Clinoptilolite Type Research Articles

Thermochemical study of sorption of pyridine derivates by copper forms of synthetic and natural zeolites

Sorption of hazardous pyridine derivates by copper forms of synthetic zeolite ZSM5 and natural zeolite of the clinoptilolite type (CT) has been investigated. Sorption of 2-chloropyridine (clpy) and 2-ethylpyridine (ethylpy) from liquid and gas phase by copper forms of zeolites (Cu-ZSM5 and Cu-CT) has been studied by CHN analysis, thermal (TG, DTG and DTA) analysis, FTIR spectroscopy, X-ray powder diffractometry and determination of the surface areas and the pore volumes by low-temperature adsorption of nitrogen. The results of thermal analyses of Cu-ZSM5, Cu-(clpy) x -ZSM5, Cu-(ethylpy) x -ZSM5, Cu-CT, Cu-(clpy) x -CT and Cu-(ethylpy) x -CT zeolitic products with different composition (x depends on the experimental conditions of sorption of pyridine derivates) clearly confirmed their different thermal properties and the sorption of pyridine derivates. The main part of the decomposition process of zeolitic samples containing pyridine derivates occurs at considerably higher temperatures than the boiling point of pyridine derivates proving strong bond and irreversibility of clpy- and/or ethylpy–zeolite interaction. FTIR spectra showed well-resolved bands for pyridine derivates in the Cu-(clpy) x -zeolite and Cu-(ethylpy) x -zeolite. Surface area and pore volumes of the samples Cu-clpy-ZSM5, Cu-ethylpy-ZSM5, Cu-clpy-CT and Cu-ethylpy-CT in comparison with Cu-ZSM5 and Cu-CT decreased due to the adsorption of pyridine derivates.

Removal of pyridine from liquid and gas phase by copper forms of natural and synthetic zeolites

Zeoadsorbents on the basis of copper forms of synthetic zeolite ZSM5 and natural zeolite of the clinoptilolite type (CT) have been studied taking into account their environmental application in removing harmful pyridine (py) from liquid and gas phase. Sorption of pyridine by copper forms of zeolites (Cu-ZSM5 and Cu-CT) has been studied by CHN, X-ray photoelectron spectroscopy, X-ray powder diffractometry, FTIR spectroscopy, thermal analysis (TG, DTA and DTG) and analysis of the surface areas and the pore volumes by low-temperature adsorption of nitrogen. The results of thermal analyses of Cu-ZSM5, Cu-(py)xZSM5, Cu-CT and Cu-(py)xCT zeolitic products with different composition (x depends on the experimental conditions of sorption of pyridine) clearly confirmed their different thermal properties as well as the sorption of pyridine. In the zeolitic pyridine containing samples the main part of the pyridine release process occurs at considerably higher temperatures than is the boiling point of pyridine, which proves strong bond and irreversibility of py–zeolite interaction. FTIR spectra of Cu-(py)xzeolite samples showed well resolved bands of pyridine. The results of thermal analysis and FTIR spectroscopy are in a good agreement with the results of other used methods.

Ammonia Removal from Nitrogenous Industrial Waste Water Using Iranian Natural Zeolite of Clinoptilolite Type

Ammonia Removal from Nitrogenous Industrial Waste Water Using Iranian Natural Zeolite of Clinoptilolite Type

Single and binary adsorption of reactive dyes from aqueous solutions onto clinoptilolite

The adsorption of Reactive Blue 21 (RB21) and Reactive Red 195 (RR195) onto clinoptilolite type natural zeolite (ZEC) has been investigated at 298.15K. The uptake of single and binary reactive dyes from aqueous solutions has been determined by UV–vis spectroscopy. Two mono-component (RB21 and RR195) and binary component (RB21 with RR195, and RR195 with RB21), isotherms were determined. The mono-component Langmuir isotherm model was applied to experimental data and the isotherm constants were calculated for RB21 and RR195 dyes. The monolayer coverage capacities of clinoptilolite for RB21 and RR195 dyes in single solution system were found as 9.652 and 3.186mg/g, respectively. Equilibrium adsorption for binary systems was analyzed by using the extended Langmuir models. The rate of kinetic processes of single and binary dye systems onto clinoptilolite was described by using two kinetics adsorption models. The pseudo-second-order model was the best choice among the kinetic models to describe the adsorption behaviour of single and binary dyes onto clinoptilolite.

Heavy metal adsorption by clinoptilolite from aqueous solutions

The present investigation has been carried out to assess a chromium, cobalt, and cadmium from wastewaters by natural and modified zeolites were examined by using batch type method. A clinoptilolite type synthetic / natural zeolite were pretreated with HCl and HNO 3 to improve the adsorption capacity for heavy metals. The removal efficiencies and kinetics of heavy metals such as chromium, cobalt and cadmium on natural modified zeolites were determined. The kinetics of adsorption indicates the process to be diffusion controlled. This process is very well work in industrial treatment plant of various industries using heavy metals for their production.

