesium were below detection limits. XRD revealed crystalline inorganic phases consistent with the sulfur-, potassium-, and aluminum-based constituents. At a single concentration (2% v/v), GD reduced ACh-induced contractile responses by 40.74–56.25% across all ACh concentrations tested (5–80 µg), indicating a consistent antispasmodic effect. These findings provide a preliminary analytical and pharmacological characterization of GD and warrant further mechanistic, toxicological, and clinical evaluation. Full article

Microplastics, MPs, plastic particles with dimensions between 0.1 and 5 mm, represent an important environmental pollutant. The removal of microplastics from natural and wastewater is a challenging research topic. In this regard, high-performance technical solutions must be identified, which can be based on existing treatment and purification technologies, to ensure their removal at concentration values in accordance with the legislation in force. In this study, the efficiency of removing some fractions of polyurethane microplastics, with dimensions smaller than 500 µm, from aqueous synthetic solutions with a concentration of 0.2 g L⁻¹, i.e., around 175 NTU, was evaluated. In the first stage of the study, the doses of coagulants and flocculants effective for the removal of microplastics were identified through the Jar Test. The variation in turbidity and their removal efficiencies were evaluated in the presence of classic coagulants, such as aluminum sulfate, Al₂(SO₄)₃·18H₂O, SA; iron sulfate (ferrous sulfate), FeSO₄, IS; polyaluminum chloride, [Al₂(OH)_nCl_6−n], PAC; Aloe Vera, AV, a flocculant; and activated carbon, AC, of the Norit GAC 830 W type. Classic coagulants, such as aluminum sulfate, have a good efficiency in removing microplastics, being able to provide a residual turbidity in the range of 6–10 NTU after a retention time of 50–60 min. In the second stage of the study, the removal efficiency of microplastics was tested using a laboratory pilot plant—called in the study the Smart Decantation-Filtration System, SDFS. The efficiency of the decanter was studied using Response Surface Methodology (RSM) to identify mathematical models that characterize the influence of key process variables: flow rate (A), microplastic size (B) and aluminum sulfate concentration (C) on microplastic removal efficiency. Sedimentation in the specially constructed decanter can raise the optimal value of the removal efficiency of polyurethane microplastics to 98.98%, and filtration can ensure an efficiency that reaches over 99.5%. Through this research, we aimed to identify viable solutions that can be applied to remove microplastics, MPs, from natural and wastewater. A novel element is the fact that we chose to study the removal of polyurethane, which is studied little in the literature. We identified the optimal doses of coagulants and flocculants that help sedimentation of MPs. The efficiency of an installation called Smart Decantation-Filtration System, specially designed to ensure increased efficiency in the removal of microplastics, was determined. The results obtained were encouraging. Full article

Herbaceous biomass is a promising renewable energy resource, but its use in thermochemical systems is often limited by severe fouling and ash agglomeration resulting from alkali-rich ash chemistry. This study directly compares two practical fouling mitigation strategies, kaolin addition and acid washing, for alkali-rich torrefied kenaf biomass under identical experimental conditions. The study quantitatively distinguishes aluminosilicate-based alkali stabilization from pretreatment-based alkali removal as two distinct pathways for controlling ash transformation. Kenaf exhibited severe ash agglomeration and contained high levels of K₂O (17.38 wt.%), CaO (31.52 wt.%), MgO (14.98 wt.%), SO₃ (9.43 wt.%), and P₂O₅ (6.90 wt.%). Kaolin addition progressively shifted the ash composition toward a SiO₂–Al₂O₃-rich system. From KA-10 to KA-30, SiO₂ increased from 22.86 to 33.58 wt.%, while Al₂O₃ increased from 7.65 to 15.43 wt.%. X-ray diffraction (XRD) analysis further showed that increasing kaolin addition suppressed alkali-salt phases and promoted the formation of aluminum-silicate phases. In contrast, acid washing directly reduced alkali species, decreasing K₂O to 5.66–7.83 wt.% and eliminating detectable Na₂O. The acid-washed samples were characterized by calcium-rich sulfate and silicate phases, indicating a distinct ash transformation pathway. Kaolin addition primarily reduced fouling by promoting aluminosilicate-based alkali stabilization, whereas acid washing reduced alkali–metal contents before thermal treatment. This distinction clarifies the different roles of additive-based and pretreatment-based strategies for fouling control in alkali-rich herbaceous biomass. Full article

