background: formaldehyde is one of the most serious air contaminant that can be found everywhere. some of the source of formaldehyde include product of building materials, decorated materials, cigarette smoke, etc. aldehydes compounds especially formaldehyde are used as disinfectants for sterilization in different industries. in this study we measured formaldehyde workplace exposure with niosh ...

While microwave enhancement of chemical syntheses has been demonstrated for a broad variety of chemical reactions, there is no accepted universal mechanism. Is the enhancement due to more efficient heating, to overheating, to nonuniform heating, or to nonthermal effects? Analyses are complicated due to the often significant spatial and temporal temperature variations in microwave reactor system...

Gas separation efficiencies of three zeolite membranes (Faujasite, MFI, and Chabazite) have been examined using the method of molecular dynamics. Our investigation has allowed us to study the effects of pore size and structure, state conditions, and compositions on the permeation of two binary gas mixtures, O(2)N(2) and CO(2)N(2). We have found that for the mixture components with similar sizes...

In the context of deep desulfurization transport fuels, present work aimed at identifying a suitable material for selective removal thiophene from fuels. Dispersion corrected density functional theory (DFT) calculations have been carried out in order to investigate adsorption benzene and various faujasite zeolite formulations including DAY, HY, LiY, NaY, KY, CsY, Cu(I)Y, Cu(II)Y, Ag(I)Y, Zn(II)...

The ion exchange of Na for Cr/K, Cr/Mg and Cr/Ca in Y and X zeolites was studied using breakthrough curves. It was observed that Cr ions were able to remove some competitive ions that had already been exchanged at the zeolitic sites, producing a sequential ion exchange. Some mass transfer parameters such as length of unused bed, overall mass transfer coefficient, operational ratio and dimension...

The investigation on the modification of NaY zeolite on LaHY and AEHY (AE refers Ca and Sr and the molar ratio of Ca and Sr is 1:1) zeolites was proformed by XRD, N2-physisorption (BET), XRF, XPS, NH3-TPD, Py-IR, hydrothermal stability, and catalytic cracking test. These results indicate that HY zeolite with ultra low content Na can be obtained from NaY zeolite through four exchange four calcin...

In this work, zeolite NaY was prepared by hydrothermal method. Then, silver ions were replaced in the zeolite NaY with silver nitrate (AgNO3) solution via using ion exchange (IE) method. The Manganese dioxide (MnO2) nanoparticles (9.3 and 15.8 wt %) for guest were deposited in the zeolite AgY(host) structure with Mn(NO3)2 aqueous and KMnO4 solutions by confined space synthesis (CSS) metho...

Faujasitic zeolites are employed in a range of industrial contexts including separation processes, gas purification and dehydration, and shape selective catalysis. The simulation of the interaction of small molecules with faujasite based zeolites is increasingly practical and the resulting information provides the basis for efficient materials selection and design. When experimental data are sc...

The spin-lattice relaxation time T\ of 2 , N a N M R in dehydrated zeolite NaY has been measured from 26 to 300 K. The magnetization recovery curve is not single-exponential at all measured temperatures and 1 increases in proportion to the square of temperature above 200 K. The result is analyzed with a theory of the Raman process based on covalency. The value of T\ is compared with that of NaX...