Zeolitic Tuff Research Articles

Bioplastic Production Utilizing Jordanian Zeolite and Kaolin

The study investigates the production of biodegradable plastic films using gelatin as a biopolymer, glycerol as a plasticizer, and natural fillers (Jordanian zeolitic tuff and kaolin) via solution casting method. Key findings demonstrate that incorporating these fillers enhances the films' mechanical properties, biodegradability, and ductility. Increased filler concentration improves film thickness, density, tensile strength (up to 4.97 MPa with kaolin), and toughness while reducing moisture content, solubility, and elongation at break. Biodegradation tests reveal significant weight loss over time, indicating the films' potential for rapid environmental breakdown. The ductility of the films decreases with increasing filler concentration, suggesting enhanced rigidity. These results highlight the potential of utilizing Jordanian natural resources to develop eco-friendly bioplastics with applications in packaging, soil additives, and other industries.

Effect of Incorporating Natural Zeolitic Tuffs in Concrete Mixed and Cured Using Seawater

Concrete production has increasingly used seawater to overcome the challenge of freshwater scarcity. Although the use of seawater in concrete still has a controversial reputation, it is a promising application, particularly when combined with mineral admixtures such as natural zeolitic tuffs (ZT). This paper aims to investigate the effect of using locally quarried ZT on the strength of unreinforced concrete mixed and/or cured using seawater. The mix proportions of the concrete were selected to obtain the optimum combination for the M20 grade of concrete with a water-to-cement ratio of 0.69. Moreover, 150mm-cubes and cylinders of 100 mm diameter by 200mm height were cast from the concrete mixtures, which contain 0%, 5%, 7.5%, 10%, and 25% of ZT as a partial replacement of silica sand. Splitting tensile tests and compressive strength tests were conducted on these specimens at 7, 28, and 90 days. The results show the harmful effect of seawater on the strength of plain concrete (without ZT) at 7, 28, and 90 days of curing, especially when seawater is used in both mixing and curing of the concrete. However, adding ZT in seawater-based concrete improved its strength apparently, especially at early curing ages. For example, using 10% of ZT as a partial replacement of silica sand increased the compressive strength of seawater based-concrete by 105.4%, 28.3%, and 34.6% after 7, 28, and 90 days of curing, compared with concrete without ZT and produced using seawater. These results contribute to the enhancement of the sustainability of both freshwater and concrete material through the use of ZT in producing concrete, particularly in areas where freshwater is scarce or expensive.

Sustainable fabrication of lightweight geopolymer foams from silica-fume and zeolite tuffs: Utilizing Al as foaming agent for thermal insulation

In response to the increasing demand for eco-friendly thermal insulation materials in construction, this research focuses on the development of geopolymer foams with optimized thermal insulation properties. The study employs silica fume and zeolite tuff as primary raw materials, activated by sodium hydroxide and sodium silicate solution, and incorporates aluminum powder and sodium lauryl sulfate (SLS) as additives to enhance porosity and refine pore size distribution. A comprehensive analysis of technical properties, including compressive strength, porosity, bulk density, and thermal conductivity, is conducted to assess the influence of these additives. The findings demonstrate that SLS plays a main role in modifying the microstructure, resulting in more uniform and interconnected pores. The addition of moderate amounts of SLS (0.9 wt%) promotes the formation of consistent cell sizes and porosity, contributing to the overall structural integrity of the foams. The foams are predominantly amorphous, with some residual crystalline phases observed. Scanning electron microscopy (SEM) reveals the development of sodium aluminum silicate whiskers, which serve as reinforcement, enhancing the mechanical strength of the geopolymer matrix. The resulting geopolymer foams exhibit high porosity (64.36–81.32 %), low thermal conductivity (0.29–0.07 W/m·K), and sufficient compressive strength (0.96–2.71 MPa), indicating their potential as sustainable insulation materials for construction applications.

