Zeolitic Rocks Research Articles

Use of zeolite and biogenic silica rich rocks as olive oil mill waste absorbents

Microporous materials have been tested as absorbent of olive oil mill waste (OOMW) from a three-phase mill. The aim of the present study is to characterise and test the OOMW absorption capacity of fine-grained rocks. The materials tested were zeolite-rich tuff, clay and zeolite-rich tuff, opal-A-rich clayey rock and opal-CT and zeolite-rich clays. The samples were characterised and physico-chemically analysed. The samples exhibit significant differences of their physicochemical properties. Correlations indicated that the OOMW absorption capacity depended mainly on the cumulative volume of pores. Very small pores did not affect considerably the OOMW uptake in contrast to the bigger pores. The opal-CT and zeolite-rich clayey rock was the most efficient absorbent. It is concluded that the synergistic action of three structurally diverse, randomly ordered microporous components which rarely coexist in rocks naturally, results in high cumulative volume of pores and an increased absorption capacity.

Research on the use of zeolite for smoothing surfaces in tumbler machining

The article presents the proposal of using grounded zeolite rocks for container processing. The hardness of 5-6 according to the Mohs scale classifies this material as medium hard. Which is applicable for roughing of elements and deburring and polishing processes. The aim of the research was to assess the quality of zeolite application as a cutting material. Effectiveness of removing corrosion and geometric structure of the surface changes of objects made of carbon steel were investigated. Specified mass losses depending on the length of the vibratory machining process and changes in the geometric structure of the surface. The results were compared to analogous processes carried out with the use of ceramic abrasive media.

Mechanical and thermal properties of concrete suitable for radioactive waste disposal sites

Secondary casing as a part of a multi-barrier system serves to meet the safety requirements on the radioactive waste repositories. Such casing needs to be durable, radiation- and thermal resistant, with good mechanical properties; these requirements are fulfilled by concrete. However, the casing should also serve as a barrier limiting the leaching of radionuclides, in case of failure of primary package. This problem is addressed in the article by the addition of a sorption material (natural zeolite rock) in the concrete mixture. Mechanical and thermal properties of concrete containing different amount of natural zeolite rock are studied with the link to concrete porosity. The addition of natural zeolite is found to cause a decrease in thermal conductivity and specific heat capacity. Both compressive and flexural strength decrease as well when natural zeolite is added in the mixture, which correlates with the increase of open porosity of studied concrete mixtures.

Evaluation of the Natural Zeolite Lethal Effects on Adults of the Bean Weevil Under Different Temperatures and Relative Humidity Regimes.

We studied the insecticidal activity of different concentrations of very high quality natural zeolites (zeolitic rock containing 92 wt% clinoptilolite) applied on dry beans. The test species was adult bean weevils Acanthoscelides obtectus (Say; Coleoptera: Bruchidae), and the variables included different temperatures and humidity regimes. At certain natural zeolite concentrations the adult mortality approached 100% within the first day of exposure. The lethal natural zeolite concentration for 50% adult mortality (LD50) was 1.1 g/kg dry beans 1 d after exposure. The temperature had no significant effects on the insecticidal potential of the tested natural zeolite formulations. The lethal time (LT) for 50% adult mortality (LT50), at a concentration of 0.5 g/kg dry beans was 106.429, 101.951, and 90.084 min at 15, 20, and 25°C, respectively. It did not differ significantly. In contrast, relative humidity (RH) and exposure time as well as their interactions had a significant effect on natural zeolite formulation and insecticidal potential. At a constant concentration of 0.5 g/kg dry beans and 25°C at 23%, 34%, 53%, and 88% RH the LT50 ranged from 61.6 to 75.9 min; at 72% RH the LT50 was 110.6 min. The results indicate that natural zeolite at low concentrations is promising for the control of the bean weevil under different temperatures and RH regimes.

Ionic strength-dependent pre-asymptoic diffusion coefficient distribution in porous media - Determination through the pulsed field gradient technique

1H pulsed-field gradient nuclear magnetic resonance was used to study early-time water diffusivity in porous media. The method has also been proven useful to characterize porous media from the standpoint of time-dependent diffusion. In porous media such as zeolite, biological cells or reservoir rocks, water molecular diffusion is time-as well as ionic strength-dependent. Diffusion phenomena are relevant transport mechanisms in low-permeability gas reservoirs and consequently in characterization efforts. Model systems are used here to unveil effects of ionic strength and pore size on the self- and effective-diffusion coefficient distributions. For this purpose, diffusion in aqueous phase in beadpacks made up of different glass bead sizes is analyzed. Ion size, ionic strength and hydration play an important role on the resulting diffusion coefficient. Ion-ion interaction leads to an increase of the diffusion coefficient by distorting water structure (hydrogen bond). While for the diffusion coefficient distribution derived using the regularized Inverse Laplace Transform method, ionic strength has little effect on the dominant peak position. With the increase in pore size, the dominant peak shifts to larger diffusion coefficient.

