Comparative Study of Metakaolin and Zeolite Tuff Influence on Properties of High-Strength Concrete

Composite admixtures which include active pozzolanic components and high-range water reducers, allows to obtain high-strength, particularly dense and durable concrete to achieve a reduction in resources and energy consumption of manufacturing.Zeolite, containing a significant amount of active silica, can serve as one of the alternative substances to resources and energy consuming mineral admixtures like metakaolin and silica fume. The deposits of zeolites are developed in Transcarpathia (Ukraine), USA, Japan, New Zealand, Iceland and other countries. It is known that zeolite tuffs exhibit pozzolanic properties and are capable to substitution reactions with calcium hydroxide.However, the high dispersion of zeolite rocks leads to a significant increase in the water consumption of concrete. Simultaneous introduction of zeolite tuffs with superplasticizers, which significantly reduce the water content, creates the preconditions for their effective use in high-strength concrete.Along with dehydrated (calcined) zeolite, natural (non-calcined) zeolite expresses itself as an effective mineral admixture of concrete. When using non-calcined zeolite, the effect of increasing in compressive strength at the age of 3 and 7 days is close to the effect obtained when using dehydrated zeolite: 8-10% and 10- 12%, respectively, and 28 days the strength growth is 13-22%. The use of non-calcined zeolite has a significant economic feasibility, so it certainly deserves attention. There were compared the effect of zeolite to metakaolinThe results of the research indicate that the use of composite admixtures, consisted of calcined (non-calcined) zeolite tuff of high dispersity and superplasticizer of naphthalene formaldehyde type, allows to obtain concretes classes C50…C65.

Reduction of Lead and Antimony Ions from the Crystal Glass Wastewaters Utilising Adsorption

The presented research examined five adsorbents, i.e., zeolite 4A, a mixture of three zeolites (4A, 13X, and ZSM-5), natural zeolite (tuff), activated carbon, and peat, and their potential capability for removal of exceeded ions of lead (Pb), antimony (Sb), sulphates (SO42−), and fluorides (F−) from real wastewater generated in the crystal glass industry, which was previously treated in-situ by flocculation, with the aim to attain the statutory values for discharge into watercourses or possible recycling. The screening experiment evidenced that the tuff was the most suitable adsorbent for the reduction of Pb (93.8%) and F− (98.1%). It also lowered wastewater’s pH sufficiently from 9.6 to 7.8, although it was less appropriate for the reduction of Sb (66.7%) as compared to activated carbon (96.7%) or peat (99.9%). By adjusting the pH of the initial wastewater to pH 5, its adsorption capacity even enlarged. Results from the tuff-filled column experiment revealed reduction of Pb up to 97%, Sb up to 80%, and F− up to 96%, depending on the velocity flow, and thus it could be used for post-treatment (and recycling) of wastewaters from the crystal glass industry. Moreover, the system showed an explicit buffering capacity, but negligible reduction of the SO42−.

Coriolus versicolor Mushroom Grown on Selenium-Rich Zeolite Tuff as a Potential Novel Food Supplement

