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Search Results (206)

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Keywords = zeolite clinoptilolite

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18 pages, 1515 KiB  
Article
Enhancing Professional Periodontal Therapy with a Novel PMA-Zeolite Application: A Clinical Study on Periodontal Outcomes and Microbiological Changes
by Ines Đapić, Andrej Aurer, Jurica Žučko, Marinka Mravak-Stipetić, Marinka Baranović Baričević, Krešimir Pavelić, Fusun Ozer and Sandra Kraljević Pavelić
J. Funct. Biomater. 2025, 16(8), 270; https://doi.org/10.3390/jfb16080270 - 22 Jul 2025
Viewed by 469
Abstract
Periodontitis is a chronic, multifactorial inflammatory disease characterized by the progressive destruction of the periodontal supporting tissues, including alveolar bone, potentially resulting in tooth loss. Etiopathogenesis involves a dysbiotic shift in the subgingival microbiota where the presence of pathogenic species such as Porphyromonas [...] Read more.
Periodontitis is a chronic, multifactorial inflammatory disease characterized by the progressive destruction of the periodontal supporting tissues, including alveolar bone, potentially resulting in tooth loss. Etiopathogenesis involves a dysbiotic shift in the subgingival microbiota where the presence of pathogenic species such as Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Treponema denticola has been documented. This disbalance is combined with an inadequate host immune response, often exacerbated by other systemic comorbidities including diabetes mellitus and cardiovascular diseases. Conventional therapy typically comprises mechanical debridement and adjunctive local or systemic antimicrobials, but emerging antibiotic resistance highlights a need for alternative adjuvant therapeutic strategies. The present descriptive analysis of microbiome and clinical trends study evaluated the adjuvant effects of a clinoptilolite-based zeolite material, namely PMA-zeolite, with professional prophylaxis on clinical and microbiological parameters in patients with chronic periodontitis over a 10-week period. Clinical assessment revealed significant reductions in bleeding on probing (BoP) and periodontal pocket depth (PD), indicating improved inflammatory status. Microbiome profiling demonstrated a marked decrease in key periodontal pathogens, suggesting that PMA-zeolite can help rebalance the oral microbiome. These findings suggest that the combined therapy exhibits promising anti-inflammatory and antimicrobial properties, indicating its role in promoting microbial homeostasis and reducing periodontal inflammation. However, further investigation through larger, controlled clinical trials is needed to validate the efficacy of the therapy. Full article
(This article belongs to the Special Issue Active Biomedical Materials and Their Applications, 2nd Edition)
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29 pages, 3303 KiB  
Article
Synergetic Effect of Tin and Potassium as Modifying Additives on Rhodium Catalysts in the Process of Selective Dehydrogenation of Associated Petroleum Gas
by Kairat A. Kadirbekov, Mojtaba Mirzaeian, Nurdaulet A. Buzayev and Almaz K. Kadirbekov
Catalysts 2025, 15(7), 688; https://doi.org/10.3390/catal15070688 - 17 Jul 2025
Viewed by 370
Abstract
This paper presents the results of an investigation into the catalytic activity and selectivity of rhodium-based catalysts supported on natural zeolite clinoptilolite from the Shankanai field (Kazakhstan) in the dehydrogenation of light alkanes from associated petroleum gas (APG). Three modifications of the catalyst [...] Read more.