Use of Zeolite Rocks in Metal Recovery from Mine Water

Mine water at some mineral deposits in Transbaikalia contains valued metals commercially recoverable from solutions using zeolite rocks. Experimental impregnation of metal-bearing mine water from Sherlovaya Gora and Bom-Gorphon areas with sodium and ammonium kinds of clinoptilolite rocks from shivyrtuin deposit has been carried out. In the laboratory conditions, metals adsorbed by zeolite rocks are extracted by means of displacement by concentrated ammonium salts with further calcinations of the filtrate up to 500 °С. The metal content of the obtained cakes is conditioned by metal concentrations in solutions, by methods of impregnation and by the eluents applied. Saturation of ammonium types of zeolites with mine water solutions from the Sherlovaya Gora lake and further extraction of adsorbed metals by ammonium acetate yields the recovery of lantanoids of 73%. The obtained results, considering multiple recycling of the sorbent, can be used in development of an efficient technology for extraction of rare earth elements from mine solutions.

Immobilization of Pb, Cd, Cu and Zn in a Multi-Metal Contaminated Acidic Soil using Inorganic Amendment Mixtures

The objective of this study was to evaluate the effectiveness of inorganic amendment mixtures including zeolite, limestone and phosphate rock for the remediation of a multi-metal contaminated acidic soil. Firstly, a 40-day batch experiment using orthogonal design was conducted to select the best inorganic amendment mixtures for increasing soil pH and decreasing the mobility of Cd, Pb, Cu and Zn in soil. The application of mixture amendments all significantly increased soil pH and decreased the CaCl2-extractable Cd, NH4NO3-extractable Pb, Cu and Zn concentration. Among them, four kinds of inorganic amendment mixtures were selected for pot experiment with water spinach (Ipomoea aquatica F.), lettuce (Lactuca sativa L.) and Chinese flowering cabbage (Brassica campestris L.) which increased soil pH by 2.24–2.90 units and decreased the CaCl2-extractable Cd, NH4NO3-extractable Pb, Cu and Zn concentration by 96.77–100%, 98.64–99.83, 95.69–97.09 and 96.26–99.56%, respectively, and they all greatly improved plant growth and significantly reduced Cd, Pb, Cu and Zn concentration in the shoot of plants compared with the un-amended control. Furthermore, there was a significant positive correlation between the CaCl2-extractable Cd, NH4NO3-extractable Pb, Cu and Zn concentration in soil and their concentration in the shoot of plant (P < 0.05). Metal sequential fractionation data indicated that inorganic amendment mixtures substantially modified the partitioning of soil Cd, Pb, Cu and Zn from the easily exchangeable phase to less bioavailable Fe–Mn oxides bound and carbonate bound fractions. The result demonstrated that the application of inorganic amendment mixtures could offer an efficient way to immobilize heavy metals and improve plant growth in acidic multi-metal contaminated soils.

UPTAKE ABILITY OF ZEOLITIC ROCK FROM SOUTH XEROVOUNI, AVDELLA, EVROS, HELLAS

Zeolitic rock samples from South Xerovouni contain on average, 57 wt.% HEU type zeolite, 6 wt.% clay minerals, 3 wt.% mica (total of 66 wt.% microporous minerals), 19 wt.% feldspars, 10 wt.% cristobalite and 5 wt.% quartz (total of 34 wt.% non-microporous minerals). Chemically the zeolitic rock consists mainly of 69.9 wt.% SiO2, 13.2 wt.% Al2O3, 1.2 wt.% Fe2O3t, 1.0 wt.% MgO, 3.0 wt.% CaO, 1.5 wt.% Na2O and 2.2 wt.% K2O. The zeolitic rock shows an average ammonia ion exchange capacity of 150 meq/100g. HEU-type zeolite accounts for the most of the uptake ability, while clay minerals and mica contribute to a relative small extent only. The uptake ability of the five zeolitic rock samples showed positive correlations with the content of HEU-type zeolite as well as with the total content of microporous minerals (zeolite + mica + clay minerals). Such materials could be used in a wide range and scale of agricultural, aquacultural, and environmental applications.

