Search Results (367)

This study evaluated the effects of replacing 25% of wheat straw with dried carob (Ceratonia siliqua) leaves and twigs, either untreated or treated with 5% sodium hydroxide (NaOH), on growth performance, nutrient digestibility, carcass traits, meat quality, blood metabolites, and rumen microbial populations in Assaf lambs. Twenty-four male lambs (2.5 months old; 29 ± 0.5 kg) were randomly assigned to three dietary treatments (n = 8): a control diet containing wheat straw as the sole roughage source, supplemented with a concentrate feed, a diet with 25% untreated carob leaves and twigs (UCL), and a diet with 25% NaOH-treated carob leaves and twigs (TCL). Following a 14-day adaptation period, lambs were fed the corresponding experimental diet for 14 weeks. Carob inclusion improved growth performance, with UCL lambs showing the highest average daily gain (214 g/d) compared with TCL (201 g/d) and control (160 g/d), resulting in improved feed conversion ratio (9.02 vs. 5.68 and 5.63, respectively) (p < 0.001). Blood urea nitrogen was reduced (p < 0.001) in UCL lambs (26.8 vs. 38.5 mg/dL in control), suggesting improved nitrogen retention. Digestibility responses differed between treatments (p < 0.001), as TCL increased dry matter digestibility to 72.6% compared with 65.4% (UCL) and 63.6% (control), indicating enhanced nutrient utilization following NaOH treatment. Both UCL and TCL increased (p < 0.001) carcass weights (up to 24.7 vs. 21.0 kg in control), while TCL achieved the highest dressing percentage (46.6% vs. 43.4%). Meat quality traits were generally unaffected in terms of color (lightness, redness, and yellowness) and water-holding capacity; however, shear force decreased from 33.6 N (control) to 30.0 N (TCL), indicating improved tenderness. Carob inclusion modified meat composition by increasing (p < 0.001) lipid content (12.0–12.2 vs. 9.6%) and improving fatty acid profile, with reduced saturated fatty acids (53.4–56.5 vs. 61.4%) and increased α-linolenic acid (2.04 vs. 1.58%), leading to a lower n-6/n-3 ratio (5.54–5.61 vs. 6.45). Rumen fermentation was also affected (p < 0.001), as carob diets increased total bacterial populations and reduced protozoal counts, suggesting shifts toward more efficient microbial activity. In conclusion, replacing 25% of wheat straw with carob leaves improved growth performance and feed efficiency, with untreated carob primarily enhancing nitrogen utilization and treated carob improving fiber digestibility and carcass yield. These findings support the use of carob by-products as a viable alternative feed resource, although responses depend on processing method and targeted production outcomes. Full article

In recent years, oil spill accidents and oily wastewater discharge have posed severe threats to aquatic ecosystems and human health. Developing green, low-cost, efficient, and recyclable oil–water separation materials is therefore important for environmental remediation. In this work, kaolin/cellulose composite aerogels were fabricated through a low-temperature NaOH/urea dissolution system using N,N′-Methylenebisacrylamide (MBA) as the cross-linking agent, followed by freeze-drying and hydrophobic modification with Methyltrimethoxysilane (MTMS). The structure, morphology, thermal stability, wettability, mechanical behavior, oil adsorption capacity, and reusability of the aerogels were systematically investigated. The composite aerogels exhibited a honeycomb-like interconnected porous structure with low density and high porosity. Kaolin acted as an inorganic reinforcing and roughness-regulating component, which promoted the formation and anchoring of an MTMS-derived siloxane/SiO₂-like hydrophobic layer on the aerogel surface. The modified aerogels showed superhydrophobicity with a water contact angle above 152° and excellent oleophilicity. The optimized SC3K0.5 aerogel delivered adsorption capacities of 13.5 g/g for pump oil and 12.5 g/g for diesel. After 10 adsorption–desorption cycles, the adsorption capacity remained above 90% of the initial value, indicating good recyclability and mechanical stability. This recyclable kaolin/cellulose aerogel provides a feasible strategy for practical oil–water separation and oily wastewater treatment. Full article

This article presents the results of tests evaluating the physical and mechanical properties of a modified hydraulic concrete formulation based on Portland cement, intended for use in general construction. The additive consists of post-alcohol distiller’s grains (PaB), soapstock (Sp), caustic soda (NaOH), granite dust (Gr) and acrylic latex (Lx). These components contribute to transforming the strength characteristics of concrete in compression and bending, as well as its water absorption, water permeability and chemical resistance. Based on the results obtained, the effectiveness of the additive was assessed, as was the quantitative improvement in concrete properties, including an evaluation of the life cycle of reinforced concrete structures in aggressive environments. According to the research results, an optimal composition was obtained which increases compressive strength by 6.2%, flexural strength by 7.9%, decreases water absorption by 50.1%, decreases the filtration coefficient by 97.4%, and increases chemical resistance by 42.8%. Full article

