Search Results (618)

Isolating rhenium and molybdenum selectively from multicomponent acidic hydrometallurgical solutions remains problematic because of the abundance of competing cations and the low concentration of target oxoanions. This study investigates the sorption of Re(VII) and Mo(VI) oxoanions by an interpolymer system (IPS) comprising a cellulose–polyethyleneimine–glutaraldehyde (Cellulose-PEI-GA) weak-base anion exchanger and a sulfonated styrene–divinylbenzene cation-exchange resin (Lewatit MonoPlus SP112H), operating as spatially separated but solution-coupled phases. The industrial feed, a sulfuric acid leach liquor from electrostatic precipitator dust at the Zhezkazgan copper smelter, Kazakhstan (pH 1.25), was pretreated by liquid–liquid extraction with a trialkylamine-2-ethylhexanol–kerosene system followed by ammonia stripping to give an alkaline re-extract (pH 11.98) used for sorption. At the optimal 1:1 mass ratio of the two components (3:3), the IPS achieved a rhenium recovery of 77.7% (Kd = 3678 mL g⁻¹, q = 4.51 mg g⁻¹) against a markedly lower molybdenum recovery of 24.0% (Kd = 333 mL g⁻¹), giving a Re/Mo separation factor β of 8.8–15.5 across the studied compositions; this uptake exceeded the value predicted from the individual sorbents by a factor of ~2.6, indicating a cooperative rather than purely additive effect. Sorption kinetics (pseudo-first-order, pseudo-second-order and Elovich models) and diffusion mechanisms (Weber–Morris and Boyd models) were consistent with mixed film- and intraparticle-diffusion control. Desorption with hydrochloric acid recovered 91.4% of the sorbed rhenium and 89.1% of the molybdenum, and FTIR, TGA, and BET analyses (surface area increasing from 1.93 to 8.62 m² g⁻¹ for the cellulose component and from 7.21 to 8.46 m² g⁻¹ for the resin) confirmed sorbate-induced textural and compositional changes consistent with the proposed complementary anion-/cation-exchange mechanism. Full article

Ammonia-responsive gelatin-based composite films containing cobalt metal–organic frameworks (Co–MOFs) synthesized using gallic acid as an organic ligand were developed and evaluated as intelligent packaging materials. Co–MOFs were incorporated into gelatin films at concentrations of 2.5, 5.0, 7.5, and 10.0% (w/w, based on gelatin). The effects of Co–MOF incorporation on the physicochemical, structural, thermal, mechanical, and sensing properties of gelatin films were systematically investigated. Increasing Co–MOF content reduced film moisture content (from 14.47 to 13.25–13.58%) and swelling capacity (from 599.37 to 484.88–547.30%), while increasing solubility (from 39.09 to 48.88%), water vapor permeability (WVP; from 1.652 to 2.054 g·mm/m²·h·kPa), and moisture sorption behavior. Sorption isotherm analyses based on the Guggenheim–Anderson–de Boer (GAB) and Brunauer–Emmett–Teller (BET) models confirmed enhanced water adsorption capacity and increased specific surface area in the films (from 356.13 to 455.74 m²/g). Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) analyses demonstrated successful incorporation of Co–MOFs into the gelatin matrix, revealing good dispersion at low and moderate concentrations and partial aggregation at higher loadings. The incorporation of Co–MOFs improved the thermal stability of the films, while only a moderate reduction in mechanical strength was observed with increasing filler content. The composite films exhibited rapid and concentration-dependent colorimetric responses toward ammonia vapor. After 120 min of exposure, the color difference (ΔE) increased from less than 1 in the control film to approximately 12, 15, 24, and 27 for G/Co–MOF2.5, G/Co–MOF5, G/Co–MOF7.5, and G/Co–MOF10 films, respectively. Films containing higher amounts of Co–MOF showed faster response kinetics and greater color differences, enabling clear visual detection of ammonia. These findings demonstrate that gelatin/Co–MOF composite films based on gallic acid-derived metal–organic frameworks are promising intelligent packaging materials for monitoring food freshness and spoilage through ammonia detection. Full article

