-The adsorption of reactive turquoise blue QG dye on commercial activated carbon was investigated in a batch reactor to obtain isotherm and kinetic data under different experimental conditions. The adsorbent was characterized by a FTIR method to analyze surface area and pH PZC and to identify functional groups. Experiments were conducted to obtain equilibrium data at 30°C, with the pH effect being assayed in the range of 2 to 8. Experiments were then carried out under the optimal pH condition for dye removal to obtain equilibrium data at 30°C, 45°C and 60°C. Adsorption isotherm models were used to correlate the equilibrium data. Maximum dye removal capacity was observed at a pH of 2 and temperature of 30°C. The kinetic experiments were carried out at a pH of 2 and at three different temperatures: 30°C, 45°C and 60°C. Pseudo-second-order models were used to describe the kinetics of dye adsorption.

Adsorption studies are essential before implementation in an industrial plant. We studied the Reactive Blue 5G removal by activated carbon from Pinus sp. Physical and chemical characteristics of the adsorbent were evaluated with N2 adsorption/desorption experiments at 77 K, and equilibrium and kinetics studies were performed in a batch reactor at several temperatures and pH values. Our results showed that the activated carbon had a high surface area, effective diffusion coefficients were of the order of 10–12 cm2·s–1, and mass transfer coefficients were present in both fluid and solid phases. Equilibrium and kinetics experiments confirmed that pH and temperature play an important role: the dye uptake became higher as the temperature and pH decreased, and the optimum removal was at 303 K and pH 2. Finally, thermodynamics analysis suggested that the process is exothermic and chemical in nature. In summary, we showed that activated carbon can be more effective than other adsorbents already used to remove the Reactive Blue 5G from wastewater.