This paper presents the results of an investigation into the catalytic activity and selectivity of rhodium-based catalysts supported on natural zeolite clinoptilolite from the Shankanai field (Kazakhstan) in the dehydrogenation of light alkanes from associated petroleum gas (APG). Three modifications of the catalyst have been studied: basic 1%Rh/HCpt, modified with tin 1%Rh/10%SnO/HCpt, and combined with additives of tin and potassium 1%Rh/10%SnO/5%K2O/HCpt. It has been shown that the addition of tin contributes to increased thermal stability and a decreased coking rate, while the addition of potassium suppresses side reactions (cracking and isomerization), increasing the selectivity for olefins. The highest yield of olefins (~30%) is achieved with the 1%Rh/10%SnO/5%K2O/HCpt catalyst in the presence of water vapor. Using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), improved distribution of active components and reduced catalyst deactivation have been confirmed. The obtained data demonstrate the potential of the developed systems for the efficient processing of APG and the selective synthesis of olefins. Full article
(This article belongs to the Section Catalysis for Sustainable Energy)
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34 pages, 2026 KiB  
Review
Review of Applications of Zeolites in Dermatology: Molecular Perspectives and Translational Potentials
by James Curtis Dring, Matthew Kaczynski, Rina Maria Zureikat, Michael Kaczynski, Alicja Forma and Jacek Baj
Int. J. Mol. Sci. 2025, 26(14), 6821; https://doi.org/10.3390/ijms26146821 - 16 Jul 2025
Viewed by 482
Abstract
Zeolites, microporous aluminosilicates with tuneable physicochemical properties, have garnered increasing attention in dermatology due to their antimicrobial, detoxifying, and drug delivery capabilities. This review evaluates the structural characteristics, therapeutic mechanisms, and clinical applications of zeolites—including clinoptilolite, ZSM-5, ZIF-8, and silver/zinc-functionalized forms—across skin infections, [...] Read more.
Zeolites, microporous aluminosilicates with tuneable physicochemical properties, have garnered increasing attention in dermatology due to their antimicrobial, detoxifying, and drug delivery capabilities. This review evaluates the structural characteristics, therapeutic mechanisms, and clinical applications of zeolites—including clinoptilolite, ZSM-5, ZIF-8, and silver/zinc-functionalized forms—across skin infections, wound healing, acne management, and cosmetic dermatology. Zeolites demonstrated broad-spectrum antibacterial and antifungal efficacy, enhanced antioxidant activity, and biocompatible drug delivery in various dermatological models. Formulations such as silver–sulfadiazine–zeolite composites, Zn–clinoptilolite for acne, and zeolite-integrated microneedles offer innovative avenues for targeted therapy. Zeolite-based systems represent a promising shift toward multifunctional, localized dermatologic treatments. However, further research into long-term safety, formulation optimization, and clinical validation is essential to transition these materials into mainstream therapeutic use. Full article
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8 pages, 438 KiB  
Proceeding Paper
Assessment of the Oxidative State of Thermally Treated Sunflower Oil After Regeneration with Molecular Sieves
by Ljubica Vasiljević, Sanja Dobrnjac, Stevan Blagojević and Milenko Aćimović
Eng. Proc. 2025, 99(1), 20; https://doi.org/10.3390/engproc2025099020 - 27 Jun 2025
Viewed by 158
Abstract
Edible oils undergo undesirable changes over time or during thermal treatment due to enzymatic, microbial, and chemical processes, leading to spoilage. In this study, the oxidative state of sunflower oil was assessed by determining the peroxide value (PV), anisidine value (AV), and totox [...] Read more.
Edible oils undergo undesirable changes over time or during thermal treatment due to enzymatic, microbial, and chemical processes, leading to spoilage. In this study, the oxidative state of sunflower oil was assessed by determining the peroxide value (PV), anisidine value (AV), and totox value (TV) using standard methods. The oil was heated at temperatures ranging from 110 to 190 °C for 10 and 30 min, also in the presence of molecular sieves (zeolite 4A, clinoptilolite, and bentonite). When using the synthetic molecular sieve zeolite 4A, a reduction in the totox value by 35.72% was observed. When natural molecular sieves were used, a reduction of 33.19% was recorded for clinoptilolite, while for bentonite, the reduction was 31.08%. Both natural and synthetic molecular sieves demonstrated a strong ability to regenerate thermally treated oils. Full article
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20 pages, 1744 KiB  
Review
Application of Modified Natural Zeolite—Clinoptilolite for Bacterial Control in the Environment
by Jasna Hrenović and Nevenka Rajić
Materials 2025, 18(10), 2411; https://doi.org/10.3390/ma18102411 - 21 May 2025
Viewed by 857
Abstract
Natural zeolites are highly effective adsorbents that can remove various metal cations which would otherwise contaminate the environment. However, different metal cations (Cu, Zn, and Ag) within their lattice or quaternary long-chain surfactant cations on their surface modify their affinity towards hazardous anions [...] Read more.
