Properties Of Natural Zeolites Research Articles

Use of Natural Zeolite to Improve Quality and Environmental Safety of Natural Surface Waters and Waste Surface Waters

Natural zeolites are materials which, due to the peculiarities of their crystal structure and high adsorption and ion exchange properties, have wide prospects for use in technologies of adsorption purification of aquatic environments. The paper presents the results of laboratory research in dynamic and static conditions of sorption properties of natural zeolite, which is currently used for purification of natural water from suspended solids in industrial water treatment plants. The sorption capacity of different fractions of this zeolite to ammonium nitrogen, fluorides and petroleum products has been established.

Effect of Mechanical Treatment on the Structure and Properties of Natural Zeolite

The morphology, specific surface area, structure, and phase composition of natural zeolite powder from the Tokai deposit which underwent mechanical treatment in a planetary mill was studied using the following methods: scanning electron microscopy (SEM), X-ray structural analysis, Brunauer–Emmett–Teller (BET) method, laser diffraction, and elemental analysis. The identification of natural zeolite X-ray patterns showed that the powder consisted of seven phases with different contents of minerals: smectite, quartz, cristobalite, clinoptilolite, illite, orthoclase, and calcite. Initially, the average size of the zeolite particles was 27 μm; after the treatment for 20 min, it was 5.5 μm; and after 600 min, it was 28 μm. Moreover, most of the particles lost their initial shape during the mechanical activation and acquired a spherical shape. It was shown that, during the first 60 min of mechanical treatment in the planetary mill, powder particles were ground, and the specific surface area increased to 33 m2/g. The further mechanical activation was determined by agglomeration of particles and a decrease in the specific surface area. The X-ray structural analysis showed that the studied powder consisted of four phases: hexagonal, monoclinic, orthorhombic, and tetragonal modifications. Mechanical treatment of natural zeolite led to the decrease in the coherent scattering regions and to the growth of microdistortions of the crystal lattice. It was shown that the continuous mechanical effect on zeolite led to the increase in the amount of an amorphous phase in the powder from 13 to 52%. The changes in the specific surface area determined by the BET method and calculated from the coherent scattering region (CSR) had the same character, and the phase composition determined the specific surface area of natural zeolite.

РЕОЛОГІЧНІ ДОСЛІДЖЕННЯ ПАСТИ ЦЕОЛІТУ ПРИРОДНОГО З КРЕМНІЮ ДІОКСИДОМ

Мета роботи. Вивчити реологічні властивості пасти цеоліту природного (кліноптилоліту) з кремнію діоксидом як загущувачем для вибору їх оптимальних концентрацій.Матеріали і методи. Об’єктами дослідження були модельні композиції паст, що містили в якості діючої речовини порошок цеоліту природного (кліноптилоліт) у концентраціях 15 %, 20 %, 25 % та 30 %, а в якості загущувача кремнію діоксид у концентраціях 5,0 %, 6,0 %, 7,0 % та 8,0 %. Визначення реологічних параметрів проводили при температурі (20±2) °С на віскозиметрі MYR VR3000 (Іспанія), робота якого основана на методі Брукфельда. Дослідження проводили у діапазоні швидкості зсуву від 1 с-1 до 200 с-1 з використанням коаксіальних циліндрів.Результати й обговорення. Визначено, що досліджені зразки належать до тиксотропно-структурованих псевдопластичних систем зі структурою коагуляційного типу. Цеоліт природний (кліноптилоліт) разом із кремнію діоксидом чинять структуруючий вплив на дисперсну систему, а їх оптимальні концентрації, що забезпечують достатнє структуроутворення, становлять 25–30 % та 7–8 % відповідно.Висновок. Вивчено реологічні властивості пасти цеоліту природного (кліноптилоліту) з кремнію діоксидом як загущувачем, та обрані їх оптимальні структуроутворюючі концентрації. Отримані результати будуть використані при розробці складу паст ентеросорбентів із цеолітом природним.

