The crystal structure of the killer fibre erionite from Tuzköy (Cappadocia, Turkey).

Erionite is a non-asbestos fibrous zeolite classified by the International Agency for Research on Cancer (IARC) as a Group 1 carcinogen and is considered today similar to or even more carcinogenic than the six regulated asbestos minerals. Exposure to fibrous erionite has been unequivocally linked to cases of malignant mesothelioma (MM) and this killer fibre is assumed to be directly responsible for more than 50% of all deaths in the population of the villages of Karain and Tuzköy in central Anatolia (Turkey). Erionite usually occurs in bundles of thin fibres and very rarely as single acicular or needle-like fibres. For this reason, a crystal structure of this fibre has not been attempted to date although an accurate characterization of its crystal structure is of paramount importance for our understanding of the toxicity and carcinogenicity. In this work, we report on a combined approach of microscopic (SEM, TEM, electron diffraction), spectroscopic (micro-Raman) and chemical techniques with synchrotron nano-single-crystal diffraction that allowed us to obtain the first reliable ab initio crystal structure of this killer zeolite. The refined structure showed regular T-O distances (in the range 1.61-1.65 Å) and extra-framework content in line with the chemical formula (K2.63Ca1.57Mg0.76Na0.13Ba0.01)[Si28.62Al7.35]O72·28.3H2O. The synchrotron nano-diffraction data combined with three-dimensional electron diffraction (3DED) allowed us to unequivocally rule out the presence of offretite. These results are of paramount importance for understanding the mechanisms by which erionite induces toxic damage and for confirming the physical similarities with asbestos fibres.

Nanocompósitos magnéticos para concentração/remoção de contaminantes de águas / Magnetic adsorbent nanocomposites for water treatment

Zeólitas e carvão ativado são materiais eficazes para o tratamento de efluentes devido a sua grande área superficial e possibilidades de funcionalização, que permitem o desenvolvimento de novos materiais derivados visando a processos de concentração/remoção de contaminantes, por exemplo, em águas. A preparação de nanocompósitos magnéticos e sua aplicação na remoção seletiva de poluentes em meio aquoso tornou-se viável devido as interações distintas que ocorrem entre zeólita e carvão ativado com compostos orgânicos, íons metálicos e compostos nitrogenados. Assim, novos materiais voltados para sistemas de tratamento de águas residuais e monitoramento ambiental foram desenvolvidos com base em materiais bem estabelecidos. Os nanocompósitos foram caracterizados estrutural e morfologicamente por técnicas de microscopia eletrônica de varredura, termogravimetria, espectroscopia no infravermelho, espalhamento de luz, difração de raios x, bem como suas capacidades de adsorção. Foi avaliado também a viabilidade de aplicações em métodos analíticos, como pré-concentração por extração em fase sólida magnética (M-SPE), e, para tratamento de efluentes em amostras reais. Contaminação por cromo (VI), outras espécies potencialmente tóxicas e amônio foram removidos de águas residuais, gerando produtos tratados com níveis de contaminantes suficientemente baixos para atenderem as recomendações da EPA (Environmental Protection Agency) e CONAMA (Conselho Nacional do Meio Ambiente), permitindo seu descarte na natureza. Os materiais demonstraram ser adequados para pré-concentração rápida, eficiente, economicamente competitiva e ambientalmente amigável de amostras por M-SPE para quantificação analítica de espécies orgânicas ou inorgânicas, por técnicas analíticas convencionais. Assim, foi demonstrado a possibilidade de determinação simultânea de elementos potencialmente tóxicos e de outros cátions metálicos em concentrações traço (ppb), diretamente no material compósito magnético, por espectroscopia de fluorescência de raios X de energia dispersiva (EDX), além da quantificação de traços de compostos orgânicos semi-voláteis por cromatografia emfase gasosa com detector por espectrometria de massas, aumentando a sensibilidade para além do limite nominal de detecção por essas técnicas