Study of adsorption phenomena ongoing onto clinoptilolite with the immobilized interfaces

The development of innovative clean-up technologies remains a challenge as current procedures have many limitations, such as being expensive, concentration or pollutant specific, and many others. Natural zeolite of clinoptilolite type was beneficiated with surfactant octadecylammonium and alginate biopolymers using the sol-gel method. Carbonization process in pyrolysis chamber combusted organic waste materials and reaching the maximum temperature of 700°C was used for the surface carbonization, respectively.

Ammonia Removal from Aqueous Solutions by Iranian Natural Zeolite

The capability of Iranian natural clinoptilolite for ammonia removal from aqueous solutions has been thoroughly studied. Both batch and continuous (column) experiments were carried out. The viability of this natural zeolite in reducing the leakage of ammonia to the environment through waste water streams was a main focus of this research. Through the batch experiments, the effect of process variables such as the size of zeolite particles, pH, and ammonia concentration of the feed solution on the kinetics of ammonia uptake were investigated. Ammonia removal occurred rapidly and within the first 15 minutes of contact time, a major part of ammonia was removed from the solution. An adsorption capacity about 17.8 mg NH4 +/g zeolite at feed ammonia concentration of 50 mg/L was obtained and the optimum range for pH was achieved about 5.5–7.6. The adsorption capacity of clinoptilolite in the continuous mode was about 15.16 and 15.36 mg NH4 +/g zeolite for the original and regenerated types of clinoptilolite, respectively, where feed ammonium concentration was 50 mg/L. Increasing the feed ammonium concentration to 100 mg/L did not reduce the capability of the column for its ammonium removal and up to a bed volume (BV) of 85, there was only less than 1 mg/L ammonium in the column outlet. Presence of cations such as Ca2+, Mg2+ and Na+ in the feed solution reduced the clinoptilolite adsorption capacity to about 11.68 mg NH4 +/g zeolite. Regeneration experiments were carried out using concentrated sodium chloride solutions, as well as tap water. Where tap water was used as the regenerant, gradual release of ammonium from exhausted clinoptilolite was observed.

Effect of natural zeolite on biochemical and hematological parameters in blood, body mass and growth of calves

The work presents the results of investigations of the effect of natural zeolite (clinoptilolite type) on the degree of resumption of cloistral immunoglobulin, the value of hematological parameters and enzyme activity in blood serum (AST, ALT, and LDH), body mass, and daily growth of calves in the first three months of life. Investigations were carried out on three groups of 10 male and female calves each, with a 1:1 ratio of sexes, (control, K, and two experimental groups, I and II), of the black-and-white breed, Holstein type. All three groups of calves were fed with the usual rations (colostrum, collective cows' milk, fodder mix with 18% total proteins, and Lucerne hay).The experimental groups of calves, as opposed to the controls, received colostrums and collective cows' milk with the addition of a preparation based on natural zeolite in quantities of 5 and 10 g/l milk. The concentration of immunoglobulin G in blood serum of experimental groups of calves was significantly higher than the values of the control group (35.9?6.43 g/l in Group I; 32.5?7.39 g/l in Group II; 20.8?6.88 g/l in control group K). The results of the investigations of the values of hematological parameters (number of erythrocytes, hemoglobin concentration, and hematocrit value) do not show any digressions from the physiological values and are approximately the same in the experimental and the control groups of calves, which indicates that the examined quality of the zeolite-based preparation did not affect the degree of the resumption of iron and other oligoelements significant for erythropoietin. The data on the enzyme activity in blood serum indicate that the examined preparation does not cause any significant functional or morphological changes in the tissue of parenchymatous organs or muscles. There were no significant disorders in the health of calves of the experimental groups, while 3 calves of the control group had gastrointestinal disorders (diarrhea). Calves of experimental group I which received colostrum and collective cows' milk with an addition of 5g zeolite/l milk had a significantly greater average body mass and daily growth on the 90th day of life than calves of the control group (116.0-6.9: 105.3-6.4 kg, and 0.868:0.743 g). The addition of natural zeolite in quantities of 5 g/l colostrum or milk yields better results and has an advantage over the higher doze of zeolite of 10 g/l.

Natural Zeolites Used as Surface Reaction for Phthalocyanine Synthesis

Natural zeolites were characterized in order to be studied as surface reaction for phthalocyanine synthesis. Nonsubstituted phthalocyanines have been synthesized starting from phthalonitrile in various nonaqueous solvents in the presence of two different zeolites of the clinoptilolite type. The zeolites are shown to be effective matrices for phthalonitrile cyclisation at relatively low temperatures (0–40°C). The presence of CaCO3 in one of two natural mineral of zeolites suggested a low activity of the surface to promote the cyclization of phthalonitrile at low temperature. The influence of different solvents is not relevant for the heterogeneous reaction.

