الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 273 |  |  |
| | | from | 273 | | |
Abstract
The present work is directed to (i) Preparation of activated carbons from locally existing raw material ,i.e., from sawdust. (ii) Modification of the prepared samples either by treatment with different amounts of sulphuric acid or by activation with carbon dioxide to different percentages of burnoff. (iii) Characterization of the prepared carbons using FTIRtechnique, base neutralization capacity method and nitrogen adsorption measurements. (iv) A comparison between the batch experiments and continuous flow experiments for the adsorption of some metals and phenols was tried. The chemistry of the carbon surface was characterized using the neutralization capacity method and FTIR technique. Surface properties were determined by measuring the adsorption of nitrogen gas at 77K using a conventional volumetric apparatus. The adsorption data were interpreted using some proposed equations to calculate surface area and porosity of the prepared carbons. On the other hand, the adsorption of phenol from aqueous solution was found sensitive to many variables such as the surface area, pore dimension, carbon oxygen complexes on the surface, their concentration and strength, the nature and properties of the phenol, the pH of the aqueous phenolic solutions, beside other factors. No general agreement is therefore possible due to the difficulty in keeping many factors unchanged to predict the role of individual factor in determining the adsorption capacity of phenols on activated carbons. In conclusion, for the adsorption of metal ions from solution, the chemistry of carbon surface is more important or at least equally important to its surface properties (surface area and porosity). Chemically activated carbons possess acidic surface groups which are hyDROPhilic in character. These groups can act as electron donor or acceptor and may represent the active sites for the adsorption of metal ions from solution. On the other hand, activation with CO2 or steam produces carbons characterized by their high surface area and porosity which improve their adsorption capacities toward metal ions. In general the adsorption is dependent on many factors as surface chemistry, concentration of surface functional groups, texture properties (surface area and porosity ) and pH of the solution.