This research investigates the relationship between mineralogical composition and compressive strength in alkali-activated cement–sand mortars incorporating palm oil fuel ash (POFA) as a partial replacement of Portland cement. POFA was introduced at 5 wt.% and 10 wt.% of the binder, and activation was achieved using a NaOH–Na₂SiO₃ solution (3:1 mass ratio). Compressive strength and bulk density were evaluated at 7 and 28 days, while phase evolution was analyzed by X-ray diffraction (XRD) coupled with Rietveld refinement. The results demonstrate that POFA incorporation significantly modified the CaO–SiO₂–Al₂O₃ balance of the system, promoting the consumption of portlandite and the formation of Na- and K-rich aluminosilicate phases such as albite and muscovite. The control mixture exhibited the highest compressive strength values, whereas increasing POFA content reduced both strength and density due to calcium dilution, lower gel compactness, and increased porosity. Nevertheless, all mixtures exhibited progressive strength development over time, indicating continued hydration and geopolymerization reactions associated with the formation of hybrid C–(N,K)–A–S–H gels. These findings demonstrate that POFA can effectively participate in alkali-activated hybrid binders when applied at controlled replacement levels, highlighting its potential as a sustainable supplementary material for lower-carbon cementitious systems. Full article

This study aims to systematically investigate the combined effect of chemical activation of açaí seeds (Euterpe oleracea Mart.), with an aqueous sodium hydroxide (NaOH) solution at 2 mol·L⁻¹, and process temperature by pyrolysis of alkaline activated açaí seeds on the yield of reaction products (bio-oil, gas, H₂O, and biochar), physicochemical properties (acid value, density, and kinematic viscosity) and chemical composition (hydrocarbons and oxygenates) of bio-oil. Catalytic pyrolysis was carried out in a 143 L reactor at temperatures of 350 °C, 400 °C, and 450 °C, 1.0 atmosphere, operating in batch mode. The NaOH activation played a crucial role in modifying the thermal degradation pathway of the biomass, promoting the formation of specific chemical structures and altering the product yields. NaOH acted as a catalyst, enhancing the deoxygenation of the biomass and stimulating the formation of hydrocarbons. As a result, the yields of bio-oil, water, biochar, and gas varied from 5.77 to 7.20% (by mass), 14.90 to 19.77% (by mass), 41 to 54% (by mass), and 25.33 to 32.03%, respectively, influenced by the increase in temperature. FT-IR analyses indicated the presence of characteristic chemical functions of hydrocarbons (alkanes, alkenes, and aromatics) and oxygenated compounds (phenols, cresols, ketones, esters, carboxylic acids, aldehydes, and furans), with an intensification of hydrocarbon signals at higher temperatures. GC-MS analysis identified hydrocarbons and oxygenated compounds as the main chemical classes in the bio-oil, showing a strong dependence on pyrolysis temperature. It was observed that hydrocarbon concentration in bio-oil increased from 49.7% to 57.88% (area) with increasing temperature, while the concentration of oxygenated compounds decreased from 13.88% to 6.69% (area), demonstrating that NaOH activation, combined with temperature elevation, favors the formation of hydrocarbons and the reduction of oxygenated compounds, thereby improving the quality of the produced bio-oil. Full article

To meet the requirements for passive heat dissipation and self-cleaning of aluminum alloy enclosures used in 5G base-station active antenna units (AAUs), a scalable surface modification strategy involving sandblasting, NaOH etching, and PFTEOS grafting was developed for 6061 aluminum alloy. Microscale rough structures were first constructed by sandblasting, and hierarchical micro/nano structures composed of microscale pits and nanoscale plate-like/coral-like features were subsequently formed through NaOH etching and boiling-water treatment. Finally, a low-surface-energy PFTEOS layer was grafted onto the structured surface to achieve superhydrophobicity. The effects of sandblasting pressure and etching time on surface morphology, chemical composition, wettability, and infrared emissivity were systematically investigated. The results show that sandblasting enhanced infrared emissivity by increasing surface roughness and promoting optical trapping, while NaOH etching further improved emissivity through the formation of hierarchical micro/nano structures and infrared-active AlOOH/Al₂O₃ phases. After PFTEOS grafting, the surface wettability changed from hydrophilic to superhydrophobic, while the high infrared emissivity was maintained. Compared with the untreated aluminum alloy, the modified surface exhibited a remarkable increase in water contact angle from 80.10° to 153.63° and infrared emissivity from 0.0102 to 0.8951. Moreover, the water contact angle remained above 150° after continuous water-jet impact, indicating good preliminary resistance to hydraulic shear. This work provides a feasible surface-engineering route for integrating high infrared emissivity and self-cleaning capability on aluminum alloy surfaces for outdoor thermal management applications. Full article