Natural zeolites are highly effective adsorbents that can remove various metal cations which would otherwise contaminate the environment. However, different metal cations (Cu, Zn, and Ag) within their lattice or quaternary long-chain surfactant cations on their surface modify their affinity towards hazardous anions and promote antibacterial activity in natural zeolites. Specifically, natural zeolites in their non-modified form lack intrinsic antibacterial characteristics. NZ is the most widespread natural zeolite. This review presents the antibacterial efficiency of NZ containing transition metals, nano oxides, and organics. This effect is nonspecific and primarily driven by the nutritional makeup of the medium rather than the species of pathogenic bacteria under study. Studies on using NZ-based disinfectants to clean up contaminated water and soil and using modified and purified NZ to protect health are also considered. By eliminating toxic ions and, when modified by these toxic cations, removing pathogens from the environment, natural NZ can serve a dual function, providing it with the distinctive characteristics of a sustainable material. Full article
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31 pages, 8832 KiB  
Article
Stabilization of Expansive Soils Using Cement–Zeolite Mixtures: Experimental Study and Lasso Modeling
by Ibrahim Haruna Umar, Sale Abubakar, Abdullahi Balarabe Bello, Hang Lin, Jubril Izge Hassan and Rihong Cao
Materials 2025, 18(10), 2286; https://doi.org/10.3390/ma18102286 - 14 May 2025
Viewed by 612
Abstract
The stabilization of expansive soils is crucial for the construction projects to mitigate swelling, shrinkage, and bearing capacity issues. This study investigates the synergistic effects of cement and clinoptilolite zeolite on stabilizing high-plasticity clay (CH) soil from Kano State, Nigeria. A total of [...] Read more.
The stabilization of expansive soils is crucial for the construction projects to mitigate swelling, shrinkage, and bearing capacity issues. This study investigates the synergistic effects of cement and clinoptilolite zeolite on stabilizing high-plasticity clay (CH) soil from Kano State, Nigeria. A total of 30 admixture combinations—cement (0–8%) and zeolite (0–15%)—were tested via standardized laboratory methods to evaluate their free swell index (FSI), swell percentage, swell pressure, shrinkage, and California Bearing Ratio (CBR). Principal component (Lasso) “least absolute shrinkage and selection operator” regression modeled interactions between admixtures and soil properties. The key results include the following: (1) 6% cement + 12% zeolite reduced the FSI by 60% (45 → 18); (2) 8% cement + 15% zeolite decreased the swell percentage by 47.8% (22.5% → 11.75%); (3) 6% cement + 12% zeolite lowered swell pressure by 54.2% (240 kPa → 110 kPa); (4) 8% cement + 12% zeolite reduced shrinkage by 50% (5.6% → 2.8%); and (5) 6% cement + 9% zeolite achieved an unsoaked CBR of 80.01% and soaked CBR of 72.79% (resilience ratio: 0.8010). PCLR models explained 93.5% (unsoaked) and 75.0% (soaked) of the CBR variance, highlighting how zeolite’s mediation analysis indicates that zeolite improves the bearing capacity mainly by reducing the free swell index (path coefficient = −0.91429, p < 0.0001), while conditional process modeling provided greater explanatory power (R2 = 0.745) compared to moderation-only analysis (R2 = 0.618). This study demonstrates that zeolite–cement blends optimize strength and resilience in expansive soils, with implications for sustainable infrastructure in arid and semi-arid regions. Full article
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11 pages, 1070 KiB  
Article
The Application of Zeolites for Fixation of Cr(VI) Ions in Sediments
by Marjana Simonič
Physchem 2025, 5(2), 19; https://doi.org/10.3390/physchem5020019 - 8 May 2025
Viewed by 757
Abstract
The aim of the study was to investigate the fixation of Cr(VI) ions from contaminated sediments using synthetic zeolite 4A and natural zeolite clinoptilolite. Parameters such as pH, contact time, adsorption mass and temperature were investigated. If the ions of the heavy metals [...] Read more.