MINERALOGICAL CONTRAINTS TO THE FORMATION OF VEIN-TYPE ZEOLITES FROM KIZARI AREA, THRACE NORTHERN GREECE

Vein-type zeolites in Kizari area, (western Thrace) are found within fresh to zeolitic altered volcanic rocks of andesitic to dacitic composition. The zeolites stilbite-Ca, Sr-bearing heulandite-Ca and laumontite occur in epithermal-style crustiform quartz/chalcedony-calcite veins crosscuting lavas and volcanic breccias. Open-space filling is common and well-shaped crystals (up to 3cm) were observed. Smectite, feldspar, magnetite, pyrite and rutile occur in minor amounts in the veins. Halite and barite grains are included in stilbite-Ca. SEM EDS data indicate high Sr (up to 4.4 wt. % SrO) and Ba (up to 2.9 wt. % BaO) contents for heulandite-Ca. It is suggested that the studied zeolites are intergral parts of the porphyry-epithermal mineralizing systems which operated in the area during the Oligocene. Their formation took place in the outmost transitional propylitic to fresh zones of the porphyry-epithermal systems and in a submarine environment as indicated by the geological and mineralogical evidence.

THE MINERALOGICAL COMPOSITION OF THRACE ZEOLITIC ROCKS AND THEIR POTENTIAL USE AS FEED ADDITIVES AND NUTRITION SUPPLEMENTS

Thirty two (32) locations of zeolitic rocks from Thrace (29 from Evros prefecture and 3 from Rhodope prefecture) were investigated for their mineralogical composition by X-Ray Diffraction (XRD) method. According to EU Regulation No 651/2013, clinoptilolite of sedimentary origin (zeolitic tuffs) with ≥80 wt% clinoptilolite, ≤20 wt% clay minerals, free of fibres and quartz, can be used as feed additive for all animal species. The zeolitic rocks of Thrace on average contain, 23-89 wt% HEUtype zeolite (clinoptilolite-heulandite), 8-45 wt% mordenite (ten locations), 24 wt% analcime (one location), 1-11 wt% mica, 1 11 wt% clay minerals, 3-37 wt% quartz, 2-29 wt% cristobalite, 3-34 wt% feldspars and 0-22 wt% amorphous materials. Only one location contains 89 wt% HEU-type zeolite (clinoptilolite-heulandite), 2 wt% clay minerals, is free of fibres, but unfortunately it contains 3 wt% quartz and 2 wt% cristobalite. Considering the mineralogical composition, the zeolitic rocks of Thrace do not meet the requirements of the EU Regulation No 651/2013, and thus cannot be used as feed additives for all animal species and consequently as nutrition supplements, since the zeolitic rocks in all locations, contain on average 3-37 wt% quartz, 2-29 wt% cristobalite, 8-45 wt% mordenite (fibrous zeolite) in 10 locations, 24-65 wt% zeolites (HEU-type ± mordenite ± analcime) in 28 locations, 74 wt% HEUtype zeolite in 2 locations and 77 wt% HEU-type zeolite in 1 location.

Mineralogical and physico-chemical properties of Heu-type zeolitic rocks SE of Ankara, central Turkey

AbstractThis study focused on the mineralogical and physico-chemical properties of heulandite/clinoptilolite (Heu/Cpt)-rich zeolitic tuffs SE of Ankara (Turkey) and evaluated their potential for use as adsorbents. The main Heu/Cpt minerals correspond to the intermediate type and the Cpt-type of the heulandite series. Minor chabazite, erionite and rarely analcime and accessory feldspars, mica, smectite, and quartz were also detected. Three types of Heu were recognized according to their thermal behaviour. Cpt (type-III Heu) was thermally stable at 600°C, whereas type-I Heu collapsed and type-II Heu partially collapsed. The Si/Al ratios of the Hul/Cpt ranged from 3.54 to 5.03, the Γ parameter (Γ = Ca/Al + 0.115*Al) varied between 0.78 and 1.85 and Al + Fe3+varied between 6.27 and 8.00. The Na, K and Ca contents of Heu/Cpt varied widely and the Heu had an intermediate composition between types II and III. The Mg + Ca content is greater than the Na + K content in Heu-type II and smaller in Heu-type III zeolites. The BET surface area and the pore-size of the samples varied between 10.15 and 194.27 m2/g, and between 1.41 and 12.42 nm, respectively. The N2adsorption and desorption isotherms were comparable, but the adsorption/desorption capacity is greater in type III than in type II Heu zeolites. The cation exchange capacities of the Heu/Cpt-rich samples ranged from 185 to 280 meq/100 g.