Thermodynamic functions and parameters of sorption from flue gases (CO2,SOx,NOx) by Khekordzula clinoptilolite

Generation during the production process and emissions into the atmosphere with flue gases (CO2,SOx,NOx) cause the “greenhouse effect” and the problem of global warming. Despite the existing practice of using zeolite as an adsorbent for a number of gases in projects such as Carbon Capture, Utilization and Storage to prevent climate change, the thermodynamic functions and parameters of the zeolite tuff containing the mineral Khekordzula clinophtholite in the inner Kartli region of Georgia are unknown and have not been studied. According to the research data, the corresponding thermodynamic parameters were determined, namely the enthalpy of formation of the mineral clinophthylolite in the Khekordzula zeolite tuff ΔfH2980=−39,825.838kj·mol−1, Gibbs energy ΔfG2980=−36,734.784kj·mol−1, entropy S2980=−10.373j·K·mol−1; Dehydration and as well as physical sorption (CO2, SOx, NOx) start parameters: temperature T=352.90K, pressure P=6.84mmHg. The thermodynamic parameters of the Khekordzula natural clinoptilolite tuff, taking into account its basic mineralogical composition, were determined: ΔfH2980=−30,403.76kj·mol−1; ΔfG2980=−29,963.01kj·mol−1; S2980=−1.48j·K·mol−1; T=374.22K, P=0.0003mmHg. It has been confirmed that chemisorption (CO2, SOx, NOx) by Khekordzula clinophthylolite should begin at temperatures above 2000 K. The results of the conducted studies make it possible to evaluate the prospects of using Khekordzula and natural zeolites of similar composition as an adsorbent for harmful industrial gases, which will help plan and implement effective solutions to environmental problems.

From quarry by-products to a zeolites-based Zn fertilizer with increased resistance to rain leaching

In the face of an extensive literature on the use of zeolites for the removal of metals from water for environmental purposes, it is seldom considered that some metals are also essential nutrients for life and that zeolites could be profitably used to dose their release. Among these, Zn is a key micronutrient, and when its demand by crop is not fully balanced by adequate accessibility, fertilization must be provided using Zn salts that can be, however, easily leached and partly wasted in the environment.In an attempt to solve this critical problem, a new controlled-release formulation of Zn using zeolite-containing geomaterials was designed, prepared, characterized, and tested by applying a sequential, multi-method approach. Different formulations were trialed, and the most effective included 30 wt% pumice by-product and 70 wt% clinoptilolite-rich zeolitized tuff, with about 20 mg/g of exchangeable Zn2+. The enrichment process reached equilibrium after about 8 h, a timing well-tuned with technology transfer. Desorption kinetic tests in a weekly acid environment revealed gradual Zn release, with about 4.28 wt% released after 6 h. When tested as a foliar fertilizer on Vitis vinifera, this formulation demonstrated superior resistance to leaching under simulated rainfall conditions compared to conventional ZnSO4·6H2O fertilizer, maintaining the initial level of Zn (130 mg/kg of dry leaves), while about 22 % of the Zn applied with ZnSO4·6H2O was loss. This outcome was plausibly due to mineral particle adhesion to leaf. Preliminary cost estimates suggest that the product designed here can be placed in the market with competitive sales prices.

Natural Materials as Carriers of Microbial Consortium for Bioaugmentation of Anaerobic Digesters

The production of biogas is achieved during anaerobic digestion (AD) using organic matter as a substrate. In Mediterranean countries, a promising substrate is lignocellulose biomass of perennial grass Miscanthus x giganteus, due to its potentially high biogas yields, which could be comparable to maize silage. During AD, bacteria convert biomass into more minor compounds, which are further converted to methane by methanogenic archaea. The selection of appropriate microbes for the degradation of the substrate is crucial, and the enhancement of this step lies in the immobilization of microbes on biocarriers. Described here, a microbial consortium, de novo isolated and conditioned to degrade the Mischantus biomass, was immobilized onto several natural biocarriers: natural zeolitized tuff, ZeoSand® (Velebit Agro, Zagreb, Croatia), perlite, and corncob. There was no statistically significant difference in the number of immobilized bacteria across the different materials. Therefore, all proved to be suitable for the immobilization of the consortium. In the consortium, five bacterial species with different shares in the consortium were identified: Enterobacter cloacae, Klebsiella pneumoniae, Enterobacter asburiae, Leclercia adecarboxylata, and Exiguobacterium indicum. After immobilization on each carrier, the share of each species changed when compared to starting conditions, and the most dominant species was E. cloacae (71–90%), while the share for other species ranged from 2 to 23%. The share of E. indicum was 14% at the start. However, it diminished to less than 1% because it was overgrown during the competition with other bacterial species, not due to an inability to immobilize.