The aim of the study was to investigate the fixation of Cr(VI) ions from contaminated sediments using synthetic zeolite 4A and natural zeolite clinoptilolite. Parameters such as pH, contact time, adsorption mass and temperature were investigated. If the ions of the heavy metals were mobile, they would become toxic to the environment. After sediment digestion, the initial and final concentrations of Cr(VI) were measured in sediment samples with or without zeolite. Inductively coupled plasma with optical emission spectroscopy (ICP-OES) and X-ray diffraction (XRD) were used to characterize the material. The adsorption kinetics were investigated using a pseudo-first order model, a pseudo-second order model, and an intra-particle diffusion model. The results showed that the zeolites enhanced the fixation of Cr(VI). Chemisorption was the main mechanism when using acid-modified zeolite. Full article
(This article belongs to the Section Kinetics and Thermodynamics)
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15 pages, 5368 KiB  
Article
Radioiodide Sorption on Natural and Acid-Treated Zeolite
by Petr Belousov, Ekaterina Tyupina, Pavel Kozlov, Yulia Izosimova, Inna Tolpeshta, Tatiana Koroleva, Boris Pokidko, Victoria Krupskaya and Anastasia Rumyantseva
Minerals 2025, 15(5), 494; https://doi.org/10.3390/min15050494 - 7 May 2025
Viewed by 485
Abstract
This work is devoted to the study of the effect of acid treatment on the structural and textural properties of natural zeolite and its sorption activity with respect to radioiodide. To carry out the experiments, natural zeolite was treated with nitric acid of [...] Read more.
This work is devoted to the study of the effect of acid treatment on the structural and textural properties of natural zeolite and its sorption activity with respect to radioiodide. To carry out the experiments, natural zeolite was treated with nitric acid of various concentrations at 20 and 90 degrees. The following methods were used to study the samples: XRD, SEM, DTA, XRF, FTIR, BET, and CEC analyses. Experiments on the sorption and desorption of radioiodide were carried out. The obtained results indicate that acid treatment results in the gradual leaching of aluminum from the crystal lattice and a significant increase in the specific surface area and microporosity of the zeolite. At the same time, the morphology of clinoptilolite is not significantly changed. Additional studies have shown that acid treatment leads to the hydrophobization of zeolite channels and the formation of an amorphous aluminosilicate phase, which makes a significant contribution to the increase in the specific surface area and microporosity. It was found that, with an increase in the degree of dealumination of the zeolite, there is an increase in the sorption properties with respect to radioiodide. The maximum values of sorption capacity were obtained after treating the zeolite with a 1 M nitric acid solution at 90 °C. With a further increase in the concentration of acid, critical changes in the structure of the zeolite occur, leading to a sharp decrease in the sorption capacity. Iodide sorption is not associated with physical adsorption in the micropores of the zeolite and the newly formed amorphous phase. The main mechanism of the sorption appears to be the interaction with silanol and bridging hydroxyl groups on the surface of the zeolite and the amorphous aluminosilicate phase. Full article
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30 pages, 1810 KiB  
Article
Zeolite and Inorganic Nitrogen Fertilization Effects on Performance, Lint Yield, and Fiber Quality of Cotton Cultivated in the Mediterranean Region
by Ioannis Roussis, Antonios Mavroeidis, Panteleimon Stavropoulos, Konstantinos Baginetas, Panagiotis Kanatas, Konstantinos Pantaleon, Antigolena Folina, Dimitrios Beslemes and Ioanna Kakabouki
Crops 2025, 5(3), 27; https://doi.org/10.3390/crops5030027 - 3 May 2025
Viewed by 2060
Abstract
The continuous provision of nitrogen (N) to the crop is critical for optimal cotton production; however, the constant and excessive application of synthetic fertilizers causes adverse impacts on soil, plants, animals, and human health. The current study focused on the short-term effects (one-year [...] Read more.