Ce-modified MnCo₂O₄ flower-like nanosheet electrodes were prepared on nickel foam by a hydrothermal-calcination route and sequentially optimized with respect to reaction time, nominal Ce content, and PVP addition. Comparative SEM, XRD, XPS, and N₂-sorption analyses identify MnCo₂O₄-9 h-3%Ce-PVP as the optimized electrode, with an open hierarchical nanosheet network and a BET surface area of 210.0 m² g⁻¹. The direct XRD/XPS control comparison distinguishes Ce-associated lattice and surface-state changes from PVP-associated synthesis effects without treating either trend as proof of substitutional Ce occupancy or quantitatively established oxygen vacancies. Likewise, PVP is treated as a morphology-directing additive whose transient adsorption or bridging role remains a synthesis hypothesis rather than a directly verified molecular mechanism. The optimized positive electrode delivers 2008 F g⁻¹ at 1 A g⁻¹, retains 1227 F g⁻¹ at 20 A g⁻¹, and shows 99.0% capacitance retention after 10,000 cycles at 5 A g⁻¹. A carbon-supported iron oxide negative electrode, designated C/Fe₂O₃ only as a sample label because its exact oxide phase was not independently resolved by XRD or Raman spectroscopy, provides 443 F g⁻¹ at 1 A g⁻¹. The resulting charge-balanced asymmetric device operates over 0–1.6 V and delivers 34.6 F g⁻¹ at 1 A g⁻¹, corresponding to 12.30 Wh kg⁻¹ at 0.8 kW kg⁻¹. At 10 A g⁻¹, it retains 29.8 F g⁻¹ and delivers 10.60 Wh kg⁻¹ at 8.0 kW kg⁻¹, equivalent to 86.1% capacitance retention over a tenfold increase in current density. All device-level gravimetric values are calculated using the total active mass of both electrodes. Full article

Iron (Fe) contamination of water sources has become an increasing environmental concern, creating the need for effective, environmentally friendly, and cost-effective technologies for Fe(III) removal from aqueous systems. In the present work, the possibility of using the sulfuric acid-activated carbon made of Vigna trilobata rind waste for treating water contaminated with Fe ions was explored. The characteristics of the synthesized material were identified by physical, chemical, and spectroscopic methods, and its Fe ion sorption efficiency was studied experimentally in batch mode under various conditions. Equilibrium, kinetics, and thermodynamics of Fe ion removal by the prepared adsorbent were determined. The obtained adsorbent had a BET surface area of 20.55 m² g⁻¹ and showed high experimental adsorption capacity with the highest observed uptake of 19.81 mg g⁻¹. Based on the experimental results, the equilibrium data could be best described by the Langmuir equation (R² = 0.978). Kinetic analysis showed that the rate-limiting step in Fe ion sorption was intraparticle diffusion (R² = 0.921). Thermodynamic calculations indicated that the adsorption process occurred spontaneously (ΔG° = −4.31 to −6.53 kJ mol⁻¹) and endothermically (ΔH° = +7.11 kJ mol⁻¹). A comparative analysis showed that the sorption capacity of the studied adsorbent corresponded to that reported for the analogous materials produced from other biomasses. Full article

Direct utilization of biomass-derived silica in neutral surfactant-templated mesoporous synthesis remains underexplored with respect to mesostructure control and functional integration. High-purity silica extracted from acid-treated rice husk ash (~98.4 wt% SiO₂) was employed as the sole precursor in a fluoride-assisted sol–gel route to synthesize MSU-X frameworks without chemical modification. Systematic parametric variation—pH, Si/surfactant ratio, hydrothermal temperature, and aging duration—establishes quantitative structure–processing correlations. Under optimized conditions (pH 2, Si/Tergitol = 8, 60 °C, 96 h), the resulting material exhibits a wormhole-like mesoarchitecture with a BET surface area of 816 m² g⁻¹, mean pore diameter of ~3.6 nm, and three-dimensionally interconnected channels, confirmed by SAXS, TEM, and N₂ sorption. EDXRF analysis confirms effective impurity removal and high silica incorporation efficiency (~95–96%); thermal stability persists to 700 °C, with incipient crystallization near 800 °C. As a functional demonstration, MSU-X served as an anti-agglomeration scaffold for ZIF-8 crystallization during DDT adsorption. Despite attenuated kinetics relative to pristine ZIF-8—where severe agglomeration occludes active imidazole nodes—the Z8/MSU-X composite achieved near-quantitative DDT removal (74.10 mg g⁻¹). This performance stems from the mesoporous matrix driving size-confined, highly dispersed ZIF-8 growth, thereby maximizing active-site exposure. Operating within a reagent-limited regime rather than a capacity-saturated boundary, this efficient depletion confirms that the scaffold successfully suppresses site loss. Ultimately, these findings validate biogenic silica as a directly integrable precursor for tailored mesostructure assembly, positioning agricultural waste as a high-performance feedstock for hierarchical adsorption architectures. Full article