Zeolites and activated carbon are effective materials for the treatment of effluents due to their large surface area and functionalisation possibilities, which allow the development of new derived materials aiming at the concentration/removal of contaminants from water, for example. The preparation of magnetic nanocomposites and their application in the selective removal of pollutants in aqueous media has become feasible due to the distinct interactions that occur between zeolite and activated carbon with organic compounds, metal ions and nitrogen compounds. Thus, new materials for wastewater treatment and environmental monitoring systems were developed based on well-established materials. The nanocomposites were structural and morphologically characterized by scanning electron microscopy, thermogravimetry, infrared spectroscopy, light scattering, x-ray diffraction, as well as their adsorption capacities, viability of applications in analytical methods such as preconcentration by extraction in magnetic solid phase, M-SPE, were evaluated, and the composite materials Cmag and Zmag applied for treatment of real samples. Chromium (VI) contamination, heavy metal cations and ammonium were removed from wastewater, generating treated products with levels of contaminants low enough to meet the EPA and CONAMA recommendations, allowing their disposal in the wild. The materials have been shown to be suitable for rapid, efficient, economically competitive and environmentally friendly preconcentration of samples per M-SPE for analytical quantification of organic or inorganic species by conventional analytical techniques. Thus, it was demonstrated the possibility of simultaneous analysis of heavy metals and other metal cations in trace concentrations (ppb), directly in the magnetic composite material, by dispersive energy X-ray fluorescence spectroscopy (EDX), in addition to the quantification of traces of volatile organic compounds (VOC) by gas chromatography with mass spectrometry detector, increasing the sensitivity beyond the nominal limit of detection by these techniques

Assessing occupational erionite and respirable crystalline silica exposure among outdoor workers in Wyoming, South Dakota, and Montana.

Erionite is a naturally occurring fibrous mineral found in many parts of the world, including the western United States. Inhalational exposure to erionite fibers in some localities is associated with health effects similar to those caused by asbestos exposure, including malignant mesothelioma. Therefore, there is concern regarding occupational exposures in the western United States. Currently, there are no standard sampling and analytical methods for airborne erionite fibers, as well as no established occupational exposure limits. Due to the potential adverse health effects, characterizing and minimizing exposures is prudent. Crystalline silica also occurs naturally in areas where erionite is found, principally as the mineral quartz. Work activities involving rocks containing quartz and soils derived from those rocks can lead to exposure to respirable crystalline silica (RCS). The typically dry and dusty environment of the western United States can increase the likelihood of exposures to aerosolized rocks and soils, but inhalation exposure is also possible in more humid conditions. In this case study, we describe several outdoor occupational environments with potential exposures to erionite and RCS. We describe our method for evaluating those exposures and demonstrate: (1) the occurrence of occupational exposures to airborne erionite and RCS, (2) that the chemical make-up of the erionite mineral can be determined, and (3) that effective dust control practices are needed to reduce employee exposures to these minerals.

Iron-impregnated zeolite catalyst for efficient removal of micropollutants at very low concentration from Meurthe river.

In this paper, for the first time, faujasite Y zeolite impregnated with iron (III) was employed as a catalyst to remove a real cocktail of micropollutants inside real water samples from the Meurthe river by the means of the heterogeneous photo-Fenton process. The catalyst was prepared by the wet impregnation method using iron (III) nitrate nonahydrate as iron precursor. First, an optimization of the process parameters was conducted using phenol as model macro-pollutant. The hydrogen peroxide concentration, the light wavelength (UV and visible) and intensity, the iron loading immobilized, as well as the pH of the solution were investigated. Complete photo-Fenton degradation of the contaminant was achieved using faujasite containing 20 wt.% of iron, under UV light, and in the presence of 0.007 mol/L of H2O2 at pH 5.5. In a second step, the optimized process was used with real water samples from the Meurthe river. Twenty-one micropollutants (endocrine disruptors, pharmaceuticals, personal care products, and perfluorinated compounds) including 17 pharmaceutical compounds were specifically targeted, detected, and quantified. All the initial concentrations remained in the range of nanogram per liter (0.8-88 ng/L). The majority of the micropollutants had a large affinity for the surface of the iron-impregnated faujasite. Our results emphasized the very good efficiency of the photo-Fenton process with a cocktail of a minimum of 21 micropollutants. Except for sulfamethoxazole and PFOA, the concentrations of all the other microcontaminants (bisphenol A, carbamazepine, carbamazepine-10,11-epoxide, clarithromycin, diclofenac, estrone, ibuprofen, ketoprofen, lidocaine, naproxen, PFOS, triclosan, etc.) became lower than the limit of quantification of the LC-MS/MS after 30 min or 6 h of photo-Fenton treatment depending on their initial concentrations. The photo-Fenton degradation of PFOA can be neglected. The photo-Fenton degradation of sulfamethoxazole obeys first-order kinetics in the presence of the cocktail of the other micropollutants.