The continuous provision of nitrogen (N) to the crop is critical for optimal cotton production; however, the constant and excessive application of synthetic fertilizers causes adverse impacts on soil, plants, animals, and human health. The current study focused on the short-term effects (one-year study) of adding different rates of clinoptilolite zeolite, as part of an integrated nutrient management plan, and different rates of inorganic N fertilizer to improve soil and crop performance of cotton in three locations (ATH, MES, and KAR) in Greece. Each experiment was set up according to a split-plot design with three replications, three main plots (zeolite application at rates of 0, 5, and 7.5 t ha−1), and four sub-plots (N fertilization regimes at rates of 0, 100, 150, and 200 kg N ha−1). The results of this study indicated that increasing rates of the examined factors increased cotton yields (seed cotton yield, lint yield, and lint percentage), with the greatest lint yield recorded under the highest rates of zeolite (7.5 t ha−1: 1808, 1723, and 1847 kg ha−1 in ATH, MES, and KAR, respectively) and N fertilization (200 kg N ha−1: 1804, 1768, and 1911 kg ha−1 in ATH, MES, and KAR, respectively). From the evaluated parameters, most soil parameters (soil organic matter, soil total nitrogen, and total porosity), root and shoot development (root length density, plant height, leaf area index, and dry weight), fiber maturity traits (micronaire, maturity, fiber strength, and elongation), fiber length traits (upper half mean length, uniformity index, and short fiber index), as well as color (reflectance and spinning consistency index) and trash traits (trash area and trash grade), were positively impacted by the increasing rates of the evaluated factors. In conclusion, the results of the present research suggest that increasing zeolite and N fertilization rates to 7.5 t ha−1 and 200 kg N ha−1, respectively, improved soil properties (except mean weight diameter), stimulated crop development, and enhanced cotton and lint yield, as well as improved the fiber maturity, length, and color parameters of cotton grown in clay-loam soils in the Mediterranean region. Full article
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14 pages, 4616 KiB  
Article
Modification and Application of Natural Clinoptilolite and Mordenite from Almaty Region for Drinking Water Purification
by Mudasir Zahid, Yerlan Doszhanov, Karina Saurykova, Noorahmad Ahmadi, Didar Bolatova, Meruyert Kurmanbayeva, Akbope Aydarbek, Rahmuddin Ihsas, Makpal Seitzhanova, Dana Akhmetzhanova, Almagul Kerimkulova and Ospan Doszhanov
Molecules 2025, 30(9), 2021; https://doi.org/10.3390/molecules30092021 - 30 Apr 2025
Viewed by 551
Abstract
In this paper, the modification of natural clinoptilolite and mordenite zeolites from Almaty using acid treatment is addressed for the purposes of improving adsorption performance and for drinking water purification. Structural chemical transformation was characterized by the use of X-ray diffraction (XRD), Fourier-transform [...] Read more.