Characterization and Utilization of Natural Zeolites in Technical Applications

Zeolites and zeolite rocks are commonly used in different industrial applications. Natural zeolites present an attractive material for environmental applications because of their high abundance, availability and low costs. Depending on geological settings and conditions during mineral formation, natural zeolite deposits usually represent a heterogeneous mixture of zeolite minerals together with varying amounts of gangue minerals (e. g. quartz, feldspars and phyllosilicates). Hence, profound mineralogical knowledge and a detailed characterization of natural zeolites are essential for tapping their full potential in any practical application. However, this is rarely done as detailed mineralogical characterizations are elaborate and often neglected in favour of bulk chemical analyses (e. g. XRF).In this paper we describe typical technical applications for natural zeolites as well as the requirements demanded for their use. An analytical protocol has been developed for the detailed characterization of natural zeolites for ammonium exchange consisting of a combination of mineralogical and chemical methods and is exemplarily demonstrated. The methodology comprises mineralogical investigations with X‑ray diffraction (XRD) and electron microprobe analyses (EPMA) to provide qualitative data on mineral compositions and in-situ analysis of mineral chemistry (Si/Al-ratio, cation contents). The examinations are accompanied by bulk chemical analysis (XRF) as well as thermoanalytical investigations (TG/DSC) to distinguish between certain zeolite minerals. Finally, ion exchange experiments for ammonium have been carried out to determine the cation exchange capacity (CEC) of zeolite samples for a defined range of concentrations.The aim of the study is to develop an analytical routine in order to enable the detailed characterization of natural zeolite samples with standardized means of mineralogical/chemical analysis prior to their application in technical processes. This is important for quality assurance and for identifying the best suited zeolites for specific technical processes, especially when the proposed applications are not standardized.

Use of Zeolite Rocks in Metal Recovery from Mine Water

Use of Zeolite Rocks in Metal Recovery from Mine Water

Optimization of porous heat-insulating ceramics manufacturing from zeolitic rocks

Lightweight porous ceramics prepared from common zeolite-containing rocks is an energy-saving alternative to conventional foam glass. Here we show that not only chemical and mineral composition of the raw rock is important for choosing an appropriate technology to obtain a porous ceramics with the best performance, but the raw rock microstructure as well. Rocks with open-crystalline zeolitization can be used for manufacturing of the most lightweight (100–150kg/m3) porous ceramics without mechanical activation, whereas rocks with cryptocrystalline zeolitization requires additional mechanical activation to obtain such a lightweight product.

Lightweight aggregates produced from sand sludge and zeolitic rocks

This paper reports the results of investigations on manufacturing lightweight aggregates from sand sludge with zeolitic rocks added to decrease the foaming temperature. Sand sludge is a waste product from crushing and screening plants for sand and gravel production. Introduction of 20% zeolitic rock into the raw mix composition reduces the temperature required to produce lightweight aggregates by 50°C and improves their physical–mechanical characteristics. Lightweight aggregates using sand sludge with zeolitic rocks added have porous structures, with a total porosity of 60–70%; this material is recommended for use as lightweight aggregates for concrete and as heat-insulating filling.

The Efficacy of the Organo-Zeolitic Bio-fertilizer

The aim of this research is to evaluate the properties and benefits of using an organo-zeolitic fertilizer (biofertilizer) for the production of food crops and the vegetation of contaminated land. Apart from the ever increasing cost of chemical fertilizers their use over the last seventy or more years have had a deleterious effect on soil health. In contrast the bio-fertilizer, composed of organic waste and crushed zeolitic rock, containing Clinoptilolite and commonly Mordenite zeolite, functions biologically in sponsoring nitrification. Ammonium ions, provided from the degradation of the organic waste, are adsorbed to the zeolite mineral surface thus avoiding loss to the atmosphere by volatilization. Oxidation of the ammonium ions, by soil nitrifying micro-organisms, provides major and trace element nutrients. Analysis of pore water, from substrates amended with the bio-fertilizer, has shown that its electrical conductivity is orders of magnitude higher than that of pore water from un-treated substrates. This is reflected in the high ionic concentration of cations present, which covers a wide range of elements, providing essential major and beneficial trace-elements in the ionic state that are directly available for plant uptake. Further work has shown that without the organic component the degree of plant growth is greatly reduced and the converse applies in that the application of the organic waste without the crushed zeolitic rock again reduces plant growth. Many countries in the world have extensive deposits of zeolitic sediment, containing a high abundance of zeolite minerals, and the organic component, being animal or plant waste, is generally availability.

