The adsorption of phenol and ten substituted phenols on activated carbon was examined. For a comparative study, the substituted phenols were selected after nature, position, and number of functional groups; they are: o-, m-, p-cresol, o-, m-, p-chlorphenol, m-, p-nitrophenol, resorcine, and methyl-resorcine, p-chloraniline was also studied. The single solute data were statistically fitted on 13 isotherm models: the Freundlich, Langmuir, Freundlich-Langmuir, BET, Dubinin-Raduskevitch, the three parameters empirical equation proposed by Radke and Prausnitz, Redlich-Petersen, Tdth, Myers, as well as generalised, Volmer, virial and sigmoidal isotherms. A computer program was developed to determine the most precise parameter models. The prediction results on the adsorption isotherms are compared by absolute relative percent deviations.

No abstract

The present paper deals with the competitive adsorption on activated carbon of three aqueous bi-solute systems (phenol/p-nitrophenol, phenol/pchlorphenol, p-nitrophenol/p-chlorphenol) and of the tri-solute system phenol/p-nitrophenol/p-chlorphenol. In this context two experimental methods to evaluate the equilibrium characteristics for the adsorption of phenols on powdered activated carbon were used. The competitive adsorption data were statistically fitted on four models: the Langmuir competitive model, the Freundlich-Langmuir competitive model, and the Fritz-Schlunder model, the last one in two particular cases for the monosolute representation. The prediction for all models, excepting the FritzSchlunder model, were performed using only single-solute data, while the parameters for the Fritz-Schlunder model were obtained using both single and multi-solute data.

Arsenic has gained great notoriety historically for its toxic properties. In aquatic environment, arsenic can exist in several oxidation states, as both inorganic and organometallic species. As (V) is less toxic than As (III). Most research has been directed to the control of arsenic pollution of potable water. Various techniques such as precipitation with iron and alnminium hydroxides, ion exchange, reverse osmosis, and adsorption are used for As (V) removal from surface and waste waters. Because of the easy handling of sludge, its free operation and regeneration capability, the adsorption technique has secured a place as one of the advanced methods of arsenic removal.A study of As (III) and As (V) sorption onto some different adsorbents (Fe (III) -iminodiacetate resin, nanocomposite materials, Fe(III) -forager sponge) referring to kinetic considerations and modelling of the process will be presented.All the systems studied are better described by Freundlich-Langmuir isotherm and the rate constant evaluation shows a sub-unitary order for the adsorption process.

No abstract