In this paper, the modification of natural clinoptilolite and mordenite zeolites from Almaty using acid treatment is addressed for the purposes of improving adsorption performance and for drinking water purification. Structural chemical transformation was characterized by the use of X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Scanning electron microscope (SEM) techniques. Acid treatment led to a partial dealumination that was responsible for an increase in the number of surface defects and micropores, improvement in ion exchange capacity, and selectivity toward heavy metals. Additionally, modifications greatly enhance the uptake capacities of Pb2+, Cd2+, and As3+. The clinoptilolite post-modification removal efficiencies reached 94%, 86%, and 84%, respectively, while mordenite zeolites achieved 95%, 90%, and 87% removal efficiencies, respectively. The enhancement of performance was related to the increase in surface area and active sites for ion exchange, verified from analysis of the Brunauer-Emmett-Teller (BET) surface area. The use of different Bhatt and Kothari methods has revealed that adsorption processes followed Langmuir isotherm models for Pb2+ and Cd2+, whereas As3+ adsorption was better described by the Freundlich isotherm model. However, second-order kinetics indicate that chemisorption was the dominant mechanism. Such evidence indicates spontaneity and an endothermic process, as shown from thermodynamic studies. Results showed that modified zeolites indeed had a high degree of reusability, with over 80% of the adsorption capacity retained even after five cycles. Acid-modified zeolites can provide cheaper, greener methods of purification, generating only negligible secondary waste when compared to conventional methods of water purification, for example, activated carbon and membrane filtration. Results from this study proved that modified clinoptilolite and mordenite zeolites have the potential for sustainable heavy metal treatment in drinking water purification systems. Full article
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18 pages, 4789 KiB  
Article
Mineralogical and Chemical Characterization of Greek Natural Zeolite-Rich Rocks and Their Oviposition Deterrent Effect on the Olive Fruit Fly Bactrocera oleae (Rossi) (Diptera: Tephritidae)
by Soultana Kyriaki Kovaiou, Anastasia Kokkari, Christina Mytiglaki, Nikos A. Kouloussis, Anestis Filippidis, Nikolaos Kantiranis and Dimitrios Koveos
Minerals 2025, 15(5), 458; https://doi.org/10.3390/min15050458 - 28 Apr 2025
Viewed by 482
Abstract
High quality natural zeolites may have insecticidal effects and could be used for pest control. We determined the mineralogical and chemical composition of four representative samples of zeolite-rich rocks (zeot1–zeot4) collected from north-eastern Greece and their oviposition deterrent effect for the olive fruit [...] Read more.
High quality natural zeolites may have insecticidal effects and could be used for pest control. We determined the mineralogical and chemical composition of four representative samples of zeolite-rich rocks (zeot1–zeot4) collected from north-eastern Greece and their oviposition deterrent effect for the olive fruit fly Bactrocera oleae (Rossi) (Diptera: Tephritidae). Samples zeot1–zeot4 contain 54–70 wt.% clinoptilolite (HEU-type zeolite) and are free of fibrous minerals. Regarding the chemical composition, samples zeot1–zeot4 contain SiO2 between 64.29 (zeot4) and 68.03 wt.% (zeot3). The values of the sorption ability ranged from 134 to 195 meq/100 g, and the specific surface area ranged from 6.5 to 8.4 cm2/g. In addition, the concentration of toxic heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Se, V, and Zn) is very low and within the acceptable limits for the food sector. When females of the olive fruit fly had access to olive fruits treated with aqueous suspensions of zeot1–zeot4, a significant oviposition deterrent effect was observed. The highest oviposition deterrent effect was observed after the application of zeot3 on the olive fruits, i.e., the mean number of eggs laid by 5 females on the treated and non-treated (control) olive fruits after 8 days was 43.1 and 172.3, respectively. Among the tested zeolites, zeot3 had the highest levels of HEU-type zeolite (clinoptilolite), SiO2, Si, and Ca and the strongest sorption ability and specific surface area. The zeolites oviposition deterrent effect found in our experiments can be attributed to the creation of a thin layer (hymen) of natural zeolite on the surface of the olive fruits which inhibits females landing and egg laying. The oviposition deterrent effect of high-quality Greek zeolites with unique characteristics, if verified with field experiments, could improve the effective control of the olive fruit fly. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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25 pages, 8500 KiB  
Article
Further Insight in the High Selectivity of Pb2+ Removal over Cd2+ in Natural and Dealuminated Rich-Clinoptilolite
by Yaneth Stephanie Durán-Avendaño, Norge Cruz Hernández, A. Rabdel Ruiz-Salvador and Mohamed Abatal
Int. J. Mol. Sci. 2025, 26(9), 4154; https://doi.org/10.3390/ijms26094154 - 27 Apr 2025
Viewed by 427
Abstract
This research aims to understand the experimental results on the high selectivity of Pb2+ removal over Cd2+ in natural and dealuminated rich-clinoptilolite. For this purpose, we have considered the results of experimental and Density Functional Theory (DFT)-based simulated annealing (SA) on [...] Read more.
