The adsorption processes of three aromatic chemicals onto activated carbons (ACs) from aqueous solutions have been studied. Eucalyptus kraft lignin obtained from cellulose industry as a residual biomass has been used to prepare activated carbons by physical activation with CO 2 . The influences of the activation time on the surface areas and pore volumes of the ACs were analyzed. The physicochemical properties and the surface chemical structure of the adsorbents have been studied by means of N 2 and CO 2 adsorption, ultimate analysis, XPS, TPD and SEM. XPS and TPD spectra of the ACs have suggested the presence of aromatic rings and carbon-oxygen functional groups in the solid surfaces. The potential use of the ACs for the removal of acetaminophen (paracetamol), salicylic acid and benzoic acid has been investigated at different pH, temperature and contact time. The adsorption equilibrium data have been correlated to Langmuir isotherm model. The thermodynamic study has been developed, the values of H , G, and S have been calculated and they indicated that the processes are endothermic for acetaminophen and exothermic for salicylic and benzoic acids. The analysis of the kinetic experiments showed that the effective diffusivities are low; 10 −12 to 10 −11 cm 2 /s, and they are the corresponding to intraparticle mass transfer, which appears as the controlling step for the net adsorption processes.

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Conventional approaches to crossover app1.v the operator onlv once on the selected pair cf parents to create, precisely, two offspring. Multiple Crossover Per Couple &fCPC) is an alternative, recent& proposed [I], approach under which more than one crossover operation for each mating pair is allowed. This paper shows the empirical results obtained with Genetic Algorithms allowing MCPC when searching for minimum global values for a set of hard functions.

This paper compares two different approaches for teaching complex programming concepts in lab sessions. The first approach is based on the widely held assumption that the programming knowledge and skills which the student obtains are predominantly acquired from classroom activities undertaken at the instigation of the teacher. This automatically implies that the student must attend a minimum number of lab sessions. The second approach is to motivate student learning via a full-term activity based on the implementation of computer games from scratch.

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