High-translucency zirconia (HTZ) has superior esthetic properties, but its unreliable resin bonding limits minimally invasive anterior restorations. An in situ surface modification was developed to synthesize CaZrO₃ particulates on pre-sintered HTZ for enhanced bonding durability. HTZ specimens were randomized into control (Zr-c) and calcium-modified (Zr-Ca) groups; Zr-Ca was treated with NaF/HCl mixture, calcium chloride glycerol solution, NaOH incubation (80 °C, 2 h), and sintering. Surface characteristics were characterized by SEM/EDS, AFM, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and FTIR. Flexural strength was tested via three-point bending; shear bond strength (SBS) was evaluated immediately and after 5000 thermocycles with resin cements (with/without 10-MDP). Zr-Ca showed uniform surface particulates, increased roughness, enhanced wettability, and surface Ca; XRD/FTIR/XPS confirmed CaZrO₃ and Ca-O-P species (after MDP). Zr-Ca with 10-MDP-containing resin adhesive had significantly higher SBS before/after aging (predominantly mixed failures), with flexural strength within clinical limits. In situ CaZrO₃ formation on HTZ strengthens MDP-mediated resin bonding and thermocycling resistance while preserving mechanical integrity, providing a feasible strategy for durable adhesion. Full article

Ammonium nitrogen (NH₄⁺-N) is a key biogenic pollutant in aquatic systems. This study evaluated natural diatomite (Aktobe region) and zeolite (Shankhanai, Zhetysu region) as low-cost, environmentally benign sorbents for NH₄⁺-N removal, and examined the effects of thermal (200–750 °C; 450 °C selected) and alkaline (0.5 M NaOH) treatments on their structural, textural and adsorption properties. Materials were characterized by XRD, XRF, FTIR, SEM-EDX and adsorption performance was assessed by kinetic and equilibrium experiments. Specific surface area and pore characteristics were determined from low-temperature nitrogen adsorption–desorption measurements, and the specific surface area was calculated using the Brunauer–Emmett–Teller (BET) method. Thermal treatment at 450 °C increased the specific surface area of diatomite (46.3 m²/g) and pore volume, and subsequent alkaline activation further enhanced adsorption activity. The modified diatomite achieved up to 84.6% removal of NH₄⁺-N with an equilibrium capacity q_max = 1.758 mg/g. Adsorption kinetics were best described by the pseudo-second-order (PSO) model, which may indicate a substantive role of surface chemical interactions. Equilibrium data were fitted with Langmuir and Freundlich models: the modified diatomite fitted Langmuir best (R² = 0.999), which may suggest predominance of a monolayer adsorption mechanism under the studied conditions, whereas natural samples and the zeolite were better described by the Freundlich model, reflecting likely surface energetic heterogeneity. Separation factor values (R_L = 0.068–0.643) indicate favorable adsorption within the investigated concentration range. The point of zero charge (pHpzc) was determined for all sorbents (5.3–6.3), confirming that at pH 7 the surface carries a negative charge favorable for electrostatic attraction of NH₄⁺ cations. Reusability tests over five consecutive adsorption–desorption cycles showed that modified diatomite and modified zeolite retained 93.4% and 92.3% of their initial removal efficiency, respectively, indicating acceptable stability under the applied regeneration conditions. These results demonstrate the potential of alkaline-modified diatomite and zeolite as effective sorbents for ammonium removal from wastewaters, contributing to the mitigation of eutrophication risks. Full article

In this study, carbonaceous and hybrid adsorbents were synthesized from waste flax fibers and fly ash, integrating two abundant waste streams into a single functional material. Materials were thermally modified and activated with NaOH at 500 °C in a nitrogen atmosphere. The prepared adsorbents exhibit high efficiency for scandium ion removal, with the hybrid systems significantly outperforming the individual components. The obtained Langmuir maximum adsorption capacities for the adsorption of scandium onto hybrid adsorbents were 18.28 and 32.32 mg/g, depending on the flax fibers/fly ash ratio. The contrasting thermodynamic behavior between hybrid adsorbents of different composition highlights the significant influence of material structure on the adsorption mechanism. The results demonstrate that the synergistic integration of waste flax fibers and fly ash in hybrid materials produces efficient and environmentally sustainable adsorbents, offering a novel approach for REE recovery from aqueous systems. Full article