This research aims to understand the experimental results on the high selectivity of Pb2+ removal over Cd2+ in natural and dealuminated rich-clinoptilolite. For this purpose, we have considered the results of experimental and Density Functional Theory (DFT)-based simulated annealing (SA) on sorption of Pb2+ and Cd2+ from aqueous solution. The dealumination process of natural clinoptilolite (Nat-CLI) was done by H2SO4 solutions at different concentrations (0.1–1.0 M). The results show that the maximum sorption capacity (q,max) of Pb2+ and Cd2+ varied from 224.554 × 10−3 to 53.827 × 10−3 meq/g, and between 39.044 × 10−3 to 20.529 × 10−3 meq/g, respectively, when the values of Si/Al ratio change from 4.36 to 9.50. From a theoretical point of view, the global minimum energies of natural and dealuminated clinoptilolites before and after sorption of Pb2+ and Cd2+ were calculated by an SA method, where heating-cooling cycles were modeled by ab initio Molecular Dynamics followed by energy minimization. The theoretical results confirmed that for all Si/Al ratios, the sorption of Pb2+ and Cd2+ takes place, and for dealuminated systems, the exchange energy outcomes are more favorable for the Pb2+ cations. Since such energy differences are very small, it is not explained from a thermodynamic point of view. On the other hand, it could be understood from a kinetic perspective. In this way, we set that the atomic structural properties of the zeolite modify the first hydration coordination sphere of metal cations. Full article
(This article belongs to the Special Issue Molecular Modeling: Latest Advances and Applications)
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17 pages, 2135 KiB  
Article
Overcoming the Difficulties of Thermophilic Co-Digestion of Sewage Sludge and Beverage Industry Wastes in the Presence of Zeolite
by Aleksandra Szaja, Agnieszka Montusiewicz and Magdalena Lebiocka
Energies 2025, 18(8), 2085; https://doi.org/10.3390/en18082085 - 17 Apr 2025
Viewed by 460
Abstract
The thermophilic anaerobic bioconversion of various wastes is still challenging, mainly due to process instability and economic profitability. This group includes orange wastes (OWs) and brewery spent grain (BSG), the main by-products generated by the beverage industry. In this study, a strategy allowing [...] Read more.
The thermophilic anaerobic bioconversion of various wastes is still challenging, mainly due to process instability and economic profitability. This group includes orange wastes (OWs) and brewery spent grain (BSG), the main by-products generated by the beverage industry. In this study, a strategy allowing for improving methane production by the multicomponent co-digestion of sewage sludge (SS), OW, and BSG was proposed. To overcome the difficulties in the thermophilic co-digestion of those wastes, the application of natural zeolite (Z), i.e., clinoptilolite, was proposed. The experiment was performed in the batch mode at a temperature of 55 °C. Four experimental series were conducted with differing feedstock compositions, one of which was a control supplied only by SS. As compared with the control, in the series supplied by OW and OW with BSG, methane production decreased by 20% and 13%, respectively. In turn, significant improvements were achieved in the presence of Z. The most beneficial results were observed in the reactor supplied by SS, OW, and Z, characterized by a methane yield of 420.2 mLCH4/gVS, which is an increase of almost 14% as compared with the control. In this case, significantly improved stability parameters, as well as decreased presence of inhibitors, i.e., limonene and phenols, were achieved. It was also characterized by enhanced energy balance by 69%, as compared with the control. Full article
(This article belongs to the Section B: Energy and Environment)
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18 pages, 2665 KiB  
Article
Natural (Clinoptilolite) and Synthetic (NaP1) Zeolites in the Adsorption Process for the Removal of Acid Black 1 Dye from Aqueous Solutions
by Magdalena Pająk, Agnieszka Dzieniszewska and Joanna Kyzioł-Komosińska
Molecules 2025, 30(8), 1677; https://doi.org/10.3390/molecules30081677 - 9 Apr 2025
Cited by 1 | Viewed by 569
Abstract
This study investigates the adsorption of Acid Black 1 (ABk 1) dye onto natural clinoptilolite (CLIN) and synthetic NaP1 zeolites under various conditions of adsorbent dose (5, 10, 20 g/L), dye concentration (1–1000 mg/L), and contact time (5–1440 min). The adsorption data were [...] Read more.