Avaliação da forma de inclusão de zeólita e do nível de consumo sobre a digestibilidade da dieta e as características fecais de cães / Evaluation of zeolite inclusion and level of food intake on diet digestibility and faecal characteristics of dogs

Objetivou-se avaliar a forma de inclusão da zeólita e de níveis de consumo sobre a digestibilidade da dieta e as características fecais de cães. O experimento 1 avaliou o efeito do nível de consumo (normal e 50% a mais do que as necessidades) e da inclusão de zeólita (0 e 15g/kg) sobre a digestibilidade e as características fecais de 12 cães. No experimento 2, foi avaliada a inclusão de 5, 15 e 25g/kg de zeólita adicionada na massa ou por cobertura, em seis cães, sobre a digestibilidade da dieta e as características fecais. O experimento 3 avaliou o odor fecal de nove cães consumindo dietas contendo 0 e 15g/kg de zeólita incluída na massa ou por cobertura. A quantidade consumida e a inclusão de zeólita não afetaram a digestibilidade das dietas. O escore e a matéria seca fecal aumentaram com a inclusão de zeólita. A inclusão de zeólita na massa propiciou aumento na digestibilidade das dietas, independentemente do nível de inclusão. A inclusão de 15g/kg de zeólita, adicionada na massa e por cobertura reduziu o odor fecal dos cães. A inclusão de zeólita na massa aumenta a digestibilidade da dieta, a consistência fecal e reduz o odor fecal de cães.(AU)

This study aimed to evaluate the form of inclusion of zeolite and consumption levels on diet digestibility and fecal characteristics of dogs. The first experiment examined the effect of consumption level (normal and 50% higher than the requirements) and zeolite level (0 and 15g/kg) on diet digestibility and fecal characteristics of 12 dogs. In experiment 2 the inclusion of 5, 15 and 25g/kg of added zeolite in dough or coating in six dogs on diet digestibility and fecal characteristics was evaluated. The third experiment assessed the fecal odor of nine dogs fed diets containing 0 and 15g/kg of zeolite included in the dough or coating. The amount consumed, as well as the inclusion of zeolite, did not affect diet digestibility. Fecal score and dry matter increased with the inclusion of zeolite. The inclusion of zeolite in the dough provided an increase in diet digestibility, regardless of the level of inclusion. The inclusion of 15g/kg zeolite added to the dough and by coating reduced fecal odor of dogs. The inclusion of zeolite in dough increases diet digestibility, fecal consistency, and reduces the fecal odor of dogs.(AU)

Geological occurrence, mineralogical characterization, and risk assessment of potentially carcinogenic erionite in Italy.

Erionite is a zeolite representing a well-known health hazard. In fact, exposure of humans to its fibers has been unequivocally associated with occurrence of malignant mesothelioma. For this reason, a multi-methodological approach, based upon field investigation, morphological characterization, scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS) chemical analysis, and structure refinement through X-ray powder diffraction (XRPD), was applied to different samples of potentially carcinogenic erionite from Northern Italy. The studied crystals have a chemical composition ranging from erionite-Ca to erionite-Na and display variable morphologies, varying from prismatic, through acicular and fibrous, to extremely fibrous asbestiform habits. The fibrous samples were characterized by an unusual preferred partition of aluminum (Al) at tetrahedral site T1 instead of tetrahedral site T2. Further, a mismatch between the a-parameter of erionite-Ca and levyne-Ca that are intergrown in the asbestiform sample was detected. This misfit was coupled to a relevant micro-strain to maintain structure coherency at the boundary. Erionite occurs in 65% of the investigated sites, with an estimated quantity of 10 to 40 vol% of the associated minerals. The presence of this mineral is of concern for risk to human health, especially if one considers the vast number of quarries and mining-related activities that are operating in the zeolite host rocks. The discovery of fibrous and asbestiform erionite in Northern Italy suggests the need for a detailed risk assessment in all Italian areas showing the same potential hazard, with specific studies such as a quantification of the potentially respirable airborne fibers and targeted epidemiological surveillance.