Effects of hydrothermal alterations on physical and mechanical properties of rocks in the Kuril–Kamchatka island arc

The hydrothermal systems of the Kuril–Kamchatka island arc are hosted in volcanic formations of Neogene–Quaternary age. Thermal water alters volcanic rocks and transforms them into hydrothermal rocks such as secondary quartzites, various propylites, zeolitic rocks, argillic rocks, clays, opalites, and quartz–feldspar metasomatites. Mineralogical alteration of rocks contributes to changes of their physical and mechanical properties. The relationship between type of hydrothermal alteration and rock properties is quite variable and depends on a number of factors including parent rocks, РТ-conditions, chemical composition and type of fluid, and duration of fluid–rock interaction. The study showed that high-temperature fluids cause consolidation and strengthening of rock, decrease in their porosity and permeability, and remove hygroscopic moisture. This tendency is observed independently of fluid chemical composition. Property variations caused by low-temperature subsurface fluids are more complicated and diverse but their “deterioration” prevails i.e. a decrease in density, strength and elastic modulus, formation of secondary porosity, high hygroscopy, softening and swelling in water saturated environment.Special attention is given to the near-surface alteration zones which affects the selection of sites for power plant construction and can impact the integrity of their foundation. The subsurface horizon of hydrothermal clays is the most problematic zone due to high porosity, plasticity, hygroscopy, compressibility and occasionally swelling.

How substrate influences nitrogen transformations in tidal flow constructed wetlands treating high ammonium wastewater?

A long-term lab-scale experiment was conducted to investigate the influence of different substrates, namely, zeolite, quartz sand, biological ceramsite, and volcanic rock, on the dynamics of nitrogen transformations in constructed wetlands (CWs) with a tidal operational strategy. The zeolite-based tidal flow CW (TFCW) outperformed the quartz sand, ceramsite, and volcanic-based TFCWs in removing NH4+-N and TN under the same operational conditions. A mean removal rate of approximately 97% for ammonium at an inflow concentration of about 100mgL−1 was observed in TFCW with zeolite, higher than those of the other three TFCWs (15–34%). This superior performance was due to the competitive properties of zeolite, including its micropore volume (61.2mm3g−1), specific surface area (16.6m2g−1), and cation exchange capacity (4.3cmolkg−1). The rapidly developing biofilm in TFCWs with sufficient oxygen supply enveloped the surface of each substrate and filled the micropores, reducing the specific contacting surface area and cation exchange capacity. However, the rapid and stable removal of ammonium can be attributed not only to the high adsorption capacity of the specific substrate during the flooded phase but also to the fast nitrification during the drained phase of each tidal operation, facilitating the regeneration of the adsorption capacity of the substrates. The abundance of specific bacteria depends on various substrates, but the diversity of genes from different substrates is similar. Substrates crucially influence nitrogen transformations in TFCWs treating wastewater, so their selection should be a design criterion.

Studying the processes of damage to cement by solutions of carboxylic acids

The interaction of the solutions of certain carboxylic acids with filled cement composite has been studied via the static contact of phases. Damage to materials made up of zeolite rocks (ZRs) with cement binders during interaction with aggressive media has been analyzed.

Natural zeolite clinoptilolite-phosphate composite Membranes for water desalination by pervaporation

Natural zeolite membranes, directly sectioned from mineral deposits, have been previously reported to show molecular sieve characteristics in selective separation of water and hydrated cations. Although a high removal of cations was observed, the low water flux was a limitation for any potential industrial applications. In this study novel clinoptilolite-based phosphate composite membranes were prepared by dry pressing of mixed powder materials followed by high temperature autoclave steaming and characterized by XRD, SEM-EDX. Their performance for pervaporative water desalination was examined using different levels of salinity in a temperature range of 25–95°C and feed side pressure of 1atm. At 1400ppm Na feed salinity and 95°C, a water flux of 15kg/m2h and over 95% removal of Na+ were obtained. The water flux achieved was about 10 times higher than the flux obtained using natural zeolite rock membranes. Introducing phosphate into the composite membranes appears to provide not only mechanical strength, through the possible chemical bonding between zeolite particles and the in-situ phosphate cement, but also to create a chemically favorable interface between zeolite crystals. Such interface might facilitate the desalination process bypassing the technical difficulties of ion leakage/diffusion through the inter-crystal spaces commonly associated with synthetic zeolite membranes.