This study investigates the adsorption of Acid Black 1 (ABk 1) dye onto natural clinoptilolite (CLIN) and synthetic NaP1 zeolites under various conditions of adsorbent dose (5, 10, 20 g/L), dye concentration (1–1000 mg/L), and contact time (5–1440 min). The adsorption data were analyzed using Freundlich and Langmuir isotherms, as well as pseudo-first-order and pseudo-second-order kinetic models. Both linear and nonlinear regression methods were applied to assess the model fit. The results showed that CLIN exhibited maximum adsorption capacities of 35.32 mg/g, 21.9 mg/g, and 9.39 mg/g at doses of 5 g/L, 10 g/L, and 20 g/L, respectively. For NaP1, the corresponding values were 28.44 mg/g, 12.46 mg/g, and 9.11 mg/g. The pseudo-first-order model described adsorption at low dye concentrations and short contact times, while the pseudo-second-order model successfully explained adsorption across all tested conditions. These findings suggest that both zeolites, particularly CLIN, are effective adsorbents for ABk 1 dye removal, presenting a valuable solution for wastewater treatment applications. Full article
(This article belongs to the Special Issue Recent Research Progress of Novel Ion Adsorbents)
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27 pages, 7034 KiB  
Article
Computational Insights into Aluminum and Cation Placement in Clinoptilolite: Optimizing DFT Parameters for Natural Zeolites, Part I
by Lobna Saeed and Michael Fischer
Appl. Sci. 2025, 15(7), 3955; https://doi.org/10.3390/app15073955 - 3 Apr 2025
Viewed by 531
Abstract
Several experimental studies have shown that clinoptilolite zeolite is a suitable candidate for the adsorption of pharmaceuticals and related compounds. However, there is a significant lack of detailed molecular-level insights regarding how the adsorbed species interact with the zeolite surface. In this work, [...] Read more.
Several experimental studies have shown that clinoptilolite zeolite is a suitable candidate for the adsorption of pharmaceuticals and related compounds. However, there is a significant lack of detailed molecular-level insights regarding how the adsorbed species interact with the zeolite surface. In this work, we employ electronic structure calculations and propose a reliable set of input parameters within the CP2K code in the framework of dispersion-corrected density functional theory (DFT-D) to generate bulk models and study Al and cation distributions. We aim ultimately to investigate the adsorption of emerging contaminants at the clinoptilolite surfaces. Nine different exchange-correlation functionals were tested, and the results suggest that B97-D3 functional is the most robust for this system. Moreover, our results suggest that Na+ prefers the presence of Al at T2 and T3 sites but not at T1 sites and prefers being present in channel A and/or channel B. Ca2+ tends to favor being present in channel B and favors the presence of Al at T1, T2, and T3 sites. K+ prefers the smallest channel C and likes the presence of Al at T1 and T3 sites. Moreover, we found out that the optimization of the basis sets improves the coordination of extra-framework cations like Ca with the framework oxygens. Full article
(This article belongs to the Special Issue Development and Application of Computational Chemistry Methods)
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