This study explores the natural dyeing of banana pseudo-stem (BSS) fibers as a sustainable material for plant-based leather applications through low-energy processes. Two dye types, lac dye and indigo blue, were applied, and the optimal dyeing parameters were systematically determined. Optimal lac dyeing was achieved using pre-mordanting with a binary mordant system comprising tannic acid and aluminum potassium sulfate (5 g L⁻¹ each), a dye concentration of 10% owf, a pH of 4.23, and a dyeing duration of 6 h. For indigo dyeing, the optimal conditions involved 500 g L⁻¹ wet indigo, 30 g L⁻¹ sodium hydroxide, and 40 g L⁻¹ thiourea dioxide, with a reduction step at 30 °C for 30 min. The dyed samples exhibited good to excellent perspiration fastness in terms of staining, while color change ratings remained low due to the intrinsic sensitivity of natural dyes. Light fastness was rated fair. The dyed BSS was subsequently laminated onto a polypropylene (PP) nonwoven substrate and coated with natural rubber (NR) latex, yielding bursting strengths of 51.8–54.8 psi. Moisture management testing confirmed inherent waterproof properties. Overall, this study presents a resource-efficient approach to transforming agricultural residues into sustainable, plant-based leather alternatives. Full article

The treatment of oily wastewater represents a significant environmental challenge, requiring efficient separation technologies and waste valorization. This study evaluated different types of coagulants (ferric chloride 38% m/m, aluminum polychloride 18% m/m, aluminum sulfate 8% m/m, and ferrous sulfate 6% m/m) and anionic polymers (from six suppliers) for treating poultry slaughterhouse effluent, aiming to optimize both clarification and oil recovery from the floated sludge. Bench-scale jar tests (G = 300 s⁻¹ and 30 s⁻¹) were followed by full-scale validation in a dissolved air flotation unit (100 m³ h⁻¹) at a poultry processing WWTP. Recovered oil was extracted by hot cooking (95 °C) and tridecanter centrifugation, and its quality (moisture, acidity, saponification index) was assessed. A techno-economic analysis, including simple/discounted payback, NPV, IRR, Monte Carlo simulation (10,000 iterations, Python), and deterministic sensitivity analysis, was performed. Ferric chloride (38% m/m) produced the best technical results: treated effluent turbidity < 30 NTU, oil yield of 360 L day⁻¹ with moisture < 2% at the tridecanter outlet, and consistent sludge dewaterability (moisture 55–65%). Oil moisture increased dramatically (to >30%) after storage due to condensate contamination from an inefficient exhaust system, a critical operational flaw that must be corrected. No statistically significant effect of polymer type on oil recovery was observed, although high variability (CV > 50%) was noted during PAC tests. The simple payback period for ferric chloride was 60.7 months (discounted: 64.1 months), with a positive median NPV (USD 7925) under a 12% p.a. discount rate. Sensitivity analysis showed that the investment is most sensitive to oil price: a 20% drop in oil price leads to a negative NPV (−USD 21,727). Despite this risk, the project provides environmental compliance and waste-to-value benefits. The study demonstrates that ferric chloride enables effective oil extraction from poultry wastewater, but proper exhaust design is essential to maintain oil quality. Future work should focus on standardized test durations (≥72 h) and automated monitoring to reduce variability. Full article