Влияние механической обработки на структуру и свойства природного цеолита

Влияние механической обработки на структуру и свойства природного цеолита

Influence of mechanical activation on the properties of natural zeolites from Tokaj Mountain

This paper presents the results of a study of the influence of mechanical activation on morphology, specific surface area and phase composition of natural zeolite of Tokaj Mountain. During the mechanical activation of zeolites powders with specific surface area of 19-20 square meters per grams, significant changes in chemical and mineralogical compositions can be observed. The laboratory experiments had shown an intensive increase of specific surface area at the beginning of mechanical activation; a further relatively slow decrease and reduction of BET surfaces were observed. By increasing the mechanical activation time the amount of quartz, cristobalite-low, orthoclase mineral components were not stable, and their content have varied not so strongly as a decrease smectite 15 A, clinoptilolite, illite 2M1 or calcite. In addition, during the mechanical activation occurred amorphization, which was increased from 13% to 52%.

Свойства природного цеолита для получения высокопрочного мелкозернистого бетона

Свойства природного цеолита для получения высокопрочного мелкозернистого бетона

Electrical Properties of Natural Zeolites Modified by Bismuth Salts

The possibility of modifying natural zeolites with bismuth salts and their effect on the electric properties are investigated. No phase transitions were found at the melting point of bismuth.

Characterization and environmental application of iron-modified zeolite from the Zlatokop deposit

In this paper, characterization of iron-modified zeolite (IMZ) from the Zlatokop deposit and its potential environmental application has been described. The modification procedure includes treatment of natural zeolite (NZ) with Fe(NO3)3 in an acetate buffer at pH = 3.6 followed by treatment with NaOH and NaNO3. The properties of NZs and IMZs have been determined by analysis of their chemical composition, specific surface area and by X-ray powder diffraction method (XRPD), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDS), TG-DTG and FTIR analyses. The chemical behaviour of modified zeolite has been examined in the zeolite-ultrapure water system at adjusted initial pH values in the range of 1.71–5.08, and also by determining the zero-point charge. The NZ and IMZ samples have been tested relative to the uptake of zinc ions. The results have shown that the capacity of IMZ samples for zinc ions is three-to-four times higher compared to the NZs. The balance of exchangeable ions before and after zinc uptake confirms an almost complete stoichiometric relation for both zeolite samples indicating ion exchange as the main process. However, in IMZ samples ion exchange takes place inside the zeolite particle and on activated zeolite particle surface.

Specific features of the absorption of divalent manganese ions from aqueous solutions by zeolites

Sorption properties of natural zeolites from various Russia’s deposits for the Mn2+ ion were studied in comparison with various industrial adsorbents and some minerals. It was demonstrated that the equilibrium sorption capacity of these materials can be raised by their Na+-modification. The natural zeolites are advantageous at low Mn2+ ion concentrations over synthetic cation exchangers and activated carbons. The sorption capacity of the natural zeolites grows with increasing temperature.

Effect of mechanical activation on the properties of natural zeolites

We have examined the effect of mechanical activation on the Sr2+ and Cu2+ ion exchange selectivity of Russian natural zeolites: clinoptilolite-containing tuffs and chabazite concentrates. We have studied their structural changes and thermal properties and determined the specific surface area and porosity of the mechanically activated zeolites. At specific milling energies below 0.5–0.7 kJ/g, the dominant process is disintegration of zeolite particles and changes in their bulk porosity. At higher milling energies, amorphization prevails. Our results demonstrate that, in the initial stage of activation, one can markedly raise the Sr2+ selectivity of some zeolites (e.g., by 16 times for Shivyrtuiskoe clinoptilolites and by 300 times for chabazite) and increase the Cu2+ selectivity (by 40 to 100 times), which will persist at high specific milling energies.

Colour and TOC reduction using biofilter packed with natural zeolite for the treatment of textile wastewaters

The main contribution of the presented research is to examine the potential of natural zeolite for colour and TOC reduction when packed in a fixed-bed system, considering various parameters such as wastewater characteristics, properties of natural zeolite, loading rate and hydraulic retention time. Firstly, the diverse chemical aspects of tuff were determined using scanning electron microscopy and infrared spectroscopy with the intention of establishing the impact of tuff surface and chemical composition on its adsorption properties and decolouration possibilities. Secondly, a series of dynamic experiments were conducted on laboratory-prepared wastewaters combining chemically differ reactive dyestuffs, auxiliaries and chemicals in order to investigate biofilter’s treatment efficiency. Assessment of the biofilter’s performance was verified by monitoring absorbance and total organic carbon in initial and treated wastewaters. The results showed that when increasing the load from 22 to 37 mg/m3d (dyes) and fr...

