Molecular sieving MFI-type zeolite membranes were prepared by a secondary growth method without using an organic template. Silicalite membranes with intercrystalline pores minimized or eliminated were obtained by this synthesis method which avoids the template removal step. The silicalite membrane exhibits molecular sieving characteristics with pervaporation separation factor for p-xylene to o-...

Four pure cultures of denitrifying bacteria, which had previously been isolated on defined alkylbenzenes, were capable of anaerobic growth with crude oil as the only source of organic substrates. Chemical analyses after growth revealed that the known growth substrates toluene, ethylbenzene, and m-xylene were selectively consumed from the oil. o-Xylene and p-xylene, which as pure compounds did n...

A novel sulfate-reducing bacterium isolated from fuel-contaminated subsurface soil, strain PRTOL1, mineralizes toluene as the sole electron donor and carbon source under strictly anaerobic conditions. The mineralization of 80% of toluene carbon to CO2 was demonstrated in experiments with [ring-U-14C]toluene; 15% of toluene carbon was converted to biomass and nonvolatile metabolic by-products, p...

OBJECTIVES Ethanol may be a significant combined factor in human solvent toxicity. Lipid peroxidation has been suggested to be an important contributing mechanism involved in experimental alcohol-induced liver injury. The aim of the study was to investigate whether a short-term ethanol ingestion in rats chronically exposed to m-xylene vapor may influence the lipid peroxidation rate in the intra...

Biofiltration is an effective technology for the treatment of gaseous waste. However, a biofiltration system needs a bioreactor of large volume and it is slow to adapt to fluctuating concentrations in waste gas. To overcome these disadvantages, a bench-scale system integrating a biofilter and an adsorption unit for the treatment of gases containing o-xylene was investigated in this study. The a...

Preignition and Autoignition Behavior of the Xylene Isomers Robert H. Natelson Nicholas P. Cernansky, Ph.D. and David L. Miller, Ph.D. The relative preignition and autoignition reactivity of the xylene isomers (o-, mand p-xylene, or 1,2-, 1,3-, and 1,4-dimethylbenzene) has been studied. The principal objectives were to determine the relative reactivity among the isomers and the key oxidation br...

The objective of this study was to assess the occupational exposure of jeepney drivers to selected volatile organic compounds (VOCs) in Manila, Philippines. Personal sampling was conducted on 15 jeepney drivers. Area sampling was conducted to determine the background VOC concentration in Manila as compared to that in a rural area. Both personal and area samples were collected for 5 working days...

Pseudomonas putida mt-2 carries a plasmid (TOL, pWWO) which codes for a single set of enzymes responsible for the catabolism of toluene and m- and p-xylene to central metabolites by way of benzoate and m- and p-toluate, respectively, and subsequently by a meta cleavage pathway. Characterization of strains with mutations in structural genes of this pathway demonstrates that the inducers of the e...

In the present work, the transformation of m-xylene was studied over fresh and pre-coked HZSM-5 catalyst in a riser simulator over the temperature range of 350-500C.Significant differences were observed in both the activity and product selectivity pattern for the two forms of the catalyst. While, the fresh catalyst generally gave higher m-xylene conversion, the pre-coked catalyst produced highe...

Exposure to low levels of chemicals indoors is often to a mixture of volatile organic compounds (VOCs). It is of interest to determine if the symptomatic and sensory responses can be attributed to a single chemical or to a mixture of chemicals. To determine if sensory or symptomatic responses differ with exposure to single or mixed VOCs, 100 female subjects participated in a 6-hr exposure study...