Gypsum-based fire protection relies on thermally activated dehydration, where chemically bound water is released and evaporated, thereby providing an endothermic heat sink that delays heat penetration through assemblies. In parallel, inorganic hydrated salts are increasingly used as flame-retardant additives in gypsum-based systems to enhance heat absorption over specific temperature ranges. Fire simulation tools and performance-based fire engineering approaches require reliable kinetic data and reaction enthalpies that can be implemented as coupled thermal–chemical source terms. However, additive-specific kinetic datasets remain limited, particularly under restricted vapor exchange conditions representative of porous construction materials. This work investigates the thermal decomposition behavior and dehydration kinetics of Aluminum Trihydrate (Al(OH)₃, ATH), Magnesium Hydroxide (Mg(OH)₂, MDH), Calcium Aluminate Sulfate (3CaO·Al₂O₃·3CaSO₄·32H₂O, CAS), and Magnesium Sulfate Heptahydrate (MgSO₄·7H₂O, ESM) with emphasis on vapor-restricted conditions representative of confined porous systems. Differential scanning calorimetry (DSC) experiments were conducted at three heating rates (2, 10, and 20 K/min for MDH, CAS and ESM and 20, 40 and 60 K/min for GB-ATH) up to 600 °C using pinhole crucibles to simulate autogenous vapor pressure. The thermal analysis indicates that ATH and MDH exhibit predominantly single-step dehydration behavior, while ESM shows a complex multi-step mechanism. Although CAS presents a single dominant thermal peak in the DSC signal, the isoconversional analysis reveals a multi-stage reaction behavior, demonstrating that peak-based interpretation alone may be insufficient for such systems. Kinetic parameters were determined using both model-free (Starink) and model-fitting approaches in accordance with the recommendations of the Kinetics Committee of the International Confederation for Thermal Analysis and Calorimetry (ICTAC). All reactions were consistently described using the Avrami–Erofeev model as an effective phenomenological representation of the conversion behavior. The extracted kinetic triplets were validated through numerical simulations, showing good agreement with experimental conversion and reaction rate data. The resulting kinetic parameters and dehydration enthalpies provide a physically consistent dataset for the description of dehydration processes under restricted vapor exchange. These results support the development of thermochemical models for gypsum-based systems; however, their transferability to full-scale assemblies remains subject to validation under coupled heat- and mass-transfer conditions. Full article

Cadmium contamination of water resources represents a serious environmental and public health challenge, with conventional treatment methods often proving inadequate for industrial-level remediation. In this study, we present a novel, sustainable composite material, functionalized cellulose nanocrystal polyvinyl alcohol zinc oxide ferric chloride (CNC-PVA-ZnOFe) beads for the efficient removal of cadmium from contaminated water. The material integrates adsorption, coagulation, and flocculation mechanisms within a single hybrid platform, with coagulation–flocculation serving as the dominant mechanism given the material’s macroporous structure and limited surface area (1.2–3.3 m²/g). Functionalized cellulose nanocrystals provide supporting adsorptive sites for metal binding, while a PVA matrix incorporating ZnOFe improves structural integrity, mechanical stability, and coagulation performance. Characterization confirmed successful functionalization, enhanced thermal stability, and a macroporous structure (12–52 nm pores) conducive to floc entrapment, though with limited surface area (1.2–3.3 m²/g) for conventional adsorption. Under optimized conditions (pH 7–10, initial Cd²⁺ concentration of 100 mg/L, coagulant dose of 0.1 g, and sedimentation time of 60 min), the functionalized CNC-PVA-ZnOFe beads achieved a cadmium removal efficiency of 78%, achieving significantly higher cadmium removal efficiency than traditional coagulants, such as aluminum sulfate (69%). The beads also demonstrated good reusability, retaining 85% removal efficiency after five regeneration cycles. This work presents a scalable, eco-friendly material for cadmium removal under controlled laboratory conditions using synthetic solutions. However, further evaluation in real wastewater matrices containing competing ions and organic matter is necessary to establish practical applicability for water treatment applications. The study highlights the combined potential of multifunctional hybrid materials while acknowledging the need for validation under environmentally relevant conditions. While the results indicate successful integration of multiple removal mechanisms, direct validation of synergistic interactions through techniques such as zeta potential and XPS analysis remains an important direction for future research. Full article