Natural Zeolites in Energy Applications

Natural zeolites have been used in a wide variety of applications over the world. Among these, its utilization for carrying energy in energy conversation and heat exchanging systems is noteworthy. The main objective of the present study is to investigate potential and utilization opportunities of natural zeolites in energy-related applications. In this regard, the reserve potential of natural zeolites in Turkey is presented, while their worldwide application areas, current, and other utilization opportunities are given. High water adsorption capability and energy storage properties of natural zeolites are studied. The results of experimental studies conducted to determine the physical and chemical properties as well as the thermal conductivity values of the Gördes zeolite (Clinoptilolite type) with highly qualified, about one billion ton of mine deposit as energy storage material, are also presented.

The study of dehumidifying of carbon monoxide and ammonia adsorption by Iranian natural clinoptilolite zeolite

The natural zeolite (clinoptilolite type) was obtained from the Neibagh region of Mianeh, the city in the west of Iran. The raw zeolite was tested for quality and quantity measurements including surface area and volumetric characteristics as well as thermogravimetry analysis. The acid activation process was used to increase the adsorption rate of zeolite and in order to obtain the optimum conditions: the effect of acid concentration, reaction time and the temperature were studied. A surface area measurement test was performed in each stage to get the best results. Thus, efficient condition was selected according to the produced highest surface area. The reaction was first obtained with hydrochloric acid, and then a comparison was made using the sulfuric acid. The hydrochloric reaction proved to be better. The result of activation was 2.5 times the increase in the surface area in relation to the raw sample. The result of elemental analysis conducted once again on the activated sample showed an increase in the ratio of Si/Al (approximately 0.6). Then, using CO, NH 3 and steam, the gas adsorption capacity of both the raw and activated samples was measured and compared. Since CO was not adsorbed at ambient temperature, but steam was adsorbed relatively well, the natural clinoptilolite zeolite of Iran was suggested as a suitable material for adsorbing humidity form carbon monoxide as well as synthesis gas (H 2 and CO mixture).

Use of Zeolites for Phthalocyanine Synthesis at Low Temperature

Non-substituted phthalocyanines have been synthesised starting from phthalonitrile in various non-aqueous solvents in the presence of two different zeolites of the clinoptilolite type is studied. The zeolites are shown to be effective matrices for phthalonitrile cyclisation at relatively low temperatures (0–40°C).

Agricultural and agrochemical uses of natural zeolite of the clinoptilolite type

The present paper deals with the agricultural and agrochemical uses of natural zeolite of the clinoptilolite type from the Nižný Hrabovec deposit in Eastern Slovakia. The structure of natural clinoptilolite is ideal for sorption and ion exchange processes. Due to its structure and properties this natural, inert and non-toxic material can be used as a slowly releasing carrier of fertilizer, as well as other agrochemically, pharmaceutically and biochemically active compounds including disinfectants. Natural zeolite can also be used to improve physical properties of soils and for treatment of contaminated soils. It is also suitable—in very small amounts—as additive to animal feed.

Leaching of boron through sewage sludge amended soil: the role of clinoptilolite

A laboratory experiment was conducted to determine the release of boron from soil–sewage sludge mixtures by leaching using a clinoptilolite type natural zeolite, before land application of the sewage sludge. Soil columns were filled up with the clinoptilolite soil after mixing with sewage sludge at a rate of 30 tons ha −1 and with two different particle sizes (0.1–0.25 and 1.0–2.0 mm) of clinoptilolite each at the concentrations of 1% and 2%. The particle size and the application rate of clinoptilolite affected both boron leaching from soil compared to the control treatment (soil and sewage sludge mixture). The total soluble boron leached from a soil column varied from 66–92% depending on the applications of clinoptilolite and reached 96% for the control treatment, following application of 80 cm depth of water in all treatments. In the cases of the 1% application rate of 0.1–0.25 and 1–2 mm sized clinoptilolite 78% and 92% of the total boron leached, respectively. While at 2% application rate of 0.1–0.25 and 1–2 mm zeolite, 66% and 87% of total soluble boron leached, respectively. Boron concentrations in the soil layers increased as application rate increased and particle size of clinoptilolite decreased because of its high adsorption capacity. Adsorption isotherms indicated that clinoptilolite had a high adsorption capacity for boron compared to the sewage sludge and soil.