The sorption behavior of antibiotics in wastewater treatment systems plays a critical role in determining their environmental fate and removal efficiency. In this study, the sorption of 15 antibiotics representing multiple classes was investigated using two sewage sludge samples with different physicochemical characteristics. Batch equilibrium experiments were conducted to evaluate time-dependent sorption behavior and to determine solid–water distribution coefficients (K_d). The results showed that sorption occurred rapidly, with most compounds approaching a stable concentration within 24 h. The K_d values varied widely depending on the compound, ranging from 74 to 737 L/kg. For 13 of the 15 investigated antibiotics, higher K_d values were observed in sludge B than in sludge A, with the largest difference observed for tiamulin (402 ± 53 and 737 ± 76 L/kg for sludge A and sludge B, respectively). Sludge B generally exhibited higher sorption capacity for most compounds than sludge A, despite having a lower specific surface area, indicating that sorption was governed primarily by chemical composition and pore structure rather than surface area alone. Elemental and morphological analyses suggested that differences in metal-associated components and pore structure may contribute to the higher sorption capacity observed in sludge B. However, the specific sorption mechanisms could not be directly confirmed by the present analyses. Comparison with previous studies confirmed that the measured K_d values fall within reported ranges but are generally higher for sulfonamides, suggesting enhanced sorption capacity of the investigated sludge matrices. Application of an equilibrium-based model demonstrated that sorption alone can account for approximately 20–70% of antibiotic removal under typical activated sludge conditions, depending on compound affinity. These findings highlight the importance of sludge-specific properties in controlling antibiotic partitioning and demonstrate that incorporating such characteristics into predictive models can improve the accuracy of environmental fate assessments in wastewater treatment systems. Full article

This study investigated the impact of cobalt/nickel-silicate loadings on graphitic carbon nitride at 10% and 20% doses, designated (CoNiSi-10) and (CoNiSi-20), for the removal of ciprofloxacin (CPF), a hazardous, bioaccumulative antibiotic. The synthesized composites were characterized in detail using SEM, EDX, TEM, N₂ adsorption–desorption, XRD, and FTIR techniques. The CoNiSi-10 and CoNiSi-20 exhibited CPF q_t values of 64 and 107 mg g⁻¹, respectively, which were consistent with the surface area results. Adsorption kinetics indicated that CPF uptake on CoNiSi-10 and CoNiSi-20 fitted the Lagergren model, with the liquid-film and intraparticle-diffusion mechanisms co-governing CPF sorption. The isotherm investigations indicated CPF adsorption on CoNiSi-10 and CoNiSi-20 aligned with the Langmuir model, suggesting a homogeneous surface, while the Dubinin-Radushkevich results primarily indicated physisorption-based CPF removal. The thermodynamic analyses supported the physisorption outcome and indicated that CPF sorption onto CoNiSi-10 and CoNiSi-20 was endothermic. A five-cycle reusability test yielded average efficiencies of 94% and 96% for CoNiSi-10 and CoNiSi-20, respectively, and an after-sorption analysis indicated their stability and robustness. The ease of synthesis and excellent sorption performance may nominate CoNiSi-10 and CoNiSi-20 as promising adsorbents for treating pharmaceutically contaminated wastewater. Full article