Mineralogy and geotechnical properties of alkaline-activated kaolin with zeolitic tuff and cement kiln dust as landfill liners

Mixtures of variable proportions of kaolin, quartz sand, zeolitic tuff, and cement kiln dust were blended while adding an 8 M sodium hydroxide (NaOH) solution to allow alkali-activation of kaolin and achieve the optimum strength. This study investigated the mineralogy, microstructure, and geotechnical properties of the prepared mixtures. The aim was to produce a sustainable, environmentally friendly landfill liner. The samples were compacted in stainless steel molds to a maximum dry density and optimum moisture content, extruded from the molds, and left to cure in an oven at varying temperatures from 40°C to 80°C for 24 h. The investigations included XRD, SEM, unconfined compressive strength, and hydraulic conductivity tests. Test results showed the development of a hydroxysodalite binder due to the alkali reaction of kaolin, which caused an increase in strength ranging from 20 to 25 MPa depending on the curing temperature. Alkaline activation was effective even at temperatures as low as 40°C. A mixture of 100 units of kaolin, 45 units of sand, 45 units of zeolitic tuff, and 10% by weight cement kiln dust (CKD) with an 8 M sodium hydroxide activator was found to best achieve the required strength and hydraulic conductivity of 10−9 m/s for the landfill liner. The zeolitic tuff with high cation exchange capacity, available in the mixture, absorbs contaminants in the leachate and prevents pollution of the groundwater. The use of cement kiln dust contributes to enhancing strength and solving an acute environmental problem.

Investigating the Dynamic Creep and the Tensile Performance of Zeolitic Tuff-modified Warm Asphalt Mixtures

Aims This research investigates the effect of adding natural Jordanian Zeolitic tuffs to the SUPERPAVE asphalt mixture at the dynamic creep and the indirect tensile performance. Background Rutting and fatigue are considered the most common types of distress that affect pavements all over the world. Many factors can affect these properties, such as different aggregate properties, asphalt grades, and properties, as well as the type and amount of the mineral filler. Mineral fillers play an important role in enhancing the asphalt mixtures' performance by filling the voids in the mixture besides improving the cohesion of the binder as it has a small weight in addition to a very large surface area. Generally, the powder of limestone is the most used type of filler. However, studies showed that many materials could also be used as mineral fillers successfully. The focus of this study is using natural Jordanian Zeolitic tuff as a mineral filler. Jordanian zeolitic tuff mainly consists of Phillipsite, chabazite, and faujasite, which are considered the most abundant Zeolitic tuff minerals. The pyroclastic material is widely distributed in the Badia region of northeast Jordan. Zeolitic tuffs are located in Jabal Aritayn (30km northeast of Azraq), Tlul AlShahba (20 km east of Al Safawi), Tal Al-Rimah (35 km northeast of Al Mafraq), and other small deposits in central and south Jordan. Objectives The aim of this research was to study the impact of Zeolitic tuffs on overall Superpave asphalt mixture performance. Methods The specimens were prepared using the optimum asphalt content obtained by the SUPERPAVE method. Dynamic Testing System DTS-16 was used to apply both dynamic creep and indirect tensile tests that give a good idea about the rutting and fatigue behavior of asphalt mixtures. Both tests were conducted at 25 °C. Results The Zeolitic tuffs modified asphalt mixtures have lower accumulated strains and higher creep stiffness compared to the control mixture. Subsequently, the indirect tensile test results showed that the modified asphalt mixtures have a higher resilient modulus than the control asphalt mix. Generally, using Zeolitic tuffs as a modifier of asphalt mixtures enhanced the rutting and fatigue resistance. The results showed that asphalt mixtures fortified with 25% Zeolitic tuffs emerged as the best contenders for rutting resistance. Also, mixtures enriched with 50% Zeolitic tuffs stood out in fatigue resistance performance. Conclusion The best dynamic creep performance was by adding 25% Zeolitic tuffs by the mineral filler mass, while the best resilient modulus was by adding 50% Zeolitic tuffs by the mineral filler mass. Other The overarching goals encompass understanding the dynamic creep behavior of Zeolitic tuff-infused asphalt blends, deciphering its indirect tensile performance, pinpointing the ideal replacement ratio for mineral fillers, and drawing a performance comparison between WMA and conventional Hot Mix Asphalt (HMA) compositions.