A hybrid material based on the copolymerization of EDOT (3,4-ethylenedioxythiophene) and Py (pyrrole), 1:1 monomer ratio, onto multi-walled carbon nanotubes (MWCNTs) was synthesized through a multistep functionalization approach. The resulting P(EDOT-co-Py)@MWCNT hybrid, poly(3,4-ethylenedioxythiophene-co-pyrrol)@MWCNT hybrid, was characterized by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). These characterizations confirmed the successive functionalization steps, the effective anchoring of the monomers, and the subsequent formation of the copolymer. Transmission electron microscopy (TEM) images revealed a homogeneous polymer coating along the nanotube surface while preserving the structural integrity of the MWCNTs throughout the functionalization and polymerization processes. The P(EDOT-co-Py)@MWCNT hybrid was evaluated as an active electrode material for aluminum-ion storage in an aqueous aluminum sulfate electrolyte. The system exhibited two distinct charge-storage mechanisms: at high current densities, proton surface adsorption dominated, whereas at lower rates, a faradaic contribution associated with polymer chain redox activity and the reversible extraction/insertion of Al³⁺ became prevalent. The hybrid electrode delivered high specific capacities, reaching 200.6, 106.3, and 44.3 mAh g⁻¹ at 0.10, 0.25, and 0.50 A g⁻¹, respectively. These values are comparable to—or even exceed—those reported for similar cathodic materials designed for Al³⁺ storage, highlighting P(EDOT-co-Py)@MWCNT hybrid as a highly promising cathode candidate for aqueous aluminum-ion energy-storage systems. Full article

The management of invasive alien species (IAS) generates large amounts of plant waste biomass that is commonly disposed of by burning or destruction, leading to environmental and economic drawbacks. At the same time, the production of synthetic dyes and pigments used in printing and graphic applications remains a significant source of pollution. In this context, the valorization of IAS biomass as a source of natural colorants represents a sustainable alternative aligned with circular economy principles. Here, biocompounds and natural dyes were extracted from four invasive or non-native plant species—Arundo donax, Phytolacca americana, Tradescantia fluminensis, and Eucalyptus globulus—using five solid–liquid extraction methods: infusion, infusion with heat, thermal agitation, Soxhlet extraction, and ultrasonic-assisted extraction. Extraction efficiency and color preservation were comparatively evaluated. Although Soxhlet extraction provided the highest extraction yield (up to 30.5%), infusion with heat proved to be the most suitable method for preserving color integrity and minimizing oxidation. Liquid dyes obtained by the selected extraction method were converted into solid pigments through a lake pigment precipitation process using aluminum potassium sulfate and sodium bicarbonate. The resulting pigments were characterized in terms of chemical composition, particle size, and chromatic properties, and subsequently formulated into oil-based inks using linseed oil as binder. Scanning electron microscopy revealed pigment particle sizes ranging from approximately 2.1 to 8.3 µm, depending on the plant source, and confirmed adequate ink penetration and distribution on commercial printmaking paper. The obtained pigments exhibited color tones ranging from yellow to brown and grey, mainly associated with the phenolic and tannin content of the original biomass. Printing tests demonstrated the suitability of the developed inks for manual printmaking techniques, highlighting the potential of IAS-derived pigments as sustainable alternatives for artistic and printing applications. Full article

“Heijin” (the literal translation from Chinese being “Black Gold”) seal stone represents a unique variety of sulfur-rich, dickite-dominant jade, yet its mineralogical genesis and structural properties remain insufficiently characterized. This study utilizes a multi-analytical approach comprising polarized light microscopy, X-Ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy coupled with Energy-Dispersive X-Ray Spectroscopy (SEM-EDS), Electron Probe Microanalysis (EPMA), and Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) to investigate the phase composition, crystalline order, and thermal evolution of this material. The results demonstrate that “Heijin” stone is primarily composed of highly ordered 2M₁ dickite with a Hinckley index (HI) ranging from 0.92 to 1.50. Its distinctive black appearance originates from the disseminated distribution of micrometer-scale pyrite, which is accompanied by trace amounts of svanbergite. This aluminum phosphate–sulfate (APS) mineral serves as a critical indicator of high sulfur fugacity and acidic hydrothermal alteration environments. Furthermore, a significant correlation exists between the crystalline order of dickite, its micro-morphology, and its thermal stability. Samples characterized by high crystallinity (HI ≈ 1.50) exhibit well-developed, euhedral book-like aggregates and elevated dehydroxylation temperatures (T_m ≈ 665 °C), whereas samples with lower crystalline order correspond to fragmented microstructures and reduced thermal stability. This research defines the mineralogical identity of “Heijin” stone and provides a scientific basis for employing thermal analysis to evaluate the crystalline quality of dickite-based jade materials. Full article