Effects of the application of natural zeolite on the growth and nutrient status of radish (Raphanus sativus L.)

SummaryThe unique cation exchange, adsorption, hydration-dehydration, and catalytic properties of natural zeolites, and their abundance, have promoted their use in agriculture as soil amendments and slow-release fertilisers. This research was conducted to investigate the effects of natural Iranian zeolite on vegetative growth and the nutrient status of radish (Raphanus sativus L. cv. Cherry Belle). The experiment was performed as a completely randomised design with six treatments (0, 20, 40, 60, 80, or 100 g zeolite kg−1 soil) and four replicates. The results indicated that zeolite increased leaf number and leaf area, shoot fresh weight (FW), the diameter and FW of edible roots, the number, length and FW of fibrous roots, and harvest index. The use of zeolite also increased the concentrations of nitrogen (N) and potassium (K) in shoot tissues, and the cation-exchange capacity of the medium. It was concluded that zeolite had a pronounced positive effect on vegetative growth in radish. Zeolite may be recommended as a soil amendment for vegetable crops such as radish to decrease nutrient leaching.

Effects of Zeolite Application on Rice Yield, Nitrogen Recovery, and Nitrogen Use Efficiency

The unique cation exchange, adsorption, hydration–dehydration, and catalytic properties of natural zeolites and their abundance have promoted their use in a wide variety of agricultural processes as soil amendments, slow‐release fertilizers, and other materials. To investigate the feasibility of using a natural clinoptilolite to enhance rice grain yield, nitrogen (N) recovery and N use efficiency, an experiment was conducted in a coarse‐textured rice field in the Guilan province of Iran. Three levels of 8, 16, or 24 tons of zeolite ha−1 were incorporated into the soil with and without 60 kg N ha−1 as urea, and their effects on the grain and straw yields, available K, apparent N recovery, N use efficiency, and some soil properties were determined. Results indicated a significant positive effect of treatments on the grain yield, straw, and tiller numbers of rice. All levels of zeolite with N showed a significant increase in grain yield compared with 60 kg N ha−1 and control treatment. Zeolite application also increased soil‐available potassium and its uptake by rice straw significantly. The lowest apparent N recovery (40%) was obtained from application of 60 kg N ha−1, whereas application of 8 or 16 tons zeolite ha−1 increased apparent N recovery up to 65%. Nitrogen use efficiency was also improved.

天然ゼオライトの遠赤外放射特性とそのヒーターへの適用性

天然ゼオライトの遠赤外放射特性とそのヒーターへの適用性

天然ゼオライトの遠赤外放射特性

天然ゼオライトの遠赤外放射特性

Modification of solids with volatile organics III: Natural zeolites

The effect of pre-adsorbed benzene and ethanol on the adsorptive properties of natural zeolite (clinoptilolite) has been studied by gas-solid chromatography. It has been shown that modification of the solid surface by volatile organics has a significant influence on the adsorptive properties. The modification is of the same order as the more difficult modification by inorganics, as illustrated here by clinoptilolite modification with Co2+. Energy distribution of surface adsorptive sites appears to be continuous and confirms previous finding that only a small proportion of active sites is responsible for most adsorbate retention.

Migration of radiocesium in a zeolite-solution system

Some properties of natural zeolite from Zaloska gorica, Slovenia, Yugoslavia were investigated to establish its applicability in solidification and for storage purposes of radioactive waste. It was found that this material is a rather good sorber for cesium, with a capacity of about 0.6 meq g−1. The migration rate of Cs+ in a system ion exchanger-aqueous solution was investigated and correlated with the sorption behaviour of cesium in a system. The leaching rate of cesium from concrete containing zeolite was measured.