Exploring the Combined Effects of Different Nitrogen Sources and Chabazite Zeolite-Tuff on Nitrogen Dynamics in an Acidic Sandy-Loam Soil

Volcanic tuffs rich in chabazite zeolites have been extensively examined for their potential to enhance soil properties and increase fertilizer efficiency, both in their natural state and when enriched with nitrogen (N). However, there is a scarcity of data regarding their utilization in acidic sandy soil, particularly when used alongside organic fertilizers. This paper presents the findings of a 50-day laboratory incubation study that investigated the dynamics of N pools in an acidic sandy-loam agricultural soil treated with various N sources. These sources included urea, N-enriched chabazite zeolite tuff, and pelleted composted manure applied at a rate of 170 kg N/ha. Additionally, the N sources were tested in combination with chabazite zeolite tuff mixed into the soil to assess its role as a soil conditioner. The results revealed distinct behaviours among the tested N sources, primarily impacting soil pH and N dynamics. Soil fertilized with manure exhibited slow N mineralization, whereas N-enriched zeolite displayed a more balanced behaviour concerning net NO3−-N production and NH4+-N consumption. Both N-enriched zeolite and urea temporarily altered the soil pH, resembling a “liming” effect, while pelleted manure facilitated a prolonged shift towards neutral pH values. Considering the water adsorption capacity of zeolite minerals, caution is advised when adjusting water content and employing combustion methods to measure soil organic matter in zeolite-treated soil to avoid potential inaccuracies. In summary, N-enriched chabazite zeolite tuff emerged as a valuable N source in acidic sandy-loam soil, offering a promising alternative to synthetic fertilizers and showcasing a sustainable means of N recycling.

Transforming Zeolite Tuff and Cigarette Waste into Eco-Friendly Ceramic Bricks for Sustainable Construction

The use of waste materials has gained attention as a sustainable approach in various industries. Cigarette waste, which is typically discarded as a non-recyclable material, poses a significant environmental challenge due to its toxicity and slow decomposition rate. However, by incorporating this waste into ceramic bricks, new approaches for waste management and resource utilization are explored. This research work provides a detailed evaluation of the possibility of utilizing natural zeolite tuff incorporated with cigarette waste to produce sustainable ceramic bricks. Uniform powders are produced by milling various combinations of zeolitic tuff and cigarette waste using a planetary ball mill. The substitution ratios ranged from 0% to 12% by weight of the zeolitic tuff, with increments of 2%. Ceramic discs were formed by dry pressing and then subjected to sintering at different heat treatment temperatures (950–1250 °C). The impact of the inclusion of cigarette waste on the microstructural and technical features of zeolite tuff-based ceramic bricks has been thoroughly investigated. The results of the experiments demonstrate that incorporating cigarette waste into the development of ceramic bricks leads to improved thermal insulation properties, with thermal conductivity ranging from 0.33 to 0.93 W/m·K. Additionally, these bricks exhibit a lighter weight in a range of 1.45 to 1.96 g/cm3. Although the inclusion of cigarette waste slightly reduces the compressive strength, with values ranging from 6.96 to 58.6 MPa, it still falls within the acceptable range specified by standards. The inclusion of cigarette waste into zeolite tuff is an innovative approach and sustainable practice for reducing energy consumption in buildings while simultaneously addressing the issue of waste disposal and pollution mitigation.