Zeólitas naturais na dieta de frangos de corte / Natural zeolites in broiler diet

O objetivo deste trabalho foi avaliar o efeito da inclusão de 0,5% da zeólita natural clinoptilolita na dieta de frangos de corte sobre o consumo de água, ração e características das excretas. Foi conduzido um ensaio em gaiolas metabólicas, com frangos de corte de linhagem comercial, no período de 14 a 23 dias de idade. O experimento foi constituído de dois grupos de aves, sendo que um recebeu dieta sem inclusão de zeólitas (controle) e outro dieta com inclusão de 0,5% de zeólita (clinoptilolita) em rações isonutritivas, em um delineamento inteiramente ao acaso, com 10 repetições de 10 aves. Avaliou-se o consumo de água e de ração, nas excretas, pH, teor de nitrogênio total e umidade. A inclusão de 0,5% de zeólitas naturais na dieta não alterou (P>0,05) o consumo de água e de ração e o teor de nitrogênio das excretas, entretanto, reduziu (P<0,05) o pH e a umidade das excretas. Conclui-se que a inclusão de 0,5% de zeólitas naturais na dieta de frangos de corte reduz o pH e a umidade das excretas e pode ser utilizada como aditivo alimentar sem prejudicar o consumo de água e de ração.(AU)

The aim of this study was to evaluate the addition of 0.5% natural zeolites (clinoptilolite) to the diet of broilers and their effect on water and feed intake and excreta characteristics. The test was carried out in metabolic cages, with commercial line broilers, in the period from 14 to 23 days old. The experiment was conducted with two groups of broilers: one group received diet without zeolite inclusion (control) and the other received a diet with 0.5% inclusion of zeolite (clinoptilolite) in balanced diets, in a completely randomized design, with 10 replicates of 10 broilers. Water and feed intake, pH, total nitrogen, and moisture of excreta were evaluated. The inclusion of 0.5% of natural zeolites in the diet did not change (P>0.05) the water and feed intake and total nitrogen of excreta, nevertheless, it decreased (P<0.05) the pH and moisture of excreta. We conclude that the addition of 0.5% natural zeolites to the diet of broilers decreases pH and moisture of excreta and can be used as feed additive without compromising water and feed intake.(AU)

Potential carcinogenic erionite from Lessini Mounts, NE Italy: Morphological, mineralogical and chemical characterization.

Exposure of humans to erionite fibers of suitable morphology and dimension has been unambiguously linked to the occurrence of malignant mesothelioma. For this reason, a morphological, morphometrical, mineralogical, and chemical investigation was performed on two representative samples of potential carcinogenic, fibrous erionite from Lessini Mounts, northeastern (NE) Italy, which has not apparently been examined previously. The first sample is erionite-Ca with an extremely fibrous, hair-like and flexible appearance, and growth in intimate association with levyne. The second sample is erionite-Ca with prismatic to acicular crystals and rigid behavior, enriched in K(+) and Ca(2+) extra-framework cations. Although erionite is a nominally Fe-free phase, iron (Fe) was detected in low amounts in all the analyzed crystals. In both the investigated samples, erionite is present as individual fibers of respirable size. Considering that the toxicity and carcinogenic potential of erionite is associated with its size parameters, together with its in vivo durability and high surface area, most of the investigated fibers may also be potentially carcinogenic. The presence of erionite in extensively quarried and largely employed volcanic rocks, suggesting the need for detailed health-based studies in the region.

High incidence of lung cancer and malignant mesothelioma linked to erionite fibre exposure in a rural community in Central Mexico.