Research background. In the recent years, considerable attention has been given to selenium (Se) status since its deficiency is linked with various disorders and affects at least 13 % of world population. Additionally, mushrooms are known to possess pronounced capacity for absorption of various micronutrients, including Se, from soil/substrate. Here, the possibility of using Se-rich zeolite tuff as a supplement for production of selenized mushroom is investigated. Further, the impact of enrichment on the activity of antioxidant enzymes and biological potential of Coriolus versicolor medicinal mushroom is studied. Experimental approach. Se(IV)- and Se(VI)-modified natural zeolitic tuff from the Serbian deposit Zlatokop was used as substrate supplement in mushroom cultivation. To examine effectiveness of selenium enrichment, beside inductively coupled plasma mass spectrometry (ICP-MS) analysis of total selenium content, determination of antioxidant enzymes in fresh fruiting bodies as well as testing of biological potential of methanol extracts was done. Antioxidant activity was evaluated using tests pertaining to different ways of antioxidant action: inhibition of lipid peroxidation, DPPH free radical scavenging assay, ferric-reducing antioxidant power assay and chelating ability on ferrous ions. The antibacterial activity against foodborne pathogens was measured by broth microdilution assay. Additionally, chemical composition of prepared extracts was studied using UV-Vis and FTIR spectroscopy analyses. Results and conclusions. Content of selenium detected in biofortified C. versicolor was even 470 times higher compared to control ((140.7±3.8) vs (0.3±0.1) µg/g dry mass), proving that Se-rich zeolite tuff is excellent supplement for mushroom production. Further, the results of monitoring the activity of antioxidant enzymes revealed that most of the Se-enriched mushrooms exhibited higher superoxide dismutase (SOD) and catalase (CAT) and lower glutathione peroxidase (GSH-Px) activity than control. Due to elevated level of enzymes, selenated mushrooms could quickly respond to superoxide radicals, formed as a result of detachment, and thus presumably preserve quality for a longer period of time. Investigation of biological potential indicated that Se-enriched mushroom methanol extracts, generally, expressed enhanced antioxidant properties. Additionally, extracts asserted antibacterial activity against all tested pathogenic microorganisms. Novelty and scientific contribution. Cultivation of mushrooms on Se-enriched zeolite tuff is a new technological approach for obtaining Se-fortified food/supplements with enhanced antioxidant and antibacterial activity.

Isotherms, Kinetics, and Thermodynamics of NH4+ Adsorption in Raw Liquid Manure by Using Natural Chabazite Zeolite-Rich Tuff

The search for safer and sustainable management of animal manure is a global and topical challenge, in particular for the reduction of nitrogen (N) content. The use of natural adsorbents as zeolite-rich tuffs is recognized as a valid method to recover N, in the form of ammonium (NH4+), from animal manure. While the scientific literature is rich in studies performed on synthetic solutions and using clinoptilolite zeolites as adsorbent, it lacks information concerning adsorption in real liquid manure and using other types of zeolite-rich tuffs (e.g., chabazite). This work aims at exploring the NH4+ adsorption process from raw liquid swine manure, using a chabazite-rich zeolite tuff as adsorbent. The effects of temperature, contact time, and grain size have been assessed. Isotherms, kinetic models, and thermodynamic parameters have been investigated. Harkins-Jura isotherm correlates well with the observed data, in accordance with the formation of an adsorption multilayer. Kinetic data have been explained by intraparticle diffusion and pseudo-second-order models. In conclusion, the natural chabazite tuff has proven to be a valid material for NH4+ adsorption from raw liquid swine manure. In particular, to reach the highest adsorption capacities and adsorption rates, it is recommended to use it at a fine particle size and with dosages < 6 %.

Reduction of Nitrogen Load in a Zootechnical Wastewater Using a Natural Chabazite Zeolite: An Investigation on Sorption Mechanisms

The use of zeolite-rich tuffs is a valid method for recovering nitrogen from wastewaters. This paper aims at describing the NH4+ adsorption processes of an Italian chabazite zeolite tuff used for the treatment of raw liquid swine manure. The effects of temperature, grain size and contact time were investigated. The isothermal analysis showed a multilayer adsorption behavior, well explained by the Harkins–Jura model, while kinetics was explained by pseudo-second-order, Elovich and intraparticle diffusion models. This study highlighted the complexity of the adsorption process from raw liquid manure, as well as the significant differences between tested particle sizes of the same zeolite tuff.

POZZOLANE AND CORROSION-INHIBITING PROPERTIES OF THE NATURAL ZEOLITE TUFF

In this article the activity of the zeolite tuff of the Lulinsky deposit of Khanty-Mansiysk autonomous okrug –Yugra to calcium and sulfate ions has been evaluated . The components of zeolite tuff bind these ions to sparingly soluble products. The experimental results obtained show that tuff can be used as a natural pozzolan. Concerning the reaction products, the dynamics of the phase composition of cement paste with the zeolite tuff additives during hardening is shown. Supplementation promotes hydrolysis of alite, while the content of calcium hydrosulfoaluminate increases. The dynamics of strength and the compression of cement paste without an additive and with the zeolite tuff additive are estimated. The possibility and efficiency of using of zeolite tuff as a reinforcing additive to Portland cement is shown. It was found that a 5 % zeolite tuff additive with a particle size of 5-10 μm at 7 days increases the compressive strength by 15 %, and at 28 days by 21 %. The study of the calcium hydroxide leaching kinetics from cement stone is showed that a 5 % zeolite tuff additive leads to suppression of the leaching process and indicates anticorrosion properties of additives.