Innovative sustainable ceramic Bricks: Exploring the synergy of natural zeolite tuff and aluminum dross

This study explored the efficient utilization of natural zeolite tuff and aluminum dross for making porous ceramic bricks, aiming to address environmental damage from waste disposal. Different compositions of these materials were used to create six batches of bricks, followed by heat treatment at varying temperatures (950–1150 °C). The raw materials and the sintered samples were analyzed using various characterization techniques. The results showed that bricks incorporating 30 % aluminum dross and sintered at 1150 °C had the lowest thermal conductivity of 0.3 W/m·K. On the other hand, bricks containing 20 % aluminum dross and sintered at the same temperature exhibited the highest compressive strength (58 MPa), a bulk density of 1.9 g/cm3, and a water absorption of approximately 13 %. All samples exceeded the minimum compressive strength requirements. This study demonstrates the feasibility of using natural zeolite tuff and aluminum dross to develop composite bricks, providing an effective waste disposal solution for sustainable development and reduced environmental pollution.

Sorption of Pb2+, Zn2+, Cu2+ and Ni2+ Ions on Na-enriched Natural Zeolite for Wastewater Treatment Process: A Kinetic Approach

Low-cost and easily available natural zeolite is a promising adsorbent for metal ions removal in wastewater treatment. The possibility of using zeolitic tuff from Serbia in the form of Na-enriched natural zeolite (Na-Z) for the adsorption of Pb2+, Zn2+, Cu2+, and Ni2+ ions from wastewater was investigated in the presented paper. The research included Na-Z characterization and determination of adsorption kinetics in individual ion adsorption tests using non-linear pseudo-first-order (PFO), pseudo-second-order (PSO) and mixed-order (MO) kinetic models. The results indicate that the adsorption processes of metal ions on Na-Z are complex processes dominated by multiple rate-limiting mechanisms and best defined by the MO model. The mechanisms of ion diffusion and adsorption to active sites are equally represented in the Pb2+ ions adsorption process. The mechanism of ion diffusion is more pronounced in the Zn2+ ions adsorption process, while in the case of the adsorption of Cu2+ and Ni2+ ions adsorption on the active sites is the main kinetic mechanism. Within the MO model, the PFO rate (external/internal diffusion) and the PSO rate (adsorption on the active sites) were calculated and results were applied to a multicomponent wastewater sample in order to determine and explain the adsorption efficiency in wastewater treatment. The results show that the rate of adsorption of individual metal ions and the efficiency of ion removal from a multicomponent wastewater sample are influenced by several factors including the radius of the hydrated ion and the free energy of hydration. The achieved removal of metal ions by Na-Z is Pb2+ (89%) > Cu2+ (72%) > Zn2+ (61%) > Ni2+ (58%) and defines Na-enriched natural zeolite as an effective adsorbent in wastewater treatment.

Clinoptilolite—A Sustainable Material for the Removal of Bisphenol A from Water

Bisphenol A is a remarkable chemical compound as it has many applications, mainly in the plastics industry, but it also has toxic effects on the environment and human health. This article presents a comparative study regarding the adsorption of BPA on Active carbon and zeolitic tuff, ZTC. In this paper, the characterization of the zeolitic tuff, adsorbent, was carried out from an elemental and mineralogical point of view, and it noted the pore size and elemental distribution, using SEM, EDAX, and XRD analysis. The pore size varies from 30 nm to 10 µm, the atomic ratio is Si/Al ≥ 4, and 80% of the mineralogical composition represents Ca Clinoptilolite zeolites and Ca Clinoptilolite zeolites ((Na1.32K1.28Ca1.72Mg0.52) (Al6.77Si29.23O72)(H2O)26.84). Moreover, a comparative study of the adsorption capacity of bisphenol A, using synthetic solutions on an activated carbon type—Norit GAC 830 W, GAC—as well as on Clinoptilolite-type zeolitic tuff—ZTC, was carried out. The experiments were carried out at a temperature of 20 °C, a pH of 4.11, 6.98, and 8.12, and the ionic strength was assured using 0.01 M and 0.1 M of KCl. The adsorption capacities of GAC and ZTC were 115 mg/g and 50 mg/g, respectively, at an 8.12 pH, and an ionic strength of 0 M. The Langmuir mathematical model best describes the adsorption equilibrium of BPA. The maximum adsorption capacity for both adsorbents increased with an increasing pH, and it decreased with increasing ionic strength.