OBJECTIVE: To report the high incidence of lung cancer (LC) and malignant mesothelioma (MM) linked to environmental exposure to erionite fibres in a rural village of central Mexico. METHODS: This is a retrospective survey of clinical and mortality records from the years 2000-2012, accompanied by an environmental survey for nine Group-1 lung and pleura carcinogenic agents listed by the International Agency for Research on Cancer (IARC). RESULTS: Out of a total of 45 deaths between 2000 and 2012, 14 deaths correspond to different neoplasms of the lung, and at least four deaths to MM. The ages at diagnosis of MM were between 30 and 54 years. Annual age-standardised mortality rates per thousand due to LC and MM in the village (age >20 years) are 7.09 and 2.48 for males, and 4.75 and 1.05 for females, respectively. Erionite fibres were found in exposed rocks and soils, which can easily become airborne and be carried into streets and recreational areas near schools and homes. Other carcinogenic elements and minerals are found only in trace amounts, except for quartz dust and asbestos (chrysotile) cement sheeting, which are also present in the neighbouring villages. CONCLUSIONS: These results indicate that environmental exposure to erionite is the main cause of the high rates of MM mortality in the Village of Tierra Blanca, supporting previous similar reports for people exposed to erionite fibres in villages in Turkey.

Environmental occurrence, origin, physical and geochemical properties, and carcinogenic potential of erionite near San Miguel de Allende, Mexico.

Detailed geologic surveys and different microscopic and analytical techniques were conducted near Tierra Blanca de Abajo where lung cancer and malignant mesothelioma (MM) are the primary causes of death. Results show that erionite-K occurs as a diagenetic product in altered Oligocene-Miocene rhyolitic tuffs. The microscopic structure of erionite minerals shows concentrations of individual fibers in the range of 0.14-0.547 µm in diameter and 2.81-50 µm in length, with a few "bundles" about 0.2-2.5 µm wide by 10-50 µm long. Chemical properties of erionite show Si/Al in the range of 3.23-3.58 (at.%) and T Si in the range of 0.76-0.78 (at.%). Potassium is the dominant cation (K > Ca > Mg > Fe). Associated minerals are heulandite, clinoptilolite, quartz, sanidine, anorthite, smectite and opal. This mineral assemblage formed in the lower part of an open catchment, where bicarbonate-rich (T > 30 °C, pH > 8) groundwater discharge conditions prevailed in the past. The physical and chemical characteristics of erionite near San Miguel de Allende are similar to those of erionite from the Cappadocian region of Turkey where erionite is associated with MM. The presence of erionite and the type of respiratory diseases that occur in the village strongly suggest the need for detailed health-based studies in the region. Pliocene-Holocene fine-grain deposits, used in the past for the construction of adobe-houses and exposed in recreational areas, also contain erionite associated with erosion and alluvial transport from the rhyolitic tuffs, potentially affecting more than 13 villages located downstream toward the Allende Dam.

Geologic occurrences of erionite in the United States: an emerging national public health concern for respiratory disease.

Erionite, a mineral series within the zeolite group, is classified as a Group 1 known respiratory carcinogen. This designation resulted from extremely high incidences of mesothelioma discovered in three small villages from the Cappadocia region of Turkey, where the disease was linked to environmental exposures to fibrous forms of erionite. Natural deposits of erionite, including fibrous forms, have been identified in the past in the western United States. Until recently, these occurrences have generally been overlooked as a potential hazard. In the last several years, concerns have emerged regarding the potential for environmental and occupational exposures to erionite in the United States, such as erionite-bearing gravels in western North Dakota mined and used to surface unpaved roads. As a result, there has been much interest in identifying locations and geologic environments across the United States where erionite occurs naturally. A 1996 U.S. Geological Survey report describing erionite occurrences in the United States has been widely cited as a compilation of all US erionite deposits; however, this compilation only focused on one of several geologic environments in which erionite can form. Also, new occurrences of erionite have been identified in recent years. Using a detailed literature survey, this paper updates and expands the erionite occurrences database, provided in a supplemental file (US_erionite.xls). Epidemiology, public health, and natural hazard studies can incorporate this information on known erionite occurrences and their characteristics. By recognizing that only specific geologic settings and formations are hosts to erionite, this knowledge can be used in developing management plans designed to protect the public.

Natural analcime zeolite modified with 2,3,5,6-tetra(2-pyridyl)pyrazine for preconcentration and determination of trace amounts of cadmium by flame atomic absorption spectrometry.