Earthen immovable cultural relics, such as murals and painted clay sculptures, are prone to deterioration (e.g., efflorescence, flaking, and cracking) under long-term preservation conditions. While conventional restoration materials primarily offer reinforcement, they fail to regulate the migration of soluble salts within the relics, which is the main cause of such damage. Herein, aimed at protecting the painted sculptures and murals of the Yungang Grottoes, nano calcium-aluminum layered double hydroxides (Ca-Al LDHs) were prepared, and their effectiveness in regulating salt crystallization within the earthen ground layer, as well as their reinforcement performance were investigated. Simulated salt crystallization tests revealed that coating the ground layer with Ca-Al LDHs delayed salt-induced damage time by 150%. This can be attributed to the ability of Ca-Al LDHs to adsorb sulfate ions from soluble salts, thereby inhibiting the crystallization of magnesium sulfate on the surface of the ground layer. After curing Ca-Al LDHs-coated samples at 35 °C and 55% relative humidity (RH) for 7 days, their surface Leeb hardness increased by 3.1%, and the weight loss rate (measured via tape peeling test) decreased by 38.3%. These results indicate that the surface bonding strength was enhanced following Ca-Al LDHs coating, with the underlying mechanism being the transformation of part of the LDHs into calcium carbonate under the influence of water and carbon dioxide. This study demonstrates that Ca-Al LDHs not only suppress magnesium sulfate crystallization but also provide effective surface consolidation, showing promising potential for application in conserving painted sculptures and murals at the Yungang Grottoes. Full article

Phosphogypsum (PG), a calcium sulfate-rich byproduct of phosphate fertilizer production, is generated in vast quantities worldwide and represents a major environmental management challenge. At the same time, its chemical composition makes PG a potentially valuable soil amendment, particularly for the reclamation of saline, sodic, and acidic soils. This review critically synthesizes current knowledge on PG generation processes, physicochemical properties, agronomic performance, and associated environmental and health risks. Evidence from peer-reviewed studies demonstrates that appropriately managed PG applications can improve soil structure, enhance water infiltration, reduce sodium toxicity, alleviate aluminum stress, and increase crop productivity. However, PG contains variable levels of impurities, including heavy metals and naturally occurring radionuclides, which raise concerns regarding soil contamination, groundwater pollution, food safety, and human health, especially under high or repeated application rates. Regulatory frameworks governing PG use differ substantially between regions, reflecting inconsistencies in waste classification, radiological thresholds, and leaching criteria. This review highlights key knowledge gaps related to contaminant mobility, bioavailability, and long-term ecological impacts and discusses mitigation strategies such as purification, controlled application rates, and integrated regulatory oversight. By balancing agronomic benefits against environmental risks, this work provides a comprehensive framework for the safe valorization of phosphogypsum in agriculture, supporting sustainable land management and circular economy objectives. Full article

Leachates generated in sanitary landfills are a mixture of contaminants harmful to adjacent ecosystems. Coagulation and flocculation are common treatment methods; however, their efficiency depends on the type of coagulant–flocculant and the operating conditions. This study addressed leachate treatment using two natural biocoagulants, Nostoc sphaericum (CNS) and Opuntia ficus-indica mucilage (CMN), in combination with aluminum sulfate (CSA). Optimization was performed using response surface methodology, employing a Box–Behnken design with five factors, namely CNS, CMN, and CSA doses, as well as agitation time and agitation speed, evaluated at three levels, on turbidity reduction. Fourier transform infrared spectroscopy (FTIR) showed that the biocoagulants possess anionic surfaces with carboxyl and hydroxyl groups. The particle size of CNS exhibited a bimodal distribution with a zeta potential of −28.74 mV, while CMN showed a unimodal distribution with a zeta potential of −21.95 mV. Under optimal conditions (88.97 mg/L CNS, 105.60 mg/L CMN, 9.13 mg/L CSA, a mixing time of 25.96 min, and an agitation speed of 24.21 rpm), a turbidity reduction to 48.15 NTU was predicted. During the experimental validation of these optimal conditions, turbidity was reduced to 49.02 NTU, achieving a removal efficiency of 70%. Total organic carbon (TOC) was reduced by 65%, and metals such as arsenic were reduced by 56%. Reductions in phosphates and Biochemical Oxygen Demand (BOD₅) were moderate, while the removal of Chemical Oxygen Demand (COD), surfactants, and ammoniacal nitrogen was limited. These results indicate that the combination of CNS and CMN is a viable alternative for leachate pretreatment. Full article