Ammonium adsorption by chabazite zeolite-tuff from swine manure for soil amendment

&lt;p&gt;The use of natural sorbent geomaterials, like zeolitites (rocks containing &gt; 50% of zeolites) is recognized as a valid method to recover N in the form of ammonium ions (NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;) from Zootechnical Wastewaters (ZoWs).&lt;/p&gt;&lt;p&gt;Using zeolite-rich tuff as N sorbent from ZoWs lead to varius advantages like the decrease in environmental impact of ZoWs (decreased N content) and the subsequent creation of a high-value soil amendment employable also in organic agriculture (NH&lt;sub&gt;4&lt;/sub&gt;-charged zeolite-tuff).&lt;/p&gt;&lt;p&gt;In order to understand the characteristics of NH&lt;sub&gt;4&lt;/sub&gt;-charged zeolites (CZ) as sorbent, it is mandatory a deep investigation on their sorption dynamics when they react with ZoWs. Scientific literature is rich of studies about sorption in sintetic solutions (especially NH&lt;sub&gt;4&lt;/sub&gt;CL) while it lacks studies about sorption in real ZoWs.&lt;/p&gt;&lt;p&gt;The aim of this work was therefore to characterize the NH&lt;sub&gt;4&lt;/sub&gt; sorption dynamics of a chabazite zeolite tuff from swine manure. In particular, two grain sizes were selected, a micronized (&lt; 125 &amp;#181;m, CHA&amp;#181;) and a granular one (0.7-2.0 mm, CHAg). A series of batch experiments were performed to investigate the effects of temperature, contact time and grain size on sorption of NH&lt;sub&gt;4&lt;/sub&gt;. Equilibrium data were fitted with appropriate isothermal models; kinetic models were also investigated to characterize the kinetik sorption reactions and the thermodinamic parameters like change in free energy (&amp;#916;G), enthalpy (&amp;#916;H) and entropy (&amp;#916;S).&lt;/p&gt;&lt;p&gt;Results have shown a significant grain size effect with respect to the equilibrium loading (qe), with better performances for CHA&amp;#181; in all the temperatures investigated; the isothermal data showed that the influence of temperature is less for CHA&amp;#181; with respect to CHAg.&lt;/p&gt;&lt;p&gt;The kinetic data differs from the two grain size investigated, in particular CHAg showed an initial external surface adsorption and macropore diffusion during the first 60 minutes of contact, then the diffusion occurs also inside the micropores. The Intraparticle Diffusion model (ID) for CHA&amp;#181; showed that the diffusion in the macropores are much more fast than CHAg and the intercept indicates the formation of a boundary layer thicker than CHAg. Pseudo-second-order kinetic model well explained CHAg behavior but not that of CHA&amp;#181;. Both grain sizes were well explained by Elovich equation wich is a model used to explain the sorption kinetics for energetically heterogeneous solids surfaces (as likely the surface of the zeolite-tuff employed).&lt;/p&gt;&lt;p&gt;Thermodinamic data showed that the energy in the liquid-solid adsorption surfaces increased during adsorption (&amp;#916;H &amp;#707; 0), thus the cation exchange reaction needs energy from the liquid phase.&lt;/p&gt;&lt;p&gt;The free standard entropy change (&amp;#916;S) is also positive, indicating that the NH&lt;sub&gt;4&lt;/sub&gt; sorption is a directional process with no significant differences with respect to the tested temperatures and that the randomness at the solid-solution interface increased during adsorption.&lt;/p&gt;&lt;p&gt;The negative values of Gibbs free energy (&amp;#916;G) indicates that the NH&lt;sub&gt;4&lt;/sub&gt; sorption is an exergonic process (spontaneous reaction).&lt;/p&gt;