Mechanical and Fracture Properties of Air-Entrained FRC Containing Zeolitic Tuff

This study aimed to evaluate the influence of zeolitic tuff, an air-entraining agent, and different types of fibers on the compressive strength and fracture parameters of concrete with increased strength. Notched beams were tested in three-point bending to determine the fracture parameters of concrete. It was established that the partial replacement of Portland cement (10% by mass) with zeolitic tuff, the addition of an air-entraining agent and different types of fibers resulted in the improvement both of the compressive strength (by 3.7% after 28 days of hardening) and fracture properties of concrete (namely, the fracture energy by 35.1% and characteristic length by 61.5%) compared to the reference concrete. The beneficial effects of the air-entraining agent and the mechanisms through which it enhances the properties of concrete by incorporating zeolitic tuff and various types of fibers were explained. It has been demonstrated that the appropriate selection and optimization of various technological factors enable the production of economically effective, high-quality concrete with a 10% lower cement content. As a result, this leads to reduced CO2 emissions, aligning with a sustainable development strategy.

Sustainable zeolitic tuff incorporating tea waste fired ceramic bricks: Development and investigation

The present research examines the development of new porous ceramic bricks from Hungarian zeolitic tuff and tea waste as building materials. Recycling waste materials as a pore-forming agent in brick-making is a promising solution to environmental and economic challenges. Several zeolitic tuff/tea waste admixtures were milled in the planetary ball milling to produce homogenous powders. The substitution ratios were maintained as 0 %, 2 %, 4 %, 6 %, 8 %, 10 %, and 12 % by wt of zeolitic tuff. The ceramic disks were produced from the prepared mixtures via dry pressing and sintering at various temperatures (950–1250 °C) for consolidation. The produced bricks were investigated based on bulk density, apparent porosity, water absorption, volume shrinkage, thermal conductivity and compressive strength, as well as mineralogical, chemical, and morphological studies. The mineralogical determination confirms the existence of clinoptilolite, montmorillonite, cristobalite and illite as major phases in zeolite tuff. The experimental results reveal that the addition of tea waste produces hybrid bricks with better thermal insulation (0.17–0.504 W/m K), lighter weight (1.37–1.81 g/cm3), and lower compressive strength (5.52–34.4 MPa). However, the compressive strength value still lies within the range required by the standards. The production of burned bricks containing up to 10 wt% tea waste is viable without causing major changes in their technical characteristics. Developing new porous bricks using waste materials can help expand the application of sustainable and cost-effective insulation bricks in the construction industry.

Characterization of Volcano-Sedimentary Rocks and Related Scraps for Design of Sustainable Materials.

This work started as a joint academia and company research project with the aim of finding new applications for domestically sourced volcanic products and related waste (pumice, lapillus, zeolitic tuff and volcanic debris from Tessennano and Arlena quarry) by creating a database of secondary volcanic raw materials and their intrinsic characteristics to help industry replace virgin materials and enhance circularity. In this context, accurate chemical, mineralogical, morphological, granulometric and thermal characterizations were performed. Based on the results presented, it can be concluded that due to their lightness, these materials can be used in the design and preparation of lightweight aggregates for agronomic purposes or in the construction field. Furthermore, due to their aluminosilicate nature and amorphous fraction, pumice and lapillus can play the role of precursor or activator for geopolymer preparation. With its porous nature, zeolitic tuff can be exploited for flue gas treatment. Due to the presence of feldspathic phase (sanidine), these materials can be used in tile production as a fluxing component, and with their pozzolanic activity and calcium content, they have application in the binder field as supplementary cementitious material or as aggregates.