Bentonite is widely used as a sorbent due to its high specific surface area and ion-exchange capacity; however, its properties can be significantly influenced by the presence of additional mineral phases and chemical modification. In this study, the influence of manganese oxides and quartz sand on the sorption properties of bentonite from the Stará Kremnička was systematically investigated, with particular attention to surface characterization by X-ray photoelectron spectroscopy (XPS). The materials were also characterized by X-ray diffraction, FTIR spectroscopy, and zeta potential measurements. XPS analysis revealed that manganese in all modified samples was predominantly present in the Mn(IV) oxidation state, with Mn 2p₃/₂ binding energies of 642.5–642.7 eV, corresponding to MnO₂-type phases. Deconvolution of the O 1s spectra confirmed the presence of lattice oxygen, silicate oxygen, and surface hydroxyl groups. The reason for the modification of mainly natural materials with manganese oxides is their higher affinity for the adsorption of heavy metal cations. The maximum adsorption capacity of natural bentonite was 63.29 mg/g. In bentonite samples modified with manganese oxides, the value increased to 103.09 mg/g for BMn, and to 116.28 mg/g for the MMn mixture. The results demonstrate that sorption behavior is governed by a combination of ion exchange on bentonite and interactions with Mn oxide surface phases, providing new insight into the role of Mn(IV) species in surface-controlled metal binding processes. These findings highlight the importance of surface chemical states in designing efficient bentonite-based sorbents. Full article

This review focuses on research outputs of water purification, wastewater treatment, metallic remediation, and sorption-based experimental studies. It aims to identify the leading nations contributing to these areas and identify the journals that have published the highest number of papers from 2010 to 2025, and centers on yearly publication trends. A thorough quantitative analysis was carried out to examine key characteristics of adsorbents derived from various materials, as well as symmetry and asymmetry of wastewater treatment for the removal of metallic pollutants. Key adsorption mechanisms—including ion exchange, surface complexation, electrostatic attraction, and pore filling—are discussed alongside the structural roles of symmetric (ordered) and asymmetric (heterogeneous) adsorbent architectures. Data was collected from the Scopus database, focusing on specific keywords like “metal,” “water,” “removal,” “adsorption,” “purification,” “drinking water,” “nano adsorbent,” etc. Among approximately 29,598 publications encompassing research papers, reviews, short communications, conference papers, and book chapters, China emerged as the leading publisher with 11,957 papers, trailed by India (4324 papers), the USA (1825 papers), Iran (1739 papers), Saudi Arabia (1484 papers), Egypt (1318 papers), and Republic of Korea (1194 papers). The bibliometric mapping of conventional adsorbents and nanomaterials used in sorption-based technologies was analyzed using VOSviewer, revealing major research clusters, research hotspots, networks, and evolutionary patterns in wastewater treatment and sorption-based water purification. This study indicates that several journals from Elsevier Ltd. and Springer Nature are leading the field with a large number of publications per year. The analysis reveals a consistent upward trend in the number of research publications in recent years. In sum, the bibliometric data provided highlights the growing relevance of these areas among academicians and acts as a catalyst for further research, motivating researchers to investigate new adsorbents or modifications that could improve adsorption performance while maintaining economic viability and efficiency. Full article

Porous glycidyl methacrylate-based copolymers crosslinked with ethylene glycol dimethacrylate (EGDMA) and trimethylolpropane trimethacrylate (TMPTMA) were synthesized via suspension–emulsion polymerization and subsequently functionalized with triethylenetetramine. The effect of the monomer composition on the epoxy group content and porous structure was systematically investigated by varying the GMA-to-crosslinker molar ratio from 1:1 to 5:1. Increasing the GMA fraction enhanced the epoxy group content (2.8–5.0 mmol/g) but significantly reduced the specific surface area (333–23 m²/g), indicating a trade-off between functionality and porosity. ATR-FTIR and elemental analysis confirmed successful amine functionalization while preserving a considerable degree of porosity. The modified copolymers were evaluated for Cr(VI) removal, showing strong pH dependence, with maximum efficiency at pH 3 due to electrostatic interactions between protonated amine groups and HCrO₄⁻ ions. Equilibrium studies revealed saturation-type behavior, with a maximum sorption capacity of 165.47 mg/g for TMPTMA-based copolymers. Despite the higher nitrogen content in EGDMA-based materials, TMPTMA-crosslinked copolymers exhibited a superior adsorption performance, demonstrating that pore accessibility, rather than functional group density alone, governs adsorption efficiency. These findings provide insight into the rational design of amine-functionalized porous polymer sorbents for efficient chromium(VI) removal. Full article