This study synthesizes two highly water-soluble copolymers, p(SA-co-SMAS) and p(SA-co-SMAS-co-AMPS) using sodium alginate (SA), sodium 2-methylprop-2-ene-1-sulfonate (SMAS), and 2-acrylamido-2-methylpropane sulfonic acid (AMPS, with or without addition) as precursors. Under ball milling, these copolymers are blended with aluminum sulfate and glass fibers to produce two series of cement admixtures. Compared to systems without admixtures or with pure aluminum sulfate as sole admixture, the admixture obtained from p(SA-co-SMAS) and aluminum sulfate significantly shortens the initial setting time (4.47 vs. 33.59 and 29.51 min) and final setting time (8.46 vs. 45.26 and 35.12 min), while markedly improving compressive strength (9.2 vs. 3.5 and 4.3 MPa) and flexural strength (3.5 vs. 1.0 and 1.1 MPa). This enhancement is attributed to the formation of a unique boehmite (AlO(OH)) phase in synthesized admixture, which rapidly reacts with tricalcium silicate, gypsum, and water in cement to form ettringite (Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O). The ettringite interlocks with the two-dimensional C–S–H gel, creating a stable three-dimensional network. Further blending this admixture with 200-mesh glass fibers yields a new admixture containing Al₄SO₄(OH)₁₀·36H₂O. Compared to boehmite, this phase further reduces setting times and increases average compressive strength (10.2 vs. 9.2 MPa). The admixture derived from p(SA-co-SMAS-co-AMPS) and aluminum sulfate shows even better performance: setting times are further shortened and flexural strength is significantly enhanced, owing to the presence of the more effective Al₄SO₄(OH)₁₀·36H₂O phase. Incorporating 200-mesh glass fibers into this system results in the shortest setting times (initial: 2.24 min, final: 5.73 min) and an excellent 24 h compressive strength (9.4 MPa), likely due to a unique and unexpected pore-filling effect. In contrast to conventional uses of sodium alginate as a retarder, glass fibers as mere reinforcements, and aluminum sulfate as a strength-impairing accelerator, this work demonstrates a synergistic strategy, which enables an ultra-rapid and high-strength cement setting process, offering highly significant scientific and practical value. Full article

Soil salinization has become a major threat affecting global arable productivity. Rice cultivation with amendment application is considered an important approach for saline–sodic soil reclamation. Saline–sodic soil without vegetation was selected as the study subject to investigate the effects of amendments in rice cultivation on salinity and sodicity through a pot experiment. The results revealed that the application of desulfurization gypsum combined with aluminum sulfate to saline–sodic soil significantly contributed to decreases in soil salinity and sodicity. The soil pH in the 0–10 cm, 10–20 cm and 20–30 cm soil layers decreased from 9.41–9.84 to 8.06–9.24, whereas the exchangeable sodium percentage (ESP) decreased from 28.98–33.24% to 19.76–30.82%, respectively. The increase in soil exchangeable Ca²⁺ was accompanied by a decrease in soil exchangeable Na⁺. Additionally, the application of desulfurization gypsum combined with aluminum sulfate to saline–sodic soil resulted in significant decreases in total alkalinity (TA) and the sodium adsorption ratio (SAR) and an increase in soluble Ca²⁺. The analysis indicated that soluble Ca²⁺ derived from desulfurization gypsum is the predominant factor affecting the variation in the soil pH, ESP, SAR, and exchangeable Na⁺ and Ca²⁺. The reductions in salinity and sodicity are attributed to the replacement of Ca²⁺ derived from desulfurization gypsum with Na⁺ on soil collides. Simultaneously, H⁺ formed by the hydrolysis of aluminum sulfate neutralizes HCO₃⁻ and CO₃²⁻ in the water layer. Full article