Performance of clinoptilolite zeolite after milling as a pretreatment on hydration kinetics, shrinkage, and alkali-silica reaction of cementitious materials

Natural clinoptilolite zeolite has been a popular supplementary cementitious material (SCM) due to its acceptable pozzolanic performance and the overall lower environmental footprint. Previous research established that milling is an effective pretreatment technique to further increase the pozzolanic reactivity of zeolitic tuffs leading to an increased specific surface area and amorphous contents. Therefore, the present study characterized the zeolite particles after ball milling for 1 and 3 h using phase analysis by X-ray diffraction (XRD), particle size distribution by laser diffraction, microstructural analysis by scanning electron microscopy (SEM), moisture absorption rate, and relative chemical dissolution. The performance of milled clinoptilolite zeolite as a SCM with the replacement of up to 20% portland cement was evaluated through hydration kinetics (heat of hydration, setting time, chemical shrinkage, degree of hydration), workability, compressive strength, autogenous shrinkage, drying shrinkage, and alkali-silica reaction (ASR). Results revealed that 1 and 3 h of milling led to an increased specific surface area, moisture absorption capacity, and relative dissolution of particles, but had no visible effects on the crystalline structure of zeolite particles compared to the unmilled zeolite particles. For the hydrated system, both 1 and 3-h milled zeolite increased the overall heat of hydration leading to an increased silicate and aluminate reaction along with the acceleration effects in the setting time. The compressive strength of up to 20% milled (1 and 3 h) zeolite samples was increased by about 20 to 25% compared to the unmilled zeolite samples at an early age which suggested an increasing pozzolanic response of milled zeolite particles in the system due to an increased volume of hydrated phases and degree of hydration. Milling slightly decreased the workability by demanding a higher content of fresh water which was released at a later age leading to a higher drying and autogenous shrinkage. In addition, milling reduced the internal curing capacity leading to damage to the porous structure of zeolite particles. The use of up to 20% 3-h milled zeolite reduced the deleterious expansion by about 80% due to ASR compared to the control sample and the overall performance of milled clinoptilolite zeolite as the SCM was satisfactory in the hydrated system.

Preparation, Characterization, and Performance of Natural Zeolites as Alternative Materials for Beer Filtration.

The clarity of the beer is essential to its marketability and good consumer approval. Moreover, the beer filtration aims to remove the unwanted constituents that cause beer haze formation. Natural zeolite, an inexpensive and widespread material, was tested as a substitute filter media for diatomaceous earth in removing the haze constituents in beer. The zeolitic tuff samples were collected from two quarries in Northern Romania: Chilioara, in which the zeolitic tuff has a clinoptilolite content of about 65%, and the Valea Pomilor quarry, containing zeolitic tuff with a clinoptilolite content of about 40%. Two-grain sizes, <40 and <100 µm, from each quarry were prepared and thermally treated at 450 °C in order to improve their adsorption properties and remove organic compounds and for physico-chemical characterization. The prepared zeolites were used for beer filtration in different mixtures with commercial filter aids (DIF BO and CBL3) in laboratory-scale experiments, and the filtered beer was characterized in terms of pH, turbidity, color, taste, flavor, and concentrations of the major and trace elements. The results showed that the taste, flavor, and pH of the filtered beer were generally not affected by filtration, while turbidity and color decreased with an increase in the zeolite content used in the filtration. The concentrations of Na and Mg in the beer were not significantly altered by filtration; Ca and K slowly increased, while Cd and Co were below the limits of quantification. Our results show that natural zeolites are promising aids for beer filtration and can be readily substituted for diatomaceous earth without significant changes in brewery industry process equipment and protocols for preparation.

