effect of adsorption conditions on the capacity of Egyptian activated coals

The present work is directed to study the impact of adsorption conditions on the adsorption capacity of Egyptian activated coals. An original criterion has been developed to measure the capacity of Egyptian active coal, which depends on the measurement of the 10% breakthrough time of 1000 ppm of benzene passing through 1 gm of active carbon at specified conditions. The percentage relative humidity, air flow rate, active carbon bed temperature, concentration of benzene and the type of adsorbate have been changed. The results have revealed a correlation between the activation conditions and the extent of effects on active carbon capacity due to variation of adsorption conditions. This study is valuable in tailoring an active carbon which maintains its capacity despite the variation in adsorption conditions. This finding is of utmost technical and economical importance. Different raw materials used for coating, painting or binding in the new project were collected and tested by scanning over the whole range of spectrum in the infrared range, using an infrared gas analyzer-Miran IA, to detect different types of volatile materials. Four major constituents have been found in all the tested materials, which were: styrene, methyl styrene, chloroform and methyl ethyl ketone

udefined lacrimating gas exposure in a chemical company: a case study

A chemical company which produces chlorine as a by-product was undertaking a new project for renewal of the plant. On application of paints, tile binders and coatings, the workers complained of unusual increased eye irritation and continuous lacrimation that hindered the progress of the work. Both the company and the project contractors denied their responsibility for the problem. To define the unknown irritant, gas samples of all raw materials used were collected and scanned by infra-red gas analyzer. Further on the spot direct sampling on point of application, as well as atmospheric air samples collected on active carbon were taken and analyzed by the same technique. In the mean time, chlorine gas samples were collected and analyzed at the same locations. Chlorine gas was found to be below the TLV, which could not be responsible for the irritating effect. Infra-red analysis revealed that styrene, methyl styrene, chloroform and methyl ethyl ketone are the most abundant vapours which are still below their TLVs. It has been concluded that lacrimation occurs by the interaction between styrene and low chlorine concentration in the atmosphere that is catalyzed by ultra-violet radiation to form a strong lacrimator

Behaviour pattern of some organie solvent vapours in presence of carbon particulates in air

Association between volatile vapours and fine particulate matter in the occupational or ambient atmosphere may produce synergistic effect depending on both their characteristics and degree of interaction. The present study has been conducted in order to study the nature of interaction between organic vapours of benzene, toluene, perchloroethylene and methanol with carbon particulates under different conditions of vapour concentration and particulate weights for various contact times in a static stainless steel chamber [1.2 m]. After injection of vapour and particulate, vapour concentration was routinely monitored till almost stabilization. Considerable adsorption has been recorded for perchloroethylene and toluene followed by benzene. Methanol did not record detectable adsorption. Concave adsorption isotherms for perchloroethylene and toluene and convex isotherms for benzene were plotted. Increase in gas concentration and amount of particulate resulted in increase of adsorption but not linearly since this is an equilibrium phenomenon Increase of temperature and decrease of humidity produced an increase of benzene adsorption. Such findings emphasize the importance of evaluating both vapour and any particulate concentrations in an environment and assessing any probable association of both under prevalent environmental conditions