Synthetic dyes are an important class of organic compounds, which unfortunately are agents affecting the ecology, often found in the environment as a result of their widespread industrial use. The disposal of these dyes into water resources should be avoided, therefore different treatment techniques are used, being adsorption one of the most employed. This paper presents a study on the adsorption of methylene blue dye (MB) in aqueous solution on granular activated carbon (GAC) at 25°C. Batch experiments were conducted to determine the effect of the initial concentration (300-1100mg dm -3) and pH (4-8), on the adsorption capacity and rate of removal. The results show that the amount of MB removed increases when increasing both the initial concentration and pH. The equilibrium isotherms were analyzed based on the Langmuir and Freundlich equations using the correlation coefficient. The experimental results showed a satisfactory fit to the Langmuir isotherm. The values of maximum adsorption capacity of MB in monolayer obtained were 76.3, 79.4, 80.6, 83.3 and 87mg g-1 at pH 4, 5, 6, 7 and 8 respectively.

No abstract

This work shows to the reader a general description about the techniques of classic thermal analysis as known as Differential Scanning Calorimetry (DSC), Differential Thermal Analysis (DTA) and Thermal Gravimetric Analysis. These techniques are very used in science and material technologies (metals, metals alloys, ceramics, glass, polymer, plastic and composites) with the purpose of characterizing precursors, following and control of process, adjustment of operation conditions, thermal treatment and verifying of quality parameters.