This work focused on synthesizing MgSiO₃ (0%Mo@MgSi), 2.5%MoO3@MgSiO₃ (2.5%Mo@MgSi), 5%MoO₃@MgSiO₃ (5%Mo@MgSi), and 10%MoO₃@MgSiO₃ (10%Mo@MgSi) by a single-step process utilizing butylated hydroxytoluene (BYHT) as a novel capping agent. The X-ray diffraction analysis of the synthesized nanohybrids indicated amorphous nanohybrids, while the energy-dispersive X-ray spectroscopy results illustrated variations in the MoO₃ doping dosages. The 0%Mo@MgSi, 2.5%Mo@MgSi, 5%Mo@MgSi, and 10%Mo@MgSi nanohybrids exhibited average sizes of 17.6, 12.2, 11.7, and 9.9 nm, respectively, and surface areas of 43.53, 40.95, 42.17, and 44.98 m²·g⁻¹, respectively. The examination of 0%Mo@MgSi, 2.5%Mo@MgSi, 5%Mo@MgSi, and 10%Mo@MgSi nanohybrids toward the oxytetracycline (OTC) sorption resulted in q_t values of 72.89, 116.89, 98.39, and 78.46 mg·g⁻¹, respectively. The OTC sorption onto the 0%Mo@MgSi, 2.5%Mo@MgSi, 5%Mo@MgSi, and 10%Mo@MgSi aligned with the nonlinear pseudo-second order model, and both the intraparticle and liquid-film diffusion models co-influenced the OTC sorption onto the four nanohybrids. Increasing the temperature decreased OTC sorption on 2.5%Mo@MgSi, indicating exothermic sorption. The Langmuir isotherm model was more suitable than the Freundlich model for describing OTC adsorption on 2.5%Mo@MgSi. The Dubinin–Radushkevich energy (E_D ≤ 8.0 kJ·mol⁻¹) and the Gibbs free energy (ΔG° ≤ 20 kJ·mol⁻¹) supported each other’s outcomes about the OTC removal onto 2.5%Mo@MgSi being via physisorption. The ΔG° values increased proportionally with temperature, indicating that OTC sorption becomes more spontaneous as temperature decreases. Moreover, the 2.5%Mo@MgSi exhibited excellent stability in OTC elimination up to the third cycle. Full article

Bioadsorbents derived from food waste can not only help reduce the amount of such waste but also demonstrate significant potential for CO₂ capture from both the energy sector and other industries. This study evaluates the feasibility of using bioadsorbents obtained from various types of household biowaste—including black and green coffee grounds, tea grounds, potato peels, walnut shells and green walnut shells—for CO₂ capture from flue gas. The bioadsorbents were produced through a two-step process consisting of carbonization followed by KOH activation. The physicochemical properties of the bioadsorbents were characterized using SEM, FTIR, XRD, TGA and BET techniques. The CO₂ sorption capacity was examined for bioadsorbents and for the original biowaste and the biocarbons obtained after carbonization. Isothermal CO₂ adsorption tests were carried out at 25 °C under 100% CO₂ atmosphere. The influence of porous properties—such as specific surface area, total pore volume, micropore volume and average pore diameter—on the CO₂ sorption capacity was assessed for bioadsorbents, biocarbons and raw biowastes. The results showed that the most effective bioadsorbent for CO₂ capture was derived from spent dark roast coffee grounds, with a sorption capacity of 115.8 mg_CO2/g_A. The favorable sorption performance of this bioadsorbent was attributed to its high specific surface area (1580 m²/g), the largest total pore volume (0.84 cm³/g) and micropore volume (0.5 cm³/g) among the tested materials, as well as an optimal average pore diameter (0.96 nm). Similarly favorable structural properties were observed for the potato peel-derived bioadsorbent (APP—1604 m²/g; 0.65 cm³/g) and the bioadsorbent derived from green walnut shells (AGWS—1376 m²/g; 0.64 cm³/g). Their CO₂ adsorption capacities reached 104.1 mg_CO2/g_A and 73.2 mg_CO2/g_A, respectively, for AGWS and APP. Full article

