REDUCTION OF METAL CATIONS CONTENT FROM THE AQUEOUS SOLUTIONS BY SORBENTS

The article presents the results of research on reducing the concentration of heavy metals, such as copper and nickel, on natural zeolite in comparison with synthetic zeolite and chemically treated natural zeolite. The reduction of the content of specific types of heavy metals from aqueous solutions was investigated by the method of sorption kinetics. The results indicate the ability of natural zeolites to compete with synthetic zeolites.

Synthetic Zeolites Modified with Salts of Transition Metals in the Reaction of Chemisorption-catalytic Oxidation of Sulphur Dioxide by Air Oxygen

The effect of the nature and concentration of d-metal salts attached to synthetic zeolites NaA and KA on the kinetic and stoichiometric parameters of the chemisorption-catalytic oxidation of sulphur dioxide with air oxygen at ambient temperature was studied. It was found that the adsorption capacity of NaA zeolite relative to SO2 is 100 times higher than that of KA zeolite; the time of protective action of NaA and KA zeolites increases upon modification with transition metal salts and with an increase of their content in the compositions. It was shown that the formation of inner and outer sphere complexes and the relationship between them is determined by the nature and concentration of metal ions and by the nature of the carrier. It was proven that the chemisorption-catalytic process ends with the oxidation of SO2 to H2SO4.

A Laboratory Study of Warm Mix Asphalt with Synthetic Zeolite

Warm mix asphalt (WMA) is a recent technology used to reduce working temperatures without affecting the property of pavement. warm mix asphalt technology is a find out the optimum temperature of asphalt mixture. A number of WMA processes have been developed in recent days. One of the processes is the use of synthetic zeolite as an additive. A number or try in the laboratory to develop warm mix asphalt and using synthetic zeolite as an additive at a specified mixing and optimum temperature which were obtained after a number of trials. Warm mixing with additive is becoming popular because of mixing at a lower temperature which reduces the fuel usage and emission of hazardous gases consequently decreases the mixing as well as compaction temperature of the mix. Reduction of 20º C to 40º C has documented, such reduction has the obvious benefits of cutting fuel consumption and decreasing the production of greenhouse gases. Also, there will improvement in the performance of the pavement. In the present study, The mix asphalt with aggregate gradation as per MORTH specifications was made with varying binder contents (5%,6% and7%). The zeolite content was 0.3% by weight of aggregate. Stone dust and VG 30-grade Asphalt were used as a binder for the mixes. and the help of laboratory tests to find the physical properties of WMA with synthetic zeolite at optimum temperature. These additives are zeolites, that is, minerals of the aluminosilicate group, the crystalline structure of which contains water bound in a specific way. Its release, at mixed asphalt production temperatures, causes asphalt foaming. It is currently known that zeolites can be used in WMA, including natural and synthetic zeolites obtained using chemical reagents and waste. This review presents the results of studies of WMA technology, including the effects of zeolite addition on asphalt properties and mixes asphalt, as well as related environmental, economic, and technological benefits.

Removal of Pesticides from Waters by Adsorption: Comparison between Synthetic Zeolites and Mesoporous Silica Materials. A Review

Pesticides are pollutants found in wastewater due to increasing agricultural activities over the years. Inappropriate dosing of pesticides results in the dispersal of active ingredients in the environment. The complete removal of pesticides from wastewater is an immediate concern due to their high toxicity and mobility. At present, adsorption is one of the most widely used methods for pesticide removal, in which synthetic zeolites and mesoporous silica materials are extensively applied. This article presents a systematic and comparative review of the applications and comparison of these adsorbents, based on the data reported in the literature. The paper summarizes the information collected from various studies, including the type of adsorbents and pesticides used, experimental conditions, and results of each work. The studies analyzed were laboratory-based and show potential advantages for the treatment of pesticide-bearing waters using functionalized and unfunctionalized synthetic zeolites and mesoporous silica materials. As a whole, functionalized materials are reported to exhibit better removal performance for different pesticides than conventional materials. It is expected that the results of this review will help researchers to establish a powerful strategy for the abatement of pesticides in wastewater.