Graphene oxide (GO) was employed as an additive to improve the electrochemical activity of zinc oxide (ZnO) used as both a photoelectrocatalyst for water splitting and an electrochemical sensor for detection of diclofenac. To comprehend the influence of a small amount of GO on the electrochemical activity of ZnO, a series of ZnO/xGO (x = 0, 0.1, and 0.5) particles was synthesized by microwave processing of Zn(OH)₂ precipitate in the presence of 0.1 and 0.5 wt.% of previously prepared GO. The phase composition and crystal structure ordering of ZnO/xGO particles were investigated by XRD and Raman spectroscopy. The optical properties were studied by UV–Vis DRS and PL spectroscopy. The particle morphology was inspected by FE–SEM while the textural properties were analyzed by the low-temperature nitrogen adsorption–desorption method. The (photo)electrocatalytic and electrochemical sensing activities were examined on the ZnO/rxGO modified glassy carbon electrodes (GCEs) prepared by in situ reduction of the ZnO/xGO modified GCEs for 120 s. The electro- and photoelectrocatalytic activity of ZnO/rxGO modified GCEs for water splitting was tested in dark conditions and after 60 min under illumination, respectively, employing linear sweep voltammetry in 0.1 M NaOH and 0.1 M H₂SO₄ as electrolytes. The electrochemical sensing activity of ZnO/rxGO modified GCEs was tested for detection of diclofenac in aqueous solution. The improvement in the electrochemical activity of ZnO was correlated with the added amount of GO, structural defects, and particle morphology. Full article

The increasing scarcity of freshwater in mining regions of Chile has promoted the use of low-quality water as an alternative in flotation processes, significantly modifying their operating conditions. In particular, high salt concentrations and the presence of dissolved ionic species may interfere with the adsorption of collectors on chalcopyrite, thereby reducing its hydrophobicity. In this context, the present study analyzes the adsorption characteristics and the mechanistic role of selected representative ionic species on the chalcopyrite surface. To this end, simulations based on density functional theory (DFT) were employed to describe the interaction between the chalcopyrite (112) surface and Na⁺, Ca²⁺, Mg²⁺, and OH⁻ ions. After geometric convergence of the optimized structures was achieved, adsorption energies, charge redistribution based on Mulliken population analysis, and the final structural configurations were evaluated for each case. The results revealed clearly differentiated behaviors among the ionic species considered. The OH⁻ ion exhibited a localized and specific interaction with metal-centered sites. By contrast, Ca²⁺ and Mg²⁺ show stable adsorption near sulfur atoms, indicating a higher affinity that may lead to the occupation or blocking of active surface sites. Meanwhile, Na⁺ displays a weak interaction without inducing significant structural modifications. Overall, these findings provide an atomistic-level interpretation of how ionic species present in low-quality water can influence the surface reactivity of chalcopyrite under flotation operating conditions. Full article

The study explores the potential of thermoplastic biocomposites made from cellulose acetate, modified hemp seed hull particulate fillers and environmentally friendly plasticizer triacetin. Emphasizing the environmental advantages of utilizing natural materials, the research demonstrates the impact of different hemp hull chemical modification, such as alkali treatment or acetylation, on the mechanical properties of the resultant composites. Hemp seed hulls treated with 4–16% NaOH solution were studied using SEM imaging, FT-IR, XRD and chemical composition analyses. The study showed that alkaline treatment of hemp seed hull particles improved the mechanical properties of biocomposites, and the optimum concentration of NaOH solution ranged from 8 to 12%. The tensile modulus increased by 17–24%, and the tensile strength improved by 21–23% in biocomposites containing HH8 and HH12 fillers, while hardness increased by approximately 11–13%. It was also demonstrated that alkaline treatment of hemp seed hull fillers accelerated the biodegradation of biocomposite extrudates under aerobic conditions in a standard aqueous medium. Overall, the results demonstrated the potential of alkaline-treated hemp seed hulls as fillers in composite bioplastics. Full article

Developing practical low-cost adsorbents for dye-contaminated wastewater remains a critical challenge, especially for persistent cationic dyes such as crystal violet (CV). Here, raw rockmelon skin (RMS), an abundant fruit-processing residue, and its NaOH-modified derivative (NaOH-RMS) were investigated as adsorbents for CV adsorption. Alkaline treatment altered the biomass’s characteristics and affected its adsorption behaviour. Equilibrium was reached within 120 min, and the kinetic data were best fit by the pseudo-second-order model. Equilibrium analysis showed that the Freundlich model best described RMS. In contrast, NaOH-RMS was better represented by the Langmuir model, indicating that alkaline treatment altered the adsorption behaviour of the biomass surface. The Langmuir-derived maximum adsorption capacities were 343.7 mg g⁻¹ for RMS and 295.2 mg g⁻¹ for NaOH-RMS, indicating that NaOH modification did not increase the maximum adsorption capacity. Adsorption was spontaneous across 298–343 K, and both materials retained satisfactory removal performance over five regeneration cycles, particularly under basic desorption conditions. Overall, NaOH treatment altered the adsorption behaviour from heterogeneous adsorption on RMS to a more Langmuir-type adsorption pattern on NaOH-RMS, despite not increasing the maximum adsorption capacity. These findings support the valorisation of fruit-processing residues as practical adsorbents for dye-contaminated wastewater. Full article

Rapid and accurate urea detection is of considerable importance in environmental monitoring and biomedical analysis, as abnormal urea levels are associated with water contamination and various health conditions. In this study, a silver nanoparticle-decorated graphene oxide (Ag/GO) composite was synthesized via a simple chemical reduction method. The characterization results confirmed the successful formation of well-crystalline Ag nanoparticles (7.44 ± 1.46 nm) with uniform dispersion on GO, with a Ag loading of 39.1 wt%. The electrochemical performance for urea detection was evaluated in an alkaline medium (0.1 M NaOH) using cyclic voltammetry and chronoamperometry in a three-electrode system. The Ag/GO-modified glassy carbon electrode exhibited a strong electrocatalytic response toward urea oxidation, with a linear detection range of 1–10 mM. The sensitivity and limit of detection (LOD) were 36.8 μA mM⁻¹ and 0.11 mM, respectively. The sensor also demonstrated excellent selectivity in the presence of common interfering species, including uric acid, ascorbic acid, and glucose, along with good reproducibility, repeatability, and stability. Furthermore, the practical applicability of the sensor was assessed in real samples, where satisfactory recovery was achieved in tap water, while reduced performance was observed in milk due to matrix effects. These findings indicate that the Ag/GO composite can serve as an effective alternative electrode material for non-enzymatic electrochemical detection of urea, particularly in wastewater and biological systems. Full article

In this study, a composite powder explosion suppressant (MVTS–NaHCO₃) was prepared via the wet coating method of the solution–crystallization (WCSC) process, using modified vanadium–titanium slag (VTS) as the carrier and NaHCO₃ as the active suppressive component. A 20 L spherical explosion apparatus and a transparent pipeline explosion propagation test system were employed to investigate the effects of the composite powder explosion suppressant with different mass fractions (0%, 10%, 20%, 30%, 40%, 50%) on the explosion pressure and micro-mechanism of polyacrylonitrile (PAN) dust. The experimental results indicated that the MVTS–NaHCO₃ composite powder exhibited a significant suppression effect on PAN dust explosions. In the confined 20 L vessel, complete suppression was achieved when the mass fraction of the composite powder explosion suppressant exceeded 30%, with a maximum explosion pressure reduction of 53.2%. In the semi-open pipeline, 40% composite powder explosion suppressant reduced the maximum explosion pressure to 0.08 MPa (a reduction rate of 82.6%), and complete suppression was achieved at a mass fraction of 50%. Microstructural analysis revealed that the suppression performance of the composite powder explosion suppressant is attributed to the synergetic effects of physical and chemical mechanisms. Physically, NaHCO₃ decomposes endothermically (100 kJ/mol), releasing CO₂ and H₂O and thereby diluting the oxygen concentration, while the porous structure of MVTS enhances dispersibility. Chemically, the hydroxyl groups on the surface of MVTS bond with NaHCO₃, delaying its decomposition, while metal hydroxides (e.g., Al(OH)₃) decompose thermally to form Al₂O₃, which adsorbs and quenches free radicals (e.g., ·OH, ·H), thereby inhibiting chain reactions. This study provides new insights for the resource utilization of VTS and the prevention and control of industrial dust explosions. The findings have important reference value for optimizing explosion suppressant formulations and improving the intrinsic safety. Full article