The surface functionalization of mesoporous bioactive glasses (MBGs) is of critical importance for the development of advanced hybrid biomaterials with controlled interfacial and adsorption properties. Composite systems based on MBGs modified with cucurbit[n]urils (CB[6], CB[7], and CB[8]) were synthesized and systematically investigated to elucidate size-dependent interaction mechanisms and their influence on textural and physicochemical characteristics. Functionalization was achieved via aqueous deposition followed by controlled thermal treatment. Nitrogen sorption analysis revealed distinct pore modification behaviors: CB[6] reduced the specific surface area by 64% with partial pore occupation; CB[7] induced extensive mesopore occlusion (92.4% surface area reduction); whereas CB[8] produced a balanced decrease (71.2%) while largely preserving microporosity. Thermogravimetric analysis demonstrated comparable loading for CB[7] and CB[8], yet MBGs@CB[8] exhibited enhanced thermal stability, with the DTG maximum shifted to ~395 °C. Molecular modeling supported these findings, indicating the lowest adsorption energy for CB[8]. This combination of structural preservation and enhanced stability provides the most favorable balance between pore accessibility and structural modification, demonstrating strong potential as a versatile modifier for subsequent functionalization, including drug loading applications in bone-regenerative systems. Full article

Porous thin-film getters are extensively utilized in the field of MEMS vacuum packaging. Nevertheless, their effectiveness is frequently constrained by the comparatively modest effective surface area of conventional planar structures. In this work, a porous Au/Ti thin-film getter based on a three-dimensional black silicon scaffold is developed to enhance the effective surface area and improve gettering performance. The fabrication of black silicon nanostructures is achieved through an SF₆/O₂-based inductively coupled plasma (ICP) etching process, followed by the deposition of Au/Ti bilayer films by DC magnetron sputtering. The morphological evolution of the Ti film on the nanostructured substrate and the activation behavior of the Au/Ti bilayer are systematically investigated using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that the shadowing effect during sputtering leads to the formation of a porous film with increased surface roughness and an open structure. XPS analysis demonstrates that there is a significant increase in the oxygen content on the surface at higher activation temperatures. This suggests that effective sorption capability is achieved following activation. In comparison with planar substrates, the three-dimensional black silicon scaffold has been demonstrated to promote the formation of a more open and functional structure. The results obtained from this study indicate that the proposed fabrication strategy offers a feasible and MEMS-compatible approach for the construction of porous thin-film getters, thereby enhancing their effective surface area. Full article

This review examines microplastics (MPs) in aquatic environments, their interactions with organic pollutants (OPs), effects on organisms, and implications for human and ecological health. MPs are ubiquitous, persistent contaminants. Their small size and large surface area enhance adsorption of diverse OPs; however, the extent to which MPs influence pollutant transport, fate, and bioavailability remains highly context-dependent and is still under scientific debate. Sorption processes are influenced by polymer type, pollutant properties, environmental factors, and aging processes that increase surface reactivity, further contributing to the variability of MP–OP interactions. Detection of MPs in human tissues raises concerns about long-term health effects, including inflammatory, immune, gastrointestinal, respiratory, and endocrine responses. Despite advances in analytical techniques, challenges remain in identifying and quantifying small particles in complex matrices. This review emphasizes the need for integrated, multi-technique, and environmentally realistic studies to understand MP–OP interactions and support risk assessment. Future research should focus on standardizing methodologies, improving nano-sized particle detection, and elucidating long-term effects, including trophic transfer and potential tissue accumulation. Full article