Impact of inorganic powder additives on the size and morphology of pellets of the microscopic filamentous fungus Aspergillus niger

This paper has been focused on the impact of the set of microcrystal water-insoluble inorganic additives to dimension characteristics of pellets of the microscopic filamentous fungus Aspergillus niger. The selection of powder substances included montmorillonite clay mineral, silicon dioxide, iron oxide, one zeolitic tuff with mineral clinoptilolite as its main component, three synthetic zeolites, Na-mordenite, NaY and Na-ZSM-5, and titanium dioxide. This group is comprised of substances that are often components of various natural waters (including contaminated waters) and also frequent components of soil. Exceptions are synthetic zeolites and titanium dioxide. The impact of aforementioned substances was monitored on four Aspergillus niger strains isolated from soils at four Slovak locations, markedly differing in soil reaction values. Three of these soil samples have been affected by considerable contamination due to previous mining activities. Clay mineral montmorillonite reduced the size of the pellets regardless of the origin of strains, while the impact of other inorganic substances was either weak or variable depending on the type of inorganic substance and source location of the strains. The impact of natural zeolitic tuff was also similar, however, less significant.

A Comparative Analysis of In Vitro Toxicity of Synthetic Zeolites on IMR-90 Human Lung Fibroblast Cells

Broad industrial application of zeolites increases the opportunity of inhalation. However, the potential impact of different type and composition of zeolite on the cytotoxicity is still unknown. Four types of synthetic zeolites with have been prepared for assessing the effect on lung fibroblast: two zeolite L (LTL-R and LTL-D, ZSM-5 (MFI-S), and faujasite (FAU-S). The cytotoxicity of zeolites on human lung fibroblast (IMR-90) was assessed using WST1 cell proliferation assay, mitochondrial function, membrane leakage of lactate dehydrogenase, reduced glutathione levels, and mitochondrial membrane potential were assessed under control. Intracellular changes were examined using transmission electron microscopy (TEM). Toxicity related gene expression were evaluated by PCR array. The result showed a significantly higher toxicity in IMR-90 cells with FAU-S than LTL-R, LTL-D and MFI-S exposure. TEM showed FAU-S, spheroidal zeolite with a low Si/Al ratio, was readily internalized forming numerous phagosomes in IMR-90 cells, while the largest and disc-shaped zeolites showed the lowest toxicity and were located in submembranous phagosomes in IMR-90 cells. Differential expression of TNF related genes was detected using PCR arrays and confirmed using qRT-PCR analysis of selected genes. Collectively, the exposure of different zeolites shows different toxicity on IMR-90 cells.

How Reproducible Are Surface Areas Calculated from the BET Equation?

Porosity and surface area analysis play a prominent role in modern materials science, where 123 their determination spans the fields of natural sciences, engineering, geology and medical 124 research. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory,[1] which has been 125 a remarkably successful contribution to the field of materials science. The BET method was 126 developed in the 1930s and is now the most widely used metric for the estimation of surface 127 areas of porous materials.[2] Since the BET method was first developed, there has been an 128 explosion in the field of nanoporous materials with the discovery of synthetic zeolites,[3] 129 nanostructured silicas,[4–6] metal-organic frameworks (MOFs),[7] and others. Despite its 130 widespread use, the manual calculation of BET surface areas causes a significant spread in 131 reported areas, resulting in reproducibility problems in both academia and industry. To probe 132 this, we have brought together 60 labs with strong track records in the study of nanoporous 133 materials. We provided eighteen adsorption isotherms and asked these researchers to 134 calculate the corresponding BET areas, resulting in a wide range of values for each one. We 135 show here that the reproducibility of BET area determination from identical isotherms is a 136 largely ignored issue, raising critical concerns over the reliability of reported BET areas in 137 the literature. To solve this major issue, we have developed a new computational approach 138 to accurately and systematically determine the BET area of nanoporous materials. Our 139 software, called BET Surface Identification (BETSI), expands on the well-known Rouquerol 140 criteria and makes, for the first time, an unambiguous BET area assignment possible.