Spectral mapping of zeolite bearing paleolake deposits at Lake Tecopa, California and its implications for mapping zeolites on Mars

• Zeolitic tuff at paleolake Tecopa investigated using in-situ and orbital methods. • Reasons for limited orbital detections of zeolites in paleolake. • Importance of ground investigation to interpreting orbital data. While non-analcime zeolites are plausible mineral constituents of the Martian surface, their lack of prominent spectral characteristics in the visible to shortwave infrared wavelength region makes them difficult to identify using orbital data. This lack of detection has led to the assumption that they are limited or absent. Here we assess the capability of mapping non-analcime zeolites using different mapping techniques and present the possible reasons that could lead to limited detection of zeolites using an analog study from Paleolake Tecopa, California. We used spaceborne hyperspectral Hyperion and multispectral ASTER data to identify zeolites following X-ray Diffraction (XRD) and visible-near infrared and shortwave infrared (VNIR-SWIR) spectral analysis of collected samples containing zeolites and other associated minerals. We used four of the most common spectral mapping methods: (1) band ratios, (2) minimum noise fraction (MNF), (3) spectral angle mapper (SAM), and (4) linear spectral unmixing (LSU). We were able to map zeolite-rich tuff beds using carefully selected band indices, MNF band combinations, and the pixel spectra corresponding to a zeolite-rich abandoned quarry area. Hyperion results show less overall accuracy than the ASTER image products mostly due to the low signal-to-noise ratio of the Hyperion data. The spectral characteristics of zeolites in zeolite-rich pixels are masked by phyllosilicates (e.g., smectite) present in the ground resolution cell (GRC), making it difficult to identify zeolites in phyllosilicate-bearing deposits solely based on zeolite spectra. Therefore, the SAM product derived using the pixel spectrum of the well-exposed zeolite-rich quarry shows the highest accuracy in Hyperion image products. ASTER band ratio Band 2/Band 1, representing the ferric ion, was able to identify the zeolite-rich beds with the highest accuracies. However, most of the zeolite-rich paleolake beds were difficult to identify since they are buried by other beds, mixed with other beds due to physical weathering, or the areas of exposed beds are smaller than the GRC of the satellite. The results imply that the paucity of detected zeolites on Mars, as we see at Lake Tecopa, does not preclude their wider presence, either beneath other materials, obscured by surface dust, or mixed with more spectrally dominant phases. :

Recycling nitrogen from liquid digestate via novel reactive struvite and zeolite minerals to mitigate agricultural pollution

Recycling nutrients is of paramount importance. For this reason, struvite and nitrogen enriched zeolite fertilizers produced from wastewater treatments are receiving growing attention in European markets. However, their effects on agricultural soils are far from certain, especially struvite, which only recently was implemented in EU Fertilizing Product Regulations. In this paper, we investigate the effects of these materials in acid sandy arable soil, particularly focusing on N dynamics, evaluating potential losses, transformation pathways, and the effects of struvite and zeolitic tuffs on main soil biogeochemical parameters, in comparison to traditional fertilization with digestate. Liming effect (pH alkalinization) was observed in all treatments with varying intensities, affecting most of the soil processes. The struvite was quickly solubilized due to soil acidity, and the release of nutrients stimulated nitrifying and denitrifying microorganisms. Zeolitic tuff amendments decreased the NOx gas emissions, which are precursors to the powerful climate altering N2O gas, and the N enriched chabazite tuff also recorded smaller NH3 emissions compared to the digestate. However, a high dosage of zeolites in soil increased NH3 emissions after fertilization, due to pronounced pH shifts. Contrasting effects were observed between the two zeolitic tuffs when applied as soil amendments; while the chabazite tuff had a strong positive effect – increasing up to ∼90% the soil microbial N immobilization – the employed clinoptilolite tuff had immediate negative effects on the microbial biomass, likely due to the large quantities of sulphur released. However, when applied at lower dosages, the N enriched clinoptilolite also contributed to the increase of microbial N. From these outcomes, we confirm the potential of struvite and zeolites to mitigate the outfluxes of nutrients from agricultural systems. To gain the best results and significantly lower environmental impacts, extension practitioners could give recommendations based on the soils that are planned for zeolite application.