Study of Organo-Modified Forms of Natural Zeolite of the Clinoptilolite Type

Study of Organo-Modified Forms of Natural Zeolite of the Clinoptilolite Type

Fabrication of microporous ceramics from ceramic powders of quartz–natural zeolite mixtures

The possibility of producing ceramic powders suitable for the fabrication of microporous filters was investigated through the thermal treatment of the powder mixtures of a high-purity (99.09% SiO 2) quartz and clinoptilolite type of natural zeolite. The quartz and zeolite, mixed in the ratio of 3:1 by weight, was wet ground in a ball mill, the powder was sieved on a 90-μm screen, and the undersize was dried and sintered in the powder form at the temperatures of 1000, 1100 and 1200 °C for 7 h in an air furnace. The powder sinter products were deagglomerated by gentle crushing in an agate mortar and then characterized by phase composition, density, and specific surface area measurements. The added zeolite facilitated the transformation of quartz to cristobalite. The phase transformation of quartz to cristobalite first appeared at around 1000 °C, and, at 1200 °C, led to a ceramic powder sufficiently high in cristobalite content for the fabrication of the microporous ceramic bodies. Re-sintering at 1200 °C of the pressed forms of the ceramic powder resulted in microporous (0.5–3 μm) ceramics with a high porosity of 48.5%, and a three-point bend strength of ∼140 kg/cm 2. The ceramics obtained may have potential for filter applications.

THERMODYNAMIC AND KINETIC STUDY OF GAS DESULPHURIZATION BY ADSORPTION ON ZEOLITES

Thermodynamic and kinetic data are presented, in order to compare the adsorption of SO2 on natural and synthetic zeolites (Clinoptilolite, Mordenite, X, Y, ZSM-5 and Beta). The adsorption capacities determined on static conditions and on transient regimes are strongly dependent on the nature, structure and SiO2/Al2O3 molar ratio of the zeolites. The synthetic zeolites present greater capacities adsorption values compared to the natural ones. The natural clinoptilolite type zeolite presents low adsorption capacity for sulphur dioxide, but it reaches considerably higher values after chemical and thermal activation. The experimental adsorption isotherms are of I-type according to the Brunauer, Demming and Teller classification and fits with Langmuir-type isotherms. On the low temperature domain (200C), the adsorption process is diffusionally controlled and the apparent diffusion coefficients values are related to the channels and access opening dimensions of the zeolite structures.

Adsorption of aqueous nitrophenols on clinoptilolite

The adsorption of o-, m- and p-nitrophenols on clinoptilolite type natural zeolite has been studied as a function of the solution concentration and temperature. The adsorption rates were observed to be equal to the first-order kinetics. The rate constants were calculated for 25.0–40.0–50.0°C at constant concentration. The activation energies, ( E a) for nitrophenoles adsorption on zeolite, were estimated using the Arrhenius equation. Thermodynamic parameters were calculated for all nitrophenols. Adsorption isotherms of o-, m- and p-nitrophenols on natural zeolite were determined. These isotherms were modeled according to the Freundlich and Langmuir adsorption isotherms. The isotherms for nitrophenols on clinoptilolite were assigned as L curves. The L curve of p-nitrophenol is two step while the L curves of o- and m-nitrophenols are one-step.

Application of natural zeolites for preconcentration of arsenic species in water samples.

Zeolites of the clinoptilolite type produced in Mexico and Hungary were investigated with respect to their sorption efficiency for various redox species of arsenic. Long-term experiments showed that arsenate remains stable for a long period in spiked deionised water and drinking water, as well as in the surface water of the Biela valley in Saxony, Germany. Both clinoptilolites are able to decrease the initial arsenic concentration of 200 microg l(-1) by more than 75% in deionised, drinking, ground and surface waters. In the case of the Mexican zeolite, both the arsenite and the arsenate concentrations (200 microg l(-1)) can be lowered from 200 microg l(-1) to 10 microg l(-1), which is the World Health Organisation's (WHO's) recommended maximum level. It was found that the presence of cations and anions in the natural waters of Biela, Germany, and Zimapán, Mexico, did not reduce the efficiency of the selected zeolites. The Hungarian zeolite removed 75% of the arsenate in the Zimapán water and only 50% when the sample was first acidified. This zeolite totally desorbed the fixed arsenic into a water volume that was half the volume in the adsorption experiment.

Dilatometry of Na-, K-, Ca- and NH 4-clinoptilolite

The dilatometric behaviour of Na-, K-, NH 4- and Ca-clinoptilolite has been investigated. Na-, K- and NH 4-clinoptilolite sensibly shrink (from 0.4 to 2.0%) up to about 350°C, while for higher temperatures only very small shrinkages (0.2%) have been detected. These dilatometric behaviours appear to be dominated by dehydration upon heating. Ca-clinoptilolite moderately shrinks up to 300°C (1.0%) and undergoes a more evident shrinkage (2.1%) at higher temperatures. The former shrinkage has been ascribed to dehydration upon heating, the latter higher one to structural damages. The different dilatometric behaviours have been interpreted in terms of the thermal properties of zeolites of the clinoptilolite type.