An analytical method using natural analcime zeolite modified with tppz (2,3,5,6-tetra-pyridylpyrazine) for preconcentration of cadmium, in a column system, and their sequential determination by flame atomic absorption spectrometry (FAAS), was developed. In this work, cadmium was adsorbed onto natural analcime zeolite modified with tppz and then was recovered by nitric acid. Solutions of cadmium were passed through a glass column packed with 100 mg of the sorbent material, at pH 5.0, and cadmium was eluted with 2.0 M HNO(3) at a flow rate of 2.0 ml min(-1). The relative standard deviation (RSD) for eight replicate determinations at the 2.5 µg of cadmium was ±0.94%. The calibration curve using the preconcentration system was linear from 0.01 to 4 µg ml(-1) in final solution with a correlation coefficient of 0.9993. This method was successfully applied for the determination of cadmium in various samples.

Discrimination of zeolites and beryllium containing silicates using portable Raman spectroscometric equipment with near-infrared excitation.

In this paper Raman spectra were obtained for a series of zeolites (thomsonite, stilbite, natrolite) and beryllium containing silicates (beryl, chrysoberyl, euclase, phenacite, bavenite, milarite) using a portable Raman specrometer with a 785 nm laser excitation to show the possibility to apply this setting for unambiguous detection and discrimination of these silicate minerals. Obtained spectra contain the most intense Raman bands at the same positions ±2-4 cm(-1) as reported in the literature. The use of these bands permits the unambiguous identification of these phases. Data show the possibility to discriminate individual species of similar whitish color and aspect. Measurements showed an excellent correspondence of Raman bands obtained using the portable system and a laboratory Raman microspectrometer (with the same excitation laser wavelenght). However, for several minerals of these groups (chrysoberyl, bertrandite, chiavennite) Raman spectra were not of sufficient quality to permit unambiguous identification. The reasons are discussed. Raman spectrum of chiavennite CaMnBe(2)Si(5)O(13)(OH)(2)·2(H(2)O) - a transformation product occurring together with bavenite on the surface of beryl crystals was obtained for the first time using the laboratory Raman spectrometer.

Environmental mesothelioma associated with tremolite asbestos: lessons from the experiences of Turkey, Greece, Corsica, New Caledonia and Cyprus.

Mediterranean regions such as Greece, Turkey, Cyprus, Corsica and New Caledonia have experienced epidemics of malignant mesothelioma as a result of non-occupational, "domestic" exposure to tremolite asbestos and fibrous erionite. This exposure to tremolite asbestos and fibrous erionite is typified "domestic" due to its prevalence in regions with natural deposits of tremolite asbestos (or fibrous erionite) where the material from tremolite asbestos or fibrous erionite is used for domestic applications such as whitewashing. However, these exposures may be useful in examining the potential consequences of even small amounts of amphibole asbestos fibers in the ambient air. It can also elucidate the effects of fibers that behave like amphibole asbestos. However, this type of exposure is not useful for studying the potential effects of small amounts of asbestos in the ambient air of big cities due to the differing nature of the fiber types and modes of exposure between the regions.

Use of an iron-overexchanged clinoptilolite for the removal of Cu2+ ions from heavily contaminated drinking water samples.

Clinoptilolite, a natural zeolite, was used for the synthesis of a high surface area clinoptilolite-iron oxide system, in order to be used for the removal of Cu2+ ions from drinking water samples. The solid system was obtained by adding natural clinoptilolite in an iron nitrate solution under strongly basic conditions. The Clin-Fe system has specific surface area equal to 151 m2 g(-1) and is fully iron exchanged (Fe/Al=1.23). Batch adsorption experiments were carried out to determine the effectiveness of the Clin and the Clin-Fe system in removal of copper from drinking water. Adsorption experiments were conducted by mixing 1.00 g of each of the substrates with certain volume of water samples contaminated with 10 different Cu concentrations (from 3.15x10(-5) to 315x10(-2) M or from 2.00 to 2000 ppm Cu). For our experimental conditions, the maximum adsorbed Cu amount on Clin was 13.6 mg g(-1) whereas on the Clin-Fe system was 37.5 mg g(-1). The main factors that contribute to different adsorption capacities of the two solids are due to new surface species and negative charge of the Clin-Fe system. In addition, the release of counterbalanced ions (i.e. Ca2+, Mg2+, Na+ and K+) was examined, as well as the dissolution of framework Si and Al. It was found that for the most of the samples the Clin-Fe system releases lower concentrations of Ca, Mg and Na and higher concentrations of K than Clin, while the dissolution of Si/Al was limited. Changes in the composition of water samples, as well as in their pH and conductivities values were reported and explained.

Fixed-bed catalytic pyrolysis of cotton-seed cake: effects of pyrolysis temperature, natural zeolite content and sweeping gas flow rate.

Catalyzed pyrolysis of cotton-seed cake was studied under different experimental conditions. Variables investigated were pyrolysis temperature, zeolite content and sweeping gas flow rate. Experiments were carried out isothermally. Liquids, gases and char were obtained as products of pyrolysis. The distributions of these products were determined for various contents (1, 5, 10, 20 wt.% of raw material) of zeolite at four different pyrolysis temperatures. The maximum liquid yield obtained was 30.84% at a pyrolysis temperature of 550 degrees C with a sweeping gas flow rate of 100 cm(3) min(-1) in the presence of clinoptilolite (20% based on raw material) as catalyst. The pyrolytic and catalytic liquid products were analysed in detail to determine the predominant chemical classes and the identities of the major compounds present.

Uso de zeolitas tipo cancrinita carbonatadas e hidrotalcitas como antiácidos / Use of carbonated cancritine-type zeolites and hydrotalcite as antacid drugs

Se sintetizaron una serie de zeolitas carbonatadas tipo cancrinitas usando zeolitas FAUX como fuente de Si y Al, y comoagentes direccionadores, se emplearon los cationes metálicos: Mg, Al y la mezcla de ambos. Adicionalmente, se sintetizaron hidrotalcitas con relación Al/(Al+Mg) igual a 0,20, 0,25 y 0,33. Estos sólidos sintetizados fueron caracterizados por diversas técnicas fisicoquímicas, tales como: análisis químico, difracción de rayos X (DRX), análisis termogravimétrico (TGA), espectroscopia de infrarrojo (IR), espectroscopia UV-visible y medidas de área superficial. Los análisis de DRX de los sólidos sintetizados confirmaron la presencia de cancrinita e hidrotalcita sin otras fases colaterales. Los sólidos fueron evaluados frente a un jugo gástrico sintético simulando la hiperacidez estomacal.Pequeñas dosis de los mismos fueron suficientes para normalizar el pH del sistema. Estos resultados fueron comparados con los obtenidos usando un medicamento comercial a base de hidrotalcita, el cual presentó un comportamiento muy similar a la mejor de las cancrinitas sintetizadas. Adicionalmente, la interacción sólido-pepsina fue bastante baja, confirmado la posibilidad de utilizarlos como agentes terapéuticos contra la acidez estomacal.

Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey.

OBJECTIVES: The high incidence of malignant mesothelioma in some villages of Cappadocia (Turkey) is due to environmental exposure to erionite fibres. The aim was to evaluate the fibre burden in bronchoalveolar lavage fluid (BALF) from inhabitants of an erionite village and compare it with Turkish subjects with or without environmental exposure to tremolite asbestos. METHODS: Ferruginous bodies (FBs) and fibres were measured and analyzed by light and transmission electron microscopy (TEM) in the BALF of 16 subjects originating from Tuzköy. RESULTS: FBs were detected in the BALF of 12 subjects, with concentrations above 1 FB/ml in seven of them. Erionite was the central fibre of 95.7% of FBs. Erionite fibres were found in the BALF of all subjects, by TEM, and these fibres were low in Mg, K, and Ca compared with erionite from Tuzköy soil. The mean concentration of erionite fibres in BALF was similar to that of tremolite fibres in Turks with environmental exposure to tremolite. The proportion of fibres longer than 8 microm in BALF represented 35.6% for erionite compared with 14.0% for tremolite. The asbestos fibre concentrations in erionite villagers was not different from that in Turks without environmental exposure to tremolite. CONCLUSION: Analysis of BALF gives information about fibre retention in populations environmentally exposed to erionite for whom data on fibre burden from lung tissue samples are scarce. This may apply to exposed Turks having emigrated to other countries.