Adsorption study of the methylene blue on sawdust beech and red wood

Two adsorbents were studied from sawdust,one with using the beech wood,and the other was from red wood,the adsorbents were characterized by several techniques (ftir,sem).then they were used for the study of the adsorption of the methylene blue on wood sawdust. this study allowed us to highlight the influence of the ph of the solution,the duration of contact,the concentration of the methylene blue and the mass of the used adsorbent,on the adsorption of the methylene blue. the results show that the percentage of adsorption increases in a defined interval of each parameter and then it stabilizes at precise values,this stabilization is due to the saturation of the active sites of the adsorbent. the results obtained show that the equilibrium is established after the first 10 minutes of the adsorption,it can reach a maximum of 96% at the room temperature and the initial ph of the solution. the kinetic adsorption of methylene blue on the two waste woods is described by a pseudo-second order model. the experimental design method using the full factorial design,allowed us to define and study the influence of the adsorption parameters of methylene blue on sawdust; it enabled us to bring out the interaction between them. in order to optimise the factors acting on the adsorption of the methylene blue on red wood and beech wood sawdust,we used a central composite design. after an appropriate choice of four variables,27 experiments led to a mathematical model of the second degree linking the response (percentage of fixation) with the factors and allowing a good mastery of the adsorption process. after carrying out the tests and analysing the data,the study made it possible to know the optimum conditions necessary for obtaining a higher percentage of adsorption. these operating conditions are: a mass of wood sawdust of 0.305 g,a methylene blue concentration of 0.2 ppm,a contact time of 90 min and ph of 2. © 2017